Exploring the freshness biomarker and volatiles formation in stored pork by means of lipidomics and volatilomics.

Raw pork is prone to oxidation and rancidity as it contains a high level of unsaturated lipid molecules. Reliable biomarkers to benchmark pork freshness and their formation have not been systematically investigated. The results indicated that the peroxide values, TVB-N and rancid volatiles dramatically increased in pork during the storage period (4 °C, 0-9 d). Concentrations of most volatile compounds with carbonyl groups were increased markedly in pork during storing, including hexanal, acetic acid, and hexadecanoic acid methyl ester. Lipidomics, volatilomics and chemometrics methods were used to discriminate the freshness of pork, among which acetic acid and PC O-20:3 emerged as the most reliable freshness biomarkers. Phospholipids and neutral lipids, including phosphatidylcholines (PC), triglycerides (TG), and phosphatidylethanolamine (PE), played a crucial role in the formation of rancid volatiles and the decreased freshness. This work will provide technical supports for the efficient storage and preservation of raw meat.