Does Transglutaminase Crosslinking Reduce the Antibody Recognition Capacity of β-Lactoglobulin: An Analysis from Conformational Perspective

Food allergies are a global concern, with β-lactoglobulin (β-LG) in bovine milk being a major allergenic protein. This study investigated the effects of transglutaminase (TGase)-mediated crosslinking on the antibody recognition capacity (ARC) and structural properties of β-LG, with the aim of developing hypoallergenic dairy products. β-LG solutions were treated with TGase at varying concentrations (0, 5, 10, 15, and 20 U/g) and durations (0, 6, 18, 24, and 42 h), followed by analysis using electrophoresis, enzyme-linked immunosorbent assay (ELISA), and spectroscopy. The results demonstrated that treatment with TGase at 20 U/g significantly reduced the ARC and immunoglobulin E (IgE) binding capacity of β-LG to 90.0 ± 0.4% and 58.4 ± 1.0%, respectively, with the optimal ARC reduction observed after 6 h of treatment (86.7 ± 1.2%, <i>p</i> < 0.05). Although electrophoresis did not reveal significant crosslinking of β-LG, ultraviolet absorption, fluorescence intensity, and hydrophobicity all increased with prolonged crosslinking time, while sulfhydryl content fluctuated irregularly. These findings suggest that β-LG underwent varying degrees of structural modification, which led to the masking of antigenic epitopes during the early stages (0-24 h), followed by their re-exposure at the later stage (42 h). Overall, these results highlight the potential of TGase to reduce β-LG potential allergenicity, presenting a promising strategy for the development of hypoallergenic dairy products.