The insight into the Maillard reaction of β-lactoglobulin and chitosan with different molecular weights, and the evaluation of desensitization effects

The covalent conjugation of chitosan to β-lactoglobulin (βLg) via Maillard reaction alters its structure and characteristics, providing a method to reduce allergenicity. The molecular weight (Mw) of chitosan plays a crucial role in the conjugation process, which in turn affects the desensitization effectiveness to βLg. The degree of conjugation decreased from 46.4 % ± 2.6 % (βC-1 ) to 27.6 % ± 2.9 % (βC-100) as the Mw increased from 1 kDa to 100 kDa. Notably, βC-1 showed a significant reduction in β-sheet content, resulting in a greater increase in surface hydrophobicity and improved thermostability compared to βC-10 and βC-100. Consequently, βC-1 demonstrated the most effective desensitization, with the highest inhibition of immunoglobulin E (IgE) combining capacity and the best suppression of cytokine overproduction in KU812 cells. Additionally, the overexpression of IgE and inflammatory factors in mice was significantly suppressed after βLg was conjugated with chitosan, alleviating dysbiosis of gut microbiota at both phyla and family levels and lessening anaphylactic response to βLg. The desensitization effects were observed in the order of βC-1 > βC-10 > βC-100.