Regulation of Prunus mume Polyphenols Extracts on Muscle Protein Oxidation and Nitrosation

The regulation of plant polyphenols on oxidation and nitrosation of meat products has been a focus of current research, but the relevant regulatory mechanisms are still unclear. In view of this, the oxidative regulation of plant polyphenols on two major muscle proteins (myofibrillar protein and sarcoplasmic protein) under the simulated hydroxyl radical oxidation system was investigated with Prunus mume polyphenol extracts (PMP) as an example. The mechanism of inhibiting nitrosation of muscle protein by PMP was investigated by principal component analysis combined with the changes of 3-nitrotyrosine (3-NT) and nitrosodimethylamine (NDMA) during nitrosation. The results showed that the addition of PMP could delay the protein oxidation induced by hydroxyl radicals, which inhibited the protein carbonyls, dimerized tyrosine and free amino acids, and reduced the loss of sulfhydryl group. When the addition of PMP was 100 mg/g protein, after simulated oxidation, the 3-NT content was 30.25±2.47 nmol/mg protein (myofibrillar protein) and 37.54±2.30 nmol/mg protein (sarcoplasmic protein), respectively. Compared with the oxidation control group (without PMP), it was reduced by 39.89% and 47.88% (P<0.05), respectively. The content of NDMA was 0.76±0.05 nmol/mg protein (myofibrillar protein) and 0.67±0.06 nmol/mg protein (sarcoplasmic protein), respectively, which were decreased by 24.30% and 24.61% compared with oxidized control group (P<0.05). Correlation analysis showed that the formation of NDMA was significantly correlated with protein carbonyls, polydityrosine and sulfhydryl groups (P<0.05), confirming that PMP could inhibit the formation of nitrosamines through the oxidation regulation of proteins. The above results can provide theoretical basis for the application of plant polyphenols in nitrosation regulation of meat products.