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H*m$theFood

The authors are faculty mem_bers at lndia AgriculturalResearch lnstitute, New Dethi

K.S. Jayachandran, Vijay Sethi and Surab,hi Rai. ";:i..r..;::.;;....."l'lilx'lJo'i;1ii[ ffi "9ry1t***'-,;*; e#*,*1d",liflrj*,,,,,,ossible heeo"n"nt'. n*uril6." ffi ,T l[lXiJ ;f;j:,:."[ffieed =,,, ]T?l1,, rr:1,'il:ffi$,li###:ii"vast array of ffi *,::r"f ::,'li,',y:r : '.:.:,i:':. ,.*ilffi;]i?lffill#+Ei1ilffitiif1=''class of compounds ffi ;;"*il ""#:'j:;';:#Xi,j:'1'""'=..'tlrr.-d1.e,r.v;abre tannindtE?f@.,.8'g1called tannins. fnir ffi l:^"^yi;.*or(iin,afid.*reii,*p*n1.,.-,__,,,11?,

naturattyoccurririgpkrtporyprreners__,,glates;rJffi;=if,i++qfi;d3ilffflnill fi''ii:::l " compound ** oi",*" 9.,p. rffi il;;1":ontainino s, rffinipn+ ^.,^,1:.:,::Ylt 3llaoic acio' lfit is grt" ,jJ ii"n the *

occurrence of rannins,ffi dil;;;;;;;;ff;ffffi;:,fr;-":,3",.ilj ?iT: : :fi,ff,"#;3:ff[*,::ff" " .?tr[T: J,".J#"_ifr["1'fl""Larticle reviews the ffi :::"::

human heatth. rannins are

other suitabte $ofiis tt;ellmrbuqdp}{e.r.t, i. "f f rg,:ffiffiLoj:i.,:l:,,?n " ::{:d;i;.,J,J.ffi,Tffi,li L:ffi,i",l,Hhuman health. ffi prstoins.and'erttiermbf,rrr*areer+rae. I".li1Y1l-4=*I=itu*lEt\t

\amounts inunder the particular environmentalconditions.{Oan*ds;Chemistry of ianniof secondary compounds tounA.-ffiplants. Tltey,ar6with multiple structure unitsphenolicranging from 500 to > 20,000.

hot water

January 2005 I processed Food Industry.=r.irE+_}rei[,lk-+ tu++_

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cleavage by hydrolysis. The most food dye which is rich in tannins.common anthocyanidins produced are Foods with certain polyphenolscyanidin and delphinidin. before fermentation olten have

Tannins belong to the phenolics those polyphenols transformed intoclass. AII phenolic compounds (pri- condensed tannins after fermenta-mary and.secondary) are in one way tion. Soy beans, which are white inor another, formed via the shikimic acid colour, have few tannins beforepathway, also known as the phenyl fermentation. Perhaps aflerfermen-propanoid pathwa)A An example of how tation, the brown of the soy sauceseveral common tannins are {Ormed is indiCates that these tannins areas follows: . transformed into condensed. Gallic acid is derived from quinic tannins.acid ' r Fruitiuiceslikeapplejuice,Tannins,,+-. Ellagotannins are formed from are often added to juices, as a

neianyUr,etyClphenic esters by. the clarifuing agent, and, in some apple,., oxidative coupiingof neighbouring' ' r ciders, it is added to increase theghfiieaei{unitsattachedio*D-'mauthfeel' (astringency)ofthe... . glucose cor6,"'"'':,-,. juices. Grapes and berry juices are. 'Fijtttrer-oxidative coupling, -orms the "' ',':relafively highin tannins.hydrolyzatilFtannin (HT) polymelq. I Atcdhalic beverages like red wineF-'@ryt{tgcyaniOin'(fulprecursors -..( uetoskinlandbeer(duetohops)are le[]6ei6y.a+-idins (flavon;$4diol ocatain tannis. ' . , -,':=**df|avan-+-0fji[]pog , o Even palqiye smokett'or secondaui

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oooLL{*trsfi)I

have been said to act as a doubleedged sword with both negative andpositive effects on health.NEGATIVE EFFECTSTannins as antinutritionalfactors: Tannins are often consideredto be nutritionally undesirable. Tanninsform complexes with protein's starchesand digestive enzymes to cause areduction in nutritional values of.focds.Proteins bound to tannins becomeresistant to proteases and hencedecrease protein digestibility (Hulse efa/., 1 980). Tannins have been reportedto inhibit the enzymatic aetivities ofcellulose (Griffiths, 1 977), pectinase(Yaper ef al.,1972), amytase (Davis efal., 1979),lipases (Tamir ef. a/., 1969),proteolytic enzymes (Griffiths ef a/.,1980) and 13, galactosidase (Go.ldstiainet al., 1965). One mole of tannin isreported to bind 12 moles of protein(chung etal.,1998).

Moreover, tannins are known toaffect the utilization of vitamins andminerals.'Tannins reduce thebioavailability of vit*rnin:A, vitamin B,zand iron (Salunkhe et. al., 1989).Themajor dietary effectof tannins is theefficiency with which the digestedand. ,:,absorbed nutrients lvere cohvertedinto new body substances (Builer ef ,,,.al.,1992).

Tannins as carcinogens.. lt wasreported by Stoltz in 1982 that tanninsact as both mutagens andcarcionogens. Tannins and lannic acid

today have been listed in Calegory-tcarcinogens by the OccupationalSafetyand Health Administraiion '(OSHA). Betal nuts containing 11-26/"tannins can cause cheek and oesoph- " inhibitory effeet of gleen tea on carrerageal cancers.

Ranadive et at. (1979) studied thecarcinogenicity of paan ingredients.Betal nut, betal leaf, [ime, catechu and, been.*lrown to have a lower risk of

of food undesirable (Graham, 2000).POSITIVE EFFECTS

Ta n n in s as anticarcl noga*:Z?cformation has been well dtieu*g*:ed.lndividuals consuming green tea morefrequently or in larger qriintffiri*.?*a:egastric cancer. Sim ilarfi *n:lnre+=

, cofflatioa exists between consum -tion of diets rich in fiufts'andfqg:===

tobacco and concluded that betal nut,particularly the tannin containingfraction, and its combination with lime

migraine. Although, proline absorption=srn*.t, bc.fi.m6et' *@a*tannin's complexing ability with

and tobacco were potent carcinogens. et#les and risk of developing cancerThe staple food in combination with a (Kono ef af., 1988).The canoerfightingherbattea can cau3e st6inacE,ian'.. -.,r.: propsrry"gf tannins have triple actioR...cers. This carcinogenecity of tannins They btock th6 fo'rr etif,Ede+qgflg:,,,..8lflS..b.qoetJhe bodV's natural detOffi'ay be due'to iriiation'ehddellulat :.=. g f*;..bqost.the body,s natural

coceretnogens,orl5forttbt6iS:'*.: i,lt7=-::.,,;ir.,.:.\*fl 11lin C and vitamin Einducing cancers in the presence of beta 1998).ln: Othef.eaitifOgen.i...,: :::,:.j.+':.'=-,::::,;i,ttttlt.:=i:.it;, ,Cqqipl tfial Of Og fef#itEMigratnesandfannrhs..Many ""nf6iri:dffit*g-**umnreseersh .atg rrthat in the migraine the neuro-transmit-t*f,gerobfiin is,lit ult signilicantthat low levels of utilizable serotonin permaya@OUfi*{#a' ix$tlffiirt6-,.=:.=.i+++= et a\.,1

with,3006 months

in Finlandup studyof intake

tryptophan {a precursor to serotonin),arealsrthe body in the production of serotonin,flr,et*itry;result of this binding diets high inutilizable levels of serotonin andnumber and severity of migraines

Fa od ae eeptablW,Tannindglucopolysaccharide* in. salivdresultg

flavonoids(1ee4)Tannins have irnportant

implications in the foodindustry too. Tlnnnic acid,ellagic acid, gailic acfd,methyl gallate are used asantioxidants. Fropyl gallateis a, cErtified fdod additive.Tannic acid,eould be added.to fqod BroducL:to extend:,.:.'.'1;,, ., ,,''.-tfi*ir.shg,lf,.jife., reastt6iib wnicrr maxa iffi

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ine Senzo-(a)-pyrene, aflatoxin B, 2-;r:uraofluorene etc. (Chung et a\.,1998).--e antimutagenic potential of tannins-a.. be due to their antioxidant;'" perty in protecting cellular compo--Et"ts frorn oxidative damage. Forarie'rrple, quercetin and rutin havelreen demonstrated to scavengesiceroxide anions (Robak ef a/.,'s8).

Tannin s and cardiovascul ar

400 substances in red wine apparentlyraised the levelof high density lipopro-teins (HDL or'good' cholesterol) in theblood while decreasing the low densitylipoproteins (LDL, or'bad' cholesterol)and thereby prevent heart attack andstrokes. HDL is known to lower therisk of arterieosclerosis and heartdiseases by clearing'bad' cholesterolfrom arterial walls and helping iteliminate from the body (Wellens,

Tannins present invarying concentrationsin food have profoundeffects on humanhealth. A fine balancingact is reguired toensure the right doseof right kind of tanninsto promote optimalhealth.

dsaases.'Tanninsviatheirantioxidant 2000).:rBperty prevent the oxidation of The Chacolate Paradax: Scien-

a"rdiorescular health. There is an in red wine and tea-iannins. Epidemio-

drdesterol, a precursorto the forma- ' tists studying the chemical compo-nc,r' of artfterosclerotic plaque in blood nents of chocolate are finding theressels and in this way promote better same kind of nutrients in chocglate as

I

Consumption tif,black tea for lourr.eeks was shown in a study to

men wfto abstain from sweets. A singleeandy bar of milk chocolate contains

fiuerse association,between flavonoid . logical reports have revealed that menrtake and,slroke (Keli etar,J996). 'who eat candy live a little longerthan allowed for use at 400 ppm in frozendessert, 150 ppm in non-alcoholicbeverages, 130 ppm in hard candies,''100 ppm in baked foods and bakingmixes. Tannic aci.d could be added to. food product to extend their shelf-life.Moreover, in the lndian per$pective thewide-variety of indigenous fruits andvegetables rich in tannins opens up,ftew vislas f6'r.lheir mark*li[tg. ashealth{oods by the industry.Conclusion

Tannins present in varying concen-.: trations in food have'profound effectsor,rhuman tiealth. On theone hand, ifingested in large quantities,.they maybe involved in carcinogenesis,'""antinutritionql activi$r and other,,.adyerse effeEts and on llre other hand,the ifltake of a small quanllly may be,..beneficial by its anticarcinogenic,':: ntimicrotiial and antigrutageni-' ities an6,leducing,-lthe risk of,.cardiovasculardiseases;Thus, a figsbalan*.ing act isie,quired t6+nsure th*

'r:,rightdoEe of nght indof tanf..rinsto .:promote optimal health.t}*astrainte,''qg space'@. not alioyt.usto pubtish the Beferences. Any readerintereii.ted in it fipy contastthe Edibr

'rncrease therceistance of low density mor+lhan 300 mg of pclyphenoismcg?teins (t-Oljiooxidation ', -.., about the s&rl1e amount in an entirerlshikawd'ef,a1,, 1997). The cons:mp- day worth (five servings) of fruits andlien of red wine illiEnolics extract har,,. vegetables. Though, it is too early to -OeenE io increasethe,antioxidant'=.say for certain that there is a chocolatecapacity of the plasma (Carbonneau et paradox, it is time to think aboutal.,'lQ.and increEdC.tlp resisiancii,:,:.... chocolatea,s a source ofssential'"',,.of LDL to oxkJation (Seragini et a/., nutrients and not just eating pleasuref LDL to oj(da i,"C.n (Seragini ,qt aJ., jii{r*rients and ho$ust eating pleasuret3]=CommerC-i&f,grape juice i6'htep- (Siff*lffenberger e\a .,1999).,:Ie1l6'$ft. q -lP-i[g]|r6t*Urqt'on of '1:r=,,,.= Tannti*el antimifubiats:rniA.,.''""':.:L,-'&i+tiry]icroliaiaetivityof takninsfrave

Tfre frenEh*, leen' ,g1 documented.Tannin toxicity:L* {Day e/

tlt

cardiologist, S. Renaud fiist described to microorganisms may be due to theira p4q{oxical situdhn in France, actiqn on the rnembranes of microor-

r " r.tfu&unte fri[#'+ ganibnrs, complexation with e*uymesbd fat but relatively low or substrates (Scalbert, 1991) andor@yartery-#b1,., ifuAplexatici#.1-ujth metaf&nswhich,:.":,,..and Lorgeril(1992) can, in turn, affeet the activig ofe relalively lryh intake metalloenzlmes like peroxidase.

trf,itimicrobial-.

:.-for its wpy.l 1.,:ili;

.?i-.q

roceseed Focd fndustnl I January 2005 r,.