Abstract: In order to study the effect of roasting time on volatile compounds in the surface and inner layers of Xinjiang roast lamb leg, we applied solid phase microextraction coupled with gas chromatography-mass spectrometry (SPME-GC-MS) to analyze the volatile compounds in the surface and inner layers of roast lamb leg with roasting times of 0.5, 1, 1.5, 2, 2.5, and 3 h. The results showed that a total of 64 and 55 volatile compounds, mainly hydrocarbons, alcohols, aldehydes, heterocycles, ketones, esters and acids, were respectively detected in the surface and inner layers of roast lamb leg. As roasting proceeded, the types and contents of hydrocarbons, alcohols, aldehydes, heterocycles, ketones and esters in the surface layer of roast lamb leg were higher than those in the inner layer. Roasting time of 1.5 h was the key point to produce volatile compounds in roast lamb leg. Based on their relative odor activity values (ROAVs), it was concluded that the characteristic volatile flavor compounds detected at 2.5 h contributed the most to the surface layer and inner layer of roast lamb leg. Among them, 1-octen-3-ol, nonanal, (E,E)-2,4-decadienal, octanal and hexanal contributed the most to the aroma of roast lamb leg.

Key words: Xinjiang roast lamb leg; volatile compounds; solid phase microextraction-gas chromatography-mass spectrometry; relative odor activity value