Physicochemical Characteristics of Legumes and Oilseed Proteins

Abstract

The protein contents of the legume flours varied from 44% in soybean to 4% in coconut kernel. The maximum and minimum yield obtained as protein isolate were 87% in mungbean and 50% in coconut. The essential ammino acid distribution of coconut protein was comparatively rich specially in sulfur amino acid (SAA). The mustard protein showed significantly high amount of SAA and lysine. The lowest chemical score of 45 was found in peabean protein and highest score of 74 was in chick pea protein among the legumes studied. The chemical score of mustard protein was 100, unlike all other commercially available plant protein. The solubilities of plant proteins studied were minimum at around pH 4.0 in all cases, In mustard proteins additional isoelectric point appeared around pH 6.0. The solubility profiles of legumes and oilseed protein isolate had marked but different effects by 0.05 M NaCl at various pH region. Lentil protein isolate showed minimum and mustard protein Isolate exhibited maximum water absorption characteristics. The fat absorption characteristics of legume and oilseed protein isolates showed close resemblance to each other, the lowest being field pea and highest was mustard. The emulsifying capacity was minimum for field pea and maximum for coconut. The foaming capacity of coconut protein was the highest while that of lupin and lentil were the lowest.