Amino Acid Composition of Rice and Rice By-products
Data are presented from chromatographic analyses of amino acid contents of seven U.S.-milled rices and such milling by-products as bran, polish, bean-plus-polish, millfeed, and hulls. Values for serine, threonine, valine and isoleucine were corrected by factors based on earlier work. Cystine and methionine were determined after performic acid oxidation. Composition of each milling fraction was very similar for all varieties and process differences. However, appreciable differences occurred between different milling fractions. Ratios of individual to total essential amino acid (A/E) and of total essential amino acid to total amino acids (E/T) in milling fractions are compared with each other and with values for egg proteins as estimates of nutritional quality. Comparisons of amino acid composition found for milled rice and bran with the rather variable data reported in the current literature show generally higher present values for sulfur amino acids and others requiring special consideration for analysis.