CHEMICAL COMPOSITION AND PROTEIN CHARACTERISTICS OF LENTILS

Abstract

Chemical and amino acid compositions, protein solubility (Osborn classification), and in vitro protein quality of six genotypes of lentils (Lens culinaris Medik.) were determined. Lentils contained an average of 28.6% protein, 3.1% ash, 4.4% fiber, 0.7% ether extract, 63.1% total carbohydrate (nitrogen-free extract), 44.3% starch and 4,186 kcal/kg of gross energy. Lentil starch contained 36.1% amylose. About one-half (47.1%) of the lentil proteins were soluble in 1.0 M sodium chloride, 3.8% soluble in water, 3.1% soluble in 70% ethanol, and 14.9% soluble in dilute hydrochloric acid. Only 24.0% of the lentil proteins were not solubilized by these solvents. The lentils contained 6.8% of the meal nitrogen as nonprotein nitrogen. The amino acid compositions of the six lentil genotypes were similar. The major amino acids were glutamic acid, aspartic acid, arginine, leucine and lysine; the minor amino acids were methionine, cystine and tryptophan. Because of the lower concentrations of the latter amino acids, lentil proteins gave a chemical score of 35, a protein score of 46, and an essential amino acid index of 63, relative to egg protein.