Production of Antioxidant Hydrolysates from Bovine Caseinate and Soy Protein Using Three Non-Commercial Bacterial Proteases

The release of bioactive peptides from proteins can be achieved by enzymatic hydrolysis, whereby mainly commercial enzymes are applied, although increasing attention is focused on alternative proteases. Hence, crude proteases from Bacillus sp. CL14, CL18, and CL33A were investigated to obtain antioxidant hydrolysates from bovine sodium caseinate (NaCAS) and soy protein isolate (SPI). The proteases were able to hydrolyze both substrates. Hydrolysis improved the radical-scavenging, Fe2+-chelating, and reducing power abilities of NaCAS and SPI. Higher antioxidant activities were commonly achieved at 2-3 h of hydrolysis. Overall antioxidant activities were higher for NaCAS hydrolysates produced with CL14 > CL18 > CL33 protease, and for SPI hydrolysates obtained with CL14 > CL33A similar to CL18 protease. Generation of antioxidant protein hydrolysates suggest applications of enzymes and hydrolysates in food/feed (bio)technology.