2.3. Preparation of pea protein hydrolysate (PPH)
A 5 g/100 mL protein solution of PPI was hydrolyzed for 0.5 h
with Flavourzyme (Novo Nordisk, Bagsvard, Denmark) at 50 C to
produce PPH. Flavourzymewas used because itwas identified in our
previous study to be the most effective of seven proteases tested to
produce antioxidative peptides from pea protein (Zhang et al.,
2013). The enzyme-protein ratio was 1/100 and the hydrolysis pH
was 6.0. The termination of hydrolysis was achieved by heating the
hydrolysate at 80 C for 15 min. After cooling to room temperature,
the hydrolysate was titrated to pH 7.0 with 1 mol/L NaOH, centrifuged
at 9000 g for 10 min to remove insoluble particulates then
freeze-dried. The PPH powder was kept at 4 C before use.