*Article* **Characterization and Discrimination of Key Aroma Compounds in Pre- and Postrigor Roasted Mutton by GC-O-MS, GC E-Nose and Aroma Recombination Experiments**

**Huan Liu , Teng Hui, Fei Fang, Qianli Ma, Shaobo Li, Dequan Zhang and Zhenyu Wang \***

Key Laboratory of Agro-Products Processing, Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences, Ministry of Agriculture and Rural Affairs, Beijing 100193, China; sd\_lh1990@126.com (H.L.); htengui@163.com (T.H.); fangfeixdf@163.com (F.F.); mql201228@163.com (Q.M.); lishaobo@caas.cn (S.L.); dequan\_zhang0118@126.com (D.Z.)

**\*** Correspondence: food2006wzy@163.com; Tel.: +86-(10)-6281-8740

**Abstract:** The key aroma compounds in the pre- and postrigor roasted mutton were studied in this study. The results showed that 33 and 30 odorants were detected in the pre- and postrigor roasted mutton, respectively. Eight aroma compounds, including 3-methylbutanal, pentanal, hexanal, heptanal, octanal, nonanal, 1-octen-3-ol, and 2-pentylfuran, were confirmed as key odorants by aroma recombination and omission experiments. The aroma profiles of pre- and postrigor roasted mutton both presented great fatty, roasty, meaty, grassy, and sweet odors. Particularly, the concentrations of hexanal, heptanal, octanal, nonanal, 1-octen-3-ol, and 2-pentylfuran in postrigor roasted mutton were significantly higher (*p* < 0.05) than those in the prerigor roasted mutton. The postrigor *back strap* was more suitable for roasting than the prerigor *back strap*. The pre- and postrigor roasted mutton could be obviously discriminated based on the aroma compounds by orthogonal partial least squares discrimination analysis (OPLS-DA) and principal component analysis (PCA). Hexanal and 1-octen-3 ol might potential markers for the discrimination of the pre- and postrigor roasted mutton.

**Keywords:** roasted mutton; pre- and postrigor; key aroma compounds; marker; recombination and omission experiments
