Microbial transglutaminase-mediated polymerization in the presence of lactic acid bacteria affects antigenicity of soy protein component present in bio-tofu

The approach of LAB combined MTGase-treatment could help to decrease potential allergic responses of soy proteins effectively. [Display omitted] •Soymilk/mixed soy-cow milk gel (bio-tofu) coagulated by MTGase and LAB was developed.•Addition of LAB combined with MTGase promoted the polymerization of proteins.•Mixed protein polymers had lower Ab reactivity than in soymilk protein polymers.•LAB + MTGase-treated mixed milk gel had the lowest antigenicity at intestinal digestion. The aim of this study was to evaluate the antibody (Ab) reactivity of soy proteins present in bio-tofu made of soymilk or soymilk and cow milk mixture polymerized by microbial transglutaminase (MTGase) combined or not with lactic acid bacteria (LAB). Of all samples, the in vitro digestibility studies were also performed, together with Ab reactivity of the digests. In comparison with only MTGase or LAB treated samples, the use of LAB in conjunction with MTGase (LAB + MTGase) showed enhanced capacity to crosslink proteins, and could form aggregates with enlarged particle average size and negative Zeta-potential in both soymilk and soymilk-cow milk systems. Moreover, the Ab reactivity of soy proteins in LAB + MTGase-treated samples were reduced more effectively than of the only MTGase or LAB treatments. Results of this study indicate that hypoallergenic soy protein gel products could be produced by LAB+MTGase-mediated polymerization of soymilk and cow milk mixtures.