Effect of high pressure processing and heat treatment on in vitro digestibility and trypsin inhibitor activity in lentil and faba bean protein concentrates

Authors: HALL, ALEXANDRA - Cornell University; MORARU, CARMEN - Cornell University

Submitted to: LWT - Food Science and Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/20/2021
Publication Date: 8/21/2021
Citation: Hall, A.E., Moraru, C.I. 2021. Effect of high pressure processing and heat treatment on in vitro digestibility and trypsin inhibitor activity in lentil and faba bean protein concentrates. LWT - Food Science and Technology. 152. Article 112342. https://doi.org/10.1016/j.lwt.2021.112342.
DOI: https://doi.org/10.1016/j.lwt.2021.112342

Interpretive Summary: The growing interest in the use of pulse proteins as healthy food ingredients requires a better understanding of how different processing procedures impact their utility in food applications. The objective of this study was to assess the effects of high pressure processing or heat treatment on digestibility and enzyme inactivation potential in lentil and faba bean protein concentrates. Protein fractions were processed with either a high pressure or heat treatment and a lab-based procedure was used to digest the protein. Free amino acids and amino acid chains were measured as an indication of digestibility. The ability of the processed digestate to inhibit the activity of a protein digestive enzyme, called trypsin, was also determined. Protein digestibility was not impacted negatively by either treatment, but heat was much more effective at retaining trypsin enzyme activity, relative to the pressure treatment. This study demonstrates that both high pressure or heat treatments can be used to create pulse protein ingredients that retain good protein quality.

Technical 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.