Optimizing the Functional and Safety Properties of a Marine Allergen: Maillard-Induced Conjugation of Chitosan and Saccharides Attenuates the Allergenicity of Turbot (Scophthalmus maximus) Parvalbumin.

Fish allergy, mainly caused by Parvalbumin (PV), is a worldwide health issue with few effective mitigation options. This study investigated Maillard conjugation using chitosan (CS) and various saccharides to modify the structural, functional, and allergenic properties of turbot (Scophthalmus maximus) PV. Structural analyses, including SDS-PAGE, Western blotting, FTIR spectroscopy, and Circular dichroism, confirmed successful conjugation and significant changes in secondary structure, including decreases in α-helical content and increases in β-sheet and random-coil fractions. Glycation significantly boosted antioxidant activity, with total phenolic content (TPC) increasing up to 10.3 times and DPPH radical scavenging reaching 74.5% in the CS-xylose-PV conjugate (CXTPV). Indirect ELISA revealed notable (p < 0.05), sugar-dependent reductions in IgE-binding capacity, with reductions of up to approximately 72% for CXTPV. RBL-2H3 cell assays showed decreased β-hexosaminidase release (about 75% reduction), lowered IL-6 secretion, and strong inhibition of IL-4 production, indicating reduced allergenic potential and immune regulation. CXTPV demonstrated the best overall performance. These findings suggest that CS-saccharide Maillard conjugation is an effective approach for creating hypoallergenic marine ingredients with improved bioactive properties.