Hydrolysis of pea protein concentrate in subcritical water media with addition of citrus pectin and citric acid

Abstract

Pea protein concentrate (PPC) was hydrolyzed by subcritical water with citrus pectin or citric acid to obtain bioactive peptides and amino acids. Subcritical water at 160–240 oC and 50 bar for 10–60 min was used. The degree of hydrolysis (DH) significantly increased (p < 0.05) with increasing temperature. The highest DH (64.8%) was obtained at 220 oC/50 bar/10 min with a PPC:pectin ratio of 1:1 (w/w). The dominant peptide in the hydrolysate had molecular weight of 4.1 kDa. The main nd high hydronium and hydroxide ion concamino acids in the hydrolysates were hydrophilic amino acids (45.7 g/100 g protein at 180 oC/50 bar/10 min). The DPPH- scavenging activity of protein hydrolysates using citric acid was significantly higher (p < 0.05) than the ones obtained with pectin. The hydrolysates with pectin, on the other hand, had significantly (p < 0.05) higher ferric reducing antioxidant power than the ones obtained with citric acid which was likely due to the differences in the peptide size and composition.