Conformation and functional modification of porcine myofibrillar protein by pepper leaf polyphenols under oxidative condition

The effects of pepper leaf polyphenols (PLPs) on the conformation and functional characteristics of porcine myofibrillar proteins (MPs) under oxidative conditions were investigated. The addition of PLPs remarkably retarded the increase of carbonyl content and the average particle size of MPs after oxidation. Moreover, the sulfhydryl content, solubility, and the storage modulus (G′) of oxidized MPs were improved with the increased addition of PLPs to 1 g/100 mL. PLPs contributed to an increment in surface hydrophobicity when the incorporation of PLPs was 0.5 g/100 mL. The intrinsic fluorescence strength and FT-IR results indicated that PLPs altered protein conformation by exposure of the hydrophobic group and the conversion of α-helices to β-turn structures. Scanning electron microscopy results suggested that PLPs contributed to the orderly and uniform appearance of MPs. Furthermore, molecular docking analysis elucidated that arginine, glutamic acid, aspartic acid and glutamine were the predominant binding sites between MPs and the phenolic compounds of PLPs. Consequently, PLPs could be employed as a potential natural antioxidant to alleviate oxidation and modify the functional characteristics of meat products.