Abstract: Postmortem cooling aging can affect flavor components of meat. In order to explore the effect of cooling aging process on volatile flavor components in yak meat, the Longissimus dorsi muscle from yak in Sunan county was used to determine volatile flavor components by gas chromatography-mass spectrometry (GC-MS). Compared with yak meat without aging treatment, the sulfur compounds (meat flavor) in yak meat with aging treatment exhibited an increase of 24%, especially for 2-acetyl thiazole (meat flavor) and methylthiopropionaldehyde (broth flavor). Both kinds of compounds in yak meat with cooling aging treatment exhibited an increase of 100% and 78%, respectively. Meanwhile, the content of carbonyl compounds exhibited an increase of 311%, including an increase of 331% for 3-hydroxyl-2-butanone (milky aftertaste). The relative content of 3-hydroxyl-2-butanone in yak meat with aging treatment was up to 20.54%. This volatile compound exhibited the highest relative content and the highest level of increase in yak meat with aging treatment. However, phenols, terpenes and sesquiterpenes derived from herbage exhibited a decrease of 34%, which included a reduction of 70% for 4-methyl phenol (pastoral flavor), and a decline of 40% for β-caryophyllene. Therefore, postmortem aging process is beneficial to the improvement of flavor components in yak meat and the reduction of negative impact on the flavor of yak meat due to some special components in herbage.

Key words: yak meat, cooling aging, volatile flavor component, gas chromatography-mass spectrometry(GC-MS)