Effects of Three Microorganisms on Volatile Substances during Fermentation of Douchi

The effect of the use of Aspergillus oryzae, lactic acid bacteria (LAB) and Wickerhamomyces anomalus as starter cultures on volatile substances during the fermentation of Douchi. The results showed that the contents of total volatile compounds in the uninoculated control, A. oryzae, LAB, A. oryzae + LAB, and W. anomalus inoculation groups were 5 145.88, 13 972.15, 9 006.07, 4 359.72 and 5 169.42 μg/kg, respectively. The contents of alcohols, organic acids, ketones and esters were increased by A. oryzae; the contents of alcohols and organic acids were increased by LAB; the contents of alcohols and organic acids were increased by the mixture of A. oryzae and LAB, but its effect was less pronounced than that of pure culture fermentation; the contents of alcohols and organic acids were increased by W. anomalus. Compared with the control group, the contents of pyrazines and phenolics in each inoculated fermentation group were decreased. Taken together, A. oryzae was the most suitable for the fermentation of Douchi, and the other strains could assist in regulating the production of volatile compounds during the fermentation of Douchi. Our findings from this study could provide some theoretical references for the industrial production of Douchi with traditional Chinese flavor.