Abstract: The present study was intended to investigate the correlation between the three dominant microorganisms and aroma compounds of Baoquan fermented soybean paste. The volatile compounds of seven samples (BM1, BM2, BM3, BM4, BM5, BM6 and BM7) of fermented soybean paste artificially inoculated with pure or mixed cultures of the dominant microorganisms were identified by headspace solid phase microextraction combined with gas chromatography-mass spectrometry (HS-SPME-GC-MS). Furthermore, we also detected the volatile aroma compounds of these samples by an electronic nose and analyzed the sensor data by principal component analysis (PCA). The PCA results showed that the aroma of BM6 was most similar to the commercial product fermented for 34 d whereas BM7 was distinct from this product. The results of sensory evaluation and electronic nose analysis consistently indicated that BM6 was more acceptable to consumers. A total of 38 volatile compounds were identified, including 15 esters, 6 alcohols, 6 aldehydes and ketones, 3 acids and phenolics, and 8 other compounds. The esters and alcohols were derived from Zygosaccharomycse rouxii BSZ.16910 and the aldehydes and ketones from Staphylococcus epidermidis BSS.17312. There existed certain interaction between the three microorganisms on the synthesis of volatile compounds in Baoquan fermented soybean paste. Factor analysis demonstrated that S. epidermidis BSS.17312 and Z. rouxii BSZ.16910 made greater contribution to the generation of esters and alcohols.

Key words: electronic nose, dominant microorganisms, fermented soybean paste, volatile components