Effects of high hydrostatic pressure on the structure and potential allergenicity of the major allergen bovine β-lactoglobulin

Bovine beta-lactoglobulin (beta-Lg) is recognized as a significant milk allergen in several countries. In this study, beta-Lg was isolated and treated with high hydrostatic pressure (HHP) at 100, 200, 300, 400, and 500 MPa. The allergenic properties of the HHP-treated beta-Lg were characterized by indirect competitive enzyme-linked immunosorbent assay with anti-beta-Lg rabbit antibody and the sera of patients allergic to cows' milk. The conformation of the HHP-treated beta-Lg was examined with ultraviolet absorption spectroscopy, endogenous fluorescence spectroscopy, exogenous fluorescence spectroscopy, and circular dichroism spectroscopy analyses. The results indicated that IgG binding increased with treatment pressure, and IgE binding was lowest at 200 MPa and highest at 400 MPa. The tertiary structure of beta-Lg changed significantly after HHP, whereas the primary and secondary structures remained stable. Overall, this study suggests that the conformational changes in HHP-treated beta-Lg contribute to its altered allergenicity. (C) 2016 Elsevier Ltd. All rights reserved.