Improving the soy sauce flavor by the addition of aroma-producing yeast

Two strains of salt-tolerant yeast were applied to improve the flavor in the low-salt diluted-state soy sauce, and the flavors of the soy sauce before and after the fermentation were analyzed. The result showed that the contents of total acid, total esters and alcohol content increased greatly, the indexes improved from 1.77 g/100ml, 7.84 g/100ml and 0.09% to 1.94 g/100ml, 9.85 g/100ml and 2.12%, respectively. According to the analysis by GC-MS, the percentages of alcohol and esters in the volatile flavor components increased from original 43.76% and 0.99% to 64.95% and 12.08%, respectively, while the percentages of aldehydes and volatile acids decreased from original 10.08% and 14.45% to 4% and 5.4%, respectively. Especially, the soy sauce flavor was significantly improved as the proportions of isoamyl alcohol, 3-(methylthio)-1-propanol, benzeneethanol, isoamyl acetate and phenylethyl acetate increased. Through sensory evaluation, the soy sauce by addition of aroma-producing yeast was more harmonious and mellow.