Physicochemical properties, digestibility and expected glycaemic index of high amylose rice differing in length‐width ratio in Sri Lanka (original) (raw)
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PloS one, 2016
A total of 787 non-waxy rice lines- 116 hybrids and 671 inbreds-were used to study the apparent amylose content (AAC), gelatinization temperature (GT), and rapid visco analyzer (RVA) pasting viscosity properties of rice starch to understand their importance in breeding better rice varieties. The investigated traits showed a wide range of diversity for both hybrid (HG) and inbred (IG) groups. The combinations of the different categories of AAC and GT were random in HG but were non-random in IG. For inbred lines, the high level of AAC tended to combine with the low level of GT, the intermediate level of AAC tended to have high or intermediate GT, and the low level of AAC tended to have high or low GT. Some stable correlations of the AAC, GT, and RVA properties may be the results derived from the physicochemical relationships among these traits, which rice breeders could utilize for selection in advanced breeding generations. Through cluster analysis, IG and HG were divided into 52 and...
Changes in the properties of rice varieties with different amylose content on dry heat parboiling
Journal of Cereal Science, 2015
Dry heat parboiling is a unique paddy processing technique that has been scarcely exploited. Dry heat parboiling at high temperature for short time and low temperature for long time on physical and physicochemical properties of three rice varieties differing in amylose content were studied. Hardness of the kernels increased from 66.4 N, 68.8 N and 59.8 N in raw samples to 89.1 N, 86.9 N and 59.8 N in parboiled high amylose, low amylose and waxy rice samples respectively. Rapid migration and evaporation of water from severely heated kernels caused cavity formation at the centre. Irreversible damage of amylopectin structures to leachable fractions caused continuous rise of the pasting curve. Crystallinity was thereby reduced. Parboiled high amylose samples gave X-ray diffraction patterns with peaks characteristic of A, B and Vtype starch crystallinity. Crystalline starch-lipid complexes were observed in low amylose and waxy rices. The significant increase in the amount of rapidly digestible starch from 56.7%, 61.7% and 66.6% in raw samples to 92.1%, 90.8% and 94.8% respectively in severely processed rice samples and subsequent reduction in resistant starch from 24.5%, 21.2% and 18.4% to 0.4%, 1.9% and 0.1% indicated possibilities for targeted food use of the dry heat parboiled samples.
Starch - Stärke, 2003
Presently, rice cultivars are categorized according to amylose content into three groups: low, medium and high amylose content cultivars. The correlation of amylose content with gelatinization properties, retrogradation, and pasting properties of eleven cultivars of Thai rice were investigated. Rice flour was prepared from milled rice by the wet grinding process. Onset (T o ), peak (T p ) and conclusion (T c ) temperatures of gelatinization, (determined by DSC) were found to be highly positively correlated with amylose levels. This correlation could be used for prediction of amylose content of rice flour. Low amylose starch could also be characterized by low degree of retrogradation (%R). The data obtained from RVA-viscograms (peak viscosity, breakdown, setback, and pasting temperature) can be used only for characterization of the group of low amylose starches (waxy rice). It was demonstrated that low amylose rice starch provided the highest peak viscosity and breakdown and the lowest setback and pasting temperature among the groups investigated.
International Journal of Food Properties, 2014
Grain quality attribute tests based on physicochemical, textural, pasting, and in vitro digestion properties of eight different rice cultivars were studied. Basmati varieties showed higher values of amylose content, iodine absorption, blue value, hardness, cohesiveness, pasting temperature, and set back, whereas swelling power, solubility, adhesiveness, peak viscosity, and breakdown values were found to be higher in non-basmati varieties. The release of maltose from basmati rice flour (23.12-25.86 mg/g rice flour) was found to be slower as compared to non-basmati ones (27.43-28.36 mg/g rice flour). Amylose content showed significant correlations with different quality parameters at 5% level of significance.
International Journal of Food Properties, 2010
Physicochemical, morphological, thermal, and pasting properties of starches, isolated from basmati (HBC-19 and Bas-370) and non-basmati (Jaya, a coarse cultivar; P-44 and HKR-120, the medium cultivars and Sharbati, fine cultivar) rice cultivars grown in India were studied. The amylose content of starches from different cultivars ranged from 2.25 (Jaya) to 22.21 g/100 g of starch (HBC-19). Jaya, HKR-120, and P-44 cultivars showed soft gel consistency as 84, 73, and 69 mm, respectively, whereas Sharbati, Bas-370 and HBC-19 cultivars showed medium gel consistency as 54, 53, and 58 mm, respectively. Swelling power (at 95°C) indicated a significant positive correlation with amylopectin content (r = 0.828, p < 0.05) and gel consistency (r = 0.983, p < 0.01). Turbidity had a highly significant positive correlation with solubility (r = 0.919, p < 0.01) and amylose content (r = 0.945, p < 0.01). Starch form Jaya cultivar showed the presence of smallest size granules (2.4–5.7 μm) with an average size of 3.96 μm, whereas Bas-370 showed the presence of largest size granules (3.3–6.7 μm) with an average size of 5.0 μm. The transition temperatures, enthalpy of gelatinization (ΔHgel), peak height index (PHI) and gelatinization range were determined using differential scanning calorimetry (DSC). The starch from Sharbati cultivar showed highest onset temperature (To), peak temperature (Tp), conclusion temperature (Tc), enthalpy of gelatinization and peak height index (PHI) of 68.8°C, 73.2°C, 79.0°C, 11.56 J/g and 2.63 respectively. Pasting temperature of rice starches varied from 68.9°C (Jaya) to 74.5°C (Sharbati). The peak viscosities observed were in the range of 2223 to 3297 cP, lowest for HBC-19 starch and highest for Jaya starch.
International Journal of Biological Macromolecules, 2016
The research was carried out to investigate the effect of starch powder particle size, morphology, amylose content and varietal effect on physicochemical, X-ray diffraction pattern, thermal and pasting characteristics. The results indicated that starches isolated from seven traditional rice cultivars of temperate region of India have possessed higher yield (82.47 to 86.83%) with lower degree of granule damage and higher level of starch crystallinity (36.55 to 39.15%). The water and oil binding capacities were observed to correlate positively with amylose content. The bulk density and color parameters of starches were found to have linked with starch powder particle size coupled with arrangement and morphology of the starch granules. The rice cultivars having smaller starch powder particle size indicated lowest degree of crystallinity. Morphological studies revealed that the starches with tightly packed granules had greater mean granular width, while granules with openly spaced granular morphology depicted the higher values for mean granular length. The peak height index (PHI) among different starches ranged from 1.01 to 2.57 whereas the gelatinization range varied from 10.66 to 10.88. Concluding, the differences in distributional pattern of starch granule size and shape and powder particle size indicated a significant effect on the functional properties of starch.
Chemometric tests were carried out to better understand the multidimensional facet of starch fine structure-relationship concerning gelatinization and pasting properties. With Ward's hierarchical cluster analysis 20 long-grain rice starch samples were sorted out into three clusters based on similarities in functional properties, particularly, paste peak (PV) and final viscosity (FV). The three clusters (arbitrarily named Clusters A, B, and C) exhibited a pasting profile trend of PV,FV, PV,FV, and PV.FV, respectively. Cluster A samples were also lower in peak temperature, range and enthalpy of gelati-nization, and swelling power. These attributes were associated with higher amylose content (AM), b-amylolysis limit, and percentage of B1 chains (DP13-24), but lower amylopectin weight-average molar mass (M w) and percentage of A chains (DP6-12). A 5-variable linear discriminant function correctly predicted 85% of the Ward's cluster membership of the individual cultivars. The discriminant function included the variables A, B1, and B2 (DP25-36) chains, average chain length (ACL), and gyration radius (R z). Fine structure variance was fully explained by a total of nine principal components, with the first three components cumulatively accounting for 74%. The leading variables included in the three rotated components pertained to amylopectin chain length distribution (A, B2, and B31 or DP!37 chains, and ACL) and amylopectin molar mass (M w , R z , and polydispersity). AM and M w were loaded most frequently in the 4-variable, best-fit linear regression models for predicting gelatinization and pasting properties. A combination of at least two fine structure variables controls the functionality of rice starch.
In vitro digestibility and physicochemical properties of milled rice
Food Chemistry, 2015
Rice is a staple diet as well as a major ingredient in many processed foods. The physicochemical and supra-molecular structure of eight rice varieties with amylose content from 9% to 19% were studied to elucidate the factors responsible for variation in enzymatic digestibility of raw and cooked rice. Parboiled rice had a digestion rate coefficient almost 4.5 times higher than the least digestible Low GI rice. The rate coefficient was found to be independent of helical structure and long range molecular order, possibly attributed to the effect of rice flour architecture. Strong swelling and pasting behaviour and lower gelatinisation temperature were linked with apparently higher in vitro digestibility but the relationship was statistically insignificant. It is concluded that the enzymatic susceptibility of rice flours are independent of supra-molecular structure and are most likely controlled by external factors not limited to particle size, presence of intact cell wall and other non-starch polymers.
Journal of Food Science and Technology-mysore, 2010
In vitro starch digestibility and glycemic indices of three rice varieties- ‘Njavara’, ‘Jyothi’ (pigmented rice verities) and ‘IR 64’ (non-pigmented rice) with similar amylose content were studied. Starch digestibility studies showed differences in glycemic response in three types of rice. The rate of starch hydrolysis was maximum (67.3%) in ‘Njavara’ rice compared to other two rice varieties. ‘Njavara’ exhibited the lowest kinetic constant (k) indicating inherent resistance to enzymatic hydrolysis. The glycemic load (GL) and glycemic index (GI) of ‘Njavara’ were similar to ‘Jyothi’ and ‘IR 64’. Resistant starch content was high in pigmented rice varieties compared to ‘IR 64’. The resistant starch content of dehusked and cooked rice increased with the storage time at refrigeration temperature (4°C). ‘Njavara’ is an easily digestible rice and can be used for baby and geriatric foods.
Cereal Chemistry, 2020
Background and objectives: Variation in composition and functionality of glutinous rice starch greatly affects their industrial application. This study examined the starch compositional, structural, and functional variability among five Thai glutinous rice cultivars, and the effect of molecular structure and composition on starch functionality was pinpointed. Findings: Amylose content, amylopectin chain-length distribution (CLD), and relative crystallinity were not different among the cultivars (p ≤ .05), whereas RD14 possessed largest mean granule diameter. Conclusion temperature of gelatinization and peak viscosity (PV) were lowest in RD6 and RD10, respectively, while RD6, RD10, and RD14 had lower breakdown (BD) compared to others. Despite small variation within each parameter, multivariate analysis revealed the distinct characteristic of waxy donor, RD6, and RD10 compared to others. Proportion of amylopectin B1 chains and granule size showed negative correlation (r > 0.5) with PV and BD, respectively, whereas proportion of amylopectin B2 chains positively correlated (r > 0.5) with PV and final viscosity (FV). Conclusion: Amylopectin CLD and starch granule size were the key factors determining starch pasting properties among these waxy rice genotypes. Significance and novelty: Variations in composition, structure, and properties of Thai glutinous rice starches were observed, which could be adopted for a diverse array of end uses.