Structural Elucidation and Zinc Supplement Potential of the High-Bioavailability Oyster Peptide-Zinc Complex

Zinc deficiency is a severe global public health problem. Traditional inorganic and organic zinc supplements have obvious drawbacks. Oysters are rich in zinc but suffer from insufficient deep processing and low economic value. Developing oyster peptide-zinc complex (OPZ) is a feasible solution for both zinc supplementation and high-value oyster utilization. This study optimized the chelation process of OPZ via single-factor and response surface methods. The optimal parameters were confirmed as follows: chelation time 44 min, temperature 50°C, pH 6.95, liquid-to-solid ratio 1:4, peptide-zinc ratio 1:1, with a chelation rate of 5.2498 mg/g. Multispectral characterization verified OPZ formation. Amino acids residues ─NH₃ ⁺ and ─COO^- participated in chelation, and the peptide chain structure rearranged. OPZ showed good acid stability and gastrointestinal digestion resistance in simulated physiological conditions. In zinc-deficient mice, OPZ effectively restored body weight and food intake. It alleviated organ damage in liver, spleen, and small intestine. It also promoted zinc deposition in muscle, fur, serum, and femur to normal levels. OPZ had higher zinc bioavailability than zinc sulfate. This research clarifies OPZ's preparation and characterization. It provides technical support for oyster value-added processing. It also lays a foundation for developing efficient third-generation zinc supplements, with broad application prospects in functional foods and health products.