AMINO-ACID-COMPOSITION AND CHEMICAL EVALUATION OF PROTEIN-QUALITY OF CEREALS AS AFFECTED BY INSECT INFESTATION

A significant decrease in essential amino acids of wheat, maize and so rghum was observed due to grain infestation caused by mixed population s of Trogoderma granarium Everts and Rhizopertha dominica Fabricius (5 0:50). Non-essential amino acids were also adversely affected. Among t he essential amino acids, maximum reduction was found in methionine, i soleucine and lysine in infested wheat, maize and sorghum grains, resp ectively. Lysine, with lowest chemical score in uninfested and infeste d grains of three cereals, is the first limiting amino acid. Insect in festation caused significant (p<0.05) reduction in the chemical score of all the essential amino acids, yet did not change the position of f irst and second limiting amino acids in wheat and sorghum. However, in case of maize, isoleucine became the second limiting amino acid. Infe sted grains also showed substantial reduction in essential amino acid index, calculated biological value and requirement index.