Thermal and Physicochemical Properties of Rice Grain, Flour and Starch

National Food Research Institute, Kannondai 2-1-2, Tsukuba, 305-8642 Japan.
Journal of Agricultural and Food Chemistry (Impact Factor: 2.91). 08/2000; 48(7):2639-47. DOI: 10.1021/jf990374f
Source: PubMed


Three types of rices, namely, Thailand rice (Indica), Nipponbare (Japonica), and Himenomochi (Japonica waxy), in grain, flour, and starch forms have been studied for their thermal and physicochemical properties. In grain form, Indica was slender and Japonica rices were bold and thick. Indica had the highest protein and amylose equivalent. Protein contents in isolated starches varied from 0.2 to 0.9%. Cooked Indica grain was hardest and waxy rice was softest; stickiness was highest in Japonica rice. Glass transition temperature (T(g)) was highest in Indica rice flour (approximately 222 degrees C) and almost the same in Japonica rice flours. Melting point was highest for Japonica (approximately 264 degrees C) and almost the same for Japonica waxy and Indica rice flours. T(g) values of starches were almost the same in Indica and Japonica waxy (approximately 237 degrees C); defatting caused reduction in this property in all of the starches. Highest melting point was shown by Indica starch (approximately 276 degrees C) and was almost the same for the other two starches. Protein and fats play a critical role in glass transition and melting points of rice flours and their respective starches. Viscosities of the cooked pastes of flour and starch during cooking in an RVA instrument and their gel and other properties have been discussed.

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    • "Typical japonica rice is oval-shaped and exhibits moderate stickiness when cooked. By contrast, typical indica rice has a more narrow and longer grain and is less sticky when cooked [30]. This textural difference results from the specific alleles of GBSSI [31] [32] and SSIIa [33] [34]. "
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    ABSTRACT: Rice endosperm starch is composed of 0-30% linear amylose, which is entirely synthesized by granule-bound starch synthase I (GBSSI: encoded by Waxy, Wx). The remainder consists of branched amylopectin and is elongated by multiple starch synthases (SS) including SSI, IIa and IIIa. Typical japonica rice lacks active SSIIa and contains a low expressing Wx(b) causing a low amylose content (ca. 20%). WAB2-3 (SS3a/Wx(a)) lines generated by the introduction of a dominant indica Wx(a) into a japonica waxy mutant (SS3a/wx) exhibit elevated GBSSI and amylose content (ca. 25%). The japonica ss3a mutant (ss3a/Wx(b)) shows a high amylose content (ca. 30%), decreased long chains of amylopectin and increased GBSSI levels. To investigate the functional relationship between the ss3a and Wx(a) genes, the ss3a/Wx(a) line was generated by crossing ss3a/Wx(b) with SS3a/Wx(a), and the starch properties of this line were examined. The results show that the apparent amylose content of the ss3a/Wx(a) line was increased (41.3%) compared to the parental lines. However, the GBSSI quantity did not increase compared to the SS3a/Wx(a) line. The amylopectin branch structures were similar to the ss3a/Wx(b) mutant. Therefore, Wx(a) and ss3a synergistically increase the apparent amylose content in rice endosperm, and the possible reasons for this increase are discussed.
    Full-text · Article · Sep 2012 · Plant Science
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    • "They adhere to the surface of the starch and are relatively difficulty to remove. The residual protein of rice starch depends on the method of isolation (Singh et al., 2000). The morphology of starch granules depends on the biochemistry of the chloroplast or amyloplast, as well as the physiology of the plant (Bodenhuizen, 1969). "
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    ABSTRACT: This study was carried out to determine the composition, morphology, functional and pasting properties of rice starches isolated from different rice cultivars (IGR, EAR, ILR and N2R). The starches were isolated from their flours by using a modified deproteination method in 0.1% NaOH. The highest starch yield of 65.00% was obtained from EAR with a residual protein of 0.41% and the lowest starch yield of 45.70% from IGR with a residual protein of 0.42%. The apparent amylose (AAM) content of rice starches ranged from 21.88 to 26.04%. Rice starches contain 10.40-12.77%, 0.10-0.70% and 0.20-0.24% moisture, fat and ash contents, respectively. The sizes of the starch granules obtained from SEM were between 3-8 µm. Some of the granules were individual (single) while others were fused (compound granules). The rice starch granules were polygonal and angular-shaped. When heated from 55 to 95°C at 10°C intervals, starches with higher amylopectin content had higher swelling power (SP). Both SP and water solubility index increased with increased temperature. The bulk density, dispersibility and pH of the rice starches ranged from 0.41-0.56 g/ml, 75.10-82.12% and 5.3-6.9, respectively. Pasting parameters were evaluated using RVA. Significant differences were observed in individual pasting parameters of the rice starches especially in peak viscosity, trough viscosity, final viscosity and setback viscosity. The results revealed that cultivar difference has an effect on composition and pasting properties of rice starch.
    Preview · Article · Jan 2012
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    • "Genetic markers lay the foundation for genetic mapping and marker-assisted selection of agriculturally important traits [46]. High density genetic markers are crucial for fine mapping of causal variation that may contribute to quality improvement in rice cultivars and crop breeding [7,47]. To facilitate selecting potential polymorphic markers, Rice-Map integrates four genetic marker tracks, with an average of 11.39 markers for japonica and 11.05 markers for indica per 100 kb nucleotides, respectively. "
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    ABSTRACT: The concurrent release of rice genome sequences for two subspecies (Oryza sativa L. ssp. japonica and Oryza sativa L. ssp. indica) facilitates rice studies at the whole genome level. Since the advent of high-throughput analysis, huge amounts of functional genomics data have been delivered rapidly, making an integrated online genome browser indispensable for scientists to visualize and analyze these data. Based on next-generation web technologies and high-throughput experimental data, we have developed Rice-Map, a novel genome browser for researchers to navigate, analyze and annotate rice genome interactively. More than one hundred annotation tracks (81 for japonica and 82 for indica) have been compiled and loaded into Rice-Map. These pre-computed annotations cover gene models, transcript evidences, expression profiling, epigenetic modifications, inter-species and intra-species homologies, genetic markers and other genomic features. In addition to these pre-computed tracks, registered users can interactively add comments and research notes to Rice-Map as User-Defined Annotation entries. By smoothly scrolling, dragging and zooming, users can browse various genomic features simultaneously at multiple scales. On-the-fly analysis for selected entries could be performed through dedicated bioinformatic analysis platforms such as WebLab and Galaxy. Furthermore, a BioMart-powered data warehouse "Rice Mart" is offered for advanced users to fetch bulk datasets based on complex criteria. Rice-Map delivers abundant up-to-date japonica and indica annotations, providing a valuable resource for both computational and bench biologists. Rice-Map is publicly accessible at, with all data available for free downloading.
    Full-text · Article · Mar 2011 · BMC Genomics
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