Influence of frozen storage and flavoring substances on the nonvolatile metabolite profile of raw beef: Correlation of lipids and lipid-like molecules with flavor profiles

This study aimed to explore the effects of frozen storage and flavoring substances (sugar and salt) on the metabolite profiles of nonflavored (BS1) and flavored (BS2) beef samples through UHPLC-MS/MS and an untargeted method and flavor profiles using GC-MS and targeted method. Analysis was conducted during 0, 3, and 6 months of frozen storage. A comprehensive analysis of biochemical databases yielded a total of 1791 metabolites: 1183 metabolites were identified in positive ion mode and 608 in negative ion mode. There were 3 categories of metabolites under superclass classification, accounting for 77.93 % of the total metabolites, including lipids and lipid-like compounds (502 species, 33.87 %), organic acids and derivatives (459 species, 30.97 %), and organoheterocyclic compounds (194, 13.09 %). Multivariate statistical analysis showed that after 0, 3, and 6 months of frozen storage, 120, 106, and 62 differential metabolites, respectively, were identified in the comparison between the BS1 and BS2 samples. The results indicated that frozen storage has a decreasing effect on the differential metabolites, while the flavoring substances mainly enhance the metabolite profiles. It can be concluded that flavoring substances and frozen storage primarily influence the metabolites. At 0 and 6 months of frozen storage, 27 volatiles were detected. The correlation analysis displayed a positive correlation between lipids and lipid-like molecules and flavor compounds.