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BACKGROUND Chalkiness has a deleterious influence on rice appearance and milling quality. We identified a notched-belly mutant with a high percentage of white-belly, and thereby developed a novel comparison system that can minimize the influence of genetic background and growing conditions. Using this mutant, we examined the differences in chemical composition between chalky and translucent endosperm, with the aim of exploring relations between occurrence of chalkiness and accumulation of starch, protein and minerals. RESULTS Comparisons showed a significant effect of chalkiness on chemical components in the endosperm. In general, occurrence of chalkiness resulted in higher total starch concentration and lower concentrations of the majority of the amino acids measured. Chalkiness also had a positive effect on the concentrations of As, Ba, Cd, Cr, Mn, Na, Sr and V, but was negatively correlated with those of B, Ca, Cu, Fe and Ni. By contrast, no significant chalkiness effect on P, phytic acid-P, K, Mg or Zn was observed. In addition, substantial influence of the embryo on endosperm composition was detected, with the embryo showing a negative effect on total protein, amino acids such as Arg, His, Leu, Lys, Phe and Tyr, and all the 17 minerals measured, excluding Ca, Cu, P and Sr. CONCLUSION An inverse relation between starch and protein as well as amino acids was found with respect to chalkiness occurrence. Phytic acid and its colocalized elements K and Mg were not affected by chalkiness. The embryo exerted a marked influence on chemical components of the endosperm, in particular minerals, suggesting the necessity of examining the role of the embryo in chalkiness formation. © 2016 The Authors. Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

BACKGROUND Little has been reported about the sensory impact of degree of milling ( DOM) on raw, uncooked rice. This study focuses on the effects of DOM, which was measured by surface lipid content ( SLC), on appearance and aroma attributes of raw rice, as well as the appearance of cooked rice; greater DOM leads to lesser SLC levels. RESULTS Milled-rice samples with SLCs of 0.64, 0.59, 0.42 and 0.25%, as well as brown rice (2.27% total lipid content), were evaluated by trained panelists on three appearance- and five aroma-related attributes of raw rice, as well as four appearance-related attributes of the resultant cooked rice. All milled-rice samples, varying in SLC level from 0.64% to 0.25%, differed from brown rice with respect to raw-rice and cooked-rice appearance and aroma attributes. A significant sensory difference among the four raw-rice samples was present only in the degree of whiteness; however, such a difference was absent once the samples were cooked. When cooked, highly milled rice (0.25% SLC) was rated glossier than either lightly milled rice (0.64% SLC) or brown rice. CONCLUSION The present study demonstrated that sensory impacts of DOM on raw rice were present between brown rice and milled-rice samples, but not among the milled-rice samples varying in SLC level from 0.64% to 0.25%. The overall findings indicate that consumers may not detect appearance- or aroma-related differences among raw-rice samples ranging in SLC from 0.64% to 0.25%. © 2015 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

BACKGROUND Although rice ( Oryza sativa L.) is the third largest food crop, relatively fewer studies have been reported on rice geographical origin based on light element isotope ratios in comparison with other foods such as wine, beef, juice, oil and milk. Therefore this study tries to discriminate the geographical origin of the same rice cultivars grown in different Asian countries using the analysis of C, N, O and S stable isotope ratios and chemometrics. RESULTS The δ 15NAIR, δ 18OVSMOW and δ 34SVCDT values of brown rice were more markedly influenced by geographical origin than was the δ 13CVPDB value. In particular, the combination of δ 18OVSMOW and δ 34SVCDT more efficiently discriminated rice geographical origin than did the remaining combinations. Principal component analysis ( PCA) revealed a clear discrimination between different rice geographical origins but not between rice genotypes. In particular, the first components of PCA discriminated rice cultivated in the Philippines from rice cultivated in China and Korea. CONCLUSION The present findings suggest that analysis of the light element isotope composition combined with chemometrics can be potentially applicable to discriminate rice geographical origin and also may provide a valuable insight into the control of improper or fraudulent labeling regarding the geographical origin of rice worldwide. © 2015 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

BACKGROUND Zinc deficiency is prevalent among children and women in Bangladesh and parboiled rice is the major staple food consumed. Parboiling offers an opportunity to increase the zinc and iron content of rice by adding fortificants to the soaking water. RESULTS Rice zinc content increased with increasing amounts of zinc sulfate added to the parboil soaking water. Addition of 1300 mg zinc L−1 increased raw polished rice zinc content from 16.6 to 44.9 mg kg−1 and from 12.6 to 32.9 mg kg−1 in the open and closed parboiling systems, equivalent to 170% and 161% increases, respectively. Retention of zinc after washing and cooking was 70-81% across all concentrations tested. Addition of iron-ethylenediaminetetraacetic acid and zinc sulfate together increased zinc, but not iron, content of polished rice. The simulated prevalence of inadequate zinc intake was reduced by more than half among children and nearly two-thirds among women if 50% of the population were to consume the 1300 mg zinc L−1 parboiled fortified rice. CONCLUSION Addition of zinc sulfate to soaking water during parboiling increases the zinc content of rice and, if found to be bioavailable, could substantially reduce the prevalence of inadequate zinc intake by children and women in Bangladesh. © 2014 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

BACKGROUND Two cultivars of black rice were investigated for the effects of different cooking methods on anthocyanins, total phenolic compounds and antioxidant activities. RESULTS There was a significant loss of anthocyanins during cooking: roasting resulted in the greatest decrease (94%), followed by steaming (88%), pan-frying (86%) and boiling (77%). Contents of phenolic compounds decreased drastically after cooking, with significantly lower retention in the black rice cultivar that had higher amylose content. DPPH radical-scavenging activity of black rice decreased after cooking. In contrast, metal-chelating activity increased significantly after cooking. Anthocyanins showed a high positive correlation with total phenolic compounds ( r2 = 0.936) but a significant negative correlation with metal-chelating activity ( r2 = 0.6107). CONCLUSION The results indicate that cooking degraded anthocyanins and other phenolic compounds, but with a concomitant increase in phenolics from possible degradation of anthocyanins, which resulted in the enhancement of metal-chelating activity. © 2014 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Background To increase rice production in Africa, considerable research has focused on creating interspecific hybrids between African ( Oryza glaberrima Steud.) and Asian ( O. sativa L.) rice in an attempt to obtain the positive attributes of each in new cultivars. Since flavor is a key criterion in consumer acceptance of rice, as an initial inquiry we characterized and compared the aroma chemistry of selected cultivars of African O. sativa ssp. japonica, O. sativa ssp. indica, O. glaberrima, and their interspecific hybrids grown in West Africa, using gas chromatography-mass spectrometry, gas chromatography-olfactometry and descriptive sensory analysis. Results Of 41 volatiles identified across seven representative rice cultivars grown in West Africa, 3,5,5-trimethyl-2-cyclopenten-1-one, styrene, eucalyptol, linalool, myrtenal and l- α-terpineol had not been previously reported in rice. Thirty-three odor-active compounds were characterized. 4-Ethylphenol and ( E, E)-2,4-heptadienal were unique to O. glaberrima, and pyridine, eucalyptol and myrtenal were described only in an interspecific hybrid. Descriptive sensory analysis indicated 'cooked grain', 'barny' and 'earthy' attributes were statistically different among the cultivars. Conclusion The aroma chemistry data suggest that it should be possible to separate African cultivars into distinct flavor types thereby facilitating selection of new cultivars with superior flavor in African rice breeding programs. © 2013 Society of Chemical Industry [ABSTRACT FROM AUTHOR]