Digestibility and physicochemical properties of rice (Oryza sativa L.) flours and starches differing in amylose content (original) (raw)
Related papers
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.
Intrinsic and extrinsic factors affecting rice starch digestibility
Trends in Food Science & Technology, 2019
Background: The current incidence of obesity and type 2 diabetes is at global epidemic levels. To mitigate their impact, there is a need to develop starch-containing foods that give rise to a low and stable postprandial blood glucose response by increasing the proportion of slowly-digestible and indigestible carbohydrate content. Rice is an ideal target food for such dietary intervention because it is a staple food for over half the world's population. Scope and approach: The starch digestion of cooked white rice grains is usually complete or near complete upon consumption, but the rate of digestion is influenced by intrinsic food properties and extrinsic influences. This review provides an overview of the complex interplay between the starch granule and its interaction with non-starch components of the rice grain (intrinsic characteristics) as well as the effects of processing (extrinsic factors) on starch digestibility. Key findings and conclusions: The intrinsic properties of white rice grains play a significant role in starch digestibility which can be further enhanced after processing, especially by gelatinisation and retrogradation. Post-harvest storage conditions of rice were found to influence starch digestibility but this effect was temperature-dependent. Limited studies investigated starch-lipid and starch-protein interactions in rice, but changes to substrate accessibility have been implicated. Improving our understanding of the effects of processing on starch digestibility can provide an effective tool for food manufacturers to regulate starch digestibility of existing rice varieties.
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.
Rice Starch Molecular Size and its Relationship with Amylose Content
Starch - Stärke, 2007
The composition and starch molecular structure of eight rice varieties were studied. Waxy and non-waxy (long-, medium-, and short-grain) rice varieties from California and Texas were used. The amylose contents were measured using the Concanavalin A method and were found to be related to the type of rice: waxy < 1.0%, short and medium grain 8.7-15.4%, and long grain 17.1-19.9%. The weight-average molar masses (M w ) of the starches varied from 0.52 to 1.96610 8 g/mol. As would be expected, a higher M w of rice starch correlated to lower amylose content. The range of M w of amylopectin was 0.82 to 2.50 610 8 g/mol, and there was also a negative correlation of amylopectin M w with amylose content. Amylose M w ranged from 2.20 to 8.31610 5 g/ mol. After debranching the amylopectin with isoamylase, the weight-average degree of polymerization (DP w ) for the long-chain fraction correlated positively with a higher amylose content. California and Texas varieties were significantly different in their amylose content, starch M w (short-and medium-grain only), and amylopectin M w (p , 0.05).
LWT, 2017
Rice is a staple food worldwide. In this study, seven African rice (Oryza glaberrima) accessions (ARAs) were evaluated for grain quality attributes, pasting, thermal and in vitro digestion properties in comparison with two Asian rice (Oryza sativa) varieties (ARVs) and a developed cross (O. sativa x O. glaberrima cross). The ARAs were intermediate to high amylose rice types and their 1000-kernel weight and bulk densities were comparable to the ARVs. Volume expansion ratios of cooked kernels overlapped among rice varieties ranging from 2.5-4.4 and the ARAs had relatively lower cooking solids loss and harder texture compared to the ARVs which were softer and more adhesive. Flours from the ARVs formed more viscous slurries, exhibiting higher breakdown viscosities than the ARAs. Gelatinization transition temperatures and enthalpies were significantly higher for flours from ARAs than the ARVs suggesting more stable crystal structure for ARAs. This is supported by the higher energy required to liquefy the retrograded ARAs flour gels. The cooked samples of ARAs and ARVs showed close starch digestibility indices with expected glycemic index (eGI) ranging from 71-78. Differences observed in cooking characteristics and textural properties between ARAs and ARVs may be partially due to the ARAs' high amylose content.
Food Chemistry, 2009
Starches were isolated from three waxy rice varieties: Koganemochi (Kog), Hakuchomochi (Hak), and Kantomochi 172 (K172). Forty percent starch gels were prepared and the extent of starch gel digestibility was determined by an in vitro method. The distribution of chain lengths of amylopectin was analyzed and differential scanning calorimetry was used to analyze gelatinization and retrogradation of waxy rice starch. The K172 gel had significantly higher resistance to hydrolysis than had the other gels. The K172 starch contained lower proportions of the short chains of amylopectin and showed higher gelatinization temperature and enthalpy. The retrogradation peak was measured using waxy rice starch gels stored for 1 and 7 days at 5°C. The K172 gel was observed to retrograde more quickly and to have a greater extent of retrogradation than the other gels. The difference in amylopectin chain length distribution and recrystallinity contributed to the variation in the starch gel digestibility of waxy rice.
Journal of Food Science and Technology, 2018
A comparison between structural, morphological, functional and digestibility studies of starches from cereals i.e. wheat (WS), corn (CS), low amylose corn (LACS) and rice (RS), tubers i.e. potato (PS) and sweet potato (SP), and legumes i.e. kidney bean (KB) were investigated. The shape of granules varied from oval to elliptical or spherical according to the source. Distribution of iso-amylase debranched materials revealed that long and short side chains fractions of amylopectin ranged from 12.6 to 33.1% and 40.5 to 52.5% respectively. KB starch showed the highest amylose content (49.50%) while RS showed the lowest (8.51%). Starches with greater granule size (PS, SP and KB) showed higher proportion of long side chains of amylopectin (AP) (Fr.II) than short side chains of AP (Fr.III). Peak viscosity (PV), breakdown viscosity (BV) and final viscosity (FV) showed significant positive relationship with Fr. II and negative with apparent amylose content (AAC) and Fr.III. Tuber starches showed greater paste viscosities followed by legume starches. Tuber and legume starches with higher apparent amylose content and Fr. II showed greater crystallinity. Gel hardness and gelatinization temperatures showed inverse relationship with RS starch having higher proportion of smaller granules (0-10 lm). KB with higher amylose content showed maximum rapidly digestible starch (RDS) content while SP showed the highest resistant starch. Above observations would be utilized in modifying properties of native starches and help in improving texture, moisture retention capacity and gel firmness of starch and its products. Keywords Starch Á Fine structure Á Scanning electron microscopy Á X-ray diffraction Á Fourier-transform infrared spectroscopy Á In vitro digestibility
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.