Characterizing key aroma-active compounds of stewed mutton using gas chromatography-olfactometry-mass spectrometry coupled with odour activity value

Stewed mutton is popular for its nutritional and special flavour qualities. To determine the key aroma-active compounds of stewed mutton in different parts, six experimental groups (sheep fat, sheep bone, sheep brisket, sheep loin, sheep rib and sheep leg) were investigated by gas chromatography-olfactometry-mass spectrometry (GC-O-MS). Totally, 57 volatile compounds in mutton soup were identified. Of these, 22 aroma-active compounds were identified as key aroma compounds with odour activity values (OAVs) >1. The partial least squares regression (PLSR) results indicated that sheep fat (SF) was greatly related to most variables of sensory attributes, thus presented richer aroma. Among all samples, 3-hydroxy-2-butanone and (E)-2-nonenal were the major aromatic compounds they shared. There were 22 unique key aromatic compounds, including 3-methylthiopropana, (E)-2-decenal, γ-decalactone, (E)-2-octenal and hydroxyacetone, and the differences in these compounds contributed to the flavour profiles of mutton soup. Our research extends the knowledge into the flavour characteristics of different parts of mutton and provides powerful information for improving the flavour of mutton products.