Mechanism of xanthan gum in inhibiting aggregation in soy protein isolate gels after commercial Sterilization: Implications for texture-modified food for dysphagia

Abstract

This study investigated the impact of varying xanthan gum (XG) concentrations on the textural deterioration of soy protein isolate (SPI) gels following commercial sterilization, as well as its applicability in texture-modified foods. The results demonstrated that the SPI-XG composite gel prepared with 6 g/L XG exhibited optimal structural characteristics, showing significant improvements in both gel strength from 62.10 g to 74.45 g and water holding capacity from 90.95 % to 97.50 %. The incorporation of XG effectively constrained the conformational unfolding of SPI molecules and suppressed intermolecular hydrophobic interactions, thereby preventing excessive protein aggregation under high-temperature conditions. This mechanism led to the formation of significantly smaller protein aggregates, with the average particle size decreasing from 503.00 nm to 126.90 nm. The generation of smaller aggregates facilitated the formation of a gel network with greater structural homogeneity and density, as evidenced by a reduction in gel porosity from 50.031 % to 33.333 %. Furthermore, the SPI-XG composite gel exhibited texture properties corresponding to IDDSI levels 5 and 6, while maintaining high protein digestibility, making it suitable for dysphagia-friendly foods. These findings indicate that XG serves as an effective protective agent, enhancing the thermal stability of SPI gels during commercial sterilization and enabling their application in texture-modified food products.