Structure of pea protein-based complexes on high-moisture extrusion: Raw materials and extrusion zones

Abstract

Recent studies have shown a trend towards using materials containing multiple proteins by high-moisture extrusion in plant-based meat analogs (PBMA). However, research on the selection of plant proteins and multiple protein structure changes during extrusion is limited. In this study, pea protein (PP), soy protein isolate (SPI), chickpea protein (CP) and wheat gluten (WG) were blended to prepare four mixtures, PP, PP-WG, PP-SPI-WG, and PP-CP-WG, were investigated for their effects on texture properties and protein structure of the extrudates, and changes in protein structure of PP-CP-WG mixture during the extrusion process were studied. The PP-CP-WG extrudates displayed the highest levels of hardness, chewiness, and fibrous degree of extrudates (25.80 ± 0.20, 4.65 ± 0.14, and 1.25 ± 0.04, respectively, P < 0.05). High-moisture extrusion led to a significant increase in disulfide bonds content and a significant decrease in surface hydrophobicity for four mixtures (with increases ranging from 35 to 80 % and decreases ranging from 9 to 39 %). During extrusion, the content of disulfide bonds increased, reaching a maximum value of 3.36 ± 0.02 μmol/g in the die, surface hydrophobicity decreased, the β-sheet content rose from 50.25 ± 0.23 % to 56.74 ± 0.71 %, and the fluorescence intensity decreased. This study would be useful for the development of PBMA containing a variety of proteins.