Process-induced protein aggregates influenced pea globulins’ structure formation upon heating

Abstract

Pea protein ingredients play key role in formulations of plant-based foods. However, functional properties of pea ingredients are inconsistent depending on extraction process. Protein aggregation occurs simultaneously during protein extraction, thus examining the protein aggregated states as induced by processing is essential for better process design. This study investigated the influence of process-induced protein aggregated states on structure formation upon heating of pea protein ingredients. Combining rheological, spectroscopic, and microscopic techniques, the mechanisms underlining heat-induced structure formation have been unveiled from microscopic to macroscopic scales. The salt-extracted isolate (PPI*) where protein aggregation was minimized, developed mesh-like structure through intermolecular protein-protein interaction upon gelling similar to commercial protein concentrate (PPC). In turn, commercial isolate (PPI) as appeared as microscopic particles, formed gel through accumulation of protein particles with no structure development. The aggregated states of PPI* and PPI seemed to dictate vicilin and legumin purification by means of anion exchange chromatography. Purification process promoted intermolecular protein aggregate structures. However, these purified fractions regardless of parent isolates showed similar structure development as PPC and PPI* during gelling. Monitoring protein aggregation during extraction process can be a key to limit functional property variation in pea protein ingredients.