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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.

Potential allergenicity of amandin was reduced by binding amandin with (−)-epigallocatechin gallate (EGCG) via alkaline, free radical, ultrasound-assisted alkaline, and ultrasound-assisted free radical methods. These results of total phenol content, free sulfhydryl group, free amino group, surface hydrophobicity, and sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) indicated that amandin might be covalently bound to EGCG through reactive groups such as sulfhydryl and amino groups, or non-covalently through hydrophobic interactions. Fourier transformed infrared (FT-IR) spectroscopy and fluorescence spectroscopy revealed structural changes of amandin-EGCG conjugate, which also caused significant reduction in potential allergenicity of amandin. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) found that amandin bound to EGCG mainly through cysteine and glutamate residues, and linear epitope for amandin was reduced. This provided a new method and theoretical basis of hypoallergenic almond food.