Microplastics are pervasive throughout the food system. Recent research indicates that millions of microplastics are released from baby bottles during infant formula preparation. In this context, microplastics are likely to interact with milk allergens, potentially affecting the structures and characteristics of allergens, which may pose risks to human health, particularly for infants with cow's milk allergy. This study analyzed the interaction between commonly used baby bottle microplastics (polypropylene, polyethersulfone, polyphenylsulfone) and the major milk allergen β-lactoglobulin using multi-spectroscopy techniques and molecular simulation. Furthermore, microplastics-mediated alterations in protein digestibility and allergenicity were evaluated through in vitro gastrointestinal digestion, peptidomics, ELISA, and a KU812 cell degranulation model. The results indicated that microplastics adsorbed β-lactoglobulin through nonpolar interactions, with the surface chemistry of microplastics determining the binding affinity. Microplastics induced the unfolding of β-lactoglobulin tertiary structure, and β-lactoglobulin mixed with microplastics resulted in reduced digestibility. Moreover, β-lactoglobulin that interacted with microplastics showed enhanced IgE binding capacity and a greater ability to elicit KU812 cell degranulation. This effect was especially pronounced with polyphenylsulfone@β-lactoglobulin, whose IgE binding capacity increased by 3.7%, while the release of β-hexosaminidase and histamine increased by 9.4% and 65.5%, respectively. Collectively, these findings provide novel insights into the interactions between microplastics from baby bottles and milk allergens, highlighting potential implications for cow's milk allergy management and broader health risks associated with microplastics exposure in infant nutrition.

In order to explore the feasibility of replacing sodium chloride with potassium chloride or magnesium chloride to improve the functional properties of liquid whole egg (LWE), the effects of different concentrations of sodium chloride (0.2, 0.4, 0.8 and 1.6 mol/L), potassium chloride (0.2, 0.4, 0.8 and 1.6 mol/L) and magnesium chloride (5, 10, 20 and 40 mmol/L) on the physicochemical and functional properties of LWE were evaluated. The results showed that the functional properties of LWE were significantly affected by the addition of salt. After adding 0.8 and 1.6 mol/L potassium chloride, the foam stability was increased by 21.4% and 21.6%, respectively. After adding 20 and 40 mmol/L magnesium chloride, the emulsion stability was increased by 14.7% and 24.1%, respectively, and the protein solubility by 12.7% and 13.8%, respectively. In addition, the water-holding capacity and elasticity of LWE gels were not damaged after adding 40 mmol/L magnesium chloride, and the gel hardness was significantly increased. Meanwhile, 40 mmol/L magnesium chloride caused little change in the color of LWE and no significant change in its pH. In conclusion, magnesium chloride has the potential to replace sodium chloride to improve the functional properties of LWE. These results will provide a theoretical basis for adding sodium salt substitute into LWE.