Research ArticleDifferential Contribution of Jasmine Floral Volatiles tothe Aroma of Scented Green Tea
Jian-Xia Shen1 Mohammad M Rana12 Guo-Feng Liu1 Tie-Jun Ling1
Margaret Y Gruber3 and Shu Wei1
1State Key Laboratory of Tea Plant Biology and Utilization Anhui Agricultural University 130 Changjiang Ave WHefei Anhui 230036 China2Bangladesh Tea Research Institute Srimangal Maulvibazar 3210 Bangladesh3Agriculture and Agri-Food Canada Saskatoon Research Centre Saskatoon SK Canada S7N 0X2
Correspondence should be addressed to Shu Wei chsh1965163com
Received 11 April 2017 Revised 27 May 2017 Accepted 14 June 2017 Published 13 August 2017
Academic Editor Eduardo Puertolas
Copyright copy 2017 Jian-Xia Shen et al This is an open access article distributed under the Creative Commons Attribution Licensewhich permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited
Tea volatilesrsquo generation and retention over manufacturing processes are crucial for tea quality In this study floral volatileadsorption and retention in green tea scented with Jasminum sambac flowers were examined over the scenting process Out of34 enhanced volatiles in the scented tea 120573-ionone 120573-linalool indole and methyl anthranilate were the most potent odorantswith 51ndash452-fold higher odor activity values than the corresponding controls in the nonscented tea Scenting efficiencies for thefloral volatiles retained in the scented tea (the percentage of volatile abundance over its corresponding amount in jasmine flowers)ranged from 022 for 120572-farnesene to 755 for 120573-myrcene Moreover due to additional rounds of heat treatment for scentedgreen tea manufacturing some volatiles such as carotenoid-derived geraniol and 120573-ionone and lipid-derived (119885)-jasmone wereheat-enhanced and others such as nonanal were heat-desorbed in the scented green tea Our study revealed that dynamic volatileabsorption and desorption collectively determined tea volatile retention and tea aroma Our findings may have a great potential forpractical improvement of tea aroma
1 Introduction
Tea is a beverage globally consumed due to its pleasant flavorand health benefits against chronic pathologies such as cancerand cardiovascular diseases [1] The aroma is an importantcriterion in the evaluation of tea quality Extensive studieshave been conducted to elucidate tea aroma formation [2 3]Intact fresh tea leaves hardly have any scent and distinct aro-mas of differently made teas are formed from their metabolicprecursors present in tea leaves over their manufacturingprocesses [3] For example C13-norisoprenoid volatiles suchas 120573-ionone and theaspirone are generated from carotenoidsdue to enzymatic and nonenzymatic degradation [4] Freshand greenish odorants such as (119864)-2-hexanal and (119885)-3-hexanol are derived from lipid oxidation [5] However thesevolatiles generated from tea leaves over the manufacturingprocess are readily released into air and get lost Mean-while substantial amounts of these volatiles are captured
and retained in the tea leaf matrix Therefore tea aromais determined not only by volatiles generation but also bytheir retention in the processed tea leaves It is obviousthat odorants generated over the manufacturing processesare partially retained in the tea leaf matrix due to thedynamic volatile adsorption and desorption Neverthelessthis dynamic process is crucial to tea flavor but is rarelyinvestigated
The jasmine flower scented green tea practically exem-plifies floral scent enhancement of green tea owing to theconsequence of tea adsorption and desorption of the volatilesreleased from the Jasminum sambac flowers Generally themanufacturing process for jasmine flower scented green tea(jasmine tea in short) includes multiple rounds of scentingand drying steps For scenting green tea processed in theconventional way is mixed with fully opened fresh jasmineflowers and piled up for several hours Then the flowers areremoved and the scented tea leaves are heat-dried (at 90∘C
HindawiJournal of Food QualityVolume 2017 Article ID 5849501 10 pageshttpsdoiorg10115520175849501
2 Journal of Food Quality
to 100∘C for 1 h) [6 7] Depending on the desired aromaintensity this scenting (and heating) process can be repeatedseveral times In this way the characteristic jasmine scentedtea aroma forms [8] The aroma constituents in the jasminetea have already been profiled [8ndash10] and linalool and methylanthranilate (in addition to a few other compounds) are iden-tified as the potent odorants [8] However none of the studieshas focused on the dynamic adsorption and desorption ofjasmine floral volatiles and their differential contributions tothe aroma quality of the scented green tea Understandingthe mechanisms underlying the adsorptiondesorption of thefloral volatiles will surely be helpful to better elucidate teaaroma formation and retention
In this study volatile profiles of jasmine scented andnonscented green teas and fresh jasmine flowers were com-pared for identifying the key floral odorants absorbed bythe scented green tea and the factors affecting their adsorp-tiondesorption over the manufacturing process Our studyrevealed differential contribution of jasmine floral volatilesto the characteristic aroma of the scented green tea Ourfindings not only shed light on the mechanism of scented teaaroma formation but also open a new horizon towards teaflavor improvement
2 Materials and Methods
21 Chemicals Authentic standards of linalool (119864)-linalooloxide A (furanoid) (119885)-linalool oxide B (furanoid) (119864)-linalool oxide C (pyranoid) geraniol citral 120573-myrcene d-limonene 120573-ocimene nerol nerolidol 120573-ionone geranylacetone naphthalene (119885)-3-hexen-1-ol eugenol nonanalbenzyl alcohol benzene acetaldehyde methyl salicylate (119885)-3-hexenol acetate 3-octen-1-ol indole and ethyl decanoatewere purchased from Sigma-Aldrich (Shanghai China) (119885)-Jasmone was purchased fromAladdin Industrial Inc (Shang-hai China)
22 Plant Materials and Scenting Process Shoot tips withtwo folded leaves were plucked from 10-year-old plantsof Camellia sinensis var sinensis cv ldquoJin-Xuanrdquo that weregrown at Wanxiu district Wuzhou city Guangxi China(23∘4710158405810158401015840N 111∘3110158404810158401015840E) Green tea was prepared usinga standard pan-fire process typically applied in local teaindustries This included indoor spreading of harvested teacrops at about 05ndash10 kgmminus2 for 2-3 h at room temperatureimmediately after plucking heat inactivation of enzymes in apan at 220∘C for 5min and rolling and drying (120∘C for 1 h)For the scenting process fully opened flowers of Jasminumsambac were excised and mixed with the preprocessed greentea at a ratio of 4 5 (ww)Themixture of tea and flowers waspiled up for 12 h at a temperature ranging from 38∘C to 48∘CAfter scenting the flowers were removed and the scentedleaves were dried at 120∘C for 1 h Two additional rounds ofthe scenting process were performed as in the first roundAll the scented and nonscented green teas with or withoutheat treatments were then maintained at room temperaturefor future volatile profiling
23 Volatile Profiling Tea infusion volatile collection iden-tification and quantification were conducted according toHan et al [11] using a 20mL glass vessel and a headspace-solid phase microextraction (HS-SPME) fiber coupled withgas chromatography (Agilent 7697A) and mass spectrome-try (Agilent 7890A) (GCMS) In brief tea infusions wereprepared using 1 g of tea (accurate to four decimals) addedto 100mL boiling double distilled water After incubationfor 5min 5mL of each infusion was transferred to thesampling vessel and headspace volatiles were collected usinga 65 120583M PDMSDVB fiber (Supelco Bellefonte PA USA)for 1 h and then deadsorbed in the GC injection port for5min at 250∘C and resolved by a DB-5 capillary column(30m times 025mm times 025 120583m Agilent) for GCMS analysisThe oven temperature was programmed according to Hanet al [11] The assays were carried out in triplicate for eachsample Ethyl decanoate (001 5 120583L) was added to thesamples as the internal standard Volatile compounds wereidentified by comparing the retention indices (times) withthose of either commercial standard substances or the NISTdatabase according to Wei et al [12] Quantification of thesecompounds in tea infusions was carried out based on theinternal standard or the calibration curves prepared withauthentic commercial standards [13] Freshly excised jasmineflowers (1 g accurate to four decimals) were also placed in thesampling vessel and their headspace volatiles were collectedat 38∘C and analyzed using the methods described aboveThe relative concentrations of the volatiles were expressedas 120583gsdotkgminus1 based on SPME sampling and comparison withinternal standard (ethyl decanoate)
24 Statistical Analysis The data for all the assays wererepresented as mean plusmn SD from three biological replicates(tissue or infusion types) One-way analysis of variance(Duncanrsquos multiple range test) was performed using the DPSsoftware package (httpwwwchinadpsnetindexhtml) forstatistical analysis For detecting variations among samplesand to identify a subset of volatiles most important fordefining the major variations between the two tea infusionsand jasmine flowers supervised orthogonal partial least-squares discriminant analysis (OPLS-DA) was conductedusing volatile compound IDs tissueinfusion types andvolatile concentrations collected as input data [14] Com-pound ID numbers were plotted onto a 2-dimensional graphwith positive values representing compounds that make apositive contribution and negative values representing anegative contribution to tea scent according to Trygg et al[14] (Figure 1) Data points were identified as being variablesof importance (VIP) in the projection based on theOPLS-DAanalysis [15]
3 Results and Discussion
31 Distinct Volatile Profiles of Scented and Nonscented GreenTea Infusions and Jasmine Flowers In this study volatileemission profiles of fresh jasmine flowers (JF) and theinfusions of scented (ST) and nonscented (NT) green teaswere compared using OPLS-DA approach Volatile profilesshowed good reproducibility and high separability among
Journal of Food Quality 3
minus25 minus20 minus15 minus10 minus5 0
0
5
5
10
10
15
15
20
20
t[1]
minus5
minus15minus20minus25
t[2]
minus10
NT1NT2NT3
JF3
ST3 ST1ST2
JF1JF2
R2X0
[1] =
03
94
R2X[1] = 0529
(a)
minus015 minus01 minus005 0 005 01p[1]
minus02
p[2]
minus015
minus01
minus005
0
005
29 51 66 70 46 830 52 56 75 61
42 49
354 33
265760
65
51 9
25 14 45 37 21Total27
11
4443 7687 83
92
24 90 20 88 35
59
85 89 86 82 9184 50 68 73 53
58 13 31 667
557
12 19 10 62 216 41 18 15 39
22 3871
34 4879
78 80 8123
2847 72
63
4036
74 4
17 64
77
3269
R2X0
[1] =
03
94
R2X[1] = 0529
(b)
Figure 1 OPLS-DA score plot (a) and corresponding loading plot (b) derived from the integrated volatile emission data sets of jasmineflowers (JF) and the infusions of scented (ST) and nonscented (NT) green teas Datawere derived from three independent biological replicatesNames of numbered compounds in panel (b) are outlined in Supplementary Table 1 119905[1] and 119901[1] represent principal component 1 (volatilecompounds) 119905[2] and 119901[2] represent principal component 2 (sample group) Equations R2X[1] = 0529 and R2X0[1] = 0394 representrespectively the contributions of principal component 1 (R2X[1]) and component 2 (R2X0[1]) to the variation among the ST NT and JFCompounds in the left two quadrants of panel (b) make a negative contribution to tea odor discrimination and compounds in the right twoquadrants make a positive contribution Criteria for selecting top volatiles of importance were in accordance with the SIMCA-P programwhere a VIP value more than 1 was considered as a positive contributor
three biological replicates for fresh jasmine flowers andinfusions of scented and nonscented green tea (Figure 1(a))Data points for nonscented green tea were mainly positionedin the top left quadrant separate from jasmine flower in thetop-right quadrant with scented tea in between and mainlypositioned in the lower two quadrants Replicates of bothscented and nonscented green teas were closely localizedwhile those for jasmine flowers exhibited somewhat highvariation probably due to flowers not strictly picked at thesame developmental stage Generation ofmany jasmine floralscents (as well as expression of corresponding genes) variesdepending on the flowerrsquos developmental stages [16] AnOPLS-DA loading plot showed the correlation of the load-ing compounds towards different samples and compoundspositioned in the top-right quadrant contributed more tothe differences among the three groups than those in other
positions (Figure 1(b)) 120573-Linalool (21) indole (45) benzylalcohol (11) and methyl salicylate (37) were among thetop 10 variables of importance (VIP) that mainly specifiedthe volatile profile differences among the three samples(Supplementary Table 2 in SupplementaryMaterial availableonline at httpsdoiorg10115520175849501)
In addition for nonscented tea nonanal (148 plusmn61 120583g kgminus1) andmethyl anthranilate (106plusmn56 120583g kgminus1) werethe most abundant volatiles For the scented tea the mostabundant volatiles were benzyl acetate (3292 plusmn 158 120583g kgminus1)and 120573-linalool (2311 plusmn 305 120583g kgminus1) For jasmine flower120572-farnesene was the highest at 4954 plusmn 388 120583g kgminus1 followedby 120573-linalool (4405 plusmn 21 120583g kgminus1) These results indicatedclearly that the increased amounts of 120573-linalool in thescented tea resulted from the adsorption from jasmineflowers Although many compounds were common to more
4 Journal of Food Quality
than one emission profile some were unique to each of themas well (Supplementary Table 3) These dominant volatileswere reported earlier from tea infusions and jasmine flowers[8 11 17] A high level of eugenol was found in the jasminetea infusion as reported before [7 8] but not in the greentea infusion in this study although this compound wasreported as a potent odorant of green tea [17] probablybecause the manufacturing procedures applied for greenteas in this study and previous ones were different Thisphenylpropanoid compound is produced by the action ofeugenol synthases using coniferyl acetate as a substratein plants [18] but it is undetectable in the headspace ofjasmine flowers [19 20] These data together suggest thatthe enhanced eugenol in jasmine tea might be generateddue to possible hydrothermal conversions over the multiplerounds of scenting process not due to direct adsorptionfrom jasmine flowers although the details require furtherinvestigation In addition high levels of 120573-phenethyl acetateand benzyl tiglate were also found in jasmine tea but notfrom green tea or jasmine flowers in this study 120573-Phenethylacetate is reportedly detected from a jasmine flower grownin Egypt [19] but not from those grown in China [20]suggesting a possible difference between cultivars Benzyltiglate is emitted from the Quisqualis indica flowers but notfrom jasmine flowers [21] Further investigation is requiredto learn the mechanisms for the enhanced levels of the twocompounds in jasmine tea
32 Potent Odorants in the Infusions of Scented and Non-scented Green Teas and Jasmine Flowers Instead of aromaextract dilution analysis [17] the odor activity value (OAVvolatile abundance over its perception threshold) wasdeployed in this study to evaluate the odor characteristics oftested samples to avoid losses of highly volatile compoundsduring extraction and to eliminate matrix interference withthe volatility of an odorant [22] OAVs were determined forall 27 volatiles detected from the headspaces of tea infusionsand jasmine flowers with known threshold values from theliterature Those with OAV gt 1 are presented in Figure 2
For nonscented green tea out of six compounds possess-ing odor activity values over 1 120573-ionone (OAV 1423) andnonanal (147) were the most potent odorants (Figure 2)and both derived from metabolite degradation during themanufacturing process [3] In jasmine flowers 120573-linalool wasthe most potent odorant with OAV of 5507 followed byindole (3939) In the scented tea odor activities of 120573-iononeand 120573-linalool were significantly enhanced to 7313 and 2889respectively which were 51- and 452-fold higher than thecorresponding OAVs in the nonscented tea (Figure 2(a))Odorants methyl salicylate (OAV 17) geraniol (OAV 17)and (119885)-jasmone (OAV 36) exhibited 185- 76- and 47-foldhigher odor activity in scented tea than their counterparts inthe nonscented tea as well (Figure 2(b)) In addition based onthreshold values obtained an additional 6 compounds (OAVlt 1) had higher OAVs in scented tea than in nonscented teaincluding monoterpenoids d-limonene 120573-ocimene and (119864)-linalool oxide A (furanoid) These compounds might syn-ergistically contribute to the characteristic jasmine scentedtea flavor which was described by Ito and Kubota [9]
Interestingly the potent odorants nonanal and decanal bothas potent odorants of green teas (nonscented) made fromdifferent tea cultivars [11] had higher odor activity values(OAV gt 1) in the nonscented green tea than those in thescented tea We speculated that these might be due to morepronounced heat desorption of these volatiles from scentedtea since several additional rounds of heat treatment wereapplied for scenting tea manufacturing process It is knownthat linalool exhibits strong floral fruity and citrus-likescents [23] indole has fecal animal-like floral odor [24]jasmone has somewhat fruity floral and woody aroma notes[25] and ionone has woody and floral aroma notes [3 24](Supplementary Table 4) Since the majority of these floralscent volatiles were more abundant in the infusion of scentedtea than that of nonscented tea the jasmine scented green teainfusion possessed a strong floral scent Nonanal and decanalcontribute waxy fatty and aldehydic aromas [26] and thustheir reduction in scented green tea might also improve itsaroma quality
33 Scenting Enhanced Volatiles in Scented Green Tea Overthe scenting process the nonscented dry green tea (NT)was mixed with the fresh jasmine flowers (JF) at the ratioof 54 (dry teafresh flowers WW) Floral volatiles whoseabundances were higher than those of green tea in themixed headspace shared by both flowers and tea wouldbe dynamically adsorbed onto the tea leaf matrix until anequilibrium was reached In order to determine contributionof different JF volatiles to the aroma of scented green tea (ST)headspace volatile profiling was conducted not only for theinfusions of NT and ST but also for JF with an emphasison the compounds which were identified with authenticstandards or exhibited a significantly changed abundanceafter the scenting process
Compared to NT ST possessed 34 enhanced and 3reduced compounds (Figures 3 and 5) Among the enhancedcompounds seven were dominant volatiles in ST with theabundances 182-fold to 173-fold higher than their counter-parts in NT (Figure 3(a)) 120573-Linalool indole and benzylacetate in ST were enhanced 453- 424- and 336-foldrespectively Similarly another 10 volatiles but less abundantin ST were 82- to 487-fold higher than their correspond-ing volatiles detected in NT (Figure 3(b)) Moreover anadditional 10 volatiles were detected in ST only but notin NT (Figure 3(c)) The majority of these compounds arecommon tea volatiles [2 27] and all of them were found to beabundant in JF (Figure 3(d)) (except for geraniol and severalother compounds) as reported previously [19] However adirect abundance comparison of the volatiles detected fromtea infusions with those from fresh jasmine flowers wasnot adequate due to inconsistent volatile sampling methodsapplied in this study and the unknown release efficiencies ofindividual volatiles from solid plant matrix to the headspacesof the volatile sources The abundances of the JF volatilespresented in Figure 3(d) might be slightly different from theabundances of the floral volatiles the green tea was actuallyscented with because the dry green tea used for scenting was12-fold more than JF in this study Moreover 27 volatiles allpresent in the headspace of JF in high quantities (Figure 3(d))
Journal of Food Quality 5
100
100500
300
500
700
900
Methyl anthranilate Indole
OAV
NT ST
A
A
A
A
B
B
B
B
B
B
C C
JF NT ST JF NT ST JF NT ST JF120573-Linalool 120573-Ionone
(a)
AA
A A
AA A
AB
AB
A
A
A
B B BB
B
B B
B B
B B
B
C C
C
NT ST JF NT ST JF NT ST JF NT ST JF NT ST JF NT ST JF NT ST JF NT ST JF NT ST JF000204060810
369
12151821
OAV
-Myrcene Linalool oxide B Geraniol Nerolidol (Z)-3-Hexenylacetate
Methylsalicylate
Nonanal Decanal (Z)-Jasmone
(b)
Figure 2 Odor activity values of volatiles (gt1) found in the infusions of scented (ST) and nonscented (NT) green teas and jasmine flowers(JF) based on volatile abundances and their thresholds Duncanrsquos new multiple range test was performed and the columns labeled with thesame letter within the same compound had no significant difference among the three sample types 119875 lt 005 (a) Volatiles with high OAVs(b) Volatiles with low OAVs
with a few exceptions (geraniol neo-allo-ocimene and 120575-terpinene) were found to bemore abundant in ST than inNT(Figure 3) suggesting that the enhancement of these volatilesin ST could substantially result from tea adsorption of thesefloral volatiles over the scenting process For geraniol andgeranyl acetate their abundances in the JF headspace werequite low but both were found to be more abundant in STinfusion than in NT infusion (Figure 3(b)) It is known thattea aroma compounds geraniol and its derivatives can begenerated from heat-induced degradation of carotenoids andpossibly also from hydrolysis of its glycoside precursor [3]Our data suggested that chemical conversion in addition toadsorption might also occur over the scenting process
The percentage of the abundance of a volatile in scentedtea subtracted from the amount of the counterpart in the non-scented tea over the abundance of the corresponding com-pound in jasmine flowers was proposed to estimate itsscenting efficiency although differential contributions offloral volatile adsorption and chemical conversion to its
abundance change in jasmine tea are unknown For thoseenhanced volatiles the efficiencies varied ranging from022 for 120572-farnesene to 755 for 120573-myrcene (Figure 4)This finding suggested that scenting effectiveness was com-pound specific and might result from multiple causativefactors Chemical and physical properties including volatil-ity represented by vapor pressure (mmHg at 25∘C) watersolubility (mgL at 25∘C) and polarity represented bytopological polar surface area were examined for eachvolatile in Figure 4 through the public chemical struc-ture databases (httpwwwchemspidercom and httpspub-chemncbinlmnihgov) with an emphasis on their correla-tion with scenting effectiveness It was noted that majorityof the volatiles with high scenting effectiveness (gt40) hadhigh water solubility ranging from 4215mgL for ethyl ben-zoate to 323220mgL for benzyl alcohol (119885)-3-Hexenol andlinalool both possessing high scenting efficiencies (Figure 4)have 160000mgL and 15900mgL water solubility respec-tively Exceptions were found for120573-myrcene and d-limonene
6 Journal of Food Quality
0
200
400
NT ST
Benzyl acetateA
B0
150
300
NT ST
A
B0
150
300
NT ST
IndoleA
B
0
110
220
NT ST
Methyl anthranilateA
B0
100
200
NT ST
(Z)-3-Hexenyl benzoateA
B 0
40
80
NT ST
Methyl salicylateA
B0
25
50
NT ST
(Z)-3-Hexenyl acetate A
B
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)Ab
unda
nce
(g
kg)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)-Linalool
(a)
0
5
10
NT ST
(Z)-Jasmone
B
A
0
5
10
NT ST
Geraniol
B
A
0
3
6
NT ST
A
B
0
2
4
NT ST
Geranyl acetate
A
B 0
2
4
NT ST
(E)-3-Hexenyl butanoate
A
B0
1
2
NT ST
A
B
Abun
danc
e (
gkg
)Ab
unda
nce
(g
kg)
Abun
danc
e (
gkg
)Ab
unda
nce
(g
kg)
Abun
danc
e (
gkg
)Ab
unda
nce
(g
kg)
-Myrcene
(Z)--Ocimene
0
15
30
NT ST
Benzyl benzoateA
B0
10
20
NT ST
Benzyl alcoholA
B 0
5
10
NT ST
A
B0
3
6
NT ST
D-Limonene
A
BAbun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
-Cadinol
(b)
0
15
3
NT ST
(Z)-3-Hexenol
nd0
2
4
NT ST
nd0
05
1
NT ST
Neo-allo-ocimene
nd 0
05
1
NT ST
Ethyl benzoate
nd
0
1
2
NT ST
Ethyl salicylate
nd0
1
2
NT ST
nd0
05
1
NT ST
Copaene
nd
0
1
2
NT ST
nd0
1
2
NT ST
Cadina-14-diene
nd 0
02
04
NT ST
nd
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)Ab
unda
nce
(g
kg)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
-Cadinene
-Cubenene
-Farnesene -Terpinene
(c)
Figure 3 Continued
Journal of Food Quality 7
0200400600800
1000
0
2
4
6
8
Abun
danc
e (
gkg
)Ab
unda
nce (
g
kg)
JF
-F
arne
sene
-L
inal
ool
Indo
le
(Z)-
3-H
exen
yl ac
etat
e
Benz
yl ac
etat
e
-C
adin
ene
Met
hyl s
alic
ylat
e
(Z)-
3-H
exen
yl b
enzo
ate
Met
hyl a
nthr
anila
te
Benz
yl al
coho
l
(E)-
3-H
exen
yl b
utan
oate
-C
uben
ene
Cop
aene
Cadi
na-1
4-d
iene
(Z)-
-Oci
men
e
-C
adin
ol
D-L
imon
ene
-M
yrce
ne
(Z)-
Jasm
one
Ethy
l sal
icyl
ate
(Z)-
3-H
exen
ol
Ger
anyl
acet
ate
Benz
yl b
enzo
ate
Ethy
l ben
zoat
e
Ger
anio
l
Neo
-allo
-oci
men
e
-T
erpi
nene
(d)
Figure 3 Enhanced floral volatiles in scented tea probably due to tea adsorption (a) Volatiles with high abundances present in the scentedtea (b) volatiles with less abundances present in the scented tea (c) volatiles present in scented tea only (d) Volatiles present in the headspaceof fresh jasmine flowers ST scented green tea infusion NT nonscented tea infusion JF jasmine flower ND not detected Duncanrsquos newmultiple range test was performed and the columns labeled with the same letter within the same compound had no significant differenceamong the tested samples 119875 lt 005 NS no significant difference detected
0 20 40 60 80
Benzyl alcoholEthyl benzoate
Neo-allo-ocimene
Ethyl salicylate
(E)-3-Hexenyl butanoate
Cadina-14-diene
Copaene
Scenting efficiency ()
-Myrcenelowast
(Z)-3-HexenoＦlowast
D-Limonenlowast
Indollowast
-LinalooＦlowast
Methyl salicylatlowast-Terpinene
(Z)-3-Hexenyl acetatlowast
(Z)--Ocimenlowast
-Cubenene
-Cadinene-Farnesene
Figure 4 Differential scenting efficiencies of jasmine floral volatiles to the scented green tea Scenting efficiency was calculated as thepercentage of the volatile abundance detected in the scented tea subtracted from that of the same compound in nonscented tea over theabundance of the counterpart present in jasmine flower Compounds labeledwith ldquolowastrdquo were identified and quantifiedwith authentic standards
8 Journal of Food Quality
0
2
4
NT ST
Methyl heptenone
A
B
Abun
danc
e
0
3
6
NT ST
Linalool oxide A
A
B0
1
2
NT ST
A
B0
05
1
NT ST
A
B
0
4
8
NT ST
A
B0
05
1
NT ST
CedrolA
B
0
5
10
NT ST
T-Cadinol
A
B
(g
kg)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
-Terpineol -Cyclocitral
(E)--Ionone
(a)
0
13
26
NT ST
Nonanal
A
B
0
04
08
NT ST
Naphthalene
AB
0
5
10
NT ST
DecanalA
B
NSNS
0
04
08
NT ST
1-Methylnaphthalene
0
1
2
NT ST
BiphenyleneA
B
NSNS
0
07
14
NT ST
Isopropyl myristate
NSNS
0
04
08
NT ST
Caffeine
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)(b)
Figure 5 Volatiles with differential abundances between scented and nonscented teas but undetectable in the jasmine flower headspace (a)Enhanced volatiles in the scented tea (b) reduced volatiles in the scented tea ST scented green tea infusion NT nonscented tea infusionND not detected Duncanrsquos new multiple range test was performed and the columns labeled with the same letter within the same compoundhad no significant difference among the three samples 119875 lt 005 NS no significant difference detected
whose water solubility values are relatively low (69mgLand 46mgL resp) but their volatility values (23mmHgand 13mmHg resp) are higher than those of many otheraliphatic volatiles presented in Figure 4 Moreover 120572-farnesene and 120575-cadinene possessing the lowest scenting effi-ciencies have the lowest values of water solubility (001mgLand 005mgL resp) It was assumed that volatiles possessinghigh water solubility could be partially dissolved into theaqueous phase in tea leaf matrix over the scenting process inwhich tea leaves could adsorb moisture substantially releasedfrom the fresh jasmine flowersUpon tea infusion preparationwith hot water those volatiles retained in the scented teawould be largely released due to their volatility Furtherinvestigation is required to clarify the correlation betweenscenting effectiveness and water solubility and volatility of avolatile
Moreover surface compounds on the tea leaf matrixmight discriminate volatiles with different polarity whichhas been found for wool types used with natural and solidadsorbents [28] In addition many volatiles are known tobe readily modified by the action of plant enzymes such as
conversion of linalool and geraniol to many other derivativesin plants [29 30] hydrothermal conversions of these volatilesalso occur For instance sesquiterpene 120572-farnesene is stressinduced [31] and can be easily degraded due to photochem-ical allylic oxidation hydroxylation and epoxidation [32]Consistently 120572-farnesene was found to be abundant in theheadspace of excised jasmine flowers but much lower in thejasmine tea and undetectable in green tea in this study
34 Heat-Affected Volatiles in Scented Green Tea Over thescenting and heating procedure 14 volatiles were detectedfrom the infusions of the two teas only but with differentialabundances (119875 lt 005) These volatiles were undetectable inthe jasmine flower headspace suggesting that the observeddifferences between the two teas might unlikely result fromthe direct tea adsorption of these volatiles (Figure 5) Amongthese volatiles 7 were found with higher levels in the scentedtea compared to the nonscented tea including linalool oxideA 120573-ionone and another four terpenoids (Figure 5(a)) Theobserved enhancement of these terpenoids in the scented teamight be the consequence of the heat-induced degradation or
Journal of Food Quality 9
chemical conversionMcgraw et al [33] observed that terpenecompounds degraded at high temperatures and turned intoother terpene hydrocarbons and oxide terpenes Tatum etal [34] reported that 120572-terpineol component is formed byoxidative degradation of limonene In this study it was alsoobserved that abundance of 120572-terpineol was significantlyincreased after the scenting process although it was notdetected in the jasmine flowers (Figure 5) suggesting that itwas likely derived from the hydrothermal conversion over thescenting process
In addition reduced levels of a few compounds werefound in scented tea compared to nonscented tea (Fig-ure 5(b)) including lipid-derived aldehydes nonanal anddecanal [3]These lipid-derived compounds are heat-inducedandmost likely also heat-releasedMultiple additional roundsof heat treatments after scenting could result in the reduc-tion of these volatiles in the scented tea infusion Nonanalabundance in green tea is enhanced by steam processing butsuppressed by pan-fire processing [11]
4 Conclusions
Our study revealed that jasmine flower scented green teapossessed an enhanced floral scent due to the adsorption offloral scent-related volatiles from the fresh jasmine flowersThis revealed that dry tea had the capacity to adsorb substan-tial amounts of volatiles from jasmine flowers Differentialcontribution of jasmine floral volatiles to the aromaof scentedgreen tea was observed Moreover chemical conversion alsocontributed to the differential abundances of some volatilesbetween scented and nonscented teas Our study suggeststhat adsorption and retention of the volatiles generatedendogenously from tea leaveswere crucial formaintaining teaaroma and improving tea aroma quality practically
Additional Points
Practical Applications This work reveals the differentialcontributions of jasmine floral volatiles to the scented greentea and suggested that dry tea has a great capacity toadsorb substantial amounts of volatiles from jasmine flowersBased on what was found in this study heat treatment maybe applied to premade teas with fine-tuned temperaturesto desorb those off-flavor compounds Moreover pleasantaroma either from natural sources or from artificial mixturescan also be applied to enhance tea aroma with a specificdesired odor
Conflicts of Interest
The authors declare that they have no conflicts of interestregarding the publication of this paper
Authorsrsquo Contributions
Shu Wei designed the experiments and interpreted theresults Jian-Xia Shen and Guo-Feng Liu helped to doOPLS-OD data analysis Mohammad M Rana drafted themanuscript Tie-Jun Ling and Margaret Y Gruber revised
the manuscript Jian-Xia Shen and Mohammad M Rana areequal contributors
Acknowledgments
This work was financially supported by the National NaturalScience Foundation of China (Grants nos 31070614 and31370687) to Shu Wei Margaret Y Gruber has been workingat Agriculture and Agri-Food Canada Saskatoon ResearchCentre Saskatoon SK Canada but is now retired
References
[1] M S Butt R S AhmadM T SultanMM N Qayyum andANaz ldquoGreen tea and anticancer perspectives updates from lastdecaderdquo Critical Reviews in Food Science and Nutrition vol 55no 6 pp 792ndash805 2015
[2] Z Yang S Baldermann and N Watanabe ldquoRecent studies ofthe volatile compounds in teardquo Food Research International vol53 no 2 pp 585ndash599 2013
[3] C Ho X Zheng and S Li ldquoTea aroma formationrdquo Food Scienceand Human Wellness vol 4 no 1 pp 9ndash27 2015
[4] P Winterhalter and R Rouseff ldquoCarotenoid-derived aromacompounds an introductionrdquo in Carotenoid-Derived AromaCompounds P Winterhalter and R Rousef Eds ACS Sympo-sium Series pp 1ndash19 American Chemical Society WashingtonDC USA 2001
[5] T Takeo and T Tsushida ldquoChanges in lipoxygenase activity inrelation to lipid degradation in plucked tea shootsrdquo Phytochem-istry vol 19 no 12 pp 2521-2522 1980
[6] T Wu Traditional jasmine green tea scenting process 2013httpwwwtaotealeafcomblogtraditional-jasmine-green-tea-scenting-process
[7] MChen Y Zhu B Liu et al ldquoChanges in the volatiles chemicalcomponents and antioxidant activities of Chinese jasmine teaduring the scenting processesrdquo International Journal of FoodProperties vol 20 no 3 pp 681ndash693 2017
[8] Y Ito A Sugimoto T Kakuda and K Kubota ldquoIdentificationof potent odorants in Chinese jasmine green tea scented withflowers of Jasminum sambacrdquo Journal of Agricultural and FoodChemistry vol 50 no 17 pp 4878ndash4884 2002
[9] Y Ito and K Kubota ldquoSensory evaluation of the synergismamong odorants present in concentrations below their odorthreshold in a Chinese jasmine green tea infusionrdquo MolecularNutrition and Food Research vol 49 no 1 pp 61ndash68 2005
[10] Y Liang Y Wu J Lu and L Zhang ldquoApplication of chemicalcomposition and infusion colour difference analysis to qualityestimation of jasmine-scented teardquo International Journal of FoodScience and Technology vol 42 no 4 pp 459ndash468 2007
[11] Z-X Han M M Rana G-F Liu et al ldquoGreen tea flavourdeterminants and their changes over manufacturing processesrdquoFood Chemistry vol 212 pp 739ndash748 2016
[12] S Wei I Marton M Dekel et al ldquoManipulating volatileemission in tobacco leaves by expressing Aspergillus niger120573-glucosidase in different subcellular compartmentsrdquo PlantBiotechnology Journal vol 2 no 4 pp 341ndash350 2004
[13] Z Han M M Rana G Liu et al ldquoData on green teaflavor determinantes as affected by cultivars andmanufacturingprocessesrdquo Data in Brief vol 10 pp 492ndash498 2017
10 Journal of Food Quality
[14] J Trygg E Holmes and T Lundstedt ldquoChemometrics inmetabonomicsrdquo Journal of Proteome Research vol 6 no 2 pp469ndash479 2007
[15] K M O Ku J N Choi J Kim et al ldquoMetabolomics anal-ysis reveals the compositional differences of shade growntea (Camellia sinensis L)rdquo Journal of Agricultural and FoodChemistry vol 58 no 1 pp 418ndash426 2010
[16] Y-H Li W Zhang and Y Li ldquoTranscriptomic analysis offlower blooming in Jasminum sambac through de novo RNAsequencingrdquoMolecules vol 20 no 6 pp 10734ndash10747 2015
[17] R Baba and K Kumazawa ldquoCharacterization of the potentodorants contributing to the characteristic aroma of chinesegreen tea infusions by aroma extract dilution analysisrdquo Journalof Agricultural and Food Chemistry vol 62 no 33 pp 8308ndash8313 2014
[18] T Koeduka E Fridman D R Gang et al ldquoEugenol andisoeugenol characteristic aromatic constituents of spices arebiosynthesized via reduction of a coniferyl alcohol esterrdquoProceedings of the National Academy of Sciences of the UnitedStates of America vol 103 no 26 pp 10128ndash10133 2006
[19] A E Edris R Chizzola and C Franz ldquoIsolation and charac-terization of the volatile aroma compounds from the concreteheadspace and the absolute of Jasminum sambac (L) Ait(Oleaceae) flowers grown in Egyptrdquo European Food Researchand Technology vol 226 no 3 pp 621ndash626 2008
[20] Y Yu S Lyu D Chen et al ldquoVolatiles emitted at differentflowering stages of Jasminum sambac and expression of genesrelated to 120572-farnesene biosynthesisrdquo Molecules vol 22 no 4article 546 2017
[21] P K Rout Y Ramachandra Rao and S Naik ldquoAnalysis offloral volatiles by using headspace-solid phase microextractiona reviewrdquoAsian Journal of Chemistry vol 24 no 3 pp 945ndash9562012
[22] C Schuh and P Schieberle ldquoCharacterization of the key aromacompounds in the beverage prepared from Darjeeling blacktea quantitative differences between tea leaves and infusionrdquoJournal of Agricultural and Food Chemistry vol 54 no 3 pp916ndash924 2006
[23] B Bonnlander R Cappuccio F S Liverani and PWinterhalterldquoAnalysis of enantiomeric linalool ratio in green and roastedcoffeerdquo Flavour and Fragrance Journal vol 21 no 4 pp 637ndash641 2006
[24] T Katsuno H Kasuga Y Kusano et al ldquoCharacterisation ofodorant compounds and their biochemical formation in greentea with a low temperature storage processrdquo Food Chemistryvol 148 pp 388ndash395 2014
[25] J Scognamiglio L Jones C S Letizia and A M Api ldquoFra-grance material review on cis-jasmonerdquo Food and ChemicalToxicology vol 50 supplement 3 pp S613ndashS618 2012
[26] Anonymous The good scents company information system2016 httpwwwthegoodscentscompanycomsearch2html
[27] Y Sawai Y Yamaguchi and J Tanaka ldquoMethyl anthranilate isthe cause of cultivar-specific aroma in the Japanese tea cultivarlsquoSofursquordquo Japan Agricultural Research Quarterly vol 38 no 4 pp271ndash274 2004
[28] E Mansour S Curling A Stephan and G OrmondroydldquoAbsorption of volatile organic compounds by different wooltypesrdquo Green Materials vol 4 no 1 pp 1ndash7 2016
[29] R Davidovich-Rikanati Y Sitrit Y Tadmor et al ldquoEnrichmentof tomato flavor by diversion of the early plastidial terpenoidpathwayrdquoNature Biotechnology vol 25 no 8 pp 899ndash901 2007
[30] B Boachon R R Junker L Miesch et al ldquoCYP76C1(Cytochrome P450)-mediated linalool metabolism and theformation of volatile and soluble linalool oxides in arabidopsisflowers a strategy for defense against floral antagonistsrdquo PlantCell vol 27 no 10 pp 2972ndash2990 2015
[31] F Dong Z Yang S Baldermann Y Sato T Asai andNWatan-abe ldquoHerbivore-induced volatiles from tea (Camellia sinensis)plants and their involvement in intraplant communication andchanges in endogenous nonvolatile metabolitesrdquo Journal ofAgricultural and Food Chemistry vol 59 no 24 pp 13131ndash131352011
[32] J A SpicerThe oxidation of 120572-Farnesene [PhD thesis] MasseyUniversity Palmerston North New Zealand 1994
[33] GWMcgraw RW Hemingway L L Ingram Jr C S Canadyand W B Mcgraw ldquoThermal degradation of terpenes cam-phene Δ3-carene limonene and 120572-terpinenerdquo EnvironmentalScience and Technology vol 33 no 22 pp 4029ndash4033 1999
[34] J H Tatum S Nagy and R E Berry ldquoDegradation productsformed in canned single-strength orange juice during storagerdquoJournal of Food Science vol 40 no 4 pp 707ndash709 1975
to 100∘C for 1 h) [6 7] Depending on the desired aromaintensity this scenting (and heating) process can be repeatedseveral times In this way the characteristic jasmine scentedtea aroma forms [8] The aroma constituents in the jasminetea have already been profiled [8ndash10] and linalool and methylanthranilate (in addition to a few other compounds) are iden-tified as the potent odorants [8] However none of the studieshas focused on the dynamic adsorption and desorption ofjasmine floral volatiles and their differential contributions tothe aroma quality of the scented green tea Understandingthe mechanisms underlying the adsorptiondesorption of thefloral volatiles will surely be helpful to better elucidate teaaroma formation and retention
In this study volatile profiles of jasmine scented andnonscented green teas and fresh jasmine flowers were com-pared for identifying the key floral odorants absorbed bythe scented green tea and the factors affecting their adsorp-tiondesorption over the manufacturing process Our studyrevealed differential contribution of jasmine floral volatilesto the characteristic aroma of the scented green tea Ourfindings not only shed light on the mechanism of scented teaaroma formation but also open a new horizon towards teaflavor improvement
2 Materials and Methods
21 Chemicals Authentic standards of linalool (119864)-linalooloxide A (furanoid) (119885)-linalool oxide B (furanoid) (119864)-linalool oxide C (pyranoid) geraniol citral 120573-myrcene d-limonene 120573-ocimene nerol nerolidol 120573-ionone geranylacetone naphthalene (119885)-3-hexen-1-ol eugenol nonanalbenzyl alcohol benzene acetaldehyde methyl salicylate (119885)-3-hexenol acetate 3-octen-1-ol indole and ethyl decanoatewere purchased from Sigma-Aldrich (Shanghai China) (119885)-Jasmone was purchased fromAladdin Industrial Inc (Shang-hai China)
22 Plant Materials and Scenting Process Shoot tips withtwo folded leaves were plucked from 10-year-old plantsof Camellia sinensis var sinensis cv ldquoJin-Xuanrdquo that weregrown at Wanxiu district Wuzhou city Guangxi China(23∘4710158405810158401015840N 111∘3110158404810158401015840E) Green tea was prepared usinga standard pan-fire process typically applied in local teaindustries This included indoor spreading of harvested teacrops at about 05ndash10 kgmminus2 for 2-3 h at room temperatureimmediately after plucking heat inactivation of enzymes in apan at 220∘C for 5min and rolling and drying (120∘C for 1 h)For the scenting process fully opened flowers of Jasminumsambac were excised and mixed with the preprocessed greentea at a ratio of 4 5 (ww)Themixture of tea and flowers waspiled up for 12 h at a temperature ranging from 38∘C to 48∘CAfter scenting the flowers were removed and the scentedleaves were dried at 120∘C for 1 h Two additional rounds ofthe scenting process were performed as in the first roundAll the scented and nonscented green teas with or withoutheat treatments were then maintained at room temperaturefor future volatile profiling
23 Volatile Profiling Tea infusion volatile collection iden-tification and quantification were conducted according toHan et al [11] using a 20mL glass vessel and a headspace-solid phase microextraction (HS-SPME) fiber coupled withgas chromatography (Agilent 7697A) and mass spectrome-try (Agilent 7890A) (GCMS) In brief tea infusions wereprepared using 1 g of tea (accurate to four decimals) addedto 100mL boiling double distilled water After incubationfor 5min 5mL of each infusion was transferred to thesampling vessel and headspace volatiles were collected usinga 65 120583M PDMSDVB fiber (Supelco Bellefonte PA USA)for 1 h and then deadsorbed in the GC injection port for5min at 250∘C and resolved by a DB-5 capillary column(30m times 025mm times 025 120583m Agilent) for GCMS analysisThe oven temperature was programmed according to Hanet al [11] The assays were carried out in triplicate for eachsample Ethyl decanoate (001 5 120583L) was added to thesamples as the internal standard Volatile compounds wereidentified by comparing the retention indices (times) withthose of either commercial standard substances or the NISTdatabase according to Wei et al [12] Quantification of thesecompounds in tea infusions was carried out based on theinternal standard or the calibration curves prepared withauthentic commercial standards [13] Freshly excised jasmineflowers (1 g accurate to four decimals) were also placed in thesampling vessel and their headspace volatiles were collectedat 38∘C and analyzed using the methods described aboveThe relative concentrations of the volatiles were expressedas 120583gsdotkgminus1 based on SPME sampling and comparison withinternal standard (ethyl decanoate)
24 Statistical Analysis The data for all the assays wererepresented as mean plusmn SD from three biological replicates(tissue or infusion types) One-way analysis of variance(Duncanrsquos multiple range test) was performed using the DPSsoftware package (httpwwwchinadpsnetindexhtml) forstatistical analysis For detecting variations among samplesand to identify a subset of volatiles most important fordefining the major variations between the two tea infusionsand jasmine flowers supervised orthogonal partial least-squares discriminant analysis (OPLS-DA) was conductedusing volatile compound IDs tissueinfusion types andvolatile concentrations collected as input data [14] Com-pound ID numbers were plotted onto a 2-dimensional graphwith positive values representing compounds that make apositive contribution and negative values representing anegative contribution to tea scent according to Trygg et al[14] (Figure 1) Data points were identified as being variablesof importance (VIP) in the projection based on theOPLS-DAanalysis [15]
3 Results and Discussion
31 Distinct Volatile Profiles of Scented and Nonscented GreenTea Infusions and Jasmine Flowers In this study volatileemission profiles of fresh jasmine flowers (JF) and theinfusions of scented (ST) and nonscented (NT) green teaswere compared using OPLS-DA approach Volatile profilesshowed good reproducibility and high separability among
Journal of Food Quality 3
minus25 minus20 minus15 minus10 minus5 0
0
5
5
10
10
15
15
20
20
t[1]
minus5
minus15minus20minus25
t[2]
minus10
NT1NT2NT3
JF3
ST3 ST1ST2
JF1JF2
R2X0
[1] =
03
94
R2X[1] = 0529
(a)
minus015 minus01 minus005 0 005 01p[1]
minus02
p[2]
minus015
minus01
minus005
0
005
29 51 66 70 46 830 52 56 75 61
42 49
354 33
265760
65
51 9
25 14 45 37 21Total27
11
4443 7687 83
92
24 90 20 88 35
59
85 89 86 82 9184 50 68 73 53
58 13 31 667
557
12 19 10 62 216 41 18 15 39
22 3871
34 4879
78 80 8123
2847 72
63
4036
74 4
17 64
77
3269
R2X0
[1] =
03
94
R2X[1] = 0529
(b)
Figure 1 OPLS-DA score plot (a) and corresponding loading plot (b) derived from the integrated volatile emission data sets of jasmineflowers (JF) and the infusions of scented (ST) and nonscented (NT) green teas Datawere derived from three independent biological replicatesNames of numbered compounds in panel (b) are outlined in Supplementary Table 1 119905[1] and 119901[1] represent principal component 1 (volatilecompounds) 119905[2] and 119901[2] represent principal component 2 (sample group) Equations R2X[1] = 0529 and R2X0[1] = 0394 representrespectively the contributions of principal component 1 (R2X[1]) and component 2 (R2X0[1]) to the variation among the ST NT and JFCompounds in the left two quadrants of panel (b) make a negative contribution to tea odor discrimination and compounds in the right twoquadrants make a positive contribution Criteria for selecting top volatiles of importance were in accordance with the SIMCA-P programwhere a VIP value more than 1 was considered as a positive contributor
three biological replicates for fresh jasmine flowers andinfusions of scented and nonscented green tea (Figure 1(a))Data points for nonscented green tea were mainly positionedin the top left quadrant separate from jasmine flower in thetop-right quadrant with scented tea in between and mainlypositioned in the lower two quadrants Replicates of bothscented and nonscented green teas were closely localizedwhile those for jasmine flowers exhibited somewhat highvariation probably due to flowers not strictly picked at thesame developmental stage Generation ofmany jasmine floralscents (as well as expression of corresponding genes) variesdepending on the flowerrsquos developmental stages [16] AnOPLS-DA loading plot showed the correlation of the load-ing compounds towards different samples and compoundspositioned in the top-right quadrant contributed more tothe differences among the three groups than those in other
positions (Figure 1(b)) 120573-Linalool (21) indole (45) benzylalcohol (11) and methyl salicylate (37) were among thetop 10 variables of importance (VIP) that mainly specifiedthe volatile profile differences among the three samples(Supplementary Table 2 in SupplementaryMaterial availableonline at httpsdoiorg10115520175849501)
In addition for nonscented tea nonanal (148 plusmn61 120583g kgminus1) andmethyl anthranilate (106plusmn56 120583g kgminus1) werethe most abundant volatiles For the scented tea the mostabundant volatiles were benzyl acetate (3292 plusmn 158 120583g kgminus1)and 120573-linalool (2311 plusmn 305 120583g kgminus1) For jasmine flower120572-farnesene was the highest at 4954 plusmn 388 120583g kgminus1 followedby 120573-linalool (4405 plusmn 21 120583g kgminus1) These results indicatedclearly that the increased amounts of 120573-linalool in thescented tea resulted from the adsorption from jasmineflowers Although many compounds were common to more
4 Journal of Food Quality
than one emission profile some were unique to each of themas well (Supplementary Table 3) These dominant volatileswere reported earlier from tea infusions and jasmine flowers[8 11 17] A high level of eugenol was found in the jasminetea infusion as reported before [7 8] but not in the greentea infusion in this study although this compound wasreported as a potent odorant of green tea [17] probablybecause the manufacturing procedures applied for greenteas in this study and previous ones were different Thisphenylpropanoid compound is produced by the action ofeugenol synthases using coniferyl acetate as a substratein plants [18] but it is undetectable in the headspace ofjasmine flowers [19 20] These data together suggest thatthe enhanced eugenol in jasmine tea might be generateddue to possible hydrothermal conversions over the multiplerounds of scenting process not due to direct adsorptionfrom jasmine flowers although the details require furtherinvestigation In addition high levels of 120573-phenethyl acetateand benzyl tiglate were also found in jasmine tea but notfrom green tea or jasmine flowers in this study 120573-Phenethylacetate is reportedly detected from a jasmine flower grownin Egypt [19] but not from those grown in China [20]suggesting a possible difference between cultivars Benzyltiglate is emitted from the Quisqualis indica flowers but notfrom jasmine flowers [21] Further investigation is requiredto learn the mechanisms for the enhanced levels of the twocompounds in jasmine tea
32 Potent Odorants in the Infusions of Scented and Non-scented Green Teas and Jasmine Flowers Instead of aromaextract dilution analysis [17] the odor activity value (OAVvolatile abundance over its perception threshold) wasdeployed in this study to evaluate the odor characteristics oftested samples to avoid losses of highly volatile compoundsduring extraction and to eliminate matrix interference withthe volatility of an odorant [22] OAVs were determined forall 27 volatiles detected from the headspaces of tea infusionsand jasmine flowers with known threshold values from theliterature Those with OAV gt 1 are presented in Figure 2
For nonscented green tea out of six compounds possess-ing odor activity values over 1 120573-ionone (OAV 1423) andnonanal (147) were the most potent odorants (Figure 2)and both derived from metabolite degradation during themanufacturing process [3] In jasmine flowers 120573-linalool wasthe most potent odorant with OAV of 5507 followed byindole (3939) In the scented tea odor activities of 120573-iononeand 120573-linalool were significantly enhanced to 7313 and 2889respectively which were 51- and 452-fold higher than thecorresponding OAVs in the nonscented tea (Figure 2(a))Odorants methyl salicylate (OAV 17) geraniol (OAV 17)and (119885)-jasmone (OAV 36) exhibited 185- 76- and 47-foldhigher odor activity in scented tea than their counterparts inthe nonscented tea as well (Figure 2(b)) In addition based onthreshold values obtained an additional 6 compounds (OAVlt 1) had higher OAVs in scented tea than in nonscented teaincluding monoterpenoids d-limonene 120573-ocimene and (119864)-linalool oxide A (furanoid) These compounds might syn-ergistically contribute to the characteristic jasmine scentedtea flavor which was described by Ito and Kubota [9]
Interestingly the potent odorants nonanal and decanal bothas potent odorants of green teas (nonscented) made fromdifferent tea cultivars [11] had higher odor activity values(OAV gt 1) in the nonscented green tea than those in thescented tea We speculated that these might be due to morepronounced heat desorption of these volatiles from scentedtea since several additional rounds of heat treatment wereapplied for scenting tea manufacturing process It is knownthat linalool exhibits strong floral fruity and citrus-likescents [23] indole has fecal animal-like floral odor [24]jasmone has somewhat fruity floral and woody aroma notes[25] and ionone has woody and floral aroma notes [3 24](Supplementary Table 4) Since the majority of these floralscent volatiles were more abundant in the infusion of scentedtea than that of nonscented tea the jasmine scented green teainfusion possessed a strong floral scent Nonanal and decanalcontribute waxy fatty and aldehydic aromas [26] and thustheir reduction in scented green tea might also improve itsaroma quality
33 Scenting Enhanced Volatiles in Scented Green Tea Overthe scenting process the nonscented dry green tea (NT)was mixed with the fresh jasmine flowers (JF) at the ratioof 54 (dry teafresh flowers WW) Floral volatiles whoseabundances were higher than those of green tea in themixed headspace shared by both flowers and tea wouldbe dynamically adsorbed onto the tea leaf matrix until anequilibrium was reached In order to determine contributionof different JF volatiles to the aroma of scented green tea (ST)headspace volatile profiling was conducted not only for theinfusions of NT and ST but also for JF with an emphasison the compounds which were identified with authenticstandards or exhibited a significantly changed abundanceafter the scenting process
Compared to NT ST possessed 34 enhanced and 3reduced compounds (Figures 3 and 5) Among the enhancedcompounds seven were dominant volatiles in ST with theabundances 182-fold to 173-fold higher than their counter-parts in NT (Figure 3(a)) 120573-Linalool indole and benzylacetate in ST were enhanced 453- 424- and 336-foldrespectively Similarly another 10 volatiles but less abundantin ST were 82- to 487-fold higher than their correspond-ing volatiles detected in NT (Figure 3(b)) Moreover anadditional 10 volatiles were detected in ST only but notin NT (Figure 3(c)) The majority of these compounds arecommon tea volatiles [2 27] and all of them were found to beabundant in JF (Figure 3(d)) (except for geraniol and severalother compounds) as reported previously [19] However adirect abundance comparison of the volatiles detected fromtea infusions with those from fresh jasmine flowers wasnot adequate due to inconsistent volatile sampling methodsapplied in this study and the unknown release efficiencies ofindividual volatiles from solid plant matrix to the headspacesof the volatile sources The abundances of the JF volatilespresented in Figure 3(d) might be slightly different from theabundances of the floral volatiles the green tea was actuallyscented with because the dry green tea used for scenting was12-fold more than JF in this study Moreover 27 volatiles allpresent in the headspace of JF in high quantities (Figure 3(d))
Journal of Food Quality 5
100
100500
300
500
700
900
Methyl anthranilate Indole
OAV
NT ST
A
A
A
A
B
B
B
B
B
B
C C
JF NT ST JF NT ST JF NT ST JF120573-Linalool 120573-Ionone
(a)
AA
A A
AA A
AB
AB
A
A
A
B B BB
B
B B
B B
B B
B
C C
C
NT ST JF NT ST JF NT ST JF NT ST JF NT ST JF NT ST JF NT ST JF NT ST JF NT ST JF000204060810
369
12151821
OAV
-Myrcene Linalool oxide B Geraniol Nerolidol (Z)-3-Hexenylacetate
Methylsalicylate
Nonanal Decanal (Z)-Jasmone
(b)
Figure 2 Odor activity values of volatiles (gt1) found in the infusions of scented (ST) and nonscented (NT) green teas and jasmine flowers(JF) based on volatile abundances and their thresholds Duncanrsquos new multiple range test was performed and the columns labeled with thesame letter within the same compound had no significant difference among the three sample types 119875 lt 005 (a) Volatiles with high OAVs(b) Volatiles with low OAVs
with a few exceptions (geraniol neo-allo-ocimene and 120575-terpinene) were found to bemore abundant in ST than inNT(Figure 3) suggesting that the enhancement of these volatilesin ST could substantially result from tea adsorption of thesefloral volatiles over the scenting process For geraniol andgeranyl acetate their abundances in the JF headspace werequite low but both were found to be more abundant in STinfusion than in NT infusion (Figure 3(b)) It is known thattea aroma compounds geraniol and its derivatives can begenerated from heat-induced degradation of carotenoids andpossibly also from hydrolysis of its glycoside precursor [3]Our data suggested that chemical conversion in addition toadsorption might also occur over the scenting process
The percentage of the abundance of a volatile in scentedtea subtracted from the amount of the counterpart in the non-scented tea over the abundance of the corresponding com-pound in jasmine flowers was proposed to estimate itsscenting efficiency although differential contributions offloral volatile adsorption and chemical conversion to its
abundance change in jasmine tea are unknown For thoseenhanced volatiles the efficiencies varied ranging from022 for 120572-farnesene to 755 for 120573-myrcene (Figure 4)This finding suggested that scenting effectiveness was com-pound specific and might result from multiple causativefactors Chemical and physical properties including volatil-ity represented by vapor pressure (mmHg at 25∘C) watersolubility (mgL at 25∘C) and polarity represented bytopological polar surface area were examined for eachvolatile in Figure 4 through the public chemical struc-ture databases (httpwwwchemspidercom and httpspub-chemncbinlmnihgov) with an emphasis on their correla-tion with scenting effectiveness It was noted that majorityof the volatiles with high scenting effectiveness (gt40) hadhigh water solubility ranging from 4215mgL for ethyl ben-zoate to 323220mgL for benzyl alcohol (119885)-3-Hexenol andlinalool both possessing high scenting efficiencies (Figure 4)have 160000mgL and 15900mgL water solubility respec-tively Exceptions were found for120573-myrcene and d-limonene
6 Journal of Food Quality
0
200
400
NT ST
Benzyl acetateA
B0
150
300
NT ST
A
B0
150
300
NT ST
IndoleA
B
0
110
220
NT ST
Methyl anthranilateA
B0
100
200
NT ST
(Z)-3-Hexenyl benzoateA
B 0
40
80
NT ST
Methyl salicylateA
B0
25
50
NT ST
(Z)-3-Hexenyl acetate A
B
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)Ab
unda
nce
(g
kg)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)-Linalool
(a)
0
5
10
NT ST
(Z)-Jasmone
B
A
0
5
10
NT ST
Geraniol
B
A
0
3
6
NT ST
A
B
0
2
4
NT ST
Geranyl acetate
A
B 0
2
4
NT ST
(E)-3-Hexenyl butanoate
A
B0
1
2
NT ST
A
B
Abun
danc
e (
gkg
)Ab
unda
nce
(g
kg)
Abun
danc
e (
gkg
)Ab
unda
nce
(g
kg)
Abun
danc
e (
gkg
)Ab
unda
nce
(g
kg)
-Myrcene
(Z)--Ocimene
0
15
30
NT ST
Benzyl benzoateA
B0
10
20
NT ST
Benzyl alcoholA
B 0
5
10
NT ST
A
B0
3
6
NT ST
D-Limonene
A
BAbun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
-Cadinol
(b)
0
15
3
NT ST
(Z)-3-Hexenol
nd0
2
4
NT ST
nd0
05
1
NT ST
Neo-allo-ocimene
nd 0
05
1
NT ST
Ethyl benzoate
nd
0
1
2
NT ST
Ethyl salicylate
nd0
1
2
NT ST
nd0
05
1
NT ST
Copaene
nd
0
1
2
NT ST
nd0
1
2
NT ST
Cadina-14-diene
nd 0
02
04
NT ST
nd
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)Ab
unda
nce
(g
kg)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
-Cadinene
-Cubenene
-Farnesene -Terpinene
(c)
Figure 3 Continued
Journal of Food Quality 7
0200400600800
1000
0
2
4
6
8
Abun
danc
e (
gkg
)Ab
unda
nce (
g
kg)
JF
-F
arne
sene
-L
inal
ool
Indo
le
(Z)-
3-H
exen
yl ac
etat
e
Benz
yl ac
etat
e
-C
adin
ene
Met
hyl s
alic
ylat
e
(Z)-
3-H
exen
yl b
enzo
ate
Met
hyl a
nthr
anila
te
Benz
yl al
coho
l
(E)-
3-H
exen
yl b
utan
oate
-C
uben
ene
Cop
aene
Cadi
na-1
4-d
iene
(Z)-
-Oci
men
e
-C
adin
ol
D-L
imon
ene
-M
yrce
ne
(Z)-
Jasm
one
Ethy
l sal
icyl
ate
(Z)-
3-H
exen
ol
Ger
anyl
acet
ate
Benz
yl b
enzo
ate
Ethy
l ben
zoat
e
Ger
anio
l
Neo
-allo
-oci
men
e
-T
erpi
nene
(d)
Figure 3 Enhanced floral volatiles in scented tea probably due to tea adsorption (a) Volatiles with high abundances present in the scentedtea (b) volatiles with less abundances present in the scented tea (c) volatiles present in scented tea only (d) Volatiles present in the headspaceof fresh jasmine flowers ST scented green tea infusion NT nonscented tea infusion JF jasmine flower ND not detected Duncanrsquos newmultiple range test was performed and the columns labeled with the same letter within the same compound had no significant differenceamong the tested samples 119875 lt 005 NS no significant difference detected
0 20 40 60 80
Benzyl alcoholEthyl benzoate
Neo-allo-ocimene
Ethyl salicylate
(E)-3-Hexenyl butanoate
Cadina-14-diene
Copaene
Scenting efficiency ()
-Myrcenelowast
(Z)-3-HexenoＦlowast
D-Limonenlowast
Indollowast
-LinalooＦlowast
Methyl salicylatlowast-Terpinene
(Z)-3-Hexenyl acetatlowast
(Z)--Ocimenlowast
-Cubenene
-Cadinene-Farnesene
Figure 4 Differential scenting efficiencies of jasmine floral volatiles to the scented green tea Scenting efficiency was calculated as thepercentage of the volatile abundance detected in the scented tea subtracted from that of the same compound in nonscented tea over theabundance of the counterpart present in jasmine flower Compounds labeledwith ldquolowastrdquo were identified and quantifiedwith authentic standards
8 Journal of Food Quality
0
2
4
NT ST
Methyl heptenone
A
B
Abun
danc
e
0
3
6
NT ST
Linalool oxide A
A
B0
1
2
NT ST
A
B0
05
1
NT ST
A
B
0
4
8
NT ST
A
B0
05
1
NT ST
CedrolA
B
0
5
10
NT ST
T-Cadinol
A
B
(g
kg)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
-Terpineol -Cyclocitral
(E)--Ionone
(a)
0
13
26
NT ST
Nonanal
A
B
0
04
08
NT ST
Naphthalene
AB
0
5
10
NT ST
DecanalA
B
NSNS
0
04
08
NT ST
1-Methylnaphthalene
0
1
2
NT ST
BiphenyleneA
B
NSNS
0
07
14
NT ST
Isopropyl myristate
NSNS
0
04
08
NT ST
Caffeine
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)(b)
Figure 5 Volatiles with differential abundances between scented and nonscented teas but undetectable in the jasmine flower headspace (a)Enhanced volatiles in the scented tea (b) reduced volatiles in the scented tea ST scented green tea infusion NT nonscented tea infusionND not detected Duncanrsquos new multiple range test was performed and the columns labeled with the same letter within the same compoundhad no significant difference among the three samples 119875 lt 005 NS no significant difference detected
whose water solubility values are relatively low (69mgLand 46mgL resp) but their volatility values (23mmHgand 13mmHg resp) are higher than those of many otheraliphatic volatiles presented in Figure 4 Moreover 120572-farnesene and 120575-cadinene possessing the lowest scenting effi-ciencies have the lowest values of water solubility (001mgLand 005mgL resp) It was assumed that volatiles possessinghigh water solubility could be partially dissolved into theaqueous phase in tea leaf matrix over the scenting process inwhich tea leaves could adsorb moisture substantially releasedfrom the fresh jasmine flowersUpon tea infusion preparationwith hot water those volatiles retained in the scented teawould be largely released due to their volatility Furtherinvestigation is required to clarify the correlation betweenscenting effectiveness and water solubility and volatility of avolatile
Moreover surface compounds on the tea leaf matrixmight discriminate volatiles with different polarity whichhas been found for wool types used with natural and solidadsorbents [28] In addition many volatiles are known tobe readily modified by the action of plant enzymes such as
conversion of linalool and geraniol to many other derivativesin plants [29 30] hydrothermal conversions of these volatilesalso occur For instance sesquiterpene 120572-farnesene is stressinduced [31] and can be easily degraded due to photochem-ical allylic oxidation hydroxylation and epoxidation [32]Consistently 120572-farnesene was found to be abundant in theheadspace of excised jasmine flowers but much lower in thejasmine tea and undetectable in green tea in this study
34 Heat-Affected Volatiles in Scented Green Tea Over thescenting and heating procedure 14 volatiles were detectedfrom the infusions of the two teas only but with differentialabundances (119875 lt 005) These volatiles were undetectable inthe jasmine flower headspace suggesting that the observeddifferences between the two teas might unlikely result fromthe direct tea adsorption of these volatiles (Figure 5) Amongthese volatiles 7 were found with higher levels in the scentedtea compared to the nonscented tea including linalool oxideA 120573-ionone and another four terpenoids (Figure 5(a)) Theobserved enhancement of these terpenoids in the scented teamight be the consequence of the heat-induced degradation or
Journal of Food Quality 9
chemical conversionMcgraw et al [33] observed that terpenecompounds degraded at high temperatures and turned intoother terpene hydrocarbons and oxide terpenes Tatum etal [34] reported that 120572-terpineol component is formed byoxidative degradation of limonene In this study it was alsoobserved that abundance of 120572-terpineol was significantlyincreased after the scenting process although it was notdetected in the jasmine flowers (Figure 5) suggesting that itwas likely derived from the hydrothermal conversion over thescenting process
In addition reduced levels of a few compounds werefound in scented tea compared to nonscented tea (Fig-ure 5(b)) including lipid-derived aldehydes nonanal anddecanal [3]These lipid-derived compounds are heat-inducedandmost likely also heat-releasedMultiple additional roundsof heat treatments after scenting could result in the reduc-tion of these volatiles in the scented tea infusion Nonanalabundance in green tea is enhanced by steam processing butsuppressed by pan-fire processing [11]
4 Conclusions
Our study revealed that jasmine flower scented green teapossessed an enhanced floral scent due to the adsorption offloral scent-related volatiles from the fresh jasmine flowersThis revealed that dry tea had the capacity to adsorb substan-tial amounts of volatiles from jasmine flowers Differentialcontribution of jasmine floral volatiles to the aromaof scentedgreen tea was observed Moreover chemical conversion alsocontributed to the differential abundances of some volatilesbetween scented and nonscented teas Our study suggeststhat adsorption and retention of the volatiles generatedendogenously from tea leaveswere crucial formaintaining teaaroma and improving tea aroma quality practically
Additional Points
Practical Applications This work reveals the differentialcontributions of jasmine floral volatiles to the scented greentea and suggested that dry tea has a great capacity toadsorb substantial amounts of volatiles from jasmine flowersBased on what was found in this study heat treatment maybe applied to premade teas with fine-tuned temperaturesto desorb those off-flavor compounds Moreover pleasantaroma either from natural sources or from artificial mixturescan also be applied to enhance tea aroma with a specificdesired odor
Conflicts of Interest
The authors declare that they have no conflicts of interestregarding the publication of this paper
Authorsrsquo Contributions
Shu Wei designed the experiments and interpreted theresults Jian-Xia Shen and Guo-Feng Liu helped to doOPLS-OD data analysis Mohammad M Rana drafted themanuscript Tie-Jun Ling and Margaret Y Gruber revised
the manuscript Jian-Xia Shen and Mohammad M Rana areequal contributors
Acknowledgments
This work was financially supported by the National NaturalScience Foundation of China (Grants nos 31070614 and31370687) to Shu Wei Margaret Y Gruber has been workingat Agriculture and Agri-Food Canada Saskatoon ResearchCentre Saskatoon SK Canada but is now retired
References
[1] M S Butt R S AhmadM T SultanMM N Qayyum andANaz ldquoGreen tea and anticancer perspectives updates from lastdecaderdquo Critical Reviews in Food Science and Nutrition vol 55no 6 pp 792ndash805 2015
[2] Z Yang S Baldermann and N Watanabe ldquoRecent studies ofthe volatile compounds in teardquo Food Research International vol53 no 2 pp 585ndash599 2013
[3] C Ho X Zheng and S Li ldquoTea aroma formationrdquo Food Scienceand Human Wellness vol 4 no 1 pp 9ndash27 2015
[4] P Winterhalter and R Rouseff ldquoCarotenoid-derived aromacompounds an introductionrdquo in Carotenoid-Derived AromaCompounds P Winterhalter and R Rousef Eds ACS Sympo-sium Series pp 1ndash19 American Chemical Society WashingtonDC USA 2001
[5] T Takeo and T Tsushida ldquoChanges in lipoxygenase activity inrelation to lipid degradation in plucked tea shootsrdquo Phytochem-istry vol 19 no 12 pp 2521-2522 1980
[6] T Wu Traditional jasmine green tea scenting process 2013httpwwwtaotealeafcomblogtraditional-jasmine-green-tea-scenting-process
[7] MChen Y Zhu B Liu et al ldquoChanges in the volatiles chemicalcomponents and antioxidant activities of Chinese jasmine teaduring the scenting processesrdquo International Journal of FoodProperties vol 20 no 3 pp 681ndash693 2017
[8] Y Ito A Sugimoto T Kakuda and K Kubota ldquoIdentificationof potent odorants in Chinese jasmine green tea scented withflowers of Jasminum sambacrdquo Journal of Agricultural and FoodChemistry vol 50 no 17 pp 4878ndash4884 2002
[9] Y Ito and K Kubota ldquoSensory evaluation of the synergismamong odorants present in concentrations below their odorthreshold in a Chinese jasmine green tea infusionrdquo MolecularNutrition and Food Research vol 49 no 1 pp 61ndash68 2005
[10] Y Liang Y Wu J Lu and L Zhang ldquoApplication of chemicalcomposition and infusion colour difference analysis to qualityestimation of jasmine-scented teardquo International Journal of FoodScience and Technology vol 42 no 4 pp 459ndash468 2007
[11] Z-X Han M M Rana G-F Liu et al ldquoGreen tea flavourdeterminants and their changes over manufacturing processesrdquoFood Chemistry vol 212 pp 739ndash748 2016
[12] S Wei I Marton M Dekel et al ldquoManipulating volatileemission in tobacco leaves by expressing Aspergillus niger120573-glucosidase in different subcellular compartmentsrdquo PlantBiotechnology Journal vol 2 no 4 pp 341ndash350 2004
[13] Z Han M M Rana G Liu et al ldquoData on green teaflavor determinantes as affected by cultivars andmanufacturingprocessesrdquo Data in Brief vol 10 pp 492ndash498 2017
10 Journal of Food Quality
[14] J Trygg E Holmes and T Lundstedt ldquoChemometrics inmetabonomicsrdquo Journal of Proteome Research vol 6 no 2 pp469ndash479 2007
[15] K M O Ku J N Choi J Kim et al ldquoMetabolomics anal-ysis reveals the compositional differences of shade growntea (Camellia sinensis L)rdquo Journal of Agricultural and FoodChemistry vol 58 no 1 pp 418ndash426 2010
[16] Y-H Li W Zhang and Y Li ldquoTranscriptomic analysis offlower blooming in Jasminum sambac through de novo RNAsequencingrdquoMolecules vol 20 no 6 pp 10734ndash10747 2015
[17] R Baba and K Kumazawa ldquoCharacterization of the potentodorants contributing to the characteristic aroma of chinesegreen tea infusions by aroma extract dilution analysisrdquo Journalof Agricultural and Food Chemistry vol 62 no 33 pp 8308ndash8313 2014
[18] T Koeduka E Fridman D R Gang et al ldquoEugenol andisoeugenol characteristic aromatic constituents of spices arebiosynthesized via reduction of a coniferyl alcohol esterrdquoProceedings of the National Academy of Sciences of the UnitedStates of America vol 103 no 26 pp 10128ndash10133 2006
[19] A E Edris R Chizzola and C Franz ldquoIsolation and charac-terization of the volatile aroma compounds from the concreteheadspace and the absolute of Jasminum sambac (L) Ait(Oleaceae) flowers grown in Egyptrdquo European Food Researchand Technology vol 226 no 3 pp 621ndash626 2008
[20] Y Yu S Lyu D Chen et al ldquoVolatiles emitted at differentflowering stages of Jasminum sambac and expression of genesrelated to 120572-farnesene biosynthesisrdquo Molecules vol 22 no 4article 546 2017
[21] P K Rout Y Ramachandra Rao and S Naik ldquoAnalysis offloral volatiles by using headspace-solid phase microextractiona reviewrdquoAsian Journal of Chemistry vol 24 no 3 pp 945ndash9562012
[22] C Schuh and P Schieberle ldquoCharacterization of the key aromacompounds in the beverage prepared from Darjeeling blacktea quantitative differences between tea leaves and infusionrdquoJournal of Agricultural and Food Chemistry vol 54 no 3 pp916ndash924 2006
[23] B Bonnlander R Cappuccio F S Liverani and PWinterhalterldquoAnalysis of enantiomeric linalool ratio in green and roastedcoffeerdquo Flavour and Fragrance Journal vol 21 no 4 pp 637ndash641 2006
[24] T Katsuno H Kasuga Y Kusano et al ldquoCharacterisation ofodorant compounds and their biochemical formation in greentea with a low temperature storage processrdquo Food Chemistryvol 148 pp 388ndash395 2014
[25] J Scognamiglio L Jones C S Letizia and A M Api ldquoFra-grance material review on cis-jasmonerdquo Food and ChemicalToxicology vol 50 supplement 3 pp S613ndashS618 2012
[26] Anonymous The good scents company information system2016 httpwwwthegoodscentscompanycomsearch2html
[27] Y Sawai Y Yamaguchi and J Tanaka ldquoMethyl anthranilate isthe cause of cultivar-specific aroma in the Japanese tea cultivarlsquoSofursquordquo Japan Agricultural Research Quarterly vol 38 no 4 pp271ndash274 2004
[28] E Mansour S Curling A Stephan and G OrmondroydldquoAbsorption of volatile organic compounds by different wooltypesrdquo Green Materials vol 4 no 1 pp 1ndash7 2016
[29] R Davidovich-Rikanati Y Sitrit Y Tadmor et al ldquoEnrichmentof tomato flavor by diversion of the early plastidial terpenoidpathwayrdquoNature Biotechnology vol 25 no 8 pp 899ndash901 2007
[30] B Boachon R R Junker L Miesch et al ldquoCYP76C1(Cytochrome P450)-mediated linalool metabolism and theformation of volatile and soluble linalool oxides in arabidopsisflowers a strategy for defense against floral antagonistsrdquo PlantCell vol 27 no 10 pp 2972ndash2990 2015
[31] F Dong Z Yang S Baldermann Y Sato T Asai andNWatan-abe ldquoHerbivore-induced volatiles from tea (Camellia sinensis)plants and their involvement in intraplant communication andchanges in endogenous nonvolatile metabolitesrdquo Journal ofAgricultural and Food Chemistry vol 59 no 24 pp 13131ndash131352011
[32] J A SpicerThe oxidation of 120572-Farnesene [PhD thesis] MasseyUniversity Palmerston North New Zealand 1994
[33] GWMcgraw RW Hemingway L L Ingram Jr C S Canadyand W B Mcgraw ldquoThermal degradation of terpenes cam-phene Δ3-carene limonene and 120572-terpinenerdquo EnvironmentalScience and Technology vol 33 no 22 pp 4029ndash4033 1999
[34] J H Tatum S Nagy and R E Berry ldquoDegradation productsformed in canned single-strength orange juice during storagerdquoJournal of Food Science vol 40 no 4 pp 707ndash709 1975
Figure 1 OPLS-DA score plot (a) and corresponding loading plot (b) derived from the integrated volatile emission data sets of jasmineflowers (JF) and the infusions of scented (ST) and nonscented (NT) green teas Datawere derived from three independent biological replicatesNames of numbered compounds in panel (b) are outlined in Supplementary Table 1 119905[1] and 119901[1] represent principal component 1 (volatilecompounds) 119905[2] and 119901[2] represent principal component 2 (sample group) Equations R2X[1] = 0529 and R2X0[1] = 0394 representrespectively the contributions of principal component 1 (R2X[1]) and component 2 (R2X0[1]) to the variation among the ST NT and JFCompounds in the left two quadrants of panel (b) make a negative contribution to tea odor discrimination and compounds in the right twoquadrants make a positive contribution Criteria for selecting top volatiles of importance were in accordance with the SIMCA-P programwhere a VIP value more than 1 was considered as a positive contributor
three biological replicates for fresh jasmine flowers andinfusions of scented and nonscented green tea (Figure 1(a))Data points for nonscented green tea were mainly positionedin the top left quadrant separate from jasmine flower in thetop-right quadrant with scented tea in between and mainlypositioned in the lower two quadrants Replicates of bothscented and nonscented green teas were closely localizedwhile those for jasmine flowers exhibited somewhat highvariation probably due to flowers not strictly picked at thesame developmental stage Generation ofmany jasmine floralscents (as well as expression of corresponding genes) variesdepending on the flowerrsquos developmental stages [16] AnOPLS-DA loading plot showed the correlation of the load-ing compounds towards different samples and compoundspositioned in the top-right quadrant contributed more tothe differences among the three groups than those in other
positions (Figure 1(b)) 120573-Linalool (21) indole (45) benzylalcohol (11) and methyl salicylate (37) were among thetop 10 variables of importance (VIP) that mainly specifiedthe volatile profile differences among the three samples(Supplementary Table 2 in SupplementaryMaterial availableonline at httpsdoiorg10115520175849501)
In addition for nonscented tea nonanal (148 plusmn61 120583g kgminus1) andmethyl anthranilate (106plusmn56 120583g kgminus1) werethe most abundant volatiles For the scented tea the mostabundant volatiles were benzyl acetate (3292 plusmn 158 120583g kgminus1)and 120573-linalool (2311 plusmn 305 120583g kgminus1) For jasmine flower120572-farnesene was the highest at 4954 plusmn 388 120583g kgminus1 followedby 120573-linalool (4405 plusmn 21 120583g kgminus1) These results indicatedclearly that the increased amounts of 120573-linalool in thescented tea resulted from the adsorption from jasmineflowers Although many compounds were common to more
4 Journal of Food Quality
than one emission profile some were unique to each of themas well (Supplementary Table 3) These dominant volatileswere reported earlier from tea infusions and jasmine flowers[8 11 17] A high level of eugenol was found in the jasminetea infusion as reported before [7 8] but not in the greentea infusion in this study although this compound wasreported as a potent odorant of green tea [17] probablybecause the manufacturing procedures applied for greenteas in this study and previous ones were different Thisphenylpropanoid compound is produced by the action ofeugenol synthases using coniferyl acetate as a substratein plants [18] but it is undetectable in the headspace ofjasmine flowers [19 20] These data together suggest thatthe enhanced eugenol in jasmine tea might be generateddue to possible hydrothermal conversions over the multiplerounds of scenting process not due to direct adsorptionfrom jasmine flowers although the details require furtherinvestigation In addition high levels of 120573-phenethyl acetateand benzyl tiglate were also found in jasmine tea but notfrom green tea or jasmine flowers in this study 120573-Phenethylacetate is reportedly detected from a jasmine flower grownin Egypt [19] but not from those grown in China [20]suggesting a possible difference between cultivars Benzyltiglate is emitted from the Quisqualis indica flowers but notfrom jasmine flowers [21] Further investigation is requiredto learn the mechanisms for the enhanced levels of the twocompounds in jasmine tea
32 Potent Odorants in the Infusions of Scented and Non-scented Green Teas and Jasmine Flowers Instead of aromaextract dilution analysis [17] the odor activity value (OAVvolatile abundance over its perception threshold) wasdeployed in this study to evaluate the odor characteristics oftested samples to avoid losses of highly volatile compoundsduring extraction and to eliminate matrix interference withthe volatility of an odorant [22] OAVs were determined forall 27 volatiles detected from the headspaces of tea infusionsand jasmine flowers with known threshold values from theliterature Those with OAV gt 1 are presented in Figure 2
For nonscented green tea out of six compounds possess-ing odor activity values over 1 120573-ionone (OAV 1423) andnonanal (147) were the most potent odorants (Figure 2)and both derived from metabolite degradation during themanufacturing process [3] In jasmine flowers 120573-linalool wasthe most potent odorant with OAV of 5507 followed byindole (3939) In the scented tea odor activities of 120573-iononeand 120573-linalool were significantly enhanced to 7313 and 2889respectively which were 51- and 452-fold higher than thecorresponding OAVs in the nonscented tea (Figure 2(a))Odorants methyl salicylate (OAV 17) geraniol (OAV 17)and (119885)-jasmone (OAV 36) exhibited 185- 76- and 47-foldhigher odor activity in scented tea than their counterparts inthe nonscented tea as well (Figure 2(b)) In addition based onthreshold values obtained an additional 6 compounds (OAVlt 1) had higher OAVs in scented tea than in nonscented teaincluding monoterpenoids d-limonene 120573-ocimene and (119864)-linalool oxide A (furanoid) These compounds might syn-ergistically contribute to the characteristic jasmine scentedtea flavor which was described by Ito and Kubota [9]
Interestingly the potent odorants nonanal and decanal bothas potent odorants of green teas (nonscented) made fromdifferent tea cultivars [11] had higher odor activity values(OAV gt 1) in the nonscented green tea than those in thescented tea We speculated that these might be due to morepronounced heat desorption of these volatiles from scentedtea since several additional rounds of heat treatment wereapplied for scenting tea manufacturing process It is knownthat linalool exhibits strong floral fruity and citrus-likescents [23] indole has fecal animal-like floral odor [24]jasmone has somewhat fruity floral and woody aroma notes[25] and ionone has woody and floral aroma notes [3 24](Supplementary Table 4) Since the majority of these floralscent volatiles were more abundant in the infusion of scentedtea than that of nonscented tea the jasmine scented green teainfusion possessed a strong floral scent Nonanal and decanalcontribute waxy fatty and aldehydic aromas [26] and thustheir reduction in scented green tea might also improve itsaroma quality
33 Scenting Enhanced Volatiles in Scented Green Tea Overthe scenting process the nonscented dry green tea (NT)was mixed with the fresh jasmine flowers (JF) at the ratioof 54 (dry teafresh flowers WW) Floral volatiles whoseabundances were higher than those of green tea in themixed headspace shared by both flowers and tea wouldbe dynamically adsorbed onto the tea leaf matrix until anequilibrium was reached In order to determine contributionof different JF volatiles to the aroma of scented green tea (ST)headspace volatile profiling was conducted not only for theinfusions of NT and ST but also for JF with an emphasison the compounds which were identified with authenticstandards or exhibited a significantly changed abundanceafter the scenting process
Compared to NT ST possessed 34 enhanced and 3reduced compounds (Figures 3 and 5) Among the enhancedcompounds seven were dominant volatiles in ST with theabundances 182-fold to 173-fold higher than their counter-parts in NT (Figure 3(a)) 120573-Linalool indole and benzylacetate in ST were enhanced 453- 424- and 336-foldrespectively Similarly another 10 volatiles but less abundantin ST were 82- to 487-fold higher than their correspond-ing volatiles detected in NT (Figure 3(b)) Moreover anadditional 10 volatiles were detected in ST only but notin NT (Figure 3(c)) The majority of these compounds arecommon tea volatiles [2 27] and all of them were found to beabundant in JF (Figure 3(d)) (except for geraniol and severalother compounds) as reported previously [19] However adirect abundance comparison of the volatiles detected fromtea infusions with those from fresh jasmine flowers wasnot adequate due to inconsistent volatile sampling methodsapplied in this study and the unknown release efficiencies ofindividual volatiles from solid plant matrix to the headspacesof the volatile sources The abundances of the JF volatilespresented in Figure 3(d) might be slightly different from theabundances of the floral volatiles the green tea was actuallyscented with because the dry green tea used for scenting was12-fold more than JF in this study Moreover 27 volatiles allpresent in the headspace of JF in high quantities (Figure 3(d))
Journal of Food Quality 5
100
100500
300
500
700
900
Methyl anthranilate Indole
OAV
NT ST
A
A
A
A
B
B
B
B
B
B
C C
JF NT ST JF NT ST JF NT ST JF120573-Linalool 120573-Ionone
(a)
AA
A A
AA A
AB
AB
A
A
A
B B BB
B
B B
B B
B B
B
C C
C
NT ST JF NT ST JF NT ST JF NT ST JF NT ST JF NT ST JF NT ST JF NT ST JF NT ST JF000204060810
369
12151821
OAV
-Myrcene Linalool oxide B Geraniol Nerolidol (Z)-3-Hexenylacetate
Methylsalicylate
Nonanal Decanal (Z)-Jasmone
(b)
Figure 2 Odor activity values of volatiles (gt1) found in the infusions of scented (ST) and nonscented (NT) green teas and jasmine flowers(JF) based on volatile abundances and their thresholds Duncanrsquos new multiple range test was performed and the columns labeled with thesame letter within the same compound had no significant difference among the three sample types 119875 lt 005 (a) Volatiles with high OAVs(b) Volatiles with low OAVs
with a few exceptions (geraniol neo-allo-ocimene and 120575-terpinene) were found to bemore abundant in ST than inNT(Figure 3) suggesting that the enhancement of these volatilesin ST could substantially result from tea adsorption of thesefloral volatiles over the scenting process For geraniol andgeranyl acetate their abundances in the JF headspace werequite low but both were found to be more abundant in STinfusion than in NT infusion (Figure 3(b)) It is known thattea aroma compounds geraniol and its derivatives can begenerated from heat-induced degradation of carotenoids andpossibly also from hydrolysis of its glycoside precursor [3]Our data suggested that chemical conversion in addition toadsorption might also occur over the scenting process
The percentage of the abundance of a volatile in scentedtea subtracted from the amount of the counterpart in the non-scented tea over the abundance of the corresponding com-pound in jasmine flowers was proposed to estimate itsscenting efficiency although differential contributions offloral volatile adsorption and chemical conversion to its
abundance change in jasmine tea are unknown For thoseenhanced volatiles the efficiencies varied ranging from022 for 120572-farnesene to 755 for 120573-myrcene (Figure 4)This finding suggested that scenting effectiveness was com-pound specific and might result from multiple causativefactors Chemical and physical properties including volatil-ity represented by vapor pressure (mmHg at 25∘C) watersolubility (mgL at 25∘C) and polarity represented bytopological polar surface area were examined for eachvolatile in Figure 4 through the public chemical struc-ture databases (httpwwwchemspidercom and httpspub-chemncbinlmnihgov) with an emphasis on their correla-tion with scenting effectiveness It was noted that majorityof the volatiles with high scenting effectiveness (gt40) hadhigh water solubility ranging from 4215mgL for ethyl ben-zoate to 323220mgL for benzyl alcohol (119885)-3-Hexenol andlinalool both possessing high scenting efficiencies (Figure 4)have 160000mgL and 15900mgL water solubility respec-tively Exceptions were found for120573-myrcene and d-limonene
6 Journal of Food Quality
0
200
400
NT ST
Benzyl acetateA
B0
150
300
NT ST
A
B0
150
300
NT ST
IndoleA
B
0
110
220
NT ST
Methyl anthranilateA
B0
100
200
NT ST
(Z)-3-Hexenyl benzoateA
B 0
40
80
NT ST
Methyl salicylateA
B0
25
50
NT ST
(Z)-3-Hexenyl acetate A
B
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)Ab
unda
nce
(g
kg)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)-Linalool
(a)
0
5
10
NT ST
(Z)-Jasmone
B
A
0
5
10
NT ST
Geraniol
B
A
0
3
6
NT ST
A
B
0
2
4
NT ST
Geranyl acetate
A
B 0
2
4
NT ST
(E)-3-Hexenyl butanoate
A
B0
1
2
NT ST
A
B
Abun
danc
e (
gkg
)Ab
unda
nce
(g
kg)
Abun
danc
e (
gkg
)Ab
unda
nce
(g
kg)
Abun
danc
e (
gkg
)Ab
unda
nce
(g
kg)
-Myrcene
(Z)--Ocimene
0
15
30
NT ST
Benzyl benzoateA
B0
10
20
NT ST
Benzyl alcoholA
B 0
5
10
NT ST
A
B0
3
6
NT ST
D-Limonene
A
BAbun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
-Cadinol
(b)
0
15
3
NT ST
(Z)-3-Hexenol
nd0
2
4
NT ST
nd0
05
1
NT ST
Neo-allo-ocimene
nd 0
05
1
NT ST
Ethyl benzoate
nd
0
1
2
NT ST
Ethyl salicylate
nd0
1
2
NT ST
nd0
05
1
NT ST
Copaene
nd
0
1
2
NT ST
nd0
1
2
NT ST
Cadina-14-diene
nd 0
02
04
NT ST
nd
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)Ab
unda
nce
(g
kg)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
-Cadinene
-Cubenene
-Farnesene -Terpinene
(c)
Figure 3 Continued
Journal of Food Quality 7
0200400600800
1000
0
2
4
6
8
Abun
danc
e (
gkg
)Ab
unda
nce (
g
kg)
JF
-F
arne
sene
-L
inal
ool
Indo
le
(Z)-
3-H
exen
yl ac
etat
e
Benz
yl ac
etat
e
-C
adin
ene
Met
hyl s
alic
ylat
e
(Z)-
3-H
exen
yl b
enzo
ate
Met
hyl a
nthr
anila
te
Benz
yl al
coho
l
(E)-
3-H
exen
yl b
utan
oate
-C
uben
ene
Cop
aene
Cadi
na-1
4-d
iene
(Z)-
-Oci
men
e
-C
adin
ol
D-L
imon
ene
-M
yrce
ne
(Z)-
Jasm
one
Ethy
l sal
icyl
ate
(Z)-
3-H
exen
ol
Ger
anyl
acet
ate
Benz
yl b
enzo
ate
Ethy
l ben
zoat
e
Ger
anio
l
Neo
-allo
-oci
men
e
-T
erpi
nene
(d)
Figure 3 Enhanced floral volatiles in scented tea probably due to tea adsorption (a) Volatiles with high abundances present in the scentedtea (b) volatiles with less abundances present in the scented tea (c) volatiles present in scented tea only (d) Volatiles present in the headspaceof fresh jasmine flowers ST scented green tea infusion NT nonscented tea infusion JF jasmine flower ND not detected Duncanrsquos newmultiple range test was performed and the columns labeled with the same letter within the same compound had no significant differenceamong the tested samples 119875 lt 005 NS no significant difference detected
0 20 40 60 80
Benzyl alcoholEthyl benzoate
Neo-allo-ocimene
Ethyl salicylate
(E)-3-Hexenyl butanoate
Cadina-14-diene
Copaene
Scenting efficiency ()
-Myrcenelowast
(Z)-3-HexenoＦlowast
D-Limonenlowast
Indollowast
-LinalooＦlowast
Methyl salicylatlowast-Terpinene
(Z)-3-Hexenyl acetatlowast
(Z)--Ocimenlowast
-Cubenene
-Cadinene-Farnesene
Figure 4 Differential scenting efficiencies of jasmine floral volatiles to the scented green tea Scenting efficiency was calculated as thepercentage of the volatile abundance detected in the scented tea subtracted from that of the same compound in nonscented tea over theabundance of the counterpart present in jasmine flower Compounds labeledwith ldquolowastrdquo were identified and quantifiedwith authentic standards
8 Journal of Food Quality
0
2
4
NT ST
Methyl heptenone
A
B
Abun
danc
e
0
3
6
NT ST
Linalool oxide A
A
B0
1
2
NT ST
A
B0
05
1
NT ST
A
B
0
4
8
NT ST
A
B0
05
1
NT ST
CedrolA
B
0
5
10
NT ST
T-Cadinol
A
B
(g
kg)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
-Terpineol -Cyclocitral
(E)--Ionone
(a)
0
13
26
NT ST
Nonanal
A
B
0
04
08
NT ST
Naphthalene
AB
0
5
10
NT ST
DecanalA
B
NSNS
0
04
08
NT ST
1-Methylnaphthalene
0
1
2
NT ST
BiphenyleneA
B
NSNS
0
07
14
NT ST
Isopropyl myristate
NSNS
0
04
08
NT ST
Caffeine
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)(b)
Figure 5 Volatiles with differential abundances between scented and nonscented teas but undetectable in the jasmine flower headspace (a)Enhanced volatiles in the scented tea (b) reduced volatiles in the scented tea ST scented green tea infusion NT nonscented tea infusionND not detected Duncanrsquos new multiple range test was performed and the columns labeled with the same letter within the same compoundhad no significant difference among the three samples 119875 lt 005 NS no significant difference detected
whose water solubility values are relatively low (69mgLand 46mgL resp) but their volatility values (23mmHgand 13mmHg resp) are higher than those of many otheraliphatic volatiles presented in Figure 4 Moreover 120572-farnesene and 120575-cadinene possessing the lowest scenting effi-ciencies have the lowest values of water solubility (001mgLand 005mgL resp) It was assumed that volatiles possessinghigh water solubility could be partially dissolved into theaqueous phase in tea leaf matrix over the scenting process inwhich tea leaves could adsorb moisture substantially releasedfrom the fresh jasmine flowersUpon tea infusion preparationwith hot water those volatiles retained in the scented teawould be largely released due to their volatility Furtherinvestigation is required to clarify the correlation betweenscenting effectiveness and water solubility and volatility of avolatile
Moreover surface compounds on the tea leaf matrixmight discriminate volatiles with different polarity whichhas been found for wool types used with natural and solidadsorbents [28] In addition many volatiles are known tobe readily modified by the action of plant enzymes such as
conversion of linalool and geraniol to many other derivativesin plants [29 30] hydrothermal conversions of these volatilesalso occur For instance sesquiterpene 120572-farnesene is stressinduced [31] and can be easily degraded due to photochem-ical allylic oxidation hydroxylation and epoxidation [32]Consistently 120572-farnesene was found to be abundant in theheadspace of excised jasmine flowers but much lower in thejasmine tea and undetectable in green tea in this study
34 Heat-Affected Volatiles in Scented Green Tea Over thescenting and heating procedure 14 volatiles were detectedfrom the infusions of the two teas only but with differentialabundances (119875 lt 005) These volatiles were undetectable inthe jasmine flower headspace suggesting that the observeddifferences between the two teas might unlikely result fromthe direct tea adsorption of these volatiles (Figure 5) Amongthese volatiles 7 were found with higher levels in the scentedtea compared to the nonscented tea including linalool oxideA 120573-ionone and another four terpenoids (Figure 5(a)) Theobserved enhancement of these terpenoids in the scented teamight be the consequence of the heat-induced degradation or
Journal of Food Quality 9
chemical conversionMcgraw et al [33] observed that terpenecompounds degraded at high temperatures and turned intoother terpene hydrocarbons and oxide terpenes Tatum etal [34] reported that 120572-terpineol component is formed byoxidative degradation of limonene In this study it was alsoobserved that abundance of 120572-terpineol was significantlyincreased after the scenting process although it was notdetected in the jasmine flowers (Figure 5) suggesting that itwas likely derived from the hydrothermal conversion over thescenting process
In addition reduced levels of a few compounds werefound in scented tea compared to nonscented tea (Fig-ure 5(b)) including lipid-derived aldehydes nonanal anddecanal [3]These lipid-derived compounds are heat-inducedandmost likely also heat-releasedMultiple additional roundsof heat treatments after scenting could result in the reduc-tion of these volatiles in the scented tea infusion Nonanalabundance in green tea is enhanced by steam processing butsuppressed by pan-fire processing [11]
4 Conclusions
Our study revealed that jasmine flower scented green teapossessed an enhanced floral scent due to the adsorption offloral scent-related volatiles from the fresh jasmine flowersThis revealed that dry tea had the capacity to adsorb substan-tial amounts of volatiles from jasmine flowers Differentialcontribution of jasmine floral volatiles to the aromaof scentedgreen tea was observed Moreover chemical conversion alsocontributed to the differential abundances of some volatilesbetween scented and nonscented teas Our study suggeststhat adsorption and retention of the volatiles generatedendogenously from tea leaveswere crucial formaintaining teaaroma and improving tea aroma quality practically
Additional Points
Practical Applications This work reveals the differentialcontributions of jasmine floral volatiles to the scented greentea and suggested that dry tea has a great capacity toadsorb substantial amounts of volatiles from jasmine flowersBased on what was found in this study heat treatment maybe applied to premade teas with fine-tuned temperaturesto desorb those off-flavor compounds Moreover pleasantaroma either from natural sources or from artificial mixturescan also be applied to enhance tea aroma with a specificdesired odor
Conflicts of Interest
The authors declare that they have no conflicts of interestregarding the publication of this paper
Authorsrsquo Contributions
Shu Wei designed the experiments and interpreted theresults Jian-Xia Shen and Guo-Feng Liu helped to doOPLS-OD data analysis Mohammad M Rana drafted themanuscript Tie-Jun Ling and Margaret Y Gruber revised
the manuscript Jian-Xia Shen and Mohammad M Rana areequal contributors
Acknowledgments
This work was financially supported by the National NaturalScience Foundation of China (Grants nos 31070614 and31370687) to Shu Wei Margaret Y Gruber has been workingat Agriculture and Agri-Food Canada Saskatoon ResearchCentre Saskatoon SK Canada but is now retired
References
[1] M S Butt R S AhmadM T SultanMM N Qayyum andANaz ldquoGreen tea and anticancer perspectives updates from lastdecaderdquo Critical Reviews in Food Science and Nutrition vol 55no 6 pp 792ndash805 2015
[2] Z Yang S Baldermann and N Watanabe ldquoRecent studies ofthe volatile compounds in teardquo Food Research International vol53 no 2 pp 585ndash599 2013
[3] C Ho X Zheng and S Li ldquoTea aroma formationrdquo Food Scienceand Human Wellness vol 4 no 1 pp 9ndash27 2015
[4] P Winterhalter and R Rouseff ldquoCarotenoid-derived aromacompounds an introductionrdquo in Carotenoid-Derived AromaCompounds P Winterhalter and R Rousef Eds ACS Sympo-sium Series pp 1ndash19 American Chemical Society WashingtonDC USA 2001
[5] T Takeo and T Tsushida ldquoChanges in lipoxygenase activity inrelation to lipid degradation in plucked tea shootsrdquo Phytochem-istry vol 19 no 12 pp 2521-2522 1980
[6] T Wu Traditional jasmine green tea scenting process 2013httpwwwtaotealeafcomblogtraditional-jasmine-green-tea-scenting-process
[7] MChen Y Zhu B Liu et al ldquoChanges in the volatiles chemicalcomponents and antioxidant activities of Chinese jasmine teaduring the scenting processesrdquo International Journal of FoodProperties vol 20 no 3 pp 681ndash693 2017
[8] Y Ito A Sugimoto T Kakuda and K Kubota ldquoIdentificationof potent odorants in Chinese jasmine green tea scented withflowers of Jasminum sambacrdquo Journal of Agricultural and FoodChemistry vol 50 no 17 pp 4878ndash4884 2002
[9] Y Ito and K Kubota ldquoSensory evaluation of the synergismamong odorants present in concentrations below their odorthreshold in a Chinese jasmine green tea infusionrdquo MolecularNutrition and Food Research vol 49 no 1 pp 61ndash68 2005
[10] Y Liang Y Wu J Lu and L Zhang ldquoApplication of chemicalcomposition and infusion colour difference analysis to qualityestimation of jasmine-scented teardquo International Journal of FoodScience and Technology vol 42 no 4 pp 459ndash468 2007
[11] Z-X Han M M Rana G-F Liu et al ldquoGreen tea flavourdeterminants and their changes over manufacturing processesrdquoFood Chemistry vol 212 pp 739ndash748 2016
[12] S Wei I Marton M Dekel et al ldquoManipulating volatileemission in tobacco leaves by expressing Aspergillus niger120573-glucosidase in different subcellular compartmentsrdquo PlantBiotechnology Journal vol 2 no 4 pp 341ndash350 2004
[13] Z Han M M Rana G Liu et al ldquoData on green teaflavor determinantes as affected by cultivars andmanufacturingprocessesrdquo Data in Brief vol 10 pp 492ndash498 2017
10 Journal of Food Quality
[14] J Trygg E Holmes and T Lundstedt ldquoChemometrics inmetabonomicsrdquo Journal of Proteome Research vol 6 no 2 pp469ndash479 2007
[15] K M O Ku J N Choi J Kim et al ldquoMetabolomics anal-ysis reveals the compositional differences of shade growntea (Camellia sinensis L)rdquo Journal of Agricultural and FoodChemistry vol 58 no 1 pp 418ndash426 2010
[16] Y-H Li W Zhang and Y Li ldquoTranscriptomic analysis offlower blooming in Jasminum sambac through de novo RNAsequencingrdquoMolecules vol 20 no 6 pp 10734ndash10747 2015
[17] R Baba and K Kumazawa ldquoCharacterization of the potentodorants contributing to the characteristic aroma of chinesegreen tea infusions by aroma extract dilution analysisrdquo Journalof Agricultural and Food Chemistry vol 62 no 33 pp 8308ndash8313 2014
[18] T Koeduka E Fridman D R Gang et al ldquoEugenol andisoeugenol characteristic aromatic constituents of spices arebiosynthesized via reduction of a coniferyl alcohol esterrdquoProceedings of the National Academy of Sciences of the UnitedStates of America vol 103 no 26 pp 10128ndash10133 2006
[19] A E Edris R Chizzola and C Franz ldquoIsolation and charac-terization of the volatile aroma compounds from the concreteheadspace and the absolute of Jasminum sambac (L) Ait(Oleaceae) flowers grown in Egyptrdquo European Food Researchand Technology vol 226 no 3 pp 621ndash626 2008
[20] Y Yu S Lyu D Chen et al ldquoVolatiles emitted at differentflowering stages of Jasminum sambac and expression of genesrelated to 120572-farnesene biosynthesisrdquo Molecules vol 22 no 4article 546 2017
[21] P K Rout Y Ramachandra Rao and S Naik ldquoAnalysis offloral volatiles by using headspace-solid phase microextractiona reviewrdquoAsian Journal of Chemistry vol 24 no 3 pp 945ndash9562012
[22] C Schuh and P Schieberle ldquoCharacterization of the key aromacompounds in the beverage prepared from Darjeeling blacktea quantitative differences between tea leaves and infusionrdquoJournal of Agricultural and Food Chemistry vol 54 no 3 pp916ndash924 2006
[23] B Bonnlander R Cappuccio F S Liverani and PWinterhalterldquoAnalysis of enantiomeric linalool ratio in green and roastedcoffeerdquo Flavour and Fragrance Journal vol 21 no 4 pp 637ndash641 2006
[24] T Katsuno H Kasuga Y Kusano et al ldquoCharacterisation ofodorant compounds and their biochemical formation in greentea with a low temperature storage processrdquo Food Chemistryvol 148 pp 388ndash395 2014
[25] J Scognamiglio L Jones C S Letizia and A M Api ldquoFra-grance material review on cis-jasmonerdquo Food and ChemicalToxicology vol 50 supplement 3 pp S613ndashS618 2012
[26] Anonymous The good scents company information system2016 httpwwwthegoodscentscompanycomsearch2html
[27] Y Sawai Y Yamaguchi and J Tanaka ldquoMethyl anthranilate isthe cause of cultivar-specific aroma in the Japanese tea cultivarlsquoSofursquordquo Japan Agricultural Research Quarterly vol 38 no 4 pp271ndash274 2004
[28] E Mansour S Curling A Stephan and G OrmondroydldquoAbsorption of volatile organic compounds by different wooltypesrdquo Green Materials vol 4 no 1 pp 1ndash7 2016
[29] R Davidovich-Rikanati Y Sitrit Y Tadmor et al ldquoEnrichmentof tomato flavor by diversion of the early plastidial terpenoidpathwayrdquoNature Biotechnology vol 25 no 8 pp 899ndash901 2007
[30] B Boachon R R Junker L Miesch et al ldquoCYP76C1(Cytochrome P450)-mediated linalool metabolism and theformation of volatile and soluble linalool oxides in arabidopsisflowers a strategy for defense against floral antagonistsrdquo PlantCell vol 27 no 10 pp 2972ndash2990 2015
[31] F Dong Z Yang S Baldermann Y Sato T Asai andNWatan-abe ldquoHerbivore-induced volatiles from tea (Camellia sinensis)plants and their involvement in intraplant communication andchanges in endogenous nonvolatile metabolitesrdquo Journal ofAgricultural and Food Chemistry vol 59 no 24 pp 13131ndash131352011
[32] J A SpicerThe oxidation of 120572-Farnesene [PhD thesis] MasseyUniversity Palmerston North New Zealand 1994
[33] GWMcgraw RW Hemingway L L Ingram Jr C S Canadyand W B Mcgraw ldquoThermal degradation of terpenes cam-phene Δ3-carene limonene and 120572-terpinenerdquo EnvironmentalScience and Technology vol 33 no 22 pp 4029ndash4033 1999
[34] J H Tatum S Nagy and R E Berry ldquoDegradation productsformed in canned single-strength orange juice during storagerdquoJournal of Food Science vol 40 no 4 pp 707ndash709 1975
than one emission profile some were unique to each of themas well (Supplementary Table 3) These dominant volatileswere reported earlier from tea infusions and jasmine flowers[8 11 17] A high level of eugenol was found in the jasminetea infusion as reported before [7 8] but not in the greentea infusion in this study although this compound wasreported as a potent odorant of green tea [17] probablybecause the manufacturing procedures applied for greenteas in this study and previous ones were different Thisphenylpropanoid compound is produced by the action ofeugenol synthases using coniferyl acetate as a substratein plants [18] but it is undetectable in the headspace ofjasmine flowers [19 20] These data together suggest thatthe enhanced eugenol in jasmine tea might be generateddue to possible hydrothermal conversions over the multiplerounds of scenting process not due to direct adsorptionfrom jasmine flowers although the details require furtherinvestigation In addition high levels of 120573-phenethyl acetateand benzyl tiglate were also found in jasmine tea but notfrom green tea or jasmine flowers in this study 120573-Phenethylacetate is reportedly detected from a jasmine flower grownin Egypt [19] but not from those grown in China [20]suggesting a possible difference between cultivars Benzyltiglate is emitted from the Quisqualis indica flowers but notfrom jasmine flowers [21] Further investigation is requiredto learn the mechanisms for the enhanced levels of the twocompounds in jasmine tea
32 Potent Odorants in the Infusions of Scented and Non-scented Green Teas and Jasmine Flowers Instead of aromaextract dilution analysis [17] the odor activity value (OAVvolatile abundance over its perception threshold) wasdeployed in this study to evaluate the odor characteristics oftested samples to avoid losses of highly volatile compoundsduring extraction and to eliminate matrix interference withthe volatility of an odorant [22] OAVs were determined forall 27 volatiles detected from the headspaces of tea infusionsand jasmine flowers with known threshold values from theliterature Those with OAV gt 1 are presented in Figure 2
For nonscented green tea out of six compounds possess-ing odor activity values over 1 120573-ionone (OAV 1423) andnonanal (147) were the most potent odorants (Figure 2)and both derived from metabolite degradation during themanufacturing process [3] In jasmine flowers 120573-linalool wasthe most potent odorant with OAV of 5507 followed byindole (3939) In the scented tea odor activities of 120573-iononeand 120573-linalool were significantly enhanced to 7313 and 2889respectively which were 51- and 452-fold higher than thecorresponding OAVs in the nonscented tea (Figure 2(a))Odorants methyl salicylate (OAV 17) geraniol (OAV 17)and (119885)-jasmone (OAV 36) exhibited 185- 76- and 47-foldhigher odor activity in scented tea than their counterparts inthe nonscented tea as well (Figure 2(b)) In addition based onthreshold values obtained an additional 6 compounds (OAVlt 1) had higher OAVs in scented tea than in nonscented teaincluding monoterpenoids d-limonene 120573-ocimene and (119864)-linalool oxide A (furanoid) These compounds might syn-ergistically contribute to the characteristic jasmine scentedtea flavor which was described by Ito and Kubota [9]
Interestingly the potent odorants nonanal and decanal bothas potent odorants of green teas (nonscented) made fromdifferent tea cultivars [11] had higher odor activity values(OAV gt 1) in the nonscented green tea than those in thescented tea We speculated that these might be due to morepronounced heat desorption of these volatiles from scentedtea since several additional rounds of heat treatment wereapplied for scenting tea manufacturing process It is knownthat linalool exhibits strong floral fruity and citrus-likescents [23] indole has fecal animal-like floral odor [24]jasmone has somewhat fruity floral and woody aroma notes[25] and ionone has woody and floral aroma notes [3 24](Supplementary Table 4) Since the majority of these floralscent volatiles were more abundant in the infusion of scentedtea than that of nonscented tea the jasmine scented green teainfusion possessed a strong floral scent Nonanal and decanalcontribute waxy fatty and aldehydic aromas [26] and thustheir reduction in scented green tea might also improve itsaroma quality
33 Scenting Enhanced Volatiles in Scented Green Tea Overthe scenting process the nonscented dry green tea (NT)was mixed with the fresh jasmine flowers (JF) at the ratioof 54 (dry teafresh flowers WW) Floral volatiles whoseabundances were higher than those of green tea in themixed headspace shared by both flowers and tea wouldbe dynamically adsorbed onto the tea leaf matrix until anequilibrium was reached In order to determine contributionof different JF volatiles to the aroma of scented green tea (ST)headspace volatile profiling was conducted not only for theinfusions of NT and ST but also for JF with an emphasison the compounds which were identified with authenticstandards or exhibited a significantly changed abundanceafter the scenting process
Compared to NT ST possessed 34 enhanced and 3reduced compounds (Figures 3 and 5) Among the enhancedcompounds seven were dominant volatiles in ST with theabundances 182-fold to 173-fold higher than their counter-parts in NT (Figure 3(a)) 120573-Linalool indole and benzylacetate in ST were enhanced 453- 424- and 336-foldrespectively Similarly another 10 volatiles but less abundantin ST were 82- to 487-fold higher than their correspond-ing volatiles detected in NT (Figure 3(b)) Moreover anadditional 10 volatiles were detected in ST only but notin NT (Figure 3(c)) The majority of these compounds arecommon tea volatiles [2 27] and all of them were found to beabundant in JF (Figure 3(d)) (except for geraniol and severalother compounds) as reported previously [19] However adirect abundance comparison of the volatiles detected fromtea infusions with those from fresh jasmine flowers wasnot adequate due to inconsistent volatile sampling methodsapplied in this study and the unknown release efficiencies ofindividual volatiles from solid plant matrix to the headspacesof the volatile sources The abundances of the JF volatilespresented in Figure 3(d) might be slightly different from theabundances of the floral volatiles the green tea was actuallyscented with because the dry green tea used for scenting was12-fold more than JF in this study Moreover 27 volatiles allpresent in the headspace of JF in high quantities (Figure 3(d))
Journal of Food Quality 5
100
100500
300
500
700
900
Methyl anthranilate Indole
OAV
NT ST
A
A
A
A
B
B
B
B
B
B
C C
JF NT ST JF NT ST JF NT ST JF120573-Linalool 120573-Ionone
(a)
AA
A A
AA A
AB
AB
A
A
A
B B BB
B
B B
B B
B B
B
C C
C
NT ST JF NT ST JF NT ST JF NT ST JF NT ST JF NT ST JF NT ST JF NT ST JF NT ST JF000204060810
369
12151821
OAV
-Myrcene Linalool oxide B Geraniol Nerolidol (Z)-3-Hexenylacetate
Methylsalicylate
Nonanal Decanal (Z)-Jasmone
(b)
Figure 2 Odor activity values of volatiles (gt1) found in the infusions of scented (ST) and nonscented (NT) green teas and jasmine flowers(JF) based on volatile abundances and their thresholds Duncanrsquos new multiple range test was performed and the columns labeled with thesame letter within the same compound had no significant difference among the three sample types 119875 lt 005 (a) Volatiles with high OAVs(b) Volatiles with low OAVs
with a few exceptions (geraniol neo-allo-ocimene and 120575-terpinene) were found to bemore abundant in ST than inNT(Figure 3) suggesting that the enhancement of these volatilesin ST could substantially result from tea adsorption of thesefloral volatiles over the scenting process For geraniol andgeranyl acetate their abundances in the JF headspace werequite low but both were found to be more abundant in STinfusion than in NT infusion (Figure 3(b)) It is known thattea aroma compounds geraniol and its derivatives can begenerated from heat-induced degradation of carotenoids andpossibly also from hydrolysis of its glycoside precursor [3]Our data suggested that chemical conversion in addition toadsorption might also occur over the scenting process
The percentage of the abundance of a volatile in scentedtea subtracted from the amount of the counterpart in the non-scented tea over the abundance of the corresponding com-pound in jasmine flowers was proposed to estimate itsscenting efficiency although differential contributions offloral volatile adsorption and chemical conversion to its
abundance change in jasmine tea are unknown For thoseenhanced volatiles the efficiencies varied ranging from022 for 120572-farnesene to 755 for 120573-myrcene (Figure 4)This finding suggested that scenting effectiveness was com-pound specific and might result from multiple causativefactors Chemical and physical properties including volatil-ity represented by vapor pressure (mmHg at 25∘C) watersolubility (mgL at 25∘C) and polarity represented bytopological polar surface area were examined for eachvolatile in Figure 4 through the public chemical struc-ture databases (httpwwwchemspidercom and httpspub-chemncbinlmnihgov) with an emphasis on their correla-tion with scenting effectiveness It was noted that majorityof the volatiles with high scenting effectiveness (gt40) hadhigh water solubility ranging from 4215mgL for ethyl ben-zoate to 323220mgL for benzyl alcohol (119885)-3-Hexenol andlinalool both possessing high scenting efficiencies (Figure 4)have 160000mgL and 15900mgL water solubility respec-tively Exceptions were found for120573-myrcene and d-limonene
6 Journal of Food Quality
0
200
400
NT ST
Benzyl acetateA
B0
150
300
NT ST
A
B0
150
300
NT ST
IndoleA
B
0
110
220
NT ST
Methyl anthranilateA
B0
100
200
NT ST
(Z)-3-Hexenyl benzoateA
B 0
40
80
NT ST
Methyl salicylateA
B0
25
50
NT ST
(Z)-3-Hexenyl acetate A
B
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)Ab
unda
nce
(g
kg)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)-Linalool
(a)
0
5
10
NT ST
(Z)-Jasmone
B
A
0
5
10
NT ST
Geraniol
B
A
0
3
6
NT ST
A
B
0
2
4
NT ST
Geranyl acetate
A
B 0
2
4
NT ST
(E)-3-Hexenyl butanoate
A
B0
1
2
NT ST
A
B
Abun
danc
e (
gkg
)Ab
unda
nce
(g
kg)
Abun
danc
e (
gkg
)Ab
unda
nce
(g
kg)
Abun
danc
e (
gkg
)Ab
unda
nce
(g
kg)
-Myrcene
(Z)--Ocimene
0
15
30
NT ST
Benzyl benzoateA
B0
10
20
NT ST
Benzyl alcoholA
B 0
5
10
NT ST
A
B0
3
6
NT ST
D-Limonene
A
BAbun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
-Cadinol
(b)
0
15
3
NT ST
(Z)-3-Hexenol
nd0
2
4
NT ST
nd0
05
1
NT ST
Neo-allo-ocimene
nd 0
05
1
NT ST
Ethyl benzoate
nd
0
1
2
NT ST
Ethyl salicylate
nd0
1
2
NT ST
nd0
05
1
NT ST
Copaene
nd
0
1
2
NT ST
nd0
1
2
NT ST
Cadina-14-diene
nd 0
02
04
NT ST
nd
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)Ab
unda
nce
(g
kg)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
-Cadinene
-Cubenene
-Farnesene -Terpinene
(c)
Figure 3 Continued
Journal of Food Quality 7
0200400600800
1000
0
2
4
6
8
Abun
danc
e (
gkg
)Ab
unda
nce (
g
kg)
JF
-F
arne
sene
-L
inal
ool
Indo
le
(Z)-
3-H
exen
yl ac
etat
e
Benz
yl ac
etat
e
-C
adin
ene
Met
hyl s
alic
ylat
e
(Z)-
3-H
exen
yl b
enzo
ate
Met
hyl a
nthr
anila
te
Benz
yl al
coho
l
(E)-
3-H
exen
yl b
utan
oate
-C
uben
ene
Cop
aene
Cadi
na-1
4-d
iene
(Z)-
-Oci
men
e
-C
adin
ol
D-L
imon
ene
-M
yrce
ne
(Z)-
Jasm
one
Ethy
l sal
icyl
ate
(Z)-
3-H
exen
ol
Ger
anyl
acet
ate
Benz
yl b
enzo
ate
Ethy
l ben
zoat
e
Ger
anio
l
Neo
-allo
-oci
men
e
-T
erpi
nene
(d)
Figure 3 Enhanced floral volatiles in scented tea probably due to tea adsorption (a) Volatiles with high abundances present in the scentedtea (b) volatiles with less abundances present in the scented tea (c) volatiles present in scented tea only (d) Volatiles present in the headspaceof fresh jasmine flowers ST scented green tea infusion NT nonscented tea infusion JF jasmine flower ND not detected Duncanrsquos newmultiple range test was performed and the columns labeled with the same letter within the same compound had no significant differenceamong the tested samples 119875 lt 005 NS no significant difference detected
0 20 40 60 80
Benzyl alcoholEthyl benzoate
Neo-allo-ocimene
Ethyl salicylate
(E)-3-Hexenyl butanoate
Cadina-14-diene
Copaene
Scenting efficiency ()
-Myrcenelowast
(Z)-3-HexenoＦlowast
D-Limonenlowast
Indollowast
-LinalooＦlowast
Methyl salicylatlowast-Terpinene
(Z)-3-Hexenyl acetatlowast
(Z)--Ocimenlowast
-Cubenene
-Cadinene-Farnesene
Figure 4 Differential scenting efficiencies of jasmine floral volatiles to the scented green tea Scenting efficiency was calculated as thepercentage of the volatile abundance detected in the scented tea subtracted from that of the same compound in nonscented tea over theabundance of the counterpart present in jasmine flower Compounds labeledwith ldquolowastrdquo were identified and quantifiedwith authentic standards
8 Journal of Food Quality
0
2
4
NT ST
Methyl heptenone
A
B
Abun
danc
e
0
3
6
NT ST
Linalool oxide A
A
B0
1
2
NT ST
A
B0
05
1
NT ST
A
B
0
4
8
NT ST
A
B0
05
1
NT ST
CedrolA
B
0
5
10
NT ST
T-Cadinol
A
B
(g
kg)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
-Terpineol -Cyclocitral
(E)--Ionone
(a)
0
13
26
NT ST
Nonanal
A
B
0
04
08
NT ST
Naphthalene
AB
0
5
10
NT ST
DecanalA
B
NSNS
0
04
08
NT ST
1-Methylnaphthalene
0
1
2
NT ST
BiphenyleneA
B
NSNS
0
07
14
NT ST
Isopropyl myristate
NSNS
0
04
08
NT ST
Caffeine
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)(b)
Figure 5 Volatiles with differential abundances between scented and nonscented teas but undetectable in the jasmine flower headspace (a)Enhanced volatiles in the scented tea (b) reduced volatiles in the scented tea ST scented green tea infusion NT nonscented tea infusionND not detected Duncanrsquos new multiple range test was performed and the columns labeled with the same letter within the same compoundhad no significant difference among the three samples 119875 lt 005 NS no significant difference detected
whose water solubility values are relatively low (69mgLand 46mgL resp) but their volatility values (23mmHgand 13mmHg resp) are higher than those of many otheraliphatic volatiles presented in Figure 4 Moreover 120572-farnesene and 120575-cadinene possessing the lowest scenting effi-ciencies have the lowest values of water solubility (001mgLand 005mgL resp) It was assumed that volatiles possessinghigh water solubility could be partially dissolved into theaqueous phase in tea leaf matrix over the scenting process inwhich tea leaves could adsorb moisture substantially releasedfrom the fresh jasmine flowersUpon tea infusion preparationwith hot water those volatiles retained in the scented teawould be largely released due to their volatility Furtherinvestigation is required to clarify the correlation betweenscenting effectiveness and water solubility and volatility of avolatile
Moreover surface compounds on the tea leaf matrixmight discriminate volatiles with different polarity whichhas been found for wool types used with natural and solidadsorbents [28] In addition many volatiles are known tobe readily modified by the action of plant enzymes such as
conversion of linalool and geraniol to many other derivativesin plants [29 30] hydrothermal conversions of these volatilesalso occur For instance sesquiterpene 120572-farnesene is stressinduced [31] and can be easily degraded due to photochem-ical allylic oxidation hydroxylation and epoxidation [32]Consistently 120572-farnesene was found to be abundant in theheadspace of excised jasmine flowers but much lower in thejasmine tea and undetectable in green tea in this study
34 Heat-Affected Volatiles in Scented Green Tea Over thescenting and heating procedure 14 volatiles were detectedfrom the infusions of the two teas only but with differentialabundances (119875 lt 005) These volatiles were undetectable inthe jasmine flower headspace suggesting that the observeddifferences between the two teas might unlikely result fromthe direct tea adsorption of these volatiles (Figure 5) Amongthese volatiles 7 were found with higher levels in the scentedtea compared to the nonscented tea including linalool oxideA 120573-ionone and another four terpenoids (Figure 5(a)) Theobserved enhancement of these terpenoids in the scented teamight be the consequence of the heat-induced degradation or
Journal of Food Quality 9
chemical conversionMcgraw et al [33] observed that terpenecompounds degraded at high temperatures and turned intoother terpene hydrocarbons and oxide terpenes Tatum etal [34] reported that 120572-terpineol component is formed byoxidative degradation of limonene In this study it was alsoobserved that abundance of 120572-terpineol was significantlyincreased after the scenting process although it was notdetected in the jasmine flowers (Figure 5) suggesting that itwas likely derived from the hydrothermal conversion over thescenting process
In addition reduced levels of a few compounds werefound in scented tea compared to nonscented tea (Fig-ure 5(b)) including lipid-derived aldehydes nonanal anddecanal [3]These lipid-derived compounds are heat-inducedandmost likely also heat-releasedMultiple additional roundsof heat treatments after scenting could result in the reduc-tion of these volatiles in the scented tea infusion Nonanalabundance in green tea is enhanced by steam processing butsuppressed by pan-fire processing [11]
4 Conclusions
Our study revealed that jasmine flower scented green teapossessed an enhanced floral scent due to the adsorption offloral scent-related volatiles from the fresh jasmine flowersThis revealed that dry tea had the capacity to adsorb substan-tial amounts of volatiles from jasmine flowers Differentialcontribution of jasmine floral volatiles to the aromaof scentedgreen tea was observed Moreover chemical conversion alsocontributed to the differential abundances of some volatilesbetween scented and nonscented teas Our study suggeststhat adsorption and retention of the volatiles generatedendogenously from tea leaveswere crucial formaintaining teaaroma and improving tea aroma quality practically
Additional Points
Practical Applications This work reveals the differentialcontributions of jasmine floral volatiles to the scented greentea and suggested that dry tea has a great capacity toadsorb substantial amounts of volatiles from jasmine flowersBased on what was found in this study heat treatment maybe applied to premade teas with fine-tuned temperaturesto desorb those off-flavor compounds Moreover pleasantaroma either from natural sources or from artificial mixturescan also be applied to enhance tea aroma with a specificdesired odor
Conflicts of Interest
The authors declare that they have no conflicts of interestregarding the publication of this paper
Authorsrsquo Contributions
Shu Wei designed the experiments and interpreted theresults Jian-Xia Shen and Guo-Feng Liu helped to doOPLS-OD data analysis Mohammad M Rana drafted themanuscript Tie-Jun Ling and Margaret Y Gruber revised
the manuscript Jian-Xia Shen and Mohammad M Rana areequal contributors
Acknowledgments
This work was financially supported by the National NaturalScience Foundation of China (Grants nos 31070614 and31370687) to Shu Wei Margaret Y Gruber has been workingat Agriculture and Agri-Food Canada Saskatoon ResearchCentre Saskatoon SK Canada but is now retired
References
[1] M S Butt R S AhmadM T SultanMM N Qayyum andANaz ldquoGreen tea and anticancer perspectives updates from lastdecaderdquo Critical Reviews in Food Science and Nutrition vol 55no 6 pp 792ndash805 2015
[2] Z Yang S Baldermann and N Watanabe ldquoRecent studies ofthe volatile compounds in teardquo Food Research International vol53 no 2 pp 585ndash599 2013
[3] C Ho X Zheng and S Li ldquoTea aroma formationrdquo Food Scienceand Human Wellness vol 4 no 1 pp 9ndash27 2015
[4] P Winterhalter and R Rouseff ldquoCarotenoid-derived aromacompounds an introductionrdquo in Carotenoid-Derived AromaCompounds P Winterhalter and R Rousef Eds ACS Sympo-sium Series pp 1ndash19 American Chemical Society WashingtonDC USA 2001
[5] T Takeo and T Tsushida ldquoChanges in lipoxygenase activity inrelation to lipid degradation in plucked tea shootsrdquo Phytochem-istry vol 19 no 12 pp 2521-2522 1980
[6] T Wu Traditional jasmine green tea scenting process 2013httpwwwtaotealeafcomblogtraditional-jasmine-green-tea-scenting-process
[7] MChen Y Zhu B Liu et al ldquoChanges in the volatiles chemicalcomponents and antioxidant activities of Chinese jasmine teaduring the scenting processesrdquo International Journal of FoodProperties vol 20 no 3 pp 681ndash693 2017
[8] Y Ito A Sugimoto T Kakuda and K Kubota ldquoIdentificationof potent odorants in Chinese jasmine green tea scented withflowers of Jasminum sambacrdquo Journal of Agricultural and FoodChemistry vol 50 no 17 pp 4878ndash4884 2002
[9] Y Ito and K Kubota ldquoSensory evaluation of the synergismamong odorants present in concentrations below their odorthreshold in a Chinese jasmine green tea infusionrdquo MolecularNutrition and Food Research vol 49 no 1 pp 61ndash68 2005
[10] Y Liang Y Wu J Lu and L Zhang ldquoApplication of chemicalcomposition and infusion colour difference analysis to qualityestimation of jasmine-scented teardquo International Journal of FoodScience and Technology vol 42 no 4 pp 459ndash468 2007
[11] Z-X Han M M Rana G-F Liu et al ldquoGreen tea flavourdeterminants and their changes over manufacturing processesrdquoFood Chemistry vol 212 pp 739ndash748 2016
[12] S Wei I Marton M Dekel et al ldquoManipulating volatileemission in tobacco leaves by expressing Aspergillus niger120573-glucosidase in different subcellular compartmentsrdquo PlantBiotechnology Journal vol 2 no 4 pp 341ndash350 2004
[13] Z Han M M Rana G Liu et al ldquoData on green teaflavor determinantes as affected by cultivars andmanufacturingprocessesrdquo Data in Brief vol 10 pp 492ndash498 2017
10 Journal of Food Quality
[14] J Trygg E Holmes and T Lundstedt ldquoChemometrics inmetabonomicsrdquo Journal of Proteome Research vol 6 no 2 pp469ndash479 2007
[15] K M O Ku J N Choi J Kim et al ldquoMetabolomics anal-ysis reveals the compositional differences of shade growntea (Camellia sinensis L)rdquo Journal of Agricultural and FoodChemistry vol 58 no 1 pp 418ndash426 2010
[16] Y-H Li W Zhang and Y Li ldquoTranscriptomic analysis offlower blooming in Jasminum sambac through de novo RNAsequencingrdquoMolecules vol 20 no 6 pp 10734ndash10747 2015
[17] R Baba and K Kumazawa ldquoCharacterization of the potentodorants contributing to the characteristic aroma of chinesegreen tea infusions by aroma extract dilution analysisrdquo Journalof Agricultural and Food Chemistry vol 62 no 33 pp 8308ndash8313 2014
[18] T Koeduka E Fridman D R Gang et al ldquoEugenol andisoeugenol characteristic aromatic constituents of spices arebiosynthesized via reduction of a coniferyl alcohol esterrdquoProceedings of the National Academy of Sciences of the UnitedStates of America vol 103 no 26 pp 10128ndash10133 2006
[19] A E Edris R Chizzola and C Franz ldquoIsolation and charac-terization of the volatile aroma compounds from the concreteheadspace and the absolute of Jasminum sambac (L) Ait(Oleaceae) flowers grown in Egyptrdquo European Food Researchand Technology vol 226 no 3 pp 621ndash626 2008
[20] Y Yu S Lyu D Chen et al ldquoVolatiles emitted at differentflowering stages of Jasminum sambac and expression of genesrelated to 120572-farnesene biosynthesisrdquo Molecules vol 22 no 4article 546 2017
[21] P K Rout Y Ramachandra Rao and S Naik ldquoAnalysis offloral volatiles by using headspace-solid phase microextractiona reviewrdquoAsian Journal of Chemistry vol 24 no 3 pp 945ndash9562012
[22] C Schuh and P Schieberle ldquoCharacterization of the key aromacompounds in the beverage prepared from Darjeeling blacktea quantitative differences between tea leaves and infusionrdquoJournal of Agricultural and Food Chemistry vol 54 no 3 pp916ndash924 2006
[23] B Bonnlander R Cappuccio F S Liverani and PWinterhalterldquoAnalysis of enantiomeric linalool ratio in green and roastedcoffeerdquo Flavour and Fragrance Journal vol 21 no 4 pp 637ndash641 2006
[24] T Katsuno H Kasuga Y Kusano et al ldquoCharacterisation ofodorant compounds and their biochemical formation in greentea with a low temperature storage processrdquo Food Chemistryvol 148 pp 388ndash395 2014
[25] J Scognamiglio L Jones C S Letizia and A M Api ldquoFra-grance material review on cis-jasmonerdquo Food and ChemicalToxicology vol 50 supplement 3 pp S613ndashS618 2012
[26] Anonymous The good scents company information system2016 httpwwwthegoodscentscompanycomsearch2html
[27] Y Sawai Y Yamaguchi and J Tanaka ldquoMethyl anthranilate isthe cause of cultivar-specific aroma in the Japanese tea cultivarlsquoSofursquordquo Japan Agricultural Research Quarterly vol 38 no 4 pp271ndash274 2004
[28] E Mansour S Curling A Stephan and G OrmondroydldquoAbsorption of volatile organic compounds by different wooltypesrdquo Green Materials vol 4 no 1 pp 1ndash7 2016
[29] R Davidovich-Rikanati Y Sitrit Y Tadmor et al ldquoEnrichmentof tomato flavor by diversion of the early plastidial terpenoidpathwayrdquoNature Biotechnology vol 25 no 8 pp 899ndash901 2007
[30] B Boachon R R Junker L Miesch et al ldquoCYP76C1(Cytochrome P450)-mediated linalool metabolism and theformation of volatile and soluble linalool oxides in arabidopsisflowers a strategy for defense against floral antagonistsrdquo PlantCell vol 27 no 10 pp 2972ndash2990 2015
[31] F Dong Z Yang S Baldermann Y Sato T Asai andNWatan-abe ldquoHerbivore-induced volatiles from tea (Camellia sinensis)plants and their involvement in intraplant communication andchanges in endogenous nonvolatile metabolitesrdquo Journal ofAgricultural and Food Chemistry vol 59 no 24 pp 13131ndash131352011
[32] J A SpicerThe oxidation of 120572-Farnesene [PhD thesis] MasseyUniversity Palmerston North New Zealand 1994
[33] GWMcgraw RW Hemingway L L Ingram Jr C S Canadyand W B Mcgraw ldquoThermal degradation of terpenes cam-phene Δ3-carene limonene and 120572-terpinenerdquo EnvironmentalScience and Technology vol 33 no 22 pp 4029ndash4033 1999
[34] J H Tatum S Nagy and R E Berry ldquoDegradation productsformed in canned single-strength orange juice during storagerdquoJournal of Food Science vol 40 no 4 pp 707ndash709 1975
JF NT ST JF NT ST JF NT ST JF120573-Linalool 120573-Ionone
(a)
AA
A A
AA A
AB
AB
A
A
A
B B BB
B
B B
B B
B B
B
C C
C
NT ST JF NT ST JF NT ST JF NT ST JF NT ST JF NT ST JF NT ST JF NT ST JF NT ST JF000204060810
369
12151821
OAV
-Myrcene Linalool oxide B Geraniol Nerolidol (Z)-3-Hexenylacetate
Methylsalicylate
Nonanal Decanal (Z)-Jasmone
(b)
Figure 2 Odor activity values of volatiles (gt1) found in the infusions of scented (ST) and nonscented (NT) green teas and jasmine flowers(JF) based on volatile abundances and their thresholds Duncanrsquos new multiple range test was performed and the columns labeled with thesame letter within the same compound had no significant difference among the three sample types 119875 lt 005 (a) Volatiles with high OAVs(b) Volatiles with low OAVs
with a few exceptions (geraniol neo-allo-ocimene and 120575-terpinene) were found to bemore abundant in ST than inNT(Figure 3) suggesting that the enhancement of these volatilesin ST could substantially result from tea adsorption of thesefloral volatiles over the scenting process For geraniol andgeranyl acetate their abundances in the JF headspace werequite low but both were found to be more abundant in STinfusion than in NT infusion (Figure 3(b)) It is known thattea aroma compounds geraniol and its derivatives can begenerated from heat-induced degradation of carotenoids andpossibly also from hydrolysis of its glycoside precursor [3]Our data suggested that chemical conversion in addition toadsorption might also occur over the scenting process
The percentage of the abundance of a volatile in scentedtea subtracted from the amount of the counterpart in the non-scented tea over the abundance of the corresponding com-pound in jasmine flowers was proposed to estimate itsscenting efficiency although differential contributions offloral volatile adsorption and chemical conversion to its
abundance change in jasmine tea are unknown For thoseenhanced volatiles the efficiencies varied ranging from022 for 120572-farnesene to 755 for 120573-myrcene (Figure 4)This finding suggested that scenting effectiveness was com-pound specific and might result from multiple causativefactors Chemical and physical properties including volatil-ity represented by vapor pressure (mmHg at 25∘C) watersolubility (mgL at 25∘C) and polarity represented bytopological polar surface area were examined for eachvolatile in Figure 4 through the public chemical struc-ture databases (httpwwwchemspidercom and httpspub-chemncbinlmnihgov) with an emphasis on their correla-tion with scenting effectiveness It was noted that majorityof the volatiles with high scenting effectiveness (gt40) hadhigh water solubility ranging from 4215mgL for ethyl ben-zoate to 323220mgL for benzyl alcohol (119885)-3-Hexenol andlinalool both possessing high scenting efficiencies (Figure 4)have 160000mgL and 15900mgL water solubility respec-tively Exceptions were found for120573-myrcene and d-limonene
6 Journal of Food Quality
0
200
400
NT ST
Benzyl acetateA
B0
150
300
NT ST
A
B0
150
300
NT ST
IndoleA
B
0
110
220
NT ST
Methyl anthranilateA
B0
100
200
NT ST
(Z)-3-Hexenyl benzoateA
B 0
40
80
NT ST
Methyl salicylateA
B0
25
50
NT ST
(Z)-3-Hexenyl acetate A
B
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)Ab
unda
nce
(g
kg)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)-Linalool
(a)
0
5
10
NT ST
(Z)-Jasmone
B
A
0
5
10
NT ST
Geraniol
B
A
0
3
6
NT ST
A
B
0
2
4
NT ST
Geranyl acetate
A
B 0
2
4
NT ST
(E)-3-Hexenyl butanoate
A
B0
1
2
NT ST
A
B
Abun
danc
e (
gkg
)Ab
unda
nce
(g
kg)
Abun
danc
e (
gkg
)Ab
unda
nce
(g
kg)
Abun
danc
e (
gkg
)Ab
unda
nce
(g
kg)
-Myrcene
(Z)--Ocimene
0
15
30
NT ST
Benzyl benzoateA
B0
10
20
NT ST
Benzyl alcoholA
B 0
5
10
NT ST
A
B0
3
6
NT ST
D-Limonene
A
BAbun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
-Cadinol
(b)
0
15
3
NT ST
(Z)-3-Hexenol
nd0
2
4
NT ST
nd0
05
1
NT ST
Neo-allo-ocimene
nd 0
05
1
NT ST
Ethyl benzoate
nd
0
1
2
NT ST
Ethyl salicylate
nd0
1
2
NT ST
nd0
05
1
NT ST
Copaene
nd
0
1
2
NT ST
nd0
1
2
NT ST
Cadina-14-diene
nd 0
02
04
NT ST
nd
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)Ab
unda
nce
(g
kg)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
-Cadinene
-Cubenene
-Farnesene -Terpinene
(c)
Figure 3 Continued
Journal of Food Quality 7
0200400600800
1000
0
2
4
6
8
Abun
danc
e (
gkg
)Ab
unda
nce (
g
kg)
JF
-F
arne
sene
-L
inal
ool
Indo
le
(Z)-
3-H
exen
yl ac
etat
e
Benz
yl ac
etat
e
-C
adin
ene
Met
hyl s
alic
ylat
e
(Z)-
3-H
exen
yl b
enzo
ate
Met
hyl a
nthr
anila
te
Benz
yl al
coho
l
(E)-
3-H
exen
yl b
utan
oate
-C
uben
ene
Cop
aene
Cadi
na-1
4-d
iene
(Z)-
-Oci
men
e
-C
adin
ol
D-L
imon
ene
-M
yrce
ne
(Z)-
Jasm
one
Ethy
l sal
icyl
ate
(Z)-
3-H
exen
ol
Ger
anyl
acet
ate
Benz
yl b
enzo
ate
Ethy
l ben
zoat
e
Ger
anio
l
Neo
-allo
-oci
men
e
-T
erpi
nene
(d)
Figure 3 Enhanced floral volatiles in scented tea probably due to tea adsorption (a) Volatiles with high abundances present in the scentedtea (b) volatiles with less abundances present in the scented tea (c) volatiles present in scented tea only (d) Volatiles present in the headspaceof fresh jasmine flowers ST scented green tea infusion NT nonscented tea infusion JF jasmine flower ND not detected Duncanrsquos newmultiple range test was performed and the columns labeled with the same letter within the same compound had no significant differenceamong the tested samples 119875 lt 005 NS no significant difference detected
0 20 40 60 80
Benzyl alcoholEthyl benzoate
Neo-allo-ocimene
Ethyl salicylate
(E)-3-Hexenyl butanoate
Cadina-14-diene
Copaene
Scenting efficiency ()
-Myrcenelowast
(Z)-3-HexenoＦlowast
D-Limonenlowast
Indollowast
-LinalooＦlowast
Methyl salicylatlowast-Terpinene
(Z)-3-Hexenyl acetatlowast
(Z)--Ocimenlowast
-Cubenene
-Cadinene-Farnesene
Figure 4 Differential scenting efficiencies of jasmine floral volatiles to the scented green tea Scenting efficiency was calculated as thepercentage of the volatile abundance detected in the scented tea subtracted from that of the same compound in nonscented tea over theabundance of the counterpart present in jasmine flower Compounds labeledwith ldquolowastrdquo were identified and quantifiedwith authentic standards
8 Journal of Food Quality
0
2
4
NT ST
Methyl heptenone
A
B
Abun
danc
e
0
3
6
NT ST
Linalool oxide A
A
B0
1
2
NT ST
A
B0
05
1
NT ST
A
B
0
4
8
NT ST
A
B0
05
1
NT ST
CedrolA
B
0
5
10
NT ST
T-Cadinol
A
B
(g
kg)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
-Terpineol -Cyclocitral
(E)--Ionone
(a)
0
13
26
NT ST
Nonanal
A
B
0
04
08
NT ST
Naphthalene
AB
0
5
10
NT ST
DecanalA
B
NSNS
0
04
08
NT ST
1-Methylnaphthalene
0
1
2
NT ST
BiphenyleneA
B
NSNS
0
07
14
NT ST
Isopropyl myristate
NSNS
0
04
08
NT ST
Caffeine
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)(b)
Figure 5 Volatiles with differential abundances between scented and nonscented teas but undetectable in the jasmine flower headspace (a)Enhanced volatiles in the scented tea (b) reduced volatiles in the scented tea ST scented green tea infusion NT nonscented tea infusionND not detected Duncanrsquos new multiple range test was performed and the columns labeled with the same letter within the same compoundhad no significant difference among the three samples 119875 lt 005 NS no significant difference detected
whose water solubility values are relatively low (69mgLand 46mgL resp) but their volatility values (23mmHgand 13mmHg resp) are higher than those of many otheraliphatic volatiles presented in Figure 4 Moreover 120572-farnesene and 120575-cadinene possessing the lowest scenting effi-ciencies have the lowest values of water solubility (001mgLand 005mgL resp) It was assumed that volatiles possessinghigh water solubility could be partially dissolved into theaqueous phase in tea leaf matrix over the scenting process inwhich tea leaves could adsorb moisture substantially releasedfrom the fresh jasmine flowersUpon tea infusion preparationwith hot water those volatiles retained in the scented teawould be largely released due to their volatility Furtherinvestigation is required to clarify the correlation betweenscenting effectiveness and water solubility and volatility of avolatile
Moreover surface compounds on the tea leaf matrixmight discriminate volatiles with different polarity whichhas been found for wool types used with natural and solidadsorbents [28] In addition many volatiles are known tobe readily modified by the action of plant enzymes such as
conversion of linalool and geraniol to many other derivativesin plants [29 30] hydrothermal conversions of these volatilesalso occur For instance sesquiterpene 120572-farnesene is stressinduced [31] and can be easily degraded due to photochem-ical allylic oxidation hydroxylation and epoxidation [32]Consistently 120572-farnesene was found to be abundant in theheadspace of excised jasmine flowers but much lower in thejasmine tea and undetectable in green tea in this study
34 Heat-Affected Volatiles in Scented Green Tea Over thescenting and heating procedure 14 volatiles were detectedfrom the infusions of the two teas only but with differentialabundances (119875 lt 005) These volatiles were undetectable inthe jasmine flower headspace suggesting that the observeddifferences between the two teas might unlikely result fromthe direct tea adsorption of these volatiles (Figure 5) Amongthese volatiles 7 were found with higher levels in the scentedtea compared to the nonscented tea including linalool oxideA 120573-ionone and another four terpenoids (Figure 5(a)) Theobserved enhancement of these terpenoids in the scented teamight be the consequence of the heat-induced degradation or
Journal of Food Quality 9
chemical conversionMcgraw et al [33] observed that terpenecompounds degraded at high temperatures and turned intoother terpene hydrocarbons and oxide terpenes Tatum etal [34] reported that 120572-terpineol component is formed byoxidative degradation of limonene In this study it was alsoobserved that abundance of 120572-terpineol was significantlyincreased after the scenting process although it was notdetected in the jasmine flowers (Figure 5) suggesting that itwas likely derived from the hydrothermal conversion over thescenting process
In addition reduced levels of a few compounds werefound in scented tea compared to nonscented tea (Fig-ure 5(b)) including lipid-derived aldehydes nonanal anddecanal [3]These lipid-derived compounds are heat-inducedandmost likely also heat-releasedMultiple additional roundsof heat treatments after scenting could result in the reduc-tion of these volatiles in the scented tea infusion Nonanalabundance in green tea is enhanced by steam processing butsuppressed by pan-fire processing [11]
4 Conclusions
Our study revealed that jasmine flower scented green teapossessed an enhanced floral scent due to the adsorption offloral scent-related volatiles from the fresh jasmine flowersThis revealed that dry tea had the capacity to adsorb substan-tial amounts of volatiles from jasmine flowers Differentialcontribution of jasmine floral volatiles to the aromaof scentedgreen tea was observed Moreover chemical conversion alsocontributed to the differential abundances of some volatilesbetween scented and nonscented teas Our study suggeststhat adsorption and retention of the volatiles generatedendogenously from tea leaveswere crucial formaintaining teaaroma and improving tea aroma quality practically
Additional Points
Practical Applications This work reveals the differentialcontributions of jasmine floral volatiles to the scented greentea and suggested that dry tea has a great capacity toadsorb substantial amounts of volatiles from jasmine flowersBased on what was found in this study heat treatment maybe applied to premade teas with fine-tuned temperaturesto desorb those off-flavor compounds Moreover pleasantaroma either from natural sources or from artificial mixturescan also be applied to enhance tea aroma with a specificdesired odor
Conflicts of Interest
The authors declare that they have no conflicts of interestregarding the publication of this paper
Authorsrsquo Contributions
Shu Wei designed the experiments and interpreted theresults Jian-Xia Shen and Guo-Feng Liu helped to doOPLS-OD data analysis Mohammad M Rana drafted themanuscript Tie-Jun Ling and Margaret Y Gruber revised
the manuscript Jian-Xia Shen and Mohammad M Rana areequal contributors
Acknowledgments
This work was financially supported by the National NaturalScience Foundation of China (Grants nos 31070614 and31370687) to Shu Wei Margaret Y Gruber has been workingat Agriculture and Agri-Food Canada Saskatoon ResearchCentre Saskatoon SK Canada but is now retired
References
[1] M S Butt R S AhmadM T SultanMM N Qayyum andANaz ldquoGreen tea and anticancer perspectives updates from lastdecaderdquo Critical Reviews in Food Science and Nutrition vol 55no 6 pp 792ndash805 2015
[2] Z Yang S Baldermann and N Watanabe ldquoRecent studies ofthe volatile compounds in teardquo Food Research International vol53 no 2 pp 585ndash599 2013
[3] C Ho X Zheng and S Li ldquoTea aroma formationrdquo Food Scienceand Human Wellness vol 4 no 1 pp 9ndash27 2015
[4] P Winterhalter and R Rouseff ldquoCarotenoid-derived aromacompounds an introductionrdquo in Carotenoid-Derived AromaCompounds P Winterhalter and R Rousef Eds ACS Sympo-sium Series pp 1ndash19 American Chemical Society WashingtonDC USA 2001
[5] T Takeo and T Tsushida ldquoChanges in lipoxygenase activity inrelation to lipid degradation in plucked tea shootsrdquo Phytochem-istry vol 19 no 12 pp 2521-2522 1980
[6] T Wu Traditional jasmine green tea scenting process 2013httpwwwtaotealeafcomblogtraditional-jasmine-green-tea-scenting-process
[7] MChen Y Zhu B Liu et al ldquoChanges in the volatiles chemicalcomponents and antioxidant activities of Chinese jasmine teaduring the scenting processesrdquo International Journal of FoodProperties vol 20 no 3 pp 681ndash693 2017
[8] Y Ito A Sugimoto T Kakuda and K Kubota ldquoIdentificationof potent odorants in Chinese jasmine green tea scented withflowers of Jasminum sambacrdquo Journal of Agricultural and FoodChemistry vol 50 no 17 pp 4878ndash4884 2002
[9] Y Ito and K Kubota ldquoSensory evaluation of the synergismamong odorants present in concentrations below their odorthreshold in a Chinese jasmine green tea infusionrdquo MolecularNutrition and Food Research vol 49 no 1 pp 61ndash68 2005
[10] Y Liang Y Wu J Lu and L Zhang ldquoApplication of chemicalcomposition and infusion colour difference analysis to qualityestimation of jasmine-scented teardquo International Journal of FoodScience and Technology vol 42 no 4 pp 459ndash468 2007
[11] Z-X Han M M Rana G-F Liu et al ldquoGreen tea flavourdeterminants and their changes over manufacturing processesrdquoFood Chemistry vol 212 pp 739ndash748 2016
[12] S Wei I Marton M Dekel et al ldquoManipulating volatileemission in tobacco leaves by expressing Aspergillus niger120573-glucosidase in different subcellular compartmentsrdquo PlantBiotechnology Journal vol 2 no 4 pp 341ndash350 2004
[13] Z Han M M Rana G Liu et al ldquoData on green teaflavor determinantes as affected by cultivars andmanufacturingprocessesrdquo Data in Brief vol 10 pp 492ndash498 2017
10 Journal of Food Quality
[14] J Trygg E Holmes and T Lundstedt ldquoChemometrics inmetabonomicsrdquo Journal of Proteome Research vol 6 no 2 pp469ndash479 2007
[15] K M O Ku J N Choi J Kim et al ldquoMetabolomics anal-ysis reveals the compositional differences of shade growntea (Camellia sinensis L)rdquo Journal of Agricultural and FoodChemistry vol 58 no 1 pp 418ndash426 2010
[16] Y-H Li W Zhang and Y Li ldquoTranscriptomic analysis offlower blooming in Jasminum sambac through de novo RNAsequencingrdquoMolecules vol 20 no 6 pp 10734ndash10747 2015
[17] R Baba and K Kumazawa ldquoCharacterization of the potentodorants contributing to the characteristic aroma of chinesegreen tea infusions by aroma extract dilution analysisrdquo Journalof Agricultural and Food Chemistry vol 62 no 33 pp 8308ndash8313 2014
[18] T Koeduka E Fridman D R Gang et al ldquoEugenol andisoeugenol characteristic aromatic constituents of spices arebiosynthesized via reduction of a coniferyl alcohol esterrdquoProceedings of the National Academy of Sciences of the UnitedStates of America vol 103 no 26 pp 10128ndash10133 2006
[19] A E Edris R Chizzola and C Franz ldquoIsolation and charac-terization of the volatile aroma compounds from the concreteheadspace and the absolute of Jasminum sambac (L) Ait(Oleaceae) flowers grown in Egyptrdquo European Food Researchand Technology vol 226 no 3 pp 621ndash626 2008
[20] Y Yu S Lyu D Chen et al ldquoVolatiles emitted at differentflowering stages of Jasminum sambac and expression of genesrelated to 120572-farnesene biosynthesisrdquo Molecules vol 22 no 4article 546 2017
[21] P K Rout Y Ramachandra Rao and S Naik ldquoAnalysis offloral volatiles by using headspace-solid phase microextractiona reviewrdquoAsian Journal of Chemistry vol 24 no 3 pp 945ndash9562012
[22] C Schuh and P Schieberle ldquoCharacterization of the key aromacompounds in the beverage prepared from Darjeeling blacktea quantitative differences between tea leaves and infusionrdquoJournal of Agricultural and Food Chemistry vol 54 no 3 pp916ndash924 2006
[23] B Bonnlander R Cappuccio F S Liverani and PWinterhalterldquoAnalysis of enantiomeric linalool ratio in green and roastedcoffeerdquo Flavour and Fragrance Journal vol 21 no 4 pp 637ndash641 2006
[24] T Katsuno H Kasuga Y Kusano et al ldquoCharacterisation ofodorant compounds and their biochemical formation in greentea with a low temperature storage processrdquo Food Chemistryvol 148 pp 388ndash395 2014
[25] J Scognamiglio L Jones C S Letizia and A M Api ldquoFra-grance material review on cis-jasmonerdquo Food and ChemicalToxicology vol 50 supplement 3 pp S613ndashS618 2012
[26] Anonymous The good scents company information system2016 httpwwwthegoodscentscompanycomsearch2html
[27] Y Sawai Y Yamaguchi and J Tanaka ldquoMethyl anthranilate isthe cause of cultivar-specific aroma in the Japanese tea cultivarlsquoSofursquordquo Japan Agricultural Research Quarterly vol 38 no 4 pp271ndash274 2004
[28] E Mansour S Curling A Stephan and G OrmondroydldquoAbsorption of volatile organic compounds by different wooltypesrdquo Green Materials vol 4 no 1 pp 1ndash7 2016
[29] R Davidovich-Rikanati Y Sitrit Y Tadmor et al ldquoEnrichmentof tomato flavor by diversion of the early plastidial terpenoidpathwayrdquoNature Biotechnology vol 25 no 8 pp 899ndash901 2007
[30] B Boachon R R Junker L Miesch et al ldquoCYP76C1(Cytochrome P450)-mediated linalool metabolism and theformation of volatile and soluble linalool oxides in arabidopsisflowers a strategy for defense against floral antagonistsrdquo PlantCell vol 27 no 10 pp 2972ndash2990 2015
[31] F Dong Z Yang S Baldermann Y Sato T Asai andNWatan-abe ldquoHerbivore-induced volatiles from tea (Camellia sinensis)plants and their involvement in intraplant communication andchanges in endogenous nonvolatile metabolitesrdquo Journal ofAgricultural and Food Chemistry vol 59 no 24 pp 13131ndash131352011
[32] J A SpicerThe oxidation of 120572-Farnesene [PhD thesis] MasseyUniversity Palmerston North New Zealand 1994
[33] GWMcgraw RW Hemingway L L Ingram Jr C S Canadyand W B Mcgraw ldquoThermal degradation of terpenes cam-phene Δ3-carene limonene and 120572-terpinenerdquo EnvironmentalScience and Technology vol 33 no 22 pp 4029ndash4033 1999
[34] J H Tatum S Nagy and R E Berry ldquoDegradation productsformed in canned single-strength orange juice during storagerdquoJournal of Food Science vol 40 no 4 pp 707ndash709 1975
Figure 3 Enhanced floral volatiles in scented tea probably due to tea adsorption (a) Volatiles with high abundances present in the scentedtea (b) volatiles with less abundances present in the scented tea (c) volatiles present in scented tea only (d) Volatiles present in the headspaceof fresh jasmine flowers ST scented green tea infusion NT nonscented tea infusion JF jasmine flower ND not detected Duncanrsquos newmultiple range test was performed and the columns labeled with the same letter within the same compound had no significant differenceamong the tested samples 119875 lt 005 NS no significant difference detected
0 20 40 60 80
Benzyl alcoholEthyl benzoate
Neo-allo-ocimene
Ethyl salicylate
(E)-3-Hexenyl butanoate
Cadina-14-diene
Copaene
Scenting efficiency ()
-Myrcenelowast
(Z)-3-HexenoＦlowast
D-Limonenlowast
Indollowast
-LinalooＦlowast
Methyl salicylatlowast-Terpinene
(Z)-3-Hexenyl acetatlowast
(Z)--Ocimenlowast
-Cubenene
-Cadinene-Farnesene
Figure 4 Differential scenting efficiencies of jasmine floral volatiles to the scented green tea Scenting efficiency was calculated as thepercentage of the volatile abundance detected in the scented tea subtracted from that of the same compound in nonscented tea over theabundance of the counterpart present in jasmine flower Compounds labeledwith ldquolowastrdquo were identified and quantifiedwith authentic standards
8 Journal of Food Quality
0
2
4
NT ST
Methyl heptenone
A
B
Abun
danc
e
0
3
6
NT ST
Linalool oxide A
A
B0
1
2
NT ST
A
B0
05
1
NT ST
A
B
0
4
8
NT ST
A
B0
05
1
NT ST
CedrolA
B
0
5
10
NT ST
T-Cadinol
A
B
(g
kg)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
-Terpineol -Cyclocitral
(E)--Ionone
(a)
0
13
26
NT ST
Nonanal
A
B
0
04
08
NT ST
Naphthalene
AB
0
5
10
NT ST
DecanalA
B
NSNS
0
04
08
NT ST
1-Methylnaphthalene
0
1
2
NT ST
BiphenyleneA
B
NSNS
0
07
14
NT ST
Isopropyl myristate
NSNS
0
04
08
NT ST
Caffeine
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)(b)
Figure 5 Volatiles with differential abundances between scented and nonscented teas but undetectable in the jasmine flower headspace (a)Enhanced volatiles in the scented tea (b) reduced volatiles in the scented tea ST scented green tea infusion NT nonscented tea infusionND not detected Duncanrsquos new multiple range test was performed and the columns labeled with the same letter within the same compoundhad no significant difference among the three samples 119875 lt 005 NS no significant difference detected
whose water solubility values are relatively low (69mgLand 46mgL resp) but their volatility values (23mmHgand 13mmHg resp) are higher than those of many otheraliphatic volatiles presented in Figure 4 Moreover 120572-farnesene and 120575-cadinene possessing the lowest scenting effi-ciencies have the lowest values of water solubility (001mgLand 005mgL resp) It was assumed that volatiles possessinghigh water solubility could be partially dissolved into theaqueous phase in tea leaf matrix over the scenting process inwhich tea leaves could adsorb moisture substantially releasedfrom the fresh jasmine flowersUpon tea infusion preparationwith hot water those volatiles retained in the scented teawould be largely released due to their volatility Furtherinvestigation is required to clarify the correlation betweenscenting effectiveness and water solubility and volatility of avolatile
Moreover surface compounds on the tea leaf matrixmight discriminate volatiles with different polarity whichhas been found for wool types used with natural and solidadsorbents [28] In addition many volatiles are known tobe readily modified by the action of plant enzymes such as
conversion of linalool and geraniol to many other derivativesin plants [29 30] hydrothermal conversions of these volatilesalso occur For instance sesquiterpene 120572-farnesene is stressinduced [31] and can be easily degraded due to photochem-ical allylic oxidation hydroxylation and epoxidation [32]Consistently 120572-farnesene was found to be abundant in theheadspace of excised jasmine flowers but much lower in thejasmine tea and undetectable in green tea in this study
34 Heat-Affected Volatiles in Scented Green Tea Over thescenting and heating procedure 14 volatiles were detectedfrom the infusions of the two teas only but with differentialabundances (119875 lt 005) These volatiles were undetectable inthe jasmine flower headspace suggesting that the observeddifferences between the two teas might unlikely result fromthe direct tea adsorption of these volatiles (Figure 5) Amongthese volatiles 7 were found with higher levels in the scentedtea compared to the nonscented tea including linalool oxideA 120573-ionone and another four terpenoids (Figure 5(a)) Theobserved enhancement of these terpenoids in the scented teamight be the consequence of the heat-induced degradation or
Journal of Food Quality 9
chemical conversionMcgraw et al [33] observed that terpenecompounds degraded at high temperatures and turned intoother terpene hydrocarbons and oxide terpenes Tatum etal [34] reported that 120572-terpineol component is formed byoxidative degradation of limonene In this study it was alsoobserved that abundance of 120572-terpineol was significantlyincreased after the scenting process although it was notdetected in the jasmine flowers (Figure 5) suggesting that itwas likely derived from the hydrothermal conversion over thescenting process
In addition reduced levels of a few compounds werefound in scented tea compared to nonscented tea (Fig-ure 5(b)) including lipid-derived aldehydes nonanal anddecanal [3]These lipid-derived compounds are heat-inducedandmost likely also heat-releasedMultiple additional roundsof heat treatments after scenting could result in the reduc-tion of these volatiles in the scented tea infusion Nonanalabundance in green tea is enhanced by steam processing butsuppressed by pan-fire processing [11]
4 Conclusions
Our study revealed that jasmine flower scented green teapossessed an enhanced floral scent due to the adsorption offloral scent-related volatiles from the fresh jasmine flowersThis revealed that dry tea had the capacity to adsorb substan-tial amounts of volatiles from jasmine flowers Differentialcontribution of jasmine floral volatiles to the aromaof scentedgreen tea was observed Moreover chemical conversion alsocontributed to the differential abundances of some volatilesbetween scented and nonscented teas Our study suggeststhat adsorption and retention of the volatiles generatedendogenously from tea leaveswere crucial formaintaining teaaroma and improving tea aroma quality practically
Additional Points
Practical Applications This work reveals the differentialcontributions of jasmine floral volatiles to the scented greentea and suggested that dry tea has a great capacity toadsorb substantial amounts of volatiles from jasmine flowersBased on what was found in this study heat treatment maybe applied to premade teas with fine-tuned temperaturesto desorb those off-flavor compounds Moreover pleasantaroma either from natural sources or from artificial mixturescan also be applied to enhance tea aroma with a specificdesired odor
Conflicts of Interest
The authors declare that they have no conflicts of interestregarding the publication of this paper
Authorsrsquo Contributions
Shu Wei designed the experiments and interpreted theresults Jian-Xia Shen and Guo-Feng Liu helped to doOPLS-OD data analysis Mohammad M Rana drafted themanuscript Tie-Jun Ling and Margaret Y Gruber revised
the manuscript Jian-Xia Shen and Mohammad M Rana areequal contributors
Acknowledgments
This work was financially supported by the National NaturalScience Foundation of China (Grants nos 31070614 and31370687) to Shu Wei Margaret Y Gruber has been workingat Agriculture and Agri-Food Canada Saskatoon ResearchCentre Saskatoon SK Canada but is now retired
References
[1] M S Butt R S AhmadM T SultanMM N Qayyum andANaz ldquoGreen tea and anticancer perspectives updates from lastdecaderdquo Critical Reviews in Food Science and Nutrition vol 55no 6 pp 792ndash805 2015
[2] Z Yang S Baldermann and N Watanabe ldquoRecent studies ofthe volatile compounds in teardquo Food Research International vol53 no 2 pp 585ndash599 2013
[3] C Ho X Zheng and S Li ldquoTea aroma formationrdquo Food Scienceand Human Wellness vol 4 no 1 pp 9ndash27 2015
[4] P Winterhalter and R Rouseff ldquoCarotenoid-derived aromacompounds an introductionrdquo in Carotenoid-Derived AromaCompounds P Winterhalter and R Rousef Eds ACS Sympo-sium Series pp 1ndash19 American Chemical Society WashingtonDC USA 2001
[5] T Takeo and T Tsushida ldquoChanges in lipoxygenase activity inrelation to lipid degradation in plucked tea shootsrdquo Phytochem-istry vol 19 no 12 pp 2521-2522 1980
[6] T Wu Traditional jasmine green tea scenting process 2013httpwwwtaotealeafcomblogtraditional-jasmine-green-tea-scenting-process
[7] MChen Y Zhu B Liu et al ldquoChanges in the volatiles chemicalcomponents and antioxidant activities of Chinese jasmine teaduring the scenting processesrdquo International Journal of FoodProperties vol 20 no 3 pp 681ndash693 2017
[8] Y Ito A Sugimoto T Kakuda and K Kubota ldquoIdentificationof potent odorants in Chinese jasmine green tea scented withflowers of Jasminum sambacrdquo Journal of Agricultural and FoodChemistry vol 50 no 17 pp 4878ndash4884 2002
[9] Y Ito and K Kubota ldquoSensory evaluation of the synergismamong odorants present in concentrations below their odorthreshold in a Chinese jasmine green tea infusionrdquo MolecularNutrition and Food Research vol 49 no 1 pp 61ndash68 2005
[10] Y Liang Y Wu J Lu and L Zhang ldquoApplication of chemicalcomposition and infusion colour difference analysis to qualityestimation of jasmine-scented teardquo International Journal of FoodScience and Technology vol 42 no 4 pp 459ndash468 2007
[11] Z-X Han M M Rana G-F Liu et al ldquoGreen tea flavourdeterminants and their changes over manufacturing processesrdquoFood Chemistry vol 212 pp 739ndash748 2016
[12] S Wei I Marton M Dekel et al ldquoManipulating volatileemission in tobacco leaves by expressing Aspergillus niger120573-glucosidase in different subcellular compartmentsrdquo PlantBiotechnology Journal vol 2 no 4 pp 341ndash350 2004
[13] Z Han M M Rana G Liu et al ldquoData on green teaflavor determinantes as affected by cultivars andmanufacturingprocessesrdquo Data in Brief vol 10 pp 492ndash498 2017
10 Journal of Food Quality
[14] J Trygg E Holmes and T Lundstedt ldquoChemometrics inmetabonomicsrdquo Journal of Proteome Research vol 6 no 2 pp469ndash479 2007
[15] K M O Ku J N Choi J Kim et al ldquoMetabolomics anal-ysis reveals the compositional differences of shade growntea (Camellia sinensis L)rdquo Journal of Agricultural and FoodChemistry vol 58 no 1 pp 418ndash426 2010
[16] Y-H Li W Zhang and Y Li ldquoTranscriptomic analysis offlower blooming in Jasminum sambac through de novo RNAsequencingrdquoMolecules vol 20 no 6 pp 10734ndash10747 2015
[17] R Baba and K Kumazawa ldquoCharacterization of the potentodorants contributing to the characteristic aroma of chinesegreen tea infusions by aroma extract dilution analysisrdquo Journalof Agricultural and Food Chemistry vol 62 no 33 pp 8308ndash8313 2014
[18] T Koeduka E Fridman D R Gang et al ldquoEugenol andisoeugenol characteristic aromatic constituents of spices arebiosynthesized via reduction of a coniferyl alcohol esterrdquoProceedings of the National Academy of Sciences of the UnitedStates of America vol 103 no 26 pp 10128ndash10133 2006
[19] A E Edris R Chizzola and C Franz ldquoIsolation and charac-terization of the volatile aroma compounds from the concreteheadspace and the absolute of Jasminum sambac (L) Ait(Oleaceae) flowers grown in Egyptrdquo European Food Researchand Technology vol 226 no 3 pp 621ndash626 2008
[20] Y Yu S Lyu D Chen et al ldquoVolatiles emitted at differentflowering stages of Jasminum sambac and expression of genesrelated to 120572-farnesene biosynthesisrdquo Molecules vol 22 no 4article 546 2017
[21] P K Rout Y Ramachandra Rao and S Naik ldquoAnalysis offloral volatiles by using headspace-solid phase microextractiona reviewrdquoAsian Journal of Chemistry vol 24 no 3 pp 945ndash9562012
[22] C Schuh and P Schieberle ldquoCharacterization of the key aromacompounds in the beverage prepared from Darjeeling blacktea quantitative differences between tea leaves and infusionrdquoJournal of Agricultural and Food Chemistry vol 54 no 3 pp916ndash924 2006
[23] B Bonnlander R Cappuccio F S Liverani and PWinterhalterldquoAnalysis of enantiomeric linalool ratio in green and roastedcoffeerdquo Flavour and Fragrance Journal vol 21 no 4 pp 637ndash641 2006
[24] T Katsuno H Kasuga Y Kusano et al ldquoCharacterisation ofodorant compounds and their biochemical formation in greentea with a low temperature storage processrdquo Food Chemistryvol 148 pp 388ndash395 2014
[25] J Scognamiglio L Jones C S Letizia and A M Api ldquoFra-grance material review on cis-jasmonerdquo Food and ChemicalToxicology vol 50 supplement 3 pp S613ndashS618 2012
[26] Anonymous The good scents company information system2016 httpwwwthegoodscentscompanycomsearch2html
[27] Y Sawai Y Yamaguchi and J Tanaka ldquoMethyl anthranilate isthe cause of cultivar-specific aroma in the Japanese tea cultivarlsquoSofursquordquo Japan Agricultural Research Quarterly vol 38 no 4 pp271ndash274 2004
[28] E Mansour S Curling A Stephan and G OrmondroydldquoAbsorption of volatile organic compounds by different wooltypesrdquo Green Materials vol 4 no 1 pp 1ndash7 2016
[29] R Davidovich-Rikanati Y Sitrit Y Tadmor et al ldquoEnrichmentof tomato flavor by diversion of the early plastidial terpenoidpathwayrdquoNature Biotechnology vol 25 no 8 pp 899ndash901 2007
[30] B Boachon R R Junker L Miesch et al ldquoCYP76C1(Cytochrome P450)-mediated linalool metabolism and theformation of volatile and soluble linalool oxides in arabidopsisflowers a strategy for defense against floral antagonistsrdquo PlantCell vol 27 no 10 pp 2972ndash2990 2015
[31] F Dong Z Yang S Baldermann Y Sato T Asai andNWatan-abe ldquoHerbivore-induced volatiles from tea (Camellia sinensis)plants and their involvement in intraplant communication andchanges in endogenous nonvolatile metabolitesrdquo Journal ofAgricultural and Food Chemistry vol 59 no 24 pp 13131ndash131352011
[32] J A SpicerThe oxidation of 120572-Farnesene [PhD thesis] MasseyUniversity Palmerston North New Zealand 1994
[33] GWMcgraw RW Hemingway L L Ingram Jr C S Canadyand W B Mcgraw ldquoThermal degradation of terpenes cam-phene Δ3-carene limonene and 120572-terpinenerdquo EnvironmentalScience and Technology vol 33 no 22 pp 4029ndash4033 1999
[34] J H Tatum S Nagy and R E Berry ldquoDegradation productsformed in canned single-strength orange juice during storagerdquoJournal of Food Science vol 40 no 4 pp 707ndash709 1975
Figure 3 Enhanced floral volatiles in scented tea probably due to tea adsorption (a) Volatiles with high abundances present in the scentedtea (b) volatiles with less abundances present in the scented tea (c) volatiles present in scented tea only (d) Volatiles present in the headspaceof fresh jasmine flowers ST scented green tea infusion NT nonscented tea infusion JF jasmine flower ND not detected Duncanrsquos newmultiple range test was performed and the columns labeled with the same letter within the same compound had no significant differenceamong the tested samples 119875 lt 005 NS no significant difference detected
0 20 40 60 80
Benzyl alcoholEthyl benzoate
Neo-allo-ocimene
Ethyl salicylate
(E)-3-Hexenyl butanoate
Cadina-14-diene
Copaene
Scenting efficiency ()
-Myrcenelowast
(Z)-3-HexenoＦlowast
D-Limonenlowast
Indollowast
-LinalooＦlowast
Methyl salicylatlowast-Terpinene
(Z)-3-Hexenyl acetatlowast
(Z)--Ocimenlowast
-Cubenene
-Cadinene-Farnesene
Figure 4 Differential scenting efficiencies of jasmine floral volatiles to the scented green tea Scenting efficiency was calculated as thepercentage of the volatile abundance detected in the scented tea subtracted from that of the same compound in nonscented tea over theabundance of the counterpart present in jasmine flower Compounds labeledwith ldquolowastrdquo were identified and quantifiedwith authentic standards
8 Journal of Food Quality
0
2
4
NT ST
Methyl heptenone
A
B
Abun
danc
e
0
3
6
NT ST
Linalool oxide A
A
B0
1
2
NT ST
A
B0
05
1
NT ST
A
B
0
4
8
NT ST
A
B0
05
1
NT ST
CedrolA
B
0
5
10
NT ST
T-Cadinol
A
B
(g
kg)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
-Terpineol -Cyclocitral
(E)--Ionone
(a)
0
13
26
NT ST
Nonanal
A
B
0
04
08
NT ST
Naphthalene
AB
0
5
10
NT ST
DecanalA
B
NSNS
0
04
08
NT ST
1-Methylnaphthalene
0
1
2
NT ST
BiphenyleneA
B
NSNS
0
07
14
NT ST
Isopropyl myristate
NSNS
0
04
08
NT ST
Caffeine
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)
Abun
danc
e (
gkg
)(b)
Figure 5 Volatiles with differential abundances between scented and nonscented teas but undetectable in the jasmine flower headspace (a)Enhanced volatiles in the scented tea (b) reduced volatiles in the scented tea ST scented green tea infusion NT nonscented tea infusionND not detected Duncanrsquos new multiple range test was performed and the columns labeled with the same letter within the same compoundhad no significant difference among the three samples 119875 lt 005 NS no significant difference detected
whose water solubility values are relatively low (69mgLand 46mgL resp) but their volatility values (23mmHgand 13mmHg resp) are higher than those of many otheraliphatic volatiles presented in Figure 4 Moreover 120572-farnesene and 120575-cadinene possessing the lowest scenting effi-ciencies have the lowest values of water solubility (001mgLand 005mgL resp) It was assumed that volatiles possessinghigh water solubility could be partially dissolved into theaqueous phase in tea leaf matrix over the scenting process inwhich tea leaves could adsorb moisture substantially releasedfrom the fresh jasmine flowersUpon tea infusion preparationwith hot water those volatiles retained in the scented teawould be largely released due to their volatility Furtherinvestigation is required to clarify the correlation betweenscenting effectiveness and water solubility and volatility of avolatile
Moreover surface compounds on the tea leaf matrixmight discriminate volatiles with different polarity whichhas been found for wool types used with natural and solidadsorbents [28] In addition many volatiles are known tobe readily modified by the action of plant enzymes such as
conversion of linalool and geraniol to many other derivativesin plants [29 30] hydrothermal conversions of these volatilesalso occur For instance sesquiterpene 120572-farnesene is stressinduced [31] and can be easily degraded due to photochem-ical allylic oxidation hydroxylation and epoxidation [32]Consistently 120572-farnesene was found to be abundant in theheadspace of excised jasmine flowers but much lower in thejasmine tea and undetectable in green tea in this study
34 Heat-Affected Volatiles in Scented Green Tea Over thescenting and heating procedure 14 volatiles were detectedfrom the infusions of the two teas only but with differentialabundances (119875 lt 005) These volatiles were undetectable inthe jasmine flower headspace suggesting that the observeddifferences between the two teas might unlikely result fromthe direct tea adsorption of these volatiles (Figure 5) Amongthese volatiles 7 were found with higher levels in the scentedtea compared to the nonscented tea including linalool oxideA 120573-ionone and another four terpenoids (Figure 5(a)) Theobserved enhancement of these terpenoids in the scented teamight be the consequence of the heat-induced degradation or
Journal of Food Quality 9
chemical conversionMcgraw et al [33] observed that terpenecompounds degraded at high temperatures and turned intoother terpene hydrocarbons and oxide terpenes Tatum etal [34] reported that 120572-terpineol component is formed byoxidative degradation of limonene In this study it was alsoobserved that abundance of 120572-terpineol was significantlyincreased after the scenting process although it was notdetected in the jasmine flowers (Figure 5) suggesting that itwas likely derived from the hydrothermal conversion over thescenting process
In addition reduced levels of a few compounds werefound in scented tea compared to nonscented tea (Fig-ure 5(b)) including lipid-derived aldehydes nonanal anddecanal [3]These lipid-derived compounds are heat-inducedandmost likely also heat-releasedMultiple additional roundsof heat treatments after scenting could result in the reduc-tion of these volatiles in the scented tea infusion Nonanalabundance in green tea is enhanced by steam processing butsuppressed by pan-fire processing [11]
4 Conclusions
Our study revealed that jasmine flower scented green teapossessed an enhanced floral scent due to the adsorption offloral scent-related volatiles from the fresh jasmine flowersThis revealed that dry tea had the capacity to adsorb substan-tial amounts of volatiles from jasmine flowers Differentialcontribution of jasmine floral volatiles to the aromaof scentedgreen tea was observed Moreover chemical conversion alsocontributed to the differential abundances of some volatilesbetween scented and nonscented teas Our study suggeststhat adsorption and retention of the volatiles generatedendogenously from tea leaveswere crucial formaintaining teaaroma and improving tea aroma quality practically
Additional Points
Practical Applications This work reveals the differentialcontributions of jasmine floral volatiles to the scented greentea and suggested that dry tea has a great capacity toadsorb substantial amounts of volatiles from jasmine flowersBased on what was found in this study heat treatment maybe applied to premade teas with fine-tuned temperaturesto desorb those off-flavor compounds Moreover pleasantaroma either from natural sources or from artificial mixturescan also be applied to enhance tea aroma with a specificdesired odor
Conflicts of Interest
The authors declare that they have no conflicts of interestregarding the publication of this paper
Authorsrsquo Contributions
Shu Wei designed the experiments and interpreted theresults Jian-Xia Shen and Guo-Feng Liu helped to doOPLS-OD data analysis Mohammad M Rana drafted themanuscript Tie-Jun Ling and Margaret Y Gruber revised
the manuscript Jian-Xia Shen and Mohammad M Rana areequal contributors
Acknowledgments
This work was financially supported by the National NaturalScience Foundation of China (Grants nos 31070614 and31370687) to Shu Wei Margaret Y Gruber has been workingat Agriculture and Agri-Food Canada Saskatoon ResearchCentre Saskatoon SK Canada but is now retired
References
[1] M S Butt R S AhmadM T SultanMM N Qayyum andANaz ldquoGreen tea and anticancer perspectives updates from lastdecaderdquo Critical Reviews in Food Science and Nutrition vol 55no 6 pp 792ndash805 2015
[2] Z Yang S Baldermann and N Watanabe ldquoRecent studies ofthe volatile compounds in teardquo Food Research International vol53 no 2 pp 585ndash599 2013
[3] C Ho X Zheng and S Li ldquoTea aroma formationrdquo Food Scienceand Human Wellness vol 4 no 1 pp 9ndash27 2015
[4] P Winterhalter and R Rouseff ldquoCarotenoid-derived aromacompounds an introductionrdquo in Carotenoid-Derived AromaCompounds P Winterhalter and R Rousef Eds ACS Sympo-sium Series pp 1ndash19 American Chemical Society WashingtonDC USA 2001
[5] T Takeo and T Tsushida ldquoChanges in lipoxygenase activity inrelation to lipid degradation in plucked tea shootsrdquo Phytochem-istry vol 19 no 12 pp 2521-2522 1980
[6] T Wu Traditional jasmine green tea scenting process 2013httpwwwtaotealeafcomblogtraditional-jasmine-green-tea-scenting-process
[7] MChen Y Zhu B Liu et al ldquoChanges in the volatiles chemicalcomponents and antioxidant activities of Chinese jasmine teaduring the scenting processesrdquo International Journal of FoodProperties vol 20 no 3 pp 681ndash693 2017
[8] Y Ito A Sugimoto T Kakuda and K Kubota ldquoIdentificationof potent odorants in Chinese jasmine green tea scented withflowers of Jasminum sambacrdquo Journal of Agricultural and FoodChemistry vol 50 no 17 pp 4878ndash4884 2002
[9] Y Ito and K Kubota ldquoSensory evaluation of the synergismamong odorants present in concentrations below their odorthreshold in a Chinese jasmine green tea infusionrdquo MolecularNutrition and Food Research vol 49 no 1 pp 61ndash68 2005
[10] Y Liang Y Wu J Lu and L Zhang ldquoApplication of chemicalcomposition and infusion colour difference analysis to qualityestimation of jasmine-scented teardquo International Journal of FoodScience and Technology vol 42 no 4 pp 459ndash468 2007
[11] Z-X Han M M Rana G-F Liu et al ldquoGreen tea flavourdeterminants and their changes over manufacturing processesrdquoFood Chemistry vol 212 pp 739ndash748 2016
[12] S Wei I Marton M Dekel et al ldquoManipulating volatileemission in tobacco leaves by expressing Aspergillus niger120573-glucosidase in different subcellular compartmentsrdquo PlantBiotechnology Journal vol 2 no 4 pp 341ndash350 2004
[13] Z Han M M Rana G Liu et al ldquoData on green teaflavor determinantes as affected by cultivars andmanufacturingprocessesrdquo Data in Brief vol 10 pp 492ndash498 2017
10 Journal of Food Quality
[14] J Trygg E Holmes and T Lundstedt ldquoChemometrics inmetabonomicsrdquo Journal of Proteome Research vol 6 no 2 pp469ndash479 2007
[15] K M O Ku J N Choi J Kim et al ldquoMetabolomics anal-ysis reveals the compositional differences of shade growntea (Camellia sinensis L)rdquo Journal of Agricultural and FoodChemistry vol 58 no 1 pp 418ndash426 2010
[16] Y-H Li W Zhang and Y Li ldquoTranscriptomic analysis offlower blooming in Jasminum sambac through de novo RNAsequencingrdquoMolecules vol 20 no 6 pp 10734ndash10747 2015
[17] R Baba and K Kumazawa ldquoCharacterization of the potentodorants contributing to the characteristic aroma of chinesegreen tea infusions by aroma extract dilution analysisrdquo Journalof Agricultural and Food Chemistry vol 62 no 33 pp 8308ndash8313 2014
[18] T Koeduka E Fridman D R Gang et al ldquoEugenol andisoeugenol characteristic aromatic constituents of spices arebiosynthesized via reduction of a coniferyl alcohol esterrdquoProceedings of the National Academy of Sciences of the UnitedStates of America vol 103 no 26 pp 10128ndash10133 2006
[19] A E Edris R Chizzola and C Franz ldquoIsolation and charac-terization of the volatile aroma compounds from the concreteheadspace and the absolute of Jasminum sambac (L) Ait(Oleaceae) flowers grown in Egyptrdquo European Food Researchand Technology vol 226 no 3 pp 621ndash626 2008
[20] Y Yu S Lyu D Chen et al ldquoVolatiles emitted at differentflowering stages of Jasminum sambac and expression of genesrelated to 120572-farnesene biosynthesisrdquo Molecules vol 22 no 4article 546 2017
[21] P K Rout Y Ramachandra Rao and S Naik ldquoAnalysis offloral volatiles by using headspace-solid phase microextractiona reviewrdquoAsian Journal of Chemistry vol 24 no 3 pp 945ndash9562012
[22] C Schuh and P Schieberle ldquoCharacterization of the key aromacompounds in the beverage prepared from Darjeeling blacktea quantitative differences between tea leaves and infusionrdquoJournal of Agricultural and Food Chemistry vol 54 no 3 pp916ndash924 2006
[23] B Bonnlander R Cappuccio F S Liverani and PWinterhalterldquoAnalysis of enantiomeric linalool ratio in green and roastedcoffeerdquo Flavour and Fragrance Journal vol 21 no 4 pp 637ndash641 2006
[24] T Katsuno H Kasuga Y Kusano et al ldquoCharacterisation ofodorant compounds and their biochemical formation in greentea with a low temperature storage processrdquo Food Chemistryvol 148 pp 388ndash395 2014
[25] J Scognamiglio L Jones C S Letizia and A M Api ldquoFra-grance material review on cis-jasmonerdquo Food and ChemicalToxicology vol 50 supplement 3 pp S613ndashS618 2012
[26] Anonymous The good scents company information system2016 httpwwwthegoodscentscompanycomsearch2html
[27] Y Sawai Y Yamaguchi and J Tanaka ldquoMethyl anthranilate isthe cause of cultivar-specific aroma in the Japanese tea cultivarlsquoSofursquordquo Japan Agricultural Research Quarterly vol 38 no 4 pp271ndash274 2004
[28] E Mansour S Curling A Stephan and G OrmondroydldquoAbsorption of volatile organic compounds by different wooltypesrdquo Green Materials vol 4 no 1 pp 1ndash7 2016
[29] R Davidovich-Rikanati Y Sitrit Y Tadmor et al ldquoEnrichmentof tomato flavor by diversion of the early plastidial terpenoidpathwayrdquoNature Biotechnology vol 25 no 8 pp 899ndash901 2007
[30] B Boachon R R Junker L Miesch et al ldquoCYP76C1(Cytochrome P450)-mediated linalool metabolism and theformation of volatile and soluble linalool oxides in arabidopsisflowers a strategy for defense against floral antagonistsrdquo PlantCell vol 27 no 10 pp 2972ndash2990 2015
[31] F Dong Z Yang S Baldermann Y Sato T Asai andNWatan-abe ldquoHerbivore-induced volatiles from tea (Camellia sinensis)plants and their involvement in intraplant communication andchanges in endogenous nonvolatile metabolitesrdquo Journal ofAgricultural and Food Chemistry vol 59 no 24 pp 13131ndash131352011
[32] J A SpicerThe oxidation of 120572-Farnesene [PhD thesis] MasseyUniversity Palmerston North New Zealand 1994
[33] GWMcgraw RW Hemingway L L Ingram Jr C S Canadyand W B Mcgraw ldquoThermal degradation of terpenes cam-phene Δ3-carene limonene and 120572-terpinenerdquo EnvironmentalScience and Technology vol 33 no 22 pp 4029ndash4033 1999
[34] J H Tatum S Nagy and R E Berry ldquoDegradation productsformed in canned single-strength orange juice during storagerdquoJournal of Food Science vol 40 no 4 pp 707ndash709 1975
Figure 5 Volatiles with differential abundances between scented and nonscented teas but undetectable in the jasmine flower headspace (a)Enhanced volatiles in the scented tea (b) reduced volatiles in the scented tea ST scented green tea infusion NT nonscented tea infusionND not detected Duncanrsquos new multiple range test was performed and the columns labeled with the same letter within the same compoundhad no significant difference among the three samples 119875 lt 005 NS no significant difference detected
whose water solubility values are relatively low (69mgLand 46mgL resp) but their volatility values (23mmHgand 13mmHg resp) are higher than those of many otheraliphatic volatiles presented in Figure 4 Moreover 120572-farnesene and 120575-cadinene possessing the lowest scenting effi-ciencies have the lowest values of water solubility (001mgLand 005mgL resp) It was assumed that volatiles possessinghigh water solubility could be partially dissolved into theaqueous phase in tea leaf matrix over the scenting process inwhich tea leaves could adsorb moisture substantially releasedfrom the fresh jasmine flowersUpon tea infusion preparationwith hot water those volatiles retained in the scented teawould be largely released due to their volatility Furtherinvestigation is required to clarify the correlation betweenscenting effectiveness and water solubility and volatility of avolatile
Moreover surface compounds on the tea leaf matrixmight discriminate volatiles with different polarity whichhas been found for wool types used with natural and solidadsorbents [28] In addition many volatiles are known tobe readily modified by the action of plant enzymes such as
conversion of linalool and geraniol to many other derivativesin plants [29 30] hydrothermal conversions of these volatilesalso occur For instance sesquiterpene 120572-farnesene is stressinduced [31] and can be easily degraded due to photochem-ical allylic oxidation hydroxylation and epoxidation [32]Consistently 120572-farnesene was found to be abundant in theheadspace of excised jasmine flowers but much lower in thejasmine tea and undetectable in green tea in this study
34 Heat-Affected Volatiles in Scented Green Tea Over thescenting and heating procedure 14 volatiles were detectedfrom the infusions of the two teas only but with differentialabundances (119875 lt 005) These volatiles were undetectable inthe jasmine flower headspace suggesting that the observeddifferences between the two teas might unlikely result fromthe direct tea adsorption of these volatiles (Figure 5) Amongthese volatiles 7 were found with higher levels in the scentedtea compared to the nonscented tea including linalool oxideA 120573-ionone and another four terpenoids (Figure 5(a)) Theobserved enhancement of these terpenoids in the scented teamight be the consequence of the heat-induced degradation or
Journal of Food Quality 9
chemical conversionMcgraw et al [33] observed that terpenecompounds degraded at high temperatures and turned intoother terpene hydrocarbons and oxide terpenes Tatum etal [34] reported that 120572-terpineol component is formed byoxidative degradation of limonene In this study it was alsoobserved that abundance of 120572-terpineol was significantlyincreased after the scenting process although it was notdetected in the jasmine flowers (Figure 5) suggesting that itwas likely derived from the hydrothermal conversion over thescenting process
In addition reduced levels of a few compounds werefound in scented tea compared to nonscented tea (Fig-ure 5(b)) including lipid-derived aldehydes nonanal anddecanal [3]These lipid-derived compounds are heat-inducedandmost likely also heat-releasedMultiple additional roundsof heat treatments after scenting could result in the reduc-tion of these volatiles in the scented tea infusion Nonanalabundance in green tea is enhanced by steam processing butsuppressed by pan-fire processing [11]
4 Conclusions
Our study revealed that jasmine flower scented green teapossessed an enhanced floral scent due to the adsorption offloral scent-related volatiles from the fresh jasmine flowersThis revealed that dry tea had the capacity to adsorb substan-tial amounts of volatiles from jasmine flowers Differentialcontribution of jasmine floral volatiles to the aromaof scentedgreen tea was observed Moreover chemical conversion alsocontributed to the differential abundances of some volatilesbetween scented and nonscented teas Our study suggeststhat adsorption and retention of the volatiles generatedendogenously from tea leaveswere crucial formaintaining teaaroma and improving tea aroma quality practically
Additional Points
Practical Applications This work reveals the differentialcontributions of jasmine floral volatiles to the scented greentea and suggested that dry tea has a great capacity toadsorb substantial amounts of volatiles from jasmine flowersBased on what was found in this study heat treatment maybe applied to premade teas with fine-tuned temperaturesto desorb those off-flavor compounds Moreover pleasantaroma either from natural sources or from artificial mixturescan also be applied to enhance tea aroma with a specificdesired odor
Conflicts of Interest
The authors declare that they have no conflicts of interestregarding the publication of this paper
Authorsrsquo Contributions
Shu Wei designed the experiments and interpreted theresults Jian-Xia Shen and Guo-Feng Liu helped to doOPLS-OD data analysis Mohammad M Rana drafted themanuscript Tie-Jun Ling and Margaret Y Gruber revised
the manuscript Jian-Xia Shen and Mohammad M Rana areequal contributors
Acknowledgments
This work was financially supported by the National NaturalScience Foundation of China (Grants nos 31070614 and31370687) to Shu Wei Margaret Y Gruber has been workingat Agriculture and Agri-Food Canada Saskatoon ResearchCentre Saskatoon SK Canada but is now retired
References
[1] M S Butt R S AhmadM T SultanMM N Qayyum andANaz ldquoGreen tea and anticancer perspectives updates from lastdecaderdquo Critical Reviews in Food Science and Nutrition vol 55no 6 pp 792ndash805 2015
[2] Z Yang S Baldermann and N Watanabe ldquoRecent studies ofthe volatile compounds in teardquo Food Research International vol53 no 2 pp 585ndash599 2013
[3] C Ho X Zheng and S Li ldquoTea aroma formationrdquo Food Scienceand Human Wellness vol 4 no 1 pp 9ndash27 2015
[4] P Winterhalter and R Rouseff ldquoCarotenoid-derived aromacompounds an introductionrdquo in Carotenoid-Derived AromaCompounds P Winterhalter and R Rousef Eds ACS Sympo-sium Series pp 1ndash19 American Chemical Society WashingtonDC USA 2001
[5] T Takeo and T Tsushida ldquoChanges in lipoxygenase activity inrelation to lipid degradation in plucked tea shootsrdquo Phytochem-istry vol 19 no 12 pp 2521-2522 1980
[6] T Wu Traditional jasmine green tea scenting process 2013httpwwwtaotealeafcomblogtraditional-jasmine-green-tea-scenting-process
[7] MChen Y Zhu B Liu et al ldquoChanges in the volatiles chemicalcomponents and antioxidant activities of Chinese jasmine teaduring the scenting processesrdquo International Journal of FoodProperties vol 20 no 3 pp 681ndash693 2017
[8] Y Ito A Sugimoto T Kakuda and K Kubota ldquoIdentificationof potent odorants in Chinese jasmine green tea scented withflowers of Jasminum sambacrdquo Journal of Agricultural and FoodChemistry vol 50 no 17 pp 4878ndash4884 2002
[9] Y Ito and K Kubota ldquoSensory evaluation of the synergismamong odorants present in concentrations below their odorthreshold in a Chinese jasmine green tea infusionrdquo MolecularNutrition and Food Research vol 49 no 1 pp 61ndash68 2005
[10] Y Liang Y Wu J Lu and L Zhang ldquoApplication of chemicalcomposition and infusion colour difference analysis to qualityestimation of jasmine-scented teardquo International Journal of FoodScience and Technology vol 42 no 4 pp 459ndash468 2007
[11] Z-X Han M M Rana G-F Liu et al ldquoGreen tea flavourdeterminants and their changes over manufacturing processesrdquoFood Chemistry vol 212 pp 739ndash748 2016
[12] S Wei I Marton M Dekel et al ldquoManipulating volatileemission in tobacco leaves by expressing Aspergillus niger120573-glucosidase in different subcellular compartmentsrdquo PlantBiotechnology Journal vol 2 no 4 pp 341ndash350 2004
[13] Z Han M M Rana G Liu et al ldquoData on green teaflavor determinantes as affected by cultivars andmanufacturingprocessesrdquo Data in Brief vol 10 pp 492ndash498 2017
10 Journal of Food Quality
[14] J Trygg E Holmes and T Lundstedt ldquoChemometrics inmetabonomicsrdquo Journal of Proteome Research vol 6 no 2 pp469ndash479 2007
[15] K M O Ku J N Choi J Kim et al ldquoMetabolomics anal-ysis reveals the compositional differences of shade growntea (Camellia sinensis L)rdquo Journal of Agricultural and FoodChemistry vol 58 no 1 pp 418ndash426 2010
[16] Y-H Li W Zhang and Y Li ldquoTranscriptomic analysis offlower blooming in Jasminum sambac through de novo RNAsequencingrdquoMolecules vol 20 no 6 pp 10734ndash10747 2015
[17] R Baba and K Kumazawa ldquoCharacterization of the potentodorants contributing to the characteristic aroma of chinesegreen tea infusions by aroma extract dilution analysisrdquo Journalof Agricultural and Food Chemistry vol 62 no 33 pp 8308ndash8313 2014
[18] T Koeduka E Fridman D R Gang et al ldquoEugenol andisoeugenol characteristic aromatic constituents of spices arebiosynthesized via reduction of a coniferyl alcohol esterrdquoProceedings of the National Academy of Sciences of the UnitedStates of America vol 103 no 26 pp 10128ndash10133 2006
[19] A E Edris R Chizzola and C Franz ldquoIsolation and charac-terization of the volatile aroma compounds from the concreteheadspace and the absolute of Jasminum sambac (L) Ait(Oleaceae) flowers grown in Egyptrdquo European Food Researchand Technology vol 226 no 3 pp 621ndash626 2008
[20] Y Yu S Lyu D Chen et al ldquoVolatiles emitted at differentflowering stages of Jasminum sambac and expression of genesrelated to 120572-farnesene biosynthesisrdquo Molecules vol 22 no 4article 546 2017
[21] P K Rout Y Ramachandra Rao and S Naik ldquoAnalysis offloral volatiles by using headspace-solid phase microextractiona reviewrdquoAsian Journal of Chemistry vol 24 no 3 pp 945ndash9562012
[22] C Schuh and P Schieberle ldquoCharacterization of the key aromacompounds in the beverage prepared from Darjeeling blacktea quantitative differences between tea leaves and infusionrdquoJournal of Agricultural and Food Chemistry vol 54 no 3 pp916ndash924 2006
[23] B Bonnlander R Cappuccio F S Liverani and PWinterhalterldquoAnalysis of enantiomeric linalool ratio in green and roastedcoffeerdquo Flavour and Fragrance Journal vol 21 no 4 pp 637ndash641 2006
[24] T Katsuno H Kasuga Y Kusano et al ldquoCharacterisation ofodorant compounds and their biochemical formation in greentea with a low temperature storage processrdquo Food Chemistryvol 148 pp 388ndash395 2014
[25] J Scognamiglio L Jones C S Letizia and A M Api ldquoFra-grance material review on cis-jasmonerdquo Food and ChemicalToxicology vol 50 supplement 3 pp S613ndashS618 2012
[26] Anonymous The good scents company information system2016 httpwwwthegoodscentscompanycomsearch2html
[27] Y Sawai Y Yamaguchi and J Tanaka ldquoMethyl anthranilate isthe cause of cultivar-specific aroma in the Japanese tea cultivarlsquoSofursquordquo Japan Agricultural Research Quarterly vol 38 no 4 pp271ndash274 2004
[28] E Mansour S Curling A Stephan and G OrmondroydldquoAbsorption of volatile organic compounds by different wooltypesrdquo Green Materials vol 4 no 1 pp 1ndash7 2016
[29] R Davidovich-Rikanati Y Sitrit Y Tadmor et al ldquoEnrichmentof tomato flavor by diversion of the early plastidial terpenoidpathwayrdquoNature Biotechnology vol 25 no 8 pp 899ndash901 2007
[30] B Boachon R R Junker L Miesch et al ldquoCYP76C1(Cytochrome P450)-mediated linalool metabolism and theformation of volatile and soluble linalool oxides in arabidopsisflowers a strategy for defense against floral antagonistsrdquo PlantCell vol 27 no 10 pp 2972ndash2990 2015
[31] F Dong Z Yang S Baldermann Y Sato T Asai andNWatan-abe ldquoHerbivore-induced volatiles from tea (Camellia sinensis)plants and their involvement in intraplant communication andchanges in endogenous nonvolatile metabolitesrdquo Journal ofAgricultural and Food Chemistry vol 59 no 24 pp 13131ndash131352011
[32] J A SpicerThe oxidation of 120572-Farnesene [PhD thesis] MasseyUniversity Palmerston North New Zealand 1994
[33] GWMcgraw RW Hemingway L L Ingram Jr C S Canadyand W B Mcgraw ldquoThermal degradation of terpenes cam-phene Δ3-carene limonene and 120572-terpinenerdquo EnvironmentalScience and Technology vol 33 no 22 pp 4029ndash4033 1999
[34] J H Tatum S Nagy and R E Berry ldquoDegradation productsformed in canned single-strength orange juice during storagerdquoJournal of Food Science vol 40 no 4 pp 707ndash709 1975
chemical conversionMcgraw et al [33] observed that terpenecompounds degraded at high temperatures and turned intoother terpene hydrocarbons and oxide terpenes Tatum etal [34] reported that 120572-terpineol component is formed byoxidative degradation of limonene In this study it was alsoobserved that abundance of 120572-terpineol was significantlyincreased after the scenting process although it was notdetected in the jasmine flowers (Figure 5) suggesting that itwas likely derived from the hydrothermal conversion over thescenting process
In addition reduced levels of a few compounds werefound in scented tea compared to nonscented tea (Fig-ure 5(b)) including lipid-derived aldehydes nonanal anddecanal [3]These lipid-derived compounds are heat-inducedandmost likely also heat-releasedMultiple additional roundsof heat treatments after scenting could result in the reduc-tion of these volatiles in the scented tea infusion Nonanalabundance in green tea is enhanced by steam processing butsuppressed by pan-fire processing [11]
4 Conclusions
Our study revealed that jasmine flower scented green teapossessed an enhanced floral scent due to the adsorption offloral scent-related volatiles from the fresh jasmine flowersThis revealed that dry tea had the capacity to adsorb substan-tial amounts of volatiles from jasmine flowers Differentialcontribution of jasmine floral volatiles to the aromaof scentedgreen tea was observed Moreover chemical conversion alsocontributed to the differential abundances of some volatilesbetween scented and nonscented teas Our study suggeststhat adsorption and retention of the volatiles generatedendogenously from tea leaveswere crucial formaintaining teaaroma and improving tea aroma quality practically
Additional Points
Practical Applications This work reveals the differentialcontributions of jasmine floral volatiles to the scented greentea and suggested that dry tea has a great capacity toadsorb substantial amounts of volatiles from jasmine flowersBased on what was found in this study heat treatment maybe applied to premade teas with fine-tuned temperaturesto desorb those off-flavor compounds Moreover pleasantaroma either from natural sources or from artificial mixturescan also be applied to enhance tea aroma with a specificdesired odor
Conflicts of Interest
The authors declare that they have no conflicts of interestregarding the publication of this paper
Authorsrsquo Contributions
Shu Wei designed the experiments and interpreted theresults Jian-Xia Shen and Guo-Feng Liu helped to doOPLS-OD data analysis Mohammad M Rana drafted themanuscript Tie-Jun Ling and Margaret Y Gruber revised
the manuscript Jian-Xia Shen and Mohammad M Rana areequal contributors
Acknowledgments
This work was financially supported by the National NaturalScience Foundation of China (Grants nos 31070614 and31370687) to Shu Wei Margaret Y Gruber has been workingat Agriculture and Agri-Food Canada Saskatoon ResearchCentre Saskatoon SK Canada but is now retired
References
[1] M S Butt R S AhmadM T SultanMM N Qayyum andANaz ldquoGreen tea and anticancer perspectives updates from lastdecaderdquo Critical Reviews in Food Science and Nutrition vol 55no 6 pp 792ndash805 2015
[2] Z Yang S Baldermann and N Watanabe ldquoRecent studies ofthe volatile compounds in teardquo Food Research International vol53 no 2 pp 585ndash599 2013
[3] C Ho X Zheng and S Li ldquoTea aroma formationrdquo Food Scienceand Human Wellness vol 4 no 1 pp 9ndash27 2015
[4] P Winterhalter and R Rouseff ldquoCarotenoid-derived aromacompounds an introductionrdquo in Carotenoid-Derived AromaCompounds P Winterhalter and R Rousef Eds ACS Sympo-sium Series pp 1ndash19 American Chemical Society WashingtonDC USA 2001
[5] T Takeo and T Tsushida ldquoChanges in lipoxygenase activity inrelation to lipid degradation in plucked tea shootsrdquo Phytochem-istry vol 19 no 12 pp 2521-2522 1980
[6] T Wu Traditional jasmine green tea scenting process 2013httpwwwtaotealeafcomblogtraditional-jasmine-green-tea-scenting-process
[7] MChen Y Zhu B Liu et al ldquoChanges in the volatiles chemicalcomponents and antioxidant activities of Chinese jasmine teaduring the scenting processesrdquo International Journal of FoodProperties vol 20 no 3 pp 681ndash693 2017
[8] Y Ito A Sugimoto T Kakuda and K Kubota ldquoIdentificationof potent odorants in Chinese jasmine green tea scented withflowers of Jasminum sambacrdquo Journal of Agricultural and FoodChemistry vol 50 no 17 pp 4878ndash4884 2002
[9] Y Ito and K Kubota ldquoSensory evaluation of the synergismamong odorants present in concentrations below their odorthreshold in a Chinese jasmine green tea infusionrdquo MolecularNutrition and Food Research vol 49 no 1 pp 61ndash68 2005
[10] Y Liang Y Wu J Lu and L Zhang ldquoApplication of chemicalcomposition and infusion colour difference analysis to qualityestimation of jasmine-scented teardquo International Journal of FoodScience and Technology vol 42 no 4 pp 459ndash468 2007
[11] Z-X Han M M Rana G-F Liu et al ldquoGreen tea flavourdeterminants and their changes over manufacturing processesrdquoFood Chemistry vol 212 pp 739ndash748 2016
[12] S Wei I Marton M Dekel et al ldquoManipulating volatileemission in tobacco leaves by expressing Aspergillus niger120573-glucosidase in different subcellular compartmentsrdquo PlantBiotechnology Journal vol 2 no 4 pp 341ndash350 2004
[13] Z Han M M Rana G Liu et al ldquoData on green teaflavor determinantes as affected by cultivars andmanufacturingprocessesrdquo Data in Brief vol 10 pp 492ndash498 2017
10 Journal of Food Quality
[14] J Trygg E Holmes and T Lundstedt ldquoChemometrics inmetabonomicsrdquo Journal of Proteome Research vol 6 no 2 pp469ndash479 2007
[15] K M O Ku J N Choi J Kim et al ldquoMetabolomics anal-ysis reveals the compositional differences of shade growntea (Camellia sinensis L)rdquo Journal of Agricultural and FoodChemistry vol 58 no 1 pp 418ndash426 2010
[16] Y-H Li W Zhang and Y Li ldquoTranscriptomic analysis offlower blooming in Jasminum sambac through de novo RNAsequencingrdquoMolecules vol 20 no 6 pp 10734ndash10747 2015
[17] R Baba and K Kumazawa ldquoCharacterization of the potentodorants contributing to the characteristic aroma of chinesegreen tea infusions by aroma extract dilution analysisrdquo Journalof Agricultural and Food Chemistry vol 62 no 33 pp 8308ndash8313 2014
[18] T Koeduka E Fridman D R Gang et al ldquoEugenol andisoeugenol characteristic aromatic constituents of spices arebiosynthesized via reduction of a coniferyl alcohol esterrdquoProceedings of the National Academy of Sciences of the UnitedStates of America vol 103 no 26 pp 10128ndash10133 2006
[19] A E Edris R Chizzola and C Franz ldquoIsolation and charac-terization of the volatile aroma compounds from the concreteheadspace and the absolute of Jasminum sambac (L) Ait(Oleaceae) flowers grown in Egyptrdquo European Food Researchand Technology vol 226 no 3 pp 621ndash626 2008
[20] Y Yu S Lyu D Chen et al ldquoVolatiles emitted at differentflowering stages of Jasminum sambac and expression of genesrelated to 120572-farnesene biosynthesisrdquo Molecules vol 22 no 4article 546 2017
[21] P K Rout Y Ramachandra Rao and S Naik ldquoAnalysis offloral volatiles by using headspace-solid phase microextractiona reviewrdquoAsian Journal of Chemistry vol 24 no 3 pp 945ndash9562012
[22] C Schuh and P Schieberle ldquoCharacterization of the key aromacompounds in the beverage prepared from Darjeeling blacktea quantitative differences between tea leaves and infusionrdquoJournal of Agricultural and Food Chemistry vol 54 no 3 pp916ndash924 2006
[23] B Bonnlander R Cappuccio F S Liverani and PWinterhalterldquoAnalysis of enantiomeric linalool ratio in green and roastedcoffeerdquo Flavour and Fragrance Journal vol 21 no 4 pp 637ndash641 2006
[24] T Katsuno H Kasuga Y Kusano et al ldquoCharacterisation ofodorant compounds and their biochemical formation in greentea with a low temperature storage processrdquo Food Chemistryvol 148 pp 388ndash395 2014
[25] J Scognamiglio L Jones C S Letizia and A M Api ldquoFra-grance material review on cis-jasmonerdquo Food and ChemicalToxicology vol 50 supplement 3 pp S613ndashS618 2012
[26] Anonymous The good scents company information system2016 httpwwwthegoodscentscompanycomsearch2html
[27] Y Sawai Y Yamaguchi and J Tanaka ldquoMethyl anthranilate isthe cause of cultivar-specific aroma in the Japanese tea cultivarlsquoSofursquordquo Japan Agricultural Research Quarterly vol 38 no 4 pp271ndash274 2004
[28] E Mansour S Curling A Stephan and G OrmondroydldquoAbsorption of volatile organic compounds by different wooltypesrdquo Green Materials vol 4 no 1 pp 1ndash7 2016
[29] R Davidovich-Rikanati Y Sitrit Y Tadmor et al ldquoEnrichmentof tomato flavor by diversion of the early plastidial terpenoidpathwayrdquoNature Biotechnology vol 25 no 8 pp 899ndash901 2007
[30] B Boachon R R Junker L Miesch et al ldquoCYP76C1(Cytochrome P450)-mediated linalool metabolism and theformation of volatile and soluble linalool oxides in arabidopsisflowers a strategy for defense against floral antagonistsrdquo PlantCell vol 27 no 10 pp 2972ndash2990 2015
[31] F Dong Z Yang S Baldermann Y Sato T Asai andNWatan-abe ldquoHerbivore-induced volatiles from tea (Camellia sinensis)plants and their involvement in intraplant communication andchanges in endogenous nonvolatile metabolitesrdquo Journal ofAgricultural and Food Chemistry vol 59 no 24 pp 13131ndash131352011
[32] J A SpicerThe oxidation of 120572-Farnesene [PhD thesis] MasseyUniversity Palmerston North New Zealand 1994
[33] GWMcgraw RW Hemingway L L Ingram Jr C S Canadyand W B Mcgraw ldquoThermal degradation of terpenes cam-phene Δ3-carene limonene and 120572-terpinenerdquo EnvironmentalScience and Technology vol 33 no 22 pp 4029ndash4033 1999
[34] J H Tatum S Nagy and R E Berry ldquoDegradation productsformed in canned single-strength orange juice during storagerdquoJournal of Food Science vol 40 no 4 pp 707ndash709 1975
[14] J Trygg E Holmes and T Lundstedt ldquoChemometrics inmetabonomicsrdquo Journal of Proteome Research vol 6 no 2 pp469ndash479 2007
[15] K M O Ku J N Choi J Kim et al ldquoMetabolomics anal-ysis reveals the compositional differences of shade growntea (Camellia sinensis L)rdquo Journal of Agricultural and FoodChemistry vol 58 no 1 pp 418ndash426 2010
[16] Y-H Li W Zhang and Y Li ldquoTranscriptomic analysis offlower blooming in Jasminum sambac through de novo RNAsequencingrdquoMolecules vol 20 no 6 pp 10734ndash10747 2015
[17] R Baba and K Kumazawa ldquoCharacterization of the potentodorants contributing to the characteristic aroma of chinesegreen tea infusions by aroma extract dilution analysisrdquo Journalof Agricultural and Food Chemistry vol 62 no 33 pp 8308ndash8313 2014
[18] T Koeduka E Fridman D R Gang et al ldquoEugenol andisoeugenol characteristic aromatic constituents of spices arebiosynthesized via reduction of a coniferyl alcohol esterrdquoProceedings of the National Academy of Sciences of the UnitedStates of America vol 103 no 26 pp 10128ndash10133 2006
[19] A E Edris R Chizzola and C Franz ldquoIsolation and charac-terization of the volatile aroma compounds from the concreteheadspace and the absolute of Jasminum sambac (L) Ait(Oleaceae) flowers grown in Egyptrdquo European Food Researchand Technology vol 226 no 3 pp 621ndash626 2008
[20] Y Yu S Lyu D Chen et al ldquoVolatiles emitted at differentflowering stages of Jasminum sambac and expression of genesrelated to 120572-farnesene biosynthesisrdquo Molecules vol 22 no 4article 546 2017
[21] P K Rout Y Ramachandra Rao and S Naik ldquoAnalysis offloral volatiles by using headspace-solid phase microextractiona reviewrdquoAsian Journal of Chemistry vol 24 no 3 pp 945ndash9562012
[22] C Schuh and P Schieberle ldquoCharacterization of the key aromacompounds in the beverage prepared from Darjeeling blacktea quantitative differences between tea leaves and infusionrdquoJournal of Agricultural and Food Chemistry vol 54 no 3 pp916ndash924 2006
[23] B Bonnlander R Cappuccio F S Liverani and PWinterhalterldquoAnalysis of enantiomeric linalool ratio in green and roastedcoffeerdquo Flavour and Fragrance Journal vol 21 no 4 pp 637ndash641 2006
[24] T Katsuno H Kasuga Y Kusano et al ldquoCharacterisation ofodorant compounds and their biochemical formation in greentea with a low temperature storage processrdquo Food Chemistryvol 148 pp 388ndash395 2014
[25] J Scognamiglio L Jones C S Letizia and A M Api ldquoFra-grance material review on cis-jasmonerdquo Food and ChemicalToxicology vol 50 supplement 3 pp S613ndashS618 2012
[26] Anonymous The good scents company information system2016 httpwwwthegoodscentscompanycomsearch2html
[27] Y Sawai Y Yamaguchi and J Tanaka ldquoMethyl anthranilate isthe cause of cultivar-specific aroma in the Japanese tea cultivarlsquoSofursquordquo Japan Agricultural Research Quarterly vol 38 no 4 pp271ndash274 2004
[28] E Mansour S Curling A Stephan and G OrmondroydldquoAbsorption of volatile organic compounds by different wooltypesrdquo Green Materials vol 4 no 1 pp 1ndash7 2016
[29] R Davidovich-Rikanati Y Sitrit Y Tadmor et al ldquoEnrichmentof tomato flavor by diversion of the early plastidial terpenoidpathwayrdquoNature Biotechnology vol 25 no 8 pp 899ndash901 2007
[30] B Boachon R R Junker L Miesch et al ldquoCYP76C1(Cytochrome P450)-mediated linalool metabolism and theformation of volatile and soluble linalool oxides in arabidopsisflowers a strategy for defense against floral antagonistsrdquo PlantCell vol 27 no 10 pp 2972ndash2990 2015
[31] F Dong Z Yang S Baldermann Y Sato T Asai andNWatan-abe ldquoHerbivore-induced volatiles from tea (Camellia sinensis)plants and their involvement in intraplant communication andchanges in endogenous nonvolatile metabolitesrdquo Journal ofAgricultural and Food Chemistry vol 59 no 24 pp 13131ndash131352011
[32] J A SpicerThe oxidation of 120572-Farnesene [PhD thesis] MasseyUniversity Palmerston North New Zealand 1994
[33] GWMcgraw RW Hemingway L L Ingram Jr C S Canadyand W B Mcgraw ldquoThermal degradation of terpenes cam-phene Δ3-carene limonene and 120572-terpinenerdquo EnvironmentalScience and Technology vol 33 no 22 pp 4029ndash4033 1999
[34] J H Tatum S Nagy and R E Berry ldquoDegradation productsformed in canned single-strength orange juice during storagerdquoJournal of Food Science vol 40 no 4 pp 707ndash709 1975
