Process-Induced Protein Aggregates Influenced Pea Globulins’ Structure Formation Upon Heating

Abstract

The processing history influences the aggregate state of pea protein, especially globulins resulting in diverse functional properties of pea protein ingredients. This work focused on the gel structure formation upon heating of the pea protein ingredients (commercial protein concentrate (PPC), lab-prepared (PPI*) and commercial (PPI) protein isolates) and their purified fractions (vicilin (Vic), legumin (Leg) and the mixture of them (VicLeg)). PPI* was extracted from PPC using salt extraction/ ultrafiltration. Vicilin and legumin were purified from either PPI* of PPI using anion exchange chromatography. The VicPPI and LegPPI shared similar polypeptide profiles, while VicPPI* and LegPPI* had distinct profiles. A progressive increase in G’ during heating was observed in PPC, PPI*, and the PPI* sub-classes. On the other hand, such an increase was not observed in PPI, VicPPI and VicLegPPI. Microscopic time-lapsed videos showed that protein in PPC and PPI* developed mesh-like structure upon heating. In contrast, the protein in PPI was in particulate form that remained almost unchanged by heating. The intermolecular β- sheet and random coil were dominated in PPI and were not found in PPC and PPI*. The process-induced protein aggregated state greatly influenced the heat-induced structure formation of pea protein ingredients and their globulin sub-classes.

Keywords: pea protein, Vicilin, Legumin, pea globulins, gelation, microstructure, 7S, 11S