Amino Acid Composition of Protein Fractions Extracted from Phaseolus Beans and the Field Bean (Vicia faba L.)

Protein fractions were extracted sequentially with 2% sodium chloride, 30% isopropyl alcohol, 4% lactic acid and 0.5% potassium hydroxide from three varieties of adzuki beans, kafae and red kafae bean, three varieties of lima beans and red lima bean, two varieties of kidney beans and field bean that were grown in the tropics and sub-tropics. The sodium chloride extract had the highest range of protein concentration (51.2 to 81.4%). The sodium chloride extract was separated into two fractions based on solubility in water. The amino acid compositions of the flour from the seed and of the two fractions from the sodium chloride extract were determined. High contents of lysine, aspartic acid, glutamic acid and leucine were obtained, whereas the sulphur-containing amino acids contents were low.