In order to determine the key odorants in Beijing dry yellow soybean sauce (BDYSS), the volatile constitutes in BDYSS were isolated by solid-phase microextraction, and the isolate was analyzed by gas chromatography-mass spectrometry-olfactometry(GC-MS-O). The structures of volatile components separated by GC were determined by MS, and conformed by comparison of retention indexes (RIs) of separated constituents with the RIs reported in the literature and by comparison of the retention times and odor characteristics of some separated constituents with those of authentic samples. A total of 53 volatile compounds, of which 20 compounds had odor activity, were identified. Their concentrations were determined by using 2-octanol as internal standard. The odor activity values (OAV) of aroma-active compounds who gave respond signals in total ion chromatogram were calculated. Seven key odorants in BDYSS were identified by OAV, they were 3-methylbutanal, dimethyl trisulfide, 2-methoxyphenol, benzeneacetaldehyde, ethyl butanoate, nonanal and 3-methylbutanoic acid.
