Proteins of Italian millet: Amino acid composition, solubility fractionation and electrophoresis of protein fractions

Abstract Determination of the protein contents of 14 varieties of Italian millet revealed considerable varietal differences. The total protein of the 14 varieties was fractionated into albumin‐globulin, prolamin and glutelin fractions. The prolamin fraction constitutes the major storage protein of the grain. There is a positive correlation between protein content and the prolamin levels of the seeds and the increase in protein content is largely due to an increase in the prolamin content. The amino acid composition of each of 14 varieties of the millet and the individual protein fractions from three varieties were determined. The limiting amino acids are lysine followed by tryptophan and the sulphur containing amino acids, methionine and cystine. The lysine content of the grain decreases with increase in protein content. The total protein has a rather high content of leucine. SDS‐polyacrylamide gel electrophoresis of the protein fractions indicated similarities in the prolamin fraction and differences in the albumin‐globulin and glutelin fractions of the different varieties.