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Kernel and starch properties of United States and imported medium/short-grain rice
J. PATINDOL (1), J. Jinn (1), Y. Wang (1), T. Siebenmorgen (1) (1) University of Arkansas, , U.S.A..

The production of medium/short-grain rice in the mid-southern United States rice-growing region is increasing. This work aimed to identify the quality traits of importance to the markets for these grain types. Twenty-five medium/short-grain milled rice samples were collected and analyzed for physical, gelatinization, pasting, and starch structural properties. Six samples were from Arkansas (AR), five were from California (CA), and fourteen were imported (IM). Cluster and principal component analyses showed that the AR samples had greater gelatinization temperature, enthalpy, and percentages of amylopectin long chains (B2 and B3 chains) but lesser kernel whiteness, total setback viscosity, and percentage of amylopectin short chains (A chains) than the CA samples. With the exception of one sample from Taiwan, chemometrics indicated that the IM samples differed from the AR samples (Cluster A) in some properties and were grouped into three clusters (Clusters B, C, and D). Cluster B samples had properties that were similar to the CA samples; Cluster C samples had lesser gelatinization temperature and peak viscosity but greater percentages of amylose and A chains than the AR samples; Cluster D samples had lesser paste breakdown but greater final viscosity and percentage of B1 chains than the AR samples. Kernel width, color, and chalk were the primary sources of variation in milled rice appearance. In relation to structure and functionality, the percentages of amylopectin A and B3 chains, and amylose content were the major sources of variation.