Understanding the Effect of Anthocyanin-rich Extract on the Gel and Digestive Properties of Soy Protein Cold-set Gels

In this work, the effect of a typical colored ingredient- anthocyanin-rich extract (derived from black soybean seed coat extract, abbreviated as BE) on the gelling and digestive properties of soy protein cold-set gels were investigated. The SEM observation revealed that upon the addition of BE, the size of protein aggregates decreased, and more string-of-beads structures appeared in the gel networks. The texture and rheological results demonstrated that BE significantly improved the hardness and storage modulus (G’) of gels, which were related to the enhancement of hydrophobic interactions and disulfide bonds in the gels. Moreover, BE limited the migration of bound water and free water in the gels as well as the in vitro digestion of gels, despite of the swelling ratio of gels in simulated digestive fluids was increased. These findings provide some useful information for the design and application of soybean gel products enriched with colored ingredients in food industry.