Structural and functional properties of soluble Antarctic krill proteins covalently modified by rutin.

New polyphenol-protein conjugates were successfully prepared by covalently crosslinking soluble Antarctic krill proteins with rutin (SAKPs-rutin). The physico-chemical and functional properties of SAKPs-rutin conjugates were systematically evaluated by measuring the changes in interfacial tension, structural conformation, and emulsifying ability, etc. The results showed that SAKPs-rutin conjugates possessed higher surface hydrophobicity, surface charge, and thermal denaturation temperature, and lower β-sheet conformation compared to native SAKPs. On this basis, the interfacial tension of SAKPs-rutin conjugates was reduced, which greatly contributed to the formation of denser and more ordered networks at the oil-water interface. Meanwhile, the emulsifier endowed the fabricated high internal phase emulsions (HIPEs) with excellent physical performance and oxidative stability, evidenced by low peroxide values (POV) and malondialdehyde (MDA) after the treatment of long-term storage (15d), heating (65 °C) and UV light treatment. These findings suggest that SAKPs-rutin conjugates are a novel and promising food resource for preparing food-grade emulsions.