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

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.