摘要
This study systematically investigated the non-covalent interaction mechanisms, structural characteristics, and functional properties of ovalbumin (OVA)–mulberry polysaccharide (MP) complexes under different pH and mixing ratios and further constructed pickering emulsions based on the optimized complex. The phase behavior of the OVA–MP system exhibited significant pH and ratio-dependent variations. As the pH decreased from 6.5 to 2.0, the turbidity of the system followed a “dissolution–aggregation–re-dissolution” pattern, with the maximum aggregation point (pH opt ) corresponding closely to the isoelectric point of OVA (pI ≈ 4.5). Spectroscopic analyses revealed that MP induced OVA conformational relaxation and hydrophobic exposure by reinforcing hydrogen bonding and electrostatic interactions. This process modulated the secondary structural order and hydrogen-bond network stability. Functionally, the OVA–MP complex exhibited significantly enhanced emulsifying activity, thermal stability, and foaming properties. Under the conditions of pH 6.0, volume ratio 2:1, and denaturation temperature ( T d ) 95.4°C, the comprehensive performance (ESI = 39.36 ± 0.33 min) was the best. Molecular dynamics (MD) simulations confirmed that OVA–MP binding was a thermodynamically spontaneous process (ΔG = –38.98 ± 0.89 kcal/mol), mainly driven by van der Waals and hydrogen-bonding interactions. The resulting O/W pickering emulsion displayed reduced droplet size, pronounced shear-thinning behavior, higher viscoelasticity (G′ > G″), and improved salt and storage stability. Overall, MP modulates OVA conformation and interfacial behavior through synergistic hydrogen bonding and electrostatic attraction, forming a structurally reinforced interface. These findings provide theoretical and technical insights into designing food-grade biopolymer emulsifiers and functional delivery systems with enhanced stability.
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