Analysis of Aroma Compounds in Yeast-fermented Soy Sauce by GC-O/MS

The formations of aroma compounds in soy sauce were closely related to the metabolism of yeast. The aim of this study was to analyze the composition and concentration of aroma compounds in soy sauce fermented by yeast. The aroma compounds in the fermented soy sauce were analyzed by solid phase microextraction(SPME)combined with gas chromatography-olfactometry-mass spectrometry(GC-O/MS). The results showed that all kinds of aroma compounds formed in the soy sauce added with yeast were more abundant,among which AY type yeast could produce more kinds of esters and alcohols;T type yeast could contribute to the formation of aldehydes. And AY-type yeast in the soy sauce brewing process produced esters,furanones,aldehydes and other compounds more abundant content,T-type yeast production of alcohol compounds were even more superior. Based on the calculation of OAV in soy sauce samples,the results found that the OAV of 5-ethyl-4-hydroxy-2-methyl-3(2H)-furanone(HEMF),2/3-methylbutanal and phenylacetaldehyde were higher than that of other samples. The OAV of 1-octen-3-ol and 3-methylthiopropionaldehyde in T soy sauce sample were higher than other samples. According to the analysis of OAV and PCA,it could be seen that the AY-type yeast fermented soy sauce had obvious advantages of aroma,and the overall aroma profiles of fermented soy sauce by T-type was cooked potato-like/mushroom-like. The overall aroma profiles of fermented soy sauce by AY-type was sweet-like/malty. Therefore,it also showed that the overall aroma in soy sauce fermented by AY-type yeasts was better than that of the soy sauce fermented by T-type yeast.