Influence of extraction method on the aggregation of pea protein during thermo-mechanical treatment

Abstract

Two methods to extract pea protein from pea flour, alkali extraction – isoelectric precipitation and salt extraction – dialysis, were compared regarding the functional behaviour of the resulting protein isolates upon thermo-mechanically induced aggregation to obtain microparticulates. In addition, the effects of pH and temperature during thermo-mechanical treatment were investigated. The resulting particles were analysed for size and morphology. Particles between 1 and 30 μm were formed. The biggest effect on the size and structure of the particle was the extraction method, followed by a variation of pH during heat treatment. Particles generated from pea protein obtained by salt extraction – dialysis were smaller and denser than particles produced from protein material obtained from alkali extraction – isoelectric precipitation. pH 4 during thermo-mechanical treatment resulted in larger and denser particles compared to particles at natural pH. Temperature variation between 88 °C and 98 °C had a minor influence. This study can serve as a base for further research on the thermal behaviour of pea protein and can help to manipulate aggregate structure for incorporation in novel innovative (vegan) food concepts.