Effects of high-temperature treatment on in vitro protein digestibility and protein profiles of pea ingredients obtained from wet and dry fractionation

Thermal treatment can improve plant protein digestibility by inactivating antinutrients and partially denaturing proteins, but depending on the conditions applied, heating may also promote aggregation and amino acid modifications that hinder protein digestibility. This study describes how heat affects the protein profile and in vitro digestibility of pea ingredients produced by wet and dry fractionation. Protein suspensions (40 wt%) of pea flour (PF), protein-rich fraction (PRF), and protein isolate (PI) were heated at 90 °C or 140 °C for 20 min. Proteomics, SDS-PAGE, trypsin inhibitor activity (TIA), and in vitro protein digestion (INFOGEST) were performed. All heated samples showed protein aggregation, likely limiting protein identification in PF and PRF. The highest temperature increased protein oxidation in PI and markedly lowered TIA in PRF (87%), improving its intestinal digestion. Nevertheless, heating did not alter overall in vitro digestibility, suggesting that matrix effects offset the advantages of TIA reduction.