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

Abstract

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.