Combined pH-shifting and glycosylation treatment enhances functionality and mitigates allergenicity of β-lactoglobulin.

As a major milk allergen with limited functionality, β-lactoglobulin (β-Lg) requires effective modification strategies to enhance its applicability. This study investigated the synergistic effects of pH-shifting pretreatment and glycation on the structure, functional properties, and allergenic potential of β-Lg. The protein was first treated under strongly acidic or basic conditions to induce conformational rearrangements, followed by glycation with galacto-oligosaccharides (GOS) or xylo-oligosaccharides (XOS). Pretreatment under acidic conditions enhanced the protein structural flexibility, exposing more glycation sites, especially for the linearly structured XOS. Acidic pH-shifting with XOS glycation significantly improved the emulsifying and foaming properties of β-Lg, while reducing its IgE-binding capacity. In comparison, basic pH-shifting plus glycation resulted in the greatest reduction in protein allergenicity through a synergistic masking effect, albeit with compromised functionality due to aggregation. Overall, the combined modulation of structure and conjugation provides an effective strategy to tailor the functionality and allergenicity of milk proteins.