Application of lactic acid bacteria and yeasts as starter cultures for reduced-salt soy sauce (moromi) fermentation

Abstract

© 2016 The use of starter cultures (Tetragenococcus halophilus TS71, Zygosaccharomyces rouxii A22, and Meyerozyma (Pichia) guilliermondii EM1Y52) in reduced-salt moromi fermentation was investigated. Reduced-salt moromi fermentation (12%NaCl) with starter cultures was monitored for changes of microbiological and biochemical properties including volatile flavor compounds (VFCs) and biogenic amines (BAs) during three months. The inoculation was done after one-month fermentation with two combinations: TS71 and A22 (L2); and TS71, A22 and EM1Y52 (L3). Controls were 12% salt (CL) and 18% salt traditional (CT) without inoculation. Total bacteria counts significantly increased (P < 0.05) in CL. Total lactic acid bacteria and total yeasts in the reduced-salt moromi with inoculation (L2 and L3) were significantly higher than both controls. Key VFCs including ethanol, 2-methyl-1-propanol, 4-hydroxy-2,5-dimethyl-3(2H)-furanone (HDMF) and 3-hydroxy-2-methyl-4H-pyran-4-one (maltol) were detected in L2 and L3 at higher levels than the traditional CT. Lower amount of BAs was accumulated in the reduced-salt moromi fermentation, particularly with lactic acid bacterium (L3) than other fermentations. Hence, the reduced-salt moromi fermentation with using starter cultures was therefore feasible for the soy sauce production without undesirable impact on formation of VFCs and safety levels of BAs.