AMINO ACID, HEMAGGLUTININ AND TRYPSIN INHIBITOR LEVELS, AND PROXIMATE ANALYSES OF FABA BEANS (VICIA FABA) AND FABA BEAN FRACTIONS

Abstract

The compositions of eight cultivars of faba beans (Vicia faba L. var. minor) selected from six locations in Manitoba and Saskatchewan were compared. Both cultivar and location had significant effects at P < 0.01 on all analyses, except for cultivar effect on ash composition (P < 0.05). The average percent composition of the cotyledon and hull portions of faba beans, which were markedly different, was: protein, 36.3 and 5.9; fat, 1.1 and 0.3; fiber, 1.4 and 53.5; ash, 3.5 and 2.5; calcium, 0.05 and 0.38; and phosphorous, 0.64 and 0.08, respectively. Amino acid composition per unit of protein of the eight cultivars was not significantly different (P > 0.05). The amino acid composition of the hull was significantly (P < 0.01) different from that of cotyledon, particularly with regard to levels of arginine, glutamic acid, glycine and tyrosine. Protein isolates and starch fractions were obtained by air classification; there were higher levels of protein, fat, fiber, ash, phosphorous, hemagglutinin activity and trypsin inhibitor in the protein fraction, but the levels of starch and calcium were higher in the starch fraction. Hemagglutinin and trypsin inhibitor levels showed considerable variation among cultivars. The distribution in the hull and the cotyledon portions of the bean was also different. All hemagglutinin activity was associated with the cotyledon, and trypsin inhibitor content per unit of dry matter was more than twofold greater in the hull than in the cotyledon.