Physicochemical characterization of hydrolysates of whey protein concentrates for their use in nutritional beverages

Abstract

Whey protein concentrates containing 50 and 60% protein were manufactured and were hydrolyzed for 0.5, 1, 2, 3, 4, and 5 h with 5 commercial enzymes (flavourzyme, protease A, protease M, protease S, and trypsin). Functional properties such as degree of hydrolysis (DH), non-protein-nitrogen (NPN), 5-hydroxymethyl-2-furfural (HMF), solubility, and free-sulfhydryl (FSH) levels were measured. In food applications functional efficiency of whey protein hydrolysates (WPHs) depended on hydrolysis time, protein composition and enzymatic specificity. WPHs treated with protease A were found to be suitable for applications that require extensively hydrolyzed (<2 h) WPHs, because they had high solubility, DH, HMF, and FSH contents. Proteases S and M hydrolysates delayed the Maillard reaction and had high DH in mild hydrolysates (≤2 h) of WPHs. Aggressive hydrolyzed WPHs of protease A, and mild hydrolysates of proteases S and M are preferred in beverage fortification for maximum functional efficiency.