Metabolic and oxidative mechanisms underlying flavor differences in yak meat across seasonal grazing–housing regimes: Evidence from integrated foodomics

This study investigated the flavor differences among summer pasture-grazed (SM), winter pasture-grazed (WM) and winter stall-fed (HM) yaks using metabolomics, lipidomics and headspace-solid-phase microextraction-gas chromatography–mass spectrometry (HS-SPME-GC–MS). The SM group showed n-3 polyunsaturated fatty acids (n-3 PUFAs) were 225% and 209% higher than those in the WM and HM groups, respectively, with higher thiobarbituric acid reactive substances (TBARS) and antioxidant enzyme activities. These changes promoted the formation of (E)-2-decenal and 1-octen-3-ol, which impart green and floral aromas. Conversely, the HM group's high-energy diet increased monounsaturated fatty acids and essential amino acids (EAAs). This promoted the production of Maillard-derived furfural and maintained the oxidative-antioxidant balance, preserving nutty and tallowy flavors. The WM group exhibited off-flavors due to oxidative imbalance, lower PUFAs content, and benzaldehyde accumulation. Overall, feeding regimes shape yak flavor by modulating fatty acid and amino acid compositions and the oxidative-antioxidant balance. This study provides a scientific basis for precision nutrition strategies to optimize flavor in yaks. • Summer pasture grazing increases n-3 PUFAs and antioxidant enzyme levels in yak muscle. • A balanced high-oxidation/high-antioxidant state promotes desirable VOCs • Winter stall feeding favors formation of Maillard-derived furfural, producing nutty aroma notes. • Winter pasture grazing disrupts redox balance and increases benzaldehyde-associated off-notes. • Multi-omics identifies redox-linked nodes controlling yak meat flavor.