Identification of a novel α-amylase inhibitory activity peptide from quinoa protein hydrolysate.

α-Amylase inhibitory activity plays an important role in reducing blood glucose. Food-derived α-amylase inhibitors have attracted significant attention due to their safety. This study obtained peptides displaying α-amylase inhibitory activity from pepsin hydrolysate of quinoa protein concentrates. Gel filtration chromatography revealed that the <1 kDa component exhibited significant α-amylase inhibitory capability, while the purified component was identified via mass spectrometry identification. Six peptides with α-amylase inhibitory activity were selected, wherein the inhibitory ability of the peptide MMFPH was 66.41 % higher than the others. Molecular docking indicated that the peptide MMFPH residues restricted the α-amylase activity by binding to the active α-amylase site. The molecular interaction experiments showed that the peptides and α-amylase were in a fast-binding and slow-dissociation mode, allowing the small peptides produced via quinoa protein digestion to bind more rapidly to α-amylase, thus preventing a rise in blood glucose in vivo.