Impact of Slaughter Weight on Flavor Metabolites in Longissimus Dorsi Muscle of Tianfu Finishing Pigs

In order to investigate the flavor compounds in the muscles of Tianfu finishing (TF) pigs with different slaughter weight (SW), 12 TF pigs were selected for the experiment. The volatile metabolic profiles of meat specimens from the longissimus dorsi (LD) muscle of TF pigs with different SW were studied by untargeted liquid chromatography-mass spectrometry. Our data revealed that the three types of TF pork showed significantly different profiles of hydrocarbons, alcohols, esters, heterocyclic compounds, and others, which could underpin the nuances of their flavors. A total of 118 differentially expressed metabolites (DEMs) were identified (2 upregulated DEMs and 116 downregulated DEMs). Among the volatile flavor compounds, hydrocarbons, alcohols, ester, and heterocyclic compound in the three groups accounted for 26.71%, 13.01%, 13.01%, and 13.70%, respectively, and their contents decreased with increasing SW. The contents of alcohols, aldehydes, and hydrocarbons in the 150-kg group was significantly higher than those in the 125-kg and 100-kg groups (p < 0.05). Taken together, raising SW to 125 kg, or more, decreased the flavor of TF pork and had no benefits to pork quality attributes. Our results provided insights into the molecular basis for sensory variations among different SW of TF pork.