PROTEIN-FRACTIONS FROM 5 VARIETIES OF GRAIN-SORGHUM - AMINO-ACID COMPOSITION AND SOLUBILITY PROPERTIES

Classic protein fractions 1, 2, 3, and 4 (albumins, globulins, prolamins, and glutelins, respectively) were obtained from five varieties of sorghum that differed in endosperm/pericarp structure and in tannin content. Amino acid profiles and protein distribution of isolated fractions showed some differences among varieties. The chemical scores varied from 9 to 91. Methionine, cysteine, isoleucine, and leucine were most limiting in fractions 1 and 2. Fractions 3 and 4 were most deficient in lysine in all five varieties. Leucine/lysine ratio was above 20 in all of the fractions 3 except for that in a high-tannin variety; the ratio of all of the other fractions was below 4. Fractions 1 and 2 extracted from the high-tannin variety contained less protein than those from the other varieties. The comparable extent of essential amino acid deficiencies and excesses in these fractions is given. © 1979, American Chemical Society. All rights reserved.