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: 3.11). 08/2000; 48(7):2639-47. DOI: 10.1021/jf990374f
Source: PubMed

ABSTRACT 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.
    Plant Science 09/2012; 193-194:62-9. DOI:10.1016/j.plantsci.2012.05.006 · 4.11 Impact Factor
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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.
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    • "Swelling power ¼ wet residue weight ðgÞ=500 À dried starch weight ðgÞ For starch solubility determination, about 10 mL supernatant obtained from the centrifugation of the starch solution was dried at 105 8C for 3 h and then weighed. The solubility was calculated using the following formula (Singh et al., 2000): "
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    ABSTRACT: Rice starch is one of the most expensive yet very useful starches due to its unique characteristics. This study aimed to isolate starch from defatted rice bran, an underutilized byproduct of milling and is a relatively inexpensive source of rice starch. Starch was extracted from the bran by first soaking it in water. The mixture was then subjected to blending and washing with water, alcohol and alkali solution. About 83% of the rice bran starch was recovered. Characterization of the rice bran starch showed that its gelatinization and retrogradation properties as well as its granule size are similar to those of starch from rice endosperm. Based on the results of this study, defatted rice bran can be a good source of starch that is suitable for applications in food and pharmaceutical industry and other new applications such as a potential material in the biomedical field.
    Journal of the Taiwan Institute of Chemical Engineers 01/2011; 42(1):86-91. DOI:10.1016/j.jtice.2010.03.013 · 3.00 Impact Factor
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