Effect of High Pressure Processing and heat treatment on in vitro digestibility and trypsin inhibitor activity in lentil and faba bean protein concentrates

Abstract

This study investigated the effects of HPP and heat treatment on digestibility and trypsin inhibitor activity in lentil protein concentrate (LPC) and faba bean protein concentrate (FPC). LPC and FPC with 15 g protein/100 g were treated with HPP (600 MPa/5 °C/4 min) or heat (95 °C/15 min), then subjected to in vitro digestion. Digesta were analyzed by SDS-PAGE for hydrolyzed protein fraction patterns and their concentrations. The concentration of peptides and free amino acids was also determined. The effect of HPP and heat treatment on trypsin inhibitor activity was determined for 5 g protein/100 g LPC and FPC. HPP and heat treatments led to different hydrolyzed peptide patterns after gastric digestion. HPP resulted in comparable or greater gastric digestibility than untreated controls, but higher gastric proteolysis than heat treatment. Neither treatment impacted overall in vitro protein digestibility, for either LPC or FPC. HPP slightly reduced trypsin inhibitor activity (~8% for LPC, ~6% for FPC), while heat treatment led to much greater reductions (86% for LPC, ~78% for FPC) than untreated controls. Overall, HPP and heat treatment did not negatively impact lentil and faba bean protein quality, which is useful information for developing new food product applications.