Physicochemical and bitterness properties of enzymatic pea protein Hydrolysates

The effects of different proteolytic treatments on the physiochemical and bitterness properties of pea protein hydrolysates were Investigated. Acommercial pea protein Isolate was digested using each of 5 different proteases to produce protein hydrolysates with varying properties. After 4 h of enzyme digestion, samples were clarified by centrifugation followed by desalting of the supernatant with a 1000 Da membrane; the retentates were then freeze-dried. Alcalase and Flavourzyme((TM)) produced protein hydrolysates with significandy higher (P < 0.05) degree of hydrolysis when compared to the other proteases. Flavourzyme, papain, and alcalase produced hydrolysates that contained the highest levels of aromatic amino acids, while trypsin hydrolysate had the highest levels of lysine and arginne. Papain hydrolysate contained high, molecular weight peptides (10 to 178 kDa) while hydrolysates from the other 4 proteases contained predominantly low molecular weight peptides (:5 23 kDa). DPPH (1,1-dlphenyl 2picrylhydrazyl) free radical scavenging activity of the Flavourzyme hydrolysatewas significantly (P < 0.05) the highest while alcalase and trypsinhydrolysates were the lowest. Inhibition of angiotensin converting enzyme (ACE) activity was significantly higher (P < 0,05) for papain hydrolysate while Flavourzyme hydrolysate had the least inhibitory activity. Sensory analysis showed that the alcalase hydrolysatewas the most bitter while papain and alpha-chymotrypsin hydrolysates were the least. Among the 5 enzymes used lit this study, papain and alpha-chymotrypsin appear to be the most desirable for producing high, quality pea protein hydrolysates because of the low bitterness scores combined with a high level of angiotensin converting enzyme Inhibition and moderate free radical scavenging activity.