Soluble Pea Protein Aggregates Form Strong Gels in the Presence of κ‑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 κ-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 κ-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 κ-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 κ-carrageenan.