Influence of InVitro Digestion on Dipeptidyl Peptidase-IV (DPP-IV) Inhibitory Activity of Plant-Protein Hydrolysates Obtained from Agro-Industrial By-Products

This study investigates the production of protein hydrolysates with dipeptidyl peptidase-IV (DPP-IV) inhibitory activity from agro-industrial by-products, namely olive seed, sunflower seed, rapeseed, and lupin meals, as well as from two plant protein isolates such as pea and potato. Furthermore, the effect of simulated gastrointestinal digestion on the DPP-IV inhibitory activity of all the hydrolysates was evaluated. Overall, the lowest values of IC50 (1.02 ± 0.09 - 1.24 ± 0.19 mg protein/mL) were observed for the hydrolysates with a high proportion of short-chain [< 1 kDa] peptides (i.e., olive seed, sunflower seed, and lupin) or high content of proline (i.e., rapeseed). Contrarily, the IC50 of the pea and potato hydrolysates was significantly higher (1.50 ± 0.13 - 1.93 ± 0.13 mg protein/mL). In vitro digestion led to an increase in peptides