Soluble Pea Protein Aggregates Form Strong Gels in the Presence of kappa-Carrageenan

Pea protein has attracted attention as an alternative for soy protein, but its weaker gelling properties have limited applications in food formulations. In this study, heat-induced soluble pea protein aggregates were prepared in the first step, followed by the heat-induced gelation of the soluble pea protein aggregates in the presence of a small amount of kappa-carrageenan. The mechanical property measurement indicated that the complex gel strength can be modulated by modifying the pea protein aggregate properties to achieve a compressive strength up to 14.15 kPa. In addition, such strong gels were achieved at a relatively low concentration of protein (7.5%) and kappa-carrageenan (0.5%) and thus are advantageous for practical applications. The surface hydrophobicity, transmission electron microscopy, and Fourier-transform infrared spectroscopy characterizations suggest that pea protein particulate aggregates with hydrophobic patches on the surface can serve as the active building blocks to establish a homogeneous three-dimensional network of highly cross-linked structures with small pore size, thus leading to gels of superior mechanical strength when compared with gels prepared from pea protein isolate with kappa-carrageenan. This research has provided a novel approach for structuring and texturization of plant-protein-based foods by using protein aggregates and contributed to the understanding of mechanism of gel formation from pea protein aggregates in the presence of kappa-carrageenan.