Combined lactic fermentation and enzymatic treatments affect the antigenicity of β-lactoglobulin in cow milk and soymilk-cow milk mixture

This study evaluated the effect of lactic acid bacteria (LAB) fermentation combined with microbial transglutaminase (MTGase)-mediated modification on the antigenicity of β-lactoglobulin (β-LG) in cow milk and soymilk-cow milk mixture (SCMM). Results showed that MTGase-treatment could reduce the antibody binding reactivity of β-LG, especially in the SCMM (declined to 37.1% compared to cow milk), and had a further significant decrease to 9.9% (P < 0.01) in the presence of LAB. Moreover, LAB combined with MTGase (LAB + MTGase) treatment enhanced the cross-linking degree of β-LG, and the particle average size of aggregates formed in both cow milk and SCMM systems were also increased compared to LAB-treatment. Although the antigenicity of β-LG was not eliminated during in vitro digestion phases, our findings suggested that LAB + MTGase-treatment could be a much more efficient approach to reduce the antigenicity of β-LG in mixed soymilk-cow milk protein polymers compared to cow milk protein polymers.