Analysis of the contribution of koji-making with Z. rouxii on volatile compounds of soy sauce

The co-inoculation fermentation of different microorganisms plays a crucial role in soy sauce fermentation in terms of enriching the composition of the volatile compounds. Therefore, the present study sought to investigate the effect of co-inoculation fermentation of Aspergillus oryzae and Zygosaccharomyces rouxii on the dynamics of volatile compounds in soy sauce using the combination of gas chromatography-mass spectrometry (GC-MS) and multivariate correlation analysis. A total of 124 volatile compounds were identified by A. oryzae and Z. rouxii inoculation alone and co-inoculation, including hydrocarbons, fatty acids, phenols, fatty esters, and benzamides. The content of phenylethyl alcohol, ethyl linoleate, and ethyl palmitate was significantly increased, and the metabolic pathways of multiple volatile compounds were affected in soy sauce inoculated with Z. rouxii. The present study results potentially contribute to the optimization of soy sauce fermentation processes.