Structure-function relationships of soy protein isolate reinforced by κ-carrageenan in high-protein konjac-based...

The development of protein-fortified plant-based food gels with tripe-mimetic texture is of great significance for replacing traditional animal-derived counterparts. In this study, a ternary composite gel was prepared using soy protein isolate (SPI), konjac glucomannan (KGM), and κ-carrageenan (KC), and the effects of SPI (6%, 8%, 10% w/w) and KC (1%, 2% w/w) concentrations on the gel structure and quality characteristics were systematically evaluated. The results showed that adding KC significantly improved the tensile properties of the SPI-KGM gel. Within the range of concentrations tested, the S2C2 gel (8% SPI, 2% KC) exhibited superior overall performance, with tensile strength, tensile toughness, and springiness of 0.0921 MPa, 0.0364 MJ/m³, and 7.63 mm, respectively, which were most similar to those of cooked tripe (0.0878 MPa, 0.0544 MJ/m³, and 7.89 mm). S2C2 exhibited a relatively uniform and dense network structure. Intermolecular force analysis indicated that hydrophobic interactions contributed to network formation, while hydrogen bonds and electrostatic interactions participated in network construction. The results showed that an appropriate ratio of SPI to KC concentrations could balance the protein-filling effect and the constraining action of the polysaccharide backbone, thereby enabling SPI addition to improve nutritional value while avoiding excessive deterioration of mechanical properties, and ultimately enhancing the overall mechanical performance of the SPI-KGM system. This study provides a theoretical basis for the structural design of high-protein plant-based tripe-mimetic gels and other biomimetic gel foods.