Rambutan peel polyphenols improve color and texture of ground pork: Identification, antioxidant and bacteriostatic function, and molecular docking

Abstract

This study investigated the application of rambutan peel polyphenols in ground pork to elucidate their mechanism in inhibiting oxidation and discoloration. Molecular docking was employed to elucidate the interactions between key polyphenols (geraniin, rutin) and myoglobin/myofibrillar protein. Rambutan peel polyphenols exhibited notable inhibitory effects on DPPH, ABTS free radicals, and lipid peroxidation. They also increased the a∗ and b∗ values of ground pork during storage. The inclusion of rambutan peel polyphenols retards the escalation of ferrimyoglobin and the reduction of oxygenated myoglobin content. Meanwhile, these polyphenols reduced TBARS and TVB-N levels in the ground pork. Molecular docking revealed that the binding energy between myoglobin and geraniin is −9.8 kcal/mol. Mechanistically, stable binding configurations involving cation-π (Lys42, Lys98, Lys102), π-π (Phe151), and hydrophobic interactions (Lys102, Gln152, Ile99) prevented myoglobin overoxidation and discoloration. The binding energy between myosin and geraniin is −10.73 kcal/mol, and the interaction included hydrophobic bonds (Asn200 and Glu159), Cation-Pi (Lys425) and π-π (His602), which enhanced the antioxidant properties of myofibrillar protein. This study showcases the antioxidant effects of rambutan peel polyphenols and provides the mechanism of protecting pork against oxidation and discoloration. • Geraniin and rutin emerged as the most abundant polyphenols in rambutan peel. • Polyphenols improved antioxidation, color and texture of ground pork. • A stable structure formed of between myoglobin and geraniin for discoloration. • Connection of myosin and geraniin protect myofibrillar protein against oxidation. • The interaction includes Cation-Pi, π-π and hydrophobic bonds.

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