Cultivar difference in physicochemical properties of starches and flours from temperate rice of Indian Himalayas Shabir Ahmad Mir, Sowriappan John Don Bosco ⇑ Department of Food Science and Technology, Pondicherry University, Puducherry 605 014, India article info Article history: Received 22 November 2013 Received in revised form 6 February 2014 Accepted 12 February 2014 Available online 24 February 2014 Keywords: Rice starch Flour Amylose Physicochemical properties Raman spectroscopy abstract Starch and flour of seven temperate rice cultivars grown in Himalayan region were evaluated for compo- sition, granule structure, crystallinity, Raman spectrometry, turbidity, swelling power, solubility, pasting properties and textural properties. The rice cultivars showed medium to high amylose content for starch (24.69–32.76%) and flour (17.78–24.86%). SKAU-382 showed the highest amount of amylose (32.76%). Rice starch showed polyhedral granule shapes and differences in their mean granule size (2.3–6.5 lm) were noted among the samples. The starch and flour samples showed type A-pattern with strong reflec- tion at 15, 18, and 23. Pasting profile and textural analysis of rice starch and flour showed that all the cultivars differences, probably due to variation in amylose content. The present study can be used for identifying differences between rice genotypes for starch and flour quality and could provide guidance to possible industries for their end use. Ó 2014 Elsevier Ltd. All rights reserved. 1. Introduction Rice (Oryza sativa L.) is the most important cereal crop and staple food of over approximately one-half of the world’s popu- lation. In Asia, more than 2000 million people obtain their 60–70% calories from rice and its products (Lin, Singh, Chang, & Chang, 2011). Diversity in rice, largely affects their physical, chemical and cooking properties of a particular cultivar (Mir, Bosco, & Sunooj, 2013; Wani et al., 2012). Physico-chemical properties of rice flour and starch depend mostly on the variety, genetic background, climatic and soil conditions during the rice grain development (Falade, Semon, Fadairo, Oladunjoye, & Orou, 2014; Wu et al., 2013). Starch is the major component of rice grain and an important energy source for human nutrition, mainly determines the accept- ability of the rice cultivar in terms of physicochemical and cooking properties. Diversification of rice cultivars has an impact on differ- ent properties of rice starches as reported by several researchers (Lee & Osman, 1991; Wang et al., 2012). Although a great number of native starches with different functionalities are available in the market, increasing demand for specific starch properties requires new strategies or, alternatively, novel sources (Wani et al., 2012). The physico-chemical characteristics of starches are of great importance because of their extensive utilization in the food and non-food industries. The starch has important role in developing food products either as a raw material or as a food additive, such as thickener, texture enhancer or stabilizer (Aina, Falade, Akingbala, & Titus, 2012). Many factors, including composition, granular size and structure, type of crystal polymorph, amylose/amylopectin ratio, gelatinization, lipid-complexed amylose, and presence of non- carbohydrate content of starch affect the quality of rice flour and its products (Lin et al., 2011; Yu, Ma, Menager, & Sun, 2012; Zhu, Liu, Wilson, Gu, & Shi, 2011). Several techniques have been used to study the properties of rice starches and flours by using different techniques, such as X-ray diffractometry (Yu et al., 2012; Zhu et al., 2011), scanning electronic microscopy (Zhu et al., 2011), Raman spectroscopy (Labanowska, Birczynska, Kurdziel, & Puch, 2013), rapid visco analysis (Puncha-arnon & Uttapap, 2013), and textural profile analysis (Puncha-Arnon & Uttapap, 2013; Yu et al., 2012). The diverse industrial applications have spurred towards inves- tigating the physico-chemical properties of rice flours and starches from different genotypes. Due to the special agro-climatic condi- tions in temperate regions of India, Kashmir is endowed with large cultivars of rice germplasm. Therefore, the objective of the present work is to compare the physico-chemical properties of starch and flour from seven different genotypes of temperate rice of Indian Himalayas. http://dx.doi.org/10.1016/j.foodchem.2014.02.057 0308-8146/Ó 2014 Elsevier Ltd. All rights reserved. ⇑ Corresponding author. Tel.: +91 413 2654623; fax: +91 413 2656743. E-mail address: [email protected](S.J.D. Bosco). Food Chemistry 157 (2014) 448–456 Contents lists available at ScienceDirect Food Chemistry journal homepage: www.elsevier.com/locate/foodchem
Starch and flour of seven temperate rice cultivars grown in Himalayan region were evaluated for compo-sition, granule structure, crystallinity, Raman spectrometry, turbidity, swelling power, solubility, pastingproperties and textural properties. The rice cultivars showed medium to high amylose content for starch(24.69–32.76%) and flour (17.78–24.86%). SKAU-382 showed the highest amount of amylose (32.76%).Rice starch showed polyhedral granule shapes and differences in their mean granule size (2.3–6.5 lm)were noted among the samples. The starch and flour samples showed type A-pattern with strong reflec-tion at 15, 18, and 23. Pasting profile and textural analysis of rice starch and flour showed that all thecultivars differences, probably due to variation in amylose content. The present study can be used foridentifying differences between rice genotypes for starch and flour quality and could provide guidanceto possible industries for their end use.
� 2014 Elsevier Ltd. All rights reserved.
1. Introduction
Rice (Oryza sativa L.) is the most important cereal crop andstaple food of over approximately one-half of the world’s popu-lation. In Asia, more than 2000 million people obtain their60–70% calories from rice and its products (Lin, Singh, Chang, &Chang, 2011). Diversity in rice, largely affects their physical,chemical and cooking properties of a particular cultivar (Mir,Bosco, & Sunooj, 2013; Wani et al., 2012). Physico-chemicalproperties of rice flour and starch depend mostly on the variety,genetic background, climatic and soil conditions during the ricegrain development (Falade, Semon, Fadairo, Oladunjoye, & Orou,2014; Wu et al., 2013).
Starch is the major component of rice grain and an importantenergy source for human nutrition, mainly determines the accept-ability of the rice cultivar in terms of physicochemical and cookingproperties. Diversification of rice cultivars has an impact on differ-ent properties of rice starches as reported by several researchers(Lee & Osman, 1991; Wang et al., 2012). Although a great numberof native starches with different functionalities are available in themarket, increasing demand for specific starch properties requiresnew strategies or, alternatively, novel sources (Wani et al., 2012).The physico-chemical characteristics of starches are of great
importance because of their extensive utilization in the food andnon-food industries. The starch has important role in developingfood products either as a raw material or as a food additive,such as thickener, texture enhancer or stabilizer (Aina, Falade,Akingbala, & Titus, 2012).
Many factors, including composition, granular size andstructure, type of crystal polymorph, amylose/amylopectin ratio,gelatinization, lipid-complexed amylose, and presence of non-carbohydrate content of starch affect the quality of rice flourand its products (Lin et al., 2011; Yu, Ma, Menager, & Sun,2012; Zhu, Liu, Wilson, Gu, & Shi, 2011). Several techniques havebeen used to study the properties of rice starches and flours byusing different techniques, such as X-ray diffractometry (Yuet al., 2012; Zhu et al., 2011), scanning electronic microscopy(Zhu et al., 2011), Raman spectroscopy (Labanowska, Birczynska,Kurdziel, & Puch, 2013), rapid visco analysis (Puncha-arnon &Uttapap, 2013), and textural profile analysis (Puncha-Arnon &Uttapap, 2013; Yu et al., 2012).
The diverse industrial applications have spurred towards inves-tigating the physico-chemical properties of rice flours and starchesfrom different genotypes. Due to the special agro-climatic condi-tions in temperate regions of India, Kashmir is endowed with largecultivars of rice germplasm. Therefore, the objective of the presentwork is to compare the physico-chemical properties of starch andflour from seven different genotypes of temperate rice of IndianHimalayas.
Seven different rice cultivars were used in this study, namelyJehlum, K-332, Khosar, Pusa-3, SKAU-345, SKAU-382 and ShalimarRice-1 grown in temperate regions of India, were collected fromSher-e-Kashmir University of Agricultural Sciences and Technologyof Kashmir, India. The grains were dried and cleaned manually toremove foreign matter. The dried and cleaned paddy samples weredehusked on a Stake Testing Rice Husker (THU-34A, Stake, Japan)to obtain brown rice.
2.2. Flour preparation
Flour was prepared by grinding the rice grains using Mini GrainMill (A11B, IKA Inc.) and sifting the material through 300 lm sieveand kept in a refrigerator at about 4 �C for further analysis.
2.3. Starch preparation
Starch was isolated according to the method of (Lawal et al.,2011) with some modifications. Rice was steeped with five timesthe weight of sodium hydroxide solution (0.3%) at 24 �C for 24 hto soften the endosperm. The steep liquor was drained off, thenthe rice was washed and ground with a blender (CromptonGreaves, CG-BX, Mumbai, India). The slurry was again dispersedin sodium hydroxide solution (0.3%) stirred manually for 20 minand allowed to settle for 6 h and the supernatant was drainedoff. The sediment was diluted to the original volume with distilledwater and the supernatant was drained off after 6 h. The processwas repeated until the supernatant was free from NaOH. The starchwas suspended in distilled water, passed through 100–200 meshnylon and repeatedly washed with water. The starch was collectedby sedimentation process. Afterwards, the slurry centrifuged at3000g for 10 min., the supernatant and any brown surface layerof the starch were removed while as, the lower white starch layerwas washed with deionised water. The slurry was suspended indistilled water, the pH was adjusted to 7.0 with HCl (0.5 M) andpassed through nylon screen (53 mm). Afterwards, it was allowedto settle for another 6 h and the clear supernatant was discarded.The starch obtained as sediment was dried in oven at 40 �C.
2.4. Chemical composition
The powdered samples of rice flour and starch were analyzedfor protein, fat, and ash content according to AACC (2000) proce-dures. The amylose content was estimated by the methoddescribed by Williams, Kuzina, and Hlynka (1970).
2.5. Scanning electron microscopy
Morphology of the starch samples was analyzed by scanningelectronic microscopy (Hitachi, S-3400N, Tokyo, Japan). The sam-ples were mounted on aluminium stubs using double sided adhe-sive tape to which the samples were fixed and afterwards werecoated with a thin layer of gold. An acceleration potential of15 kV was used during micrography.
2.6. X-ray diffraction and crystallinity
X-ray diffraction analysis was performed using an X-ray diffrac-tometer (Shimadzu XRD 7000) with Cu Ka value of 1.54060 radia-tion at a speed of 2�/min, diffraction angle of 2h at 4� and 50� at40 kV and 30 mA. The total area under the curve and the area un-
der each prominent peak was determined using OriginPro softwarepackage and the percentage crystallinity was estimated by usingthe following formula:
% Crystallinity = (Area under peaks/Total area) � 100.
2.7. Raman spectroscopy
The Raman spectra were recorded with a Raman spectrometer(InVia, Renishaw, Gloucestershire, United Kingdom), working inconfocal mode. Dry rice starch and flour samples were placed onan aluminium holder. The samples were excited with 785 nm laserline of HP NIR diode laser Renishaw (UK). The laser power was keptlow enough to ensure that it did not damage the sample. Measure-ments were performed with microscope and spectra were takenfrom the same spot size of each sample in the range of 1800 to400 cm�1.
2.8. Swelling power and solubility
Swelling power (SP) and solubility (S) of the rice starch andflour samples were determined according to the methods (Ade-booye & Singh, 2008; Li & Yeh, 2001) with slight modification.500 mg of each flour and starch sample was cooked with 20 mlof water at temperatures of 80 �C for 30 min. Then samples werecooled to room temperature and centrifuged at 2500g for 15 min.The supernatant was decanted, and the residue was weighed forswelling power estimation. The supernatant was poured into aglass dish and kept in a boiling water bath for evaporation. After-wards, the dish was dried at 105 �C and weighed. The solubilityand swelling power were calculated as follows:
S = (weight of the dried supernatant/weight of the wetsediment) � 100.
SP = (weight of the wet sediment/weight of sample-weight ofthe dried supernatant).
2.9. Turbidity
The turbidity of starch and flour samples from different rice cul-tivars were measured by the method (Sodhi & Singh, 2003) with aslight modification. A 2% aqueous suspension of starch or flourfrom each rice cultivar was heated in a boiling water bath for 1 hwith constant stirring. The suspension was cooled to room temper-ature, and then stored for 8 days at 4 �C in a refrigerator. Turbiditywas determined every 24 h by measuring absorbance at 640 nmagainst a water blank with a UV–Vis Spectrophotometer (UV-1800, Shimadzu, Japan).
2.10. Pasting properties
Pasting characteristics of rice starch and flour samples wasdetermined using the Rapid Visco Analyzer (Starch master 2, New-port Scientific Pty. Ltd, Warriewood, Australia). Each of 3 g of ricestarch and flour sample was weighed in RVA canisters and 25 mlof water was added. The prepared slurry in the canisters washeated to 50 �C and stirred at 160 rpm for 10s to enable the com-plete dispersion. The slurry was held at 50 �C for 1 min and tem-perature was raised to 95 �C for 7.5 min. and then held at 95 �Cfor 5 min. The slurry was cooled at 50 �C for 7.5 min, and then heldat 50 �C for 2 min. Pasting parameters including peak viscosity,holding viscosity, final viscosity, breakdown, setback and pastingtemperature were recorded.
2.11. Gel textural properties
The textural properties of RVA gels were determined by textureprofile analysis (HDP/BS blade of texture analyzer (TA-XT2i Stable
Micro Systems, Surrey, U.K.). The starch and flour gels preparedduring rapid visco analyser were sealed in aluminium canistersand stored at 4 �C for 24 h. Then each gel sample inside the tubewas penetrated (to a depth of 16 mm) with a cylindrical probe(5 mm in diameter). Force–time curves were obtained at a cross-head speed of 1.5 mm/s during two penetration cycles. From thetexture profile curve, hardness, cohesiveness, adhesiveness, gum-miness, springiness and chewiness were determined.
2.12. Statistical analysis
The data were analyzed statistically using package SPSS 18.0(SPSS Inc, Chicago, USA) and the means were separated using theDuncan’s multiple range test (p < 0.05). All the data are presentedas the mean with the standard deviation.
3. Results and discussion
3.1. Chemical composition
Perusal of data presented in Table 1 revealed the chemical com-position of rice flour and starch samples. Rice flour contained high-er amount of protein, fat and ash content as compared to ricestarch. Protein, fat and ash content ranged from 6.14% to 7.94%,1.32–1.55% and 18.78–26.86%, respectively in rice flour, whereasin starch samples protein ranged from (0.22% to 0.40%), fat(0.19–0.34%) and ash content (0.12–0.20%). The amylose contentof rice flour samples was found lower than their corresponding iso-lated starches. These results were in accordance with the earlierstudies (Ibanez et al., 2007; Lu et al., 2009). The amylose contentof rice starch varied from 24.69% to 32.76% with the lowest in Kho-sar (24.69%) and highest in Jehlum cultivar (32.76%), whereas, inrice flour the amylose content varied from 17.78% to 24.86% withthe highest in Jehlum (24.86%) followed by SKAU-382 (23.88%)and SKAU-345 (22.0%1). The amylose content was found withinthe range as reported by Wani et al. (2013) for the starches of tem-perate rice varieties. Wang et al. (2012) reported that amylose con-tent varied between 18.1% and 31.6% for starches isolated from
Table 1Proximate composition, crystallinity, solubility and swelling power of starch and flour fro
Values are expressed as mean ± standard deviations. Means having same letters within
Chinese rice cultivars. This difference in chemical compositionmight be due to the different agro-climatic zones and cultivars.
3.2. Morphology of starch granules
The starch granule morphology as depicted in Fig. 1 showedthat the starch granules are polyhedral with irregular shapes andsize in the range of 2.3–6.5 lm in different rice starches. SKAU-382 starch showed the presence of largest size granules (3.6–6.5 lm), whereas, K-332 (2.3–5.4 lm) had the smallest sizes. Inaddition to polyhedral granules, some were also round in shape.Sodhi and Singh (2003) reported the average size of 2.4–5.4 lmfor Indian tropical rice starches. Previous studies have also shownthe rice starch granules of varying size (Li & Yeh, 2001). Climate,agronomic practices, cultivar and starch biosynthesis are responsi-ble for starch granule diversity (Wani et al., 2012).
3.3. X-ray diffraction
The X-ray diffractograms (XRD) of starch samples are shown inFig. 2a. The XRD results of rice starch showed the typical A-typestarch crystalline pattern with strong reflections at Bragg’s angle(2h) at about 15, 18.09, and 23.5. It has been reported that X-raydiffraction of rice starch showed the typical A-type pattern andmostly strong reflections at 2h = 15, 17, 18, 23 (Singh, Kaur, Sodhi,& Sekhon, 2005; Yu et al., 2012). The results obtained in our studyare consistent with those reported in literature (Yu et al., 2012).The intensity of the reflection of rice flour was lower as comparedto their respective starch. The rice flour samples also exhibited theA-type diffraction pattern (Fig. 2b) with major peaks at Bragg’s an-gle (2h) position near 14.93, 18.09, and 22.97. The results are sim-ilar to the reports of Lamberts, Gomand, Derycke, and Delcur(2009) and Yu et al. (2012).
The relative crystallinity degrees (%) shown in Table 1. revealedthat relative crystallinity degree values of rice flour were lower ascompared to their corresponding starches. Other componentsmight affect the crystallinity like protein and lipids present in riceflour in higher amounts as compared to rice starch (Ibanez et al.,2007; Yu et al., 2012). The highest crystallinity per cent of 17.62
was exhibited by cultivar SKAU-345 followed by Khosar (17.44%)and Pusa-3 (16.76%) in rice starch. The difference in proportionsof amylose, short and long side-chain amylopectin may be respon-sible for the difference in crystallinity among different ricestarches.
3.4. Raman spectroscopy
Raman spectroscopy a fast and non-destructive qualitative andquantitative analytical tool was used to probe the internal vibra-tions of molecules. Raman spectroscopy is a suitable method for
Fig. 2. X-ray diffractographs of starch (a) and flour (b); Raman spectrum of starch (c) and flour (d) from temperate rice cultivars of Indian Himalayas. A: Jehlum; B: K-332; C:Khosar; D: Pusa-3; E: SKAU-345; F: SKAU-382; G: Shalimar Rice 1.
Table 2Positions of Raman bands and their respective assignments in starch.
Band position (cm�1) Assignment References
412 CACAO pyranose ring skeletal modes Soderholm, Roos, Meinander, and Hotokka (1999)440 Skeletal modes of pyranose ring Kaurakova and Mathlouthi (1996), Soderholm et al. (1999)478 Skeletal modes of pyranose ring Kaurakova and Mathlouthi (1996)523 Skeletal modes of pyranose ring Kaurakova and Mathlouthi (1996)718 CAC stretching Cael et al. (1973)770 CAC stretching Cael et al. (1973)865 CAOAC ring mode, C1AH bending a configuration Cael et al. (1973)940 Skeletal mode vibration of aA1,4 glycosidic linkage (CAOAC) Pigorsch (2009)1050 CAC stretching Pigorsch (2009)1083 CAOAH bending Passauer, Bender, and Fischer (2010)1109 CAC bending, (CAO), (CAOAH)1128 CAO stretching, CAOAH bending Pigorsch (2009)1260 CH2, CH2OH related mode Cael et al. (1973)1340 CH2 twisting, CAOAH bending Passauer et al. (2010)1381 CH2 scissoring, CAH and CAOAH bending Pigorsch (2009)1460 CH2 twisting, CH2 bending Cael et al., 1973
structural characterization of the sample. Raman spectra of thestarch and flour samples in the 400–1800 cm�1 region are shownin Fig. 2c and d respectively, and their band assignments werelisted in Table 2.
All the characteristic bands for rice starch samples were clearlyvisible as compared to flour samples and the positions of theobserved bands were almost the same. Vibrations in the 800–400 cm�1 region of starch sample were due to CCO and CCC
deformations, and this region is having a strong coupling which isrelated to the glycosidic ring skeletal deformations. In all the spec-tra of the samples, the highest intensity shown mostly a band at478 cm�1 due to skeletal mode, involving (CAOAC) ring modeand (CACAO). The band of 865 cm�1 is assigned to symmetric C(1) AOAC (5) stretching of the a-D-glucose ring (Cael, Koenig, &Blackwell, 1975). As reported previously, the ratio of the bands at942 cm�1 is sensitive to the ratio of linear/branched residues(Liu, Himmelsbach, & Barton, 2004). The vibrations originatingfrom a-1,4 glycosidic linkages can be observed as strong ramanbands in the 920–960 cm�1 region, and thus the band observedat 940 cm�1 was assigned to the amylose a-1,4 glycosidic linkage.Among other bands the characteristic for starch were the bands:860 cm�1 originating from (CAOAC) ring mode and C1AH bendinga-configuration.
The coupling of the CCH and COH deformation modes can beobserved in the region between 1380 and 1400 cm�1, whereas sev-eral vibrational modes are observed in the region between 1340and 1,200 cm�1 bands such as CO and CC stretching and CCH,COH and CCH deformations. The band at 1381 cm�1, usually as-signed to d (CAOH) and d (CAH) modes in polymers (Cael, Koenig,& Blackwell, 1973). Benzerdjeb, Mokhtari, and Rahal (2007)),reported the region between 1200 and 800 cm�1 is a characteristicof the CO and CC stretching and COC deformation modes, referringto the glycosidic bond. This region is also known as the fingerprintor anomeric region, and is very often cited by other authors, likeYang and Zhang (2009), and Thygesen, Lokke, Micklander, andEngelsen (2003). The observed bands at about 1460 cm�1 couldbe attributed to (CH2) twisting and CH bending, whereas1340 cm�1 to (CH2) and CAOH bending.
3.5. Swelling power
The swelling power of rice starch varied from 10.56 to 19.54 g/gstarch as shown in Table 1, with the lowest in Jehlum (10.56 g/g)and highest in Khosar cultivar (19.54 g/g). Lee and Osman (1991)reported the swelling index of rice starch in the range of 7.70–22.76 g/g starch. The difference in swelling power may be relatedto the differences in amylopectin content among the rice cultivars.Swelling power is a measure of the ability of the starch to hydrateunder specific conditions like temperature and water content. Asreported by different workers that greater swelling capacity is anindication of weaker binding forces in the starch granules (Hoover& Manuel, 1996). The swelling power of a starch depends on the ra-tio and molecular weights of amylose and amylopectin, and alsointra- and inter-molecular interactions. The amylopectin is likelyto swell due to the weakness of the intra- and inter-molecularcoherence in starch, while as, amylose acts as an inhibitor of swell-ing (Tester & Morrison, 1990).
The swelling power of rice flours shown in Table 1, varied from7.72 to 11.12 g/g rice flour with the highest observed in Khosar cul-tivar. However, the swelling power of rice flour was lower thantheir derived starches. The swelling power of flour depends onthe packing of starch granules with proteins and lipids. The swell-ing power of starch is related to gelitinization of starch reflectingbreaking of hydrogen bonds in the crystalline regions and uptakeof water by hydrogen bonds and water absorption by non-starchpolysaccharides and protein (Thitipraphunkul, Uttapap, Piya-chomkwan, & Takeda, 2003; Yu et al., 2012).
3.6. Solubility
Significant differences (p < 0.05) were observed in solubilitybetween the starch and flour samples of different rice cultivars(Table 1). The cultivar Khosar showed the highest solubility valuesfor starch (9.06 g/g) and flour (15.98 g/g) whereas, the cultivar
Jehlum showed the lowest value of (3.23 g/g) and (7.67 g/g) forstarch and flour respectively. The cultivar Khosar having the highamylopectin content as compared to other cultivars, showed highsolubility. Solubility is related to the presence of soluble moleculeslike amylose (Tester & Morrison, 1990), which will vary with culti-var. Wang et al. (2010) reported the solubility value of 17–40% forstarches from Chinese rice cultivars. Upon heating insoluble starchswells by penetrating water and weakened the infrastructure ofhydrogen bonds, and correspondingly some fragments of thestarch could be solubilised. The hydrogen bonds can be easilyweakened in the starch granules with high amylopectin contentand leading to the high solubility values.
3.7. Turbidity
The turbidity values of gelatinized starch suspension variedamong the rice cultivars as depicted in Fig 3a. The differences inturbidity might be due to difference in amylose content and theamount of swollen granule remnants (Jacobson, Obanni, & Bemil-ler, 1997), as well as the granular structure (Wang et al., 2010).The turbidity values of K-332 and Khosar starch suspension wassignificantly lower than the turbidity values of other rice cultivars.The lowest turbidity values of K-332 and Khosar starch suspensionmay be due to their low amylose content and smallest starch gran-ule size (Jacobson et al., 1997; Sodhi & Singh, 2003). The turbidityvalues of starch suspensions progressively increased with in-creased in storage period up to 4th day and further storage causeda slight increase. The aggregation and crystallization of amyloseoccur highest during first four storage days. The increase in turbid-ity during the storage period may be due to the leached amyloseand amylopectin chains that lead to the development of the
functional zone which scatter a significant amount of light (Yuet al., 2012).
The flour samples showed higher turbidity values as comparedto their derived starch as depicted in Fig. 3b. These results may bedue to the other components of the flour, such as protein, lipid andfibre, which influences the turbidity value of flour suspension. Dur-ing the gelatinization process, amylose lipid complex is formed(Kaur & Singh, 2000), which retard the starch molecule aggrega-tion, so the turbidity value of rice flour suspension increased muchslower than the starch solution. Jehlum flour samples showed thehighest turbidity value, while Khosar cultivar showed the lowestvalue. This may be due to the variation in amylose content amongthe different cultivars with highest found in the cultivars havinghigher turbidity values.
3.8. Pasting properties
Significant differences (p < 0.05) were observed among thepasting properties of starch samples of different rice cultivars aspresented in Table 3. Peak viscosity of rice starch samples rangedfrom 2657 to 3911 cP. The highest peak viscosity was shown byK-332 starch, whereas, the lowest by Pusa-3 starch. The differencein pasting properties was observed due to the variation in amylose
Table 3Pasting and textural properties of starch and rice samples from temperate rice of Indian H
Values are expressed as mean ± standard deviations. Means having same letters within
content among the rice cultivars. Holding viscosity and final vis-cosity in the rice starch samples ranged from 1335 to 3027 cPand 3492 to 5173 cP, respectively. Breakdown viscosity, measureof the starch paste resistance to heat and shear, were ranged from578 to 2541 cP with the highest in K-332 cultivar (2541 cp) fol-lowed by Khosar (2487 cp) and Shalimar Rice 1 (4171 cp) and low-est in Jehlum cultivar (578 cp). Setback viscosity showed thetendency of starch pastes to retrograde, varied significantly(p < 0.05) and ranged from 2248 (K-332) to 2882 cP (Jehlum). Past-ing temperature, the temperature at the onset of rice in viscosityvaried significantly (p < 0.05) and ranged from 70.25 to 77.65 �Cwith the highest value was observed for SKAU-382 and lowestfor K-332. The pasting properties of starches are affected by theamylose, lipid, protein contents, and swelling power (Li & Yeh,2001).
The pasting properties of rice flours varied significantly(p < 0.05) as shown in Table 3. Jehlum flour showed the highestpeak viscosity, holding viscosity, final viscosity, breakdown viscos-ity and setback viscosity of 3354, 2674, 6631, 699 and 3267 cP,respectively. However, Pusa-3 showed the lowest values 1632,1475, 3236, 143 and 1604 cP, respectively. The results indicatedthat Pusa-3 is weakly resistant to shearing, and difficult to retro-grade and can be easily used as a paste. The pasting temperature
of the flour varied significantly (p < 0.05) from 86.90 to 92.35 �C inShalimar Rice 1 and K-332 cultivar, respectively. The presence ofother components such as lipids, protein, fibre and lower amountof starch in flour influenced the pasting properties. This may bedue to the interaction between amylose and lipid or protein. Previ-ous literature reported that proteins, lipids and amylose, lipid amy-lose complex significantly influence the pasting properties of riceflours (Kaur & Singh, 2000).
3.9. Textural properties
The textural values (Table 3) of starch and flour gels of rice cul-tivars determined by textural analyzer differ significantly amongthe rice cultivars (p < 0.05). The starch samples have much hardergel firmness than their respective rice flours. The high gel hardnessin rice starches is due to high amylose content as compared to floursamples (Yu et al., 2012) and mainly caused by starch gel retrogra-dation, associated with crystallization of amylose in a short timewhich lead to harder gels (Miles, Morris, Orford, & Ring, 1985).The highest gel hardness were observed in Jehlum rice starch(65.25 g) and flour (10.91 g), whereas, the lowest value were inKhosar starch (16.42 g) and flour (6.32 g) gel. Starch gel strengthis mainly affected by factors like composition, properties of thegranules, and molecular interaction with water. Bao, Ao, and Jane(2005) reported that the amylose content served as a good indica-tor for gel hardness of rice flour paste.
The rice starch gels showed mostly higher textural values ascompared to respective flour gels. The highest springiness, gummi-ness and chewiness values were observed for Jehlum whereas,lowest for Khosar rice starch and flour gels. The gel formation ofstarch mainly depends on swollen starch granules that hold waterin the network within the granule. Amylose leaked from swollengranules plays a minor role and becomes more significant whenthe swollen granules disrupt. Other components mainly flour sam-ples, such as protein, lipid, and non-starch polysaccharides wouldalso take part in the network formation during the gel formationprocess which also influences the gel texture properties (Yuet al., 2012).
4. Conclusion
Flour and starches from different rice cultivars collected fromtemperate region of Indian Himalaya exhibit significant differencesin their physicochemical properties. The study showed significantdifferences in composition among the starches and flour of rice cul-tivars. The starch showed varied granule size from 2.3 to 6.5 lm.The X-ray diffraction patterns of rice starches and flours showedA type pattern with relative crystallinity degree varied amongthe cultivars. Raman spectroscopy method has been used to iden-tify the structural characteristics of rice starch and flour. Pastingproperties significantly varied and is useful for assessing the cook-ing quality of rice starch and flours. Swelling power, solubility, tur-bidity, and gel texture value of rice starches and flours variedamong the cultivars and were related to amylose content.
Acknowledgements
The authors are thankful to the Department of Food Science andTechnology and Central Instrumentation Facility, Pondicherry Uni-versity for providing laboratory and instrumental facilities.
References
AACC (2000). Approved methods of the AACC (eighth ed.). St Paul, MN: AmericanAssociation of Cereal Chemists.
Adebooye, O. C., & Singh, V. (2008). Physico-chemical properties of the flours andstarches of two cowpea varieties (Vigna unguiculata (L.) Walp). Innovative FoodScience and Emerging Technologies, 9(1), 92–100.
Aina, A. J., Falade, K. O., Akingbala, J. O., & Titus, P. (2012). Physicochemicalproperties of Caribbean sweet potato (Ipomoea batatas (L) Lam) starches. Foodand Bioprocess Technology, 5(2), 576–583.
Bao, J. S., Ao, Z. H., & Jane, J. L. (2005). Characterization of physical properties of flourand starch obtained from gamma-irradiated white rice. Starch/Starke, 57(10),480–487.
Benzerdjeb, A. M., Mokhtari, I. N. T., & Rahal, M. S. (2007). Normal coordinatesanalyses of disaccharides constituted by D-glucose, D-galactose and D-fructoseunits. Spectrochimica Acta Part A, 68(2), 284–299.
Cael, J. J., Koenig, J. L., & Blackwell, J. (1973). Infrared and Raman spectroscopy ofcarbohydrates, part III: Raman spectra of the polymorphic forms of amylose.Carbohydrate Research, 29(1), 123–134.
Cael, J. J., Koenig, J. L., & Blackwell, J. (1975). Infrared and Raman spectroscopy ofcarbohydrates. Part VI: Normal coordinate analysis of V-amylose. Biopolymers,14(9), 1885–1903.
Falade, K. O., Semon, M., Fadairo, O. S., Oladunjoye, A. O., & Orou, K. K. (2014).Functional and physico-chemical properties of flours and starches of Africanrice cultivars. Food Hydrocolloids, 39, 41–50.
Hoover, R., & Manuel, H. (1996). The effect of heat-moisture treatment on thestructure and physicochemical properties of normal maize, waxy maize, dullwaxy maize and amylomaize V starches. Journal of Cereal Science, 23(2),153–162.
Ibanez, A. A., Wood, D. F., Yokoyama, W. H., Park, I. M., Tinoco, M. A., Hudson, C. A.,et al. (2007). Viscoelastic properties of waxy and nonwaxy rice flours, their fatand protein-free starch, and the microstructure of their cooked kernels. Journalof Agriculture and Food Chemistry, 55(16), 6761–6771.
Jacobson, M. R., Obanni, M., & Bemiller, J. N. (1997). Retrogradation of starches fromdifferent botanical sources. Cereal Chemistry, 74(5), 511–518.
Kaur, K., & Singh, N. (2000). Amylose-lipid complex formation during cooking of riceflour. Food Chemistry, 71(4), 511–517.
Kaurakova, M., & Mathlouthi, M. (1996). FTIR and laser-Raman spectra ofoligosaccharides in water: Characterization of the glycosidic bond.Carbohydrate Research, 284(2), 145–157.
Labanowska, M., Birczynska, A. W., Kurdziel, M., & Puch, P. (2013). Thermal effectson the structure of cereal starches. EPR and Raman spectroscopy Studies.Carbohydrate Polymers, 92(1), 842–848.
Lamberts, L., Gomand, S. V., Derycke, V., & Delcur, J. (2009). Presence of amylosecrystallites in parboiled rice. Journal of Agricultural and Food Chemistry, 57(8),3210–3216.
Lawal, O. S., Lapasin, R., Bellich, B., Olayiwola, T. O., Cesàro, A., Yoshimura, M., et al.(2011). Rheology and functional properties of starches isolated from fiveimproved rice varieties from West Africa. Food Hydrocolloids, 25(7), 1785–1792.
Lee, Y. E., & Osman, E. M. (1991). Correlation of morphological changes of rice starchgranules with rheological properties during heating in excess water. Journal ofKorean Agricultural Chemical Society, 34, 379–385.
Li, J. Y., & Yeh, A. I. (2001). Relationships between thermal, rheologicalcharacteristics and swelling power for various starches. Journal of FoodEngineering, 50(3), 141–148.
Lin, J. H., Singh, H., Chang, Y. T., & Chang, Y. O. (2011). Factor analysis of thefunctional properties of rice flours from mutant genotypes. Food Chemistry,126(3), 1108–1114.
Liu, Y. L., Himmelsbach, D. S., & Barton, F. E. (2004). Two-dimensional Fourier trans-form Raman correlation spectroscopy determination of the glycosidic linkagesin amylose and amylopectin. Applied Spectroscopy, 58(6), 745–749.
Lu, Z. H., Sasaki, T., Li, Y. Y., Yoshihashi, T., Li, L. T., & Kohyama, K. (2009). Effect ofamylose content and rice type on dynamic viscoelasticity of a composite ricestarch gel. Food Hydrocolloids, 23(7), 1712–1719.
Miles, M. J., Morris, V. J., Orford, P. D., & Ring, S. G. (1985). The roles of amylose andamylopectin in the gelation and retrogradation of starch. Carbohydrate Research,135(2), 271–281.
Mir, S. A., Bosco, S. J. D., & Sunooj, K. V. (2013). Evaluation of physical properties ofrice cultivars grown in the temperate region of India. International Food ResearchJournal, 20(4), 1521–1527.
Passauer, L., Bender, H., & Fischer, S. (2010). Synthesis and characterization of starchphosphates. Carbohydrate Polymers, 82(3), 809–814.
Pigorsch, E. (2009). Spectroscopic characterization of cationic quaternaryammonium starches. Starch/Starke, 61(3), 129–138.
Puncha-Arnon, S., & Uttapap, D. (2013). Rice starch vs. Rice flour: Differences intheir properties when modified by heat–moisture treatment. Carbohydratepolymers, 91(1), 85–91.
Singh, N., Kaur, L., Sodhi, N. S., & Sekhon, K. S. (2005). Physicochemical, cooking andtextural properties of milled rice from different Indian rice cultivars. FoodChemistry, 89(2), 253–259.
Soderholm, S., Roos, Y. H., Meinander, N., & Hotokka, M. (1999). Raman spectra offructose and glucose in the amorphous and crystalline states. Journal of RamanSpectroscopy, 30(11), 1009–1018.
Sodhi, N. S., & Singh, N. (2003). Morphological, thermal and rheological properties ofstarches separated from rice cultivars grown in India. Food Chemistry, 80(1),99–108.
Tester, R. F., & Morrison, W. R. (1990). Swelling and gelatinization of cereal starches.I. Effects of amylopectin, amylose and lipids. Cereal Chemistry, 67(6), 551–557.
Thitipraphunkul, K., Uttapap, D., Piyachomkwan, K., & Takeda, Y. (2003). Acomparative study of edible canna (Canna edulis) starch from different
cultivars. Part I. Chemical composition and physicochemical properties.Carbohydrate Polymers, 53(3), 317–324.
Thygesen, L. G., Lokke, M. M., Micklander, E., & Engelsen, S. B. (2003). Vibrationalmicrospectroscopy of food. Raman vs. FT-IR. Trends in Food Science & Technology,14(1), 50–57.
Wang, L., Xie, B., Shi, J., Xue, S., Deng, Q., Wei, Y., et al. (2010). Physicochemicalproperties and structures of starches from Chinese rice cultivars. FoodHydrocolloids, 24(2), 208–216.
Wang, L., Xie, B., Xiong, G., Du, X., Qiao, Y., & Liao, Y. (2012). Study on the granularcharacteristics of starches separated from Chinese rice cultivars. Carbohydratepolymers, 87(2), 1038–1044.
Wani, A. A., Singh, P., Shah, M. A., Wani, I. A., Gotz, A., Schott, M., et al. (2013).Physico-Chemical, thermal, rheological properties of starches isolated fromnewly released rice cultivars grown in Indian temperate climates. LWT-FoodScience and Technology, 53(1), 176–183.
Wani, A. A., Singh, P., Shah, M. A., Weisz, U. S., Gul, K., & Wani, I. A. (2012). Ricestarch diversity: Effects on structural, morphological, thermal, and
physicochemical properties – A review. Comprehensive Reviews in Food Science& Safety, 11(5), 417–436.
Williams, P. C., Kuzina, F. D., & Hlynka, I. (1970). A rapid colorimeteric procedure forestimating the amylose content of starches and flours. Cereal Chemistry, 47,411–420.
Wu, F., Chen, H., Yang, N., Wang, J., Duan, X., Jin, Z., et al. (2013). Effect ofgermination time on physicochemical properties of brown rice flour and starchfrom different rice cultivars. Journal of Cereal Science, 58(2), 263–271.
Yang, L., & Zhang, L. M. (2009). Chemical structural and chain conformationalcharacterization of some bioactive polysaccharides isolated from naturalsources. Carbohydrate Polymers, 76(3), 349–361.
Yu, S., Ma, Y., Menager, L., & Sun, D. (2012). Physicochemical properties of starchand flour from different rice cultivars. Food Bioprocess Technology, 5(2),626–637.
Zhu, L. J., Liu, Q. Q., Wilson, J. D., Gu, M. H., & Shi, Y. C. (2011). Digestibility andphysicochemical properties of rice (Oryza sativa L.) flours and starches differingin amylose content. Carbohydrate Polymers, 86(4), 1751–1759.
