Inhibition of the in vitro activities of α‐amylase, α‐glucosidase and pancreatic lipase by yellow field pea (Pisum sativum L.) protein hydrolysates

Summary The aim of this work was to produce yellow field pea protein‐derived peptides as inhibitors of α‐amylase, α‐glucosidase and pancreatic lipase activities. A pea protein concentrate was hydrolysed with alcalase, chymotrypsin, pepsin or trypsin and the hydrolysates separated into different fractions (<1, 1–3, 3–5, 5–10 kDa) by membrane ultrafiltration. Peptide sequence analysis showed that the alcalase hydrolysate had higher levels of di‐ and tripeptides when compared with the chymotrypsin, pepsin and trypsin hydrolysates. The peptide fractions inhibited α‐amylase and α‐glucosidase activities at levels that were similar to the unfractionated hydrolysates. The peptides were more active against α‐amylase (inhibition at μg level) than α‐glucosidase (mg level). In contrast, the fractionated peptides had reduced ability (IC 50 >4.2 mg mL −1 ) when compared with the unfractionated hydrolysate (IC 50 <4.2 mg mL −1 ) to inhibit lipase activity. Enzyme kinetic studies revealed that the peptides reduced α‐amylase activity through competitive inhibition. However, inhibition of α‐glucosidase activity was non‐competitive.