Inhibition of α-amylase, α-glucosidase and pancreatic lipase activities in vitro by sacha inchi (Plukenetia volubilis L.) protein hydrolysates and their fractionated peptides

Protein hydrolysates were produced via enzymatic hydrolysis of sacha inchi protein isolate using three different protease enzymes: pepsin, papain and Flavourzyme. Each hydrolysate sample was then fractionated by ultrafiltration membrane at various molecular weight (MW) cut-off ranging from 1-10 kDa. The results show that peptide fraction with MW of 1-3 kDa produced with pepsin had the highest inhibitory activity against a-amylase. Peptide fraction with MW < 1 kDa produced by Flavourzyme had the highest inhibitory activity against a-glucosidase (51.06 +/- 0.08%), followed by fractions with MW < 1 kDa and 1-3 kDa (48.21 +/- 0.12% and 48.27 +/- 0.17%) produced by pepsin, and unfractionated hydrolysate produced by papain (42.81 +/- 0.38%). However, the fractionated peptides had reduced capacity in inhibiting lipase activity (IC50>3.0 mg/mL) compared with the unfractionated counterparts (IC50<3.0 mg/mL). The findings suggest that sacha inchi protein-derived peptides have the potential for being utilised as functional foods as they can play an important role in the management of caloric intake.