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Cereal Chem. 76(5):764-771Although amylose content is considered the most important determinant of cooked rice texture, this constituent falls short as a predictor, because cultivars with similar amylose contents may differ in textural properties. Thus, amylography is used as one of a battery of tests, in addition to measuring amylose content, to improve differentiation of cultivars. The purpose of our study was to determine how well amylography conducted with a Rapid Visco Analyser (RVA) serves as a predictor of cooked rice texture, alone and in combination, with amylose content. Textural properties of 87 samples representing short-, medium-, and long-grain rice cultivars were assessed by descriptive sensory and instrumental texture profile (TPA) analyses and related to RVA measurements.None of the cooked rice textural attributes, whether measured by descriptive analysis or TPA, were modeled by RVA with high accuracy (i.e., high r 2 ). Sensory texture attributes cohesiveness of mass, stickiness, and initial starchy coating and TPA attribute adhesiveness had the strongest correlations with RVA measurements. Setback explained most of the variance attributed to models describing these attributes; the strongest correlation was with cohesiveness of mass (r = 0.69; equivalent to coefficient of determination, r 2 = 0.47). Inclusion of amylose and protein contents in regression analyses did not strengthen models. Exclusion of samples that cook atypically, based on amylose content or gelatinization temperature types, slightly improved the accuracy of RVA measurements for predicting cooked rice texture.

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Cereal Chem. 85(4):445-454Descriptive sensory analysis has identified over a dozen different aromas and flavors in rice. Instrumental analyses have found over 200 volatile compounds present in rice. However, after over 30 years of research, little is known about the relationships between the numerous volatile compounds and aroma/flavor. A number of oxidation products have been tagged as likely causing stale flavor. However, the amounts of oxidation products, singly or collectively, that need to be present for rice to have stale or rancid flavor have not been established. Only one compound, 2-acetyl-1-pyrroline