The effect of enzymatic hydrolysis on the physicochemical properties of protein concentrates from Great Northern and navy beans (Phaseolus vulgaris L.) was studied and the causes of functionality improvements were comprehensively investigated. Protein concentrates from Great Northern and navy beans with a protein content around 75% were prepared and further hydrolyzed by alcalase and papain at different enzyme-to-substrate w/w ratios (E:S). To better investigate the hydrolysis effect, the original protein concentrates exposed to the hydrolysis conditions (thermal treatment without enzyme) were set as second control. The results suggested that thermal treatment alone also denatured the proteins and improved their emulsifying properties. But emulsions stabilized by alcalase hydrolysates at an 80:1000 E:S and papain hydrolysates at 1 and 5:1000 E:S showed better stability and smaller droplet sizes than the heat-treated proteins from either source. The better emulsifying properties of hydrolyzed proteins could be attributed to their better ability to lower interfacial tension. Our study demonstrated that the inclusion of a heat-treated control is necessary for analyzing the effect of enzymatic hydrolysis on protein functionality. And hydrolysis is a promising strategy to improve the functionality of common bean proteins.
Keywords: Alcalase; Emulsifying properties; Enzymatic hydrolysis; Papain; Phaseolus vulgaris.
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