Nutritional and Functional Properties of Defatted Wheat Protein Isolates

Nutritional and functional properties of wheat protein isolate (WPI), wheat germ protein isolate (WGPI) and their albumin fractions were studied. The results showed that wheat protein isolates and their albumin fractions an excellent balance of all essential amino acids, with a relatively high level of glutamic acid, aspartic acid, glycine, arginine, alanine and valine. SDS-PAGE analysis showed that molecular weights distribution of wheat protein isolates and their albumin fractions were found to be in the range (19-67 kDa). Protein digestibility (%) of albumin fractions was higher than that of protein isolates. The results revealed that wheat protein isolates had excellent water retention (especially at pH 8.0 and 70°C) and high solubility at pH 9.0. The emulsifying activity index of WGPI at pH values (1.0 to 8.0) was higher than that of WPI. Emulsifying capacity and stability of albumin fractions were higher than that of protein isolates, but their fat absorption capacities were lower than that of protein isolates. Wheat protein isolates and their albumin fractions had good foaming capacity and stability. WGPI showed higher SDS-binding capacity than others. The findings on wheat protein isolates are important for their potential application as functional food ingredients