The effect of the purslane polyphenols on the structure of rabbit meat myofibrillar protein under malondialdehyde-induced oxidative stress.

The present research aimed to assess the protective effects of purslane polyphenols on rabbit meat myofibrillar protein (MP) under malondialdehyde (MDA)-induced oxidation. The major polyphenols in purslane extract were analyzed by ultrahigh performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-QTOF-MS). To analyze the protective mechanism of purslane polyphenol monomers on MP in the oxidation system, we determined the retained MDA content in the suspension and analyzed the structure and nuclear magnetic resonance (NMR) of MP. The UPLC-QTOF-MS identification analysis indicated that purslane polyphenols mainly contained chlorogenic acid, caffeic acid, ferulic acid, rutin, kaempferol, and quercetin. Polyphenols in purslane can prevent MDA from binding to MP effectively. Chlorogenic acid showed the best inhibitory effect, and the retention content of MDA decreased to 54.79%, which was significantly lower than those of other groups. Purslane polyphenols had protective effects on sulfhydryl groups, free amino groups, intrinsic tryptophan fluorescence, α-helix structure, and morphology of MP. Moreover, the carbonyl contents, increase in surface hydrophobicity, and random coil contents of MP were reduced. In addition, the NMR results indicated that polyphenols inhibited the oxidation of protein induced by MDA through competitive inhibition. PRACTICAL APPLICATION: This study showed the efficiency of purslane polyphenol monomers in protecting the structure and function of myofibrillar protein under malondialdehyde-induced oxidative stress and their potential to preserve the nutritional value of foods rich in proteins and lipids.