Effect of temperature and enzyme/substrate ratio on the hydrolysis of pea protein isolates by trypsin

Two pea protein isolates, Pisane and Propulse, were hydrolysed by trypsin. The degree of hydrolysis (DH) was computed using a pH-stat method. Enzymatic treatment of the pea protein isolates was conducted at four different temperatures, namely 35, 40, 45 and 50°C. The relationship between DH and E/S ratio was studied at 50°C and at four different E/S ratios; these were 5, 15, 25, 35 mAU/g (AU - Anson unit). For Pisane the highest value of the final DH (10.4%) was obtained at 45°C, whereas for Propulse the optimal temperature was 50°C and a DH value of 13.2% was attained. In the case of Pisane, the highest DH (11.5%) was recorded if the enzyme/substrate ratio was 35 mAU/g whereas for Propulse, the highest DH (13.2%) was observed at an E/S ratio of 15 mAU / g.