Effects of packaging methods and storage duration on yak meat flavor profiles during chilled storage: GC-IMS and GC-MS evaluation

Yak meat is valued for its unique flavor and nutrition, but refrigerated storage packaging affects its flavor quality. This study focuses on longissimus thoracis et lumborum (LTL) of yaks and compares the regulatory effects of tray packaging (aerobic environment) and vacuum packaging (low oxygen environment) on the taste and metabolic characteristics of meat products at 3 days (mid-term of short-term storage) and 7 days (end of short-term storage, upper limit of conventional shelf life) under 4 °C refrigeration conditions. The relevant mechanisms are analyzed by combining gas chromatography-ion mobility spectrometry (GC-IMS) and gas chromatography-mass spectrometry (GC-MS) techniques. The results showed that GC-IMS detection revealed that tray packaging had significantly higher fresh flavor compounds (alcohols, aldehydes, esters) than vacuum at 3 days, better retaining initial aroma. However, when storage was extended to 7 days, substances imparting undesirable flavors (2-methylbutanal-D, 1-hydroxy-2-propanone, 2-propanethiol, and 2-ethylfuran) accumulated significantly in tray packaging meat, while vacuum packaging effectively inhibited the formation of such substances. GC-MS analysis indicated that the contents of fumaric acid and glutamine in the vacuum packaging groups (3/7 days) were consistently higher than those in tray packaging groups. After 7 days of storage, the content of free amino acids (L-cysteine, L-lysine) in vacuum packaging meat was significantly increased. Furthermore, glyceraldehyde 3-phosphate, formamide, and 1-methoxy-2-methylprop-1-en-1-ol were identified as the key differential metabolites between the two packaging methods. KEGG pathway enrichment analysis showed that amino acid metabolism was the core driving pathway for changes in the composition of flavor compounds during the oxidation of yak meat under chilled storage. The selection of yak meat packaging should be adjusted according to storage duration: tray packaging is more suitable for short-term storage (within 3 days) to retain fresh flavor, while vacuum packaging can more effectively maintain meat flavor quality during long-term storage (7 days) by inhibiting oxidative reactions and regulating umami-related metabolism. The results of this study provide experimental support for the targeted optimization of fresh yak meat packaging schemes and the extension of its flavor shelf life. • This study investigated the changes of tray and vacuum packaging on VOCs in yak meat. • The flavor of yak meat stored in different ways for 3/7 days were studied by GC-IMS. • The changes of yak meat metabolites stored in different ways were studied by GC-MS.