Exploring the formation mechanism of off-flavor of irradiated yak meat based on metabolomics

Irradiation's effects on quality, volatile compounds, and differential metabolites of yak meat were studied. Irradiation dose at 3 kGy had no effect on yak meat quality, however irradiation dose at 5 kGy resulted in yak meat quality deterioration as well as considerable irradiated off-flavors. And the level of the off-odor was strongly associated with the irradiation dose, and allyl methyl sulfide, octanal, nonanal, benzaldehyde, and 4-methylthiazole were all significant producers of off-odor. Meanwhile, with the increased of radiation dose, the amounts of cysteine, methionine, proline, linoleic acid, stearic acid changed obviously. The main generation pathway of irradiated off-flavors in yak meat were thought to be cysteine and methionine metabolism, and linoleic acid metabolism. The oxidative decomposition of sulfur-containing amino acids and unsaturated fatty acids may cause the off-flavor of irradiation yak meat. This research established a theoretical foundation for future control systems to prevent flavor quality alterations during irradiation preservation.