Comparative volatile profiles in soy sauce according to inoculated microorganisms

Area of Science:

• Food Science
• Microbiology
• Fermentation Technology

Background:

• Soy sauce fermentation involves complex microbial interactions.
• Tetragenococcus halophilus (lactic acid bacteria) and Zygosaccharomyces rouxii (yeast) are key microorganisms in soy sauce production.
• Understanding their individual contributions to volatile profiles is crucial for flavor development.

Purpose of the Study:

• To compare the volatile compounds produced by soy sauce inoculated with T. halophilus and Z. rouxii.
• To elucidate the distinct metabolic contributions of these microorganisms to soy sauce aroma.
• To investigate the potential influence of T. halophilus on Z. rouxii activity.

Main Methods:

• Solid-phase microextraction (SPME) and solvent extraction were employed for volatile compound analysis.
• Gas chromatography-mass spectrometry (GC-MS) was used for identification and quantification of volatiles.
• Comparative analysis of volatile profiles based on microbial inoculation.

Main Results:

• A total of 107 and 81 volatile compounds were identified using SPME and solvent extraction, respectively.
• T. halophilus inoculation resulted in dominant acids (acetic, formic) and aldehydes (benzaldehyde).
• Z. rouxii inoculation led to higher levels of alcohols (ethanol, butanol) and esters.
• Specific compounds like 4-hydroxy-2-ethyl-5-methyl-3(2H)-furanone were prominent with Z. rouxii.

Conclusions:

• T. halophilus and Z. rouxii exhibit distinct metabolic pathways, producing different dominant volatile compounds in soy sauce.
• T. halophilus significantly contributes acid compounds and may influence Z. rouxii activity.
• The findings support the concept of specialized roles for lactic acid bacteria and yeasts in fermentation aroma generation.