Two-Step Fermentation for Natural IMP and Glutamic Acid Flavors

The fermentation process is divided into two distinct stages: first, fungal fermentation of vegetable protein to produce amino acids and peptides; second, bacterial fermentation of the fungal fermentation broth to produce nucleic acids. This segmentation allows each microorganism to specialize in producing specific flavor components, resolving the contradiction between manufacturing simplicity and nucleic acid content.

The invention uses a composite fermentation system combining two different microorganisms (fungus and bacteria) working in sequence on the same substrate. The fungal fermentation broth serves as both product and substrate for bacterial fermentation, creating a composite process that generates both amino acids and nucleic acids, thereby increasing nucleic acid content while maintaining cost-effectiveness.

Instead of using expensive yeast extracts that carry off-flavor characteristics, the invention uses a disposable fungal fermentation broth as the substrate for bacterial fermentation. This approach produces nucleic acids without introducing the characteristic yeast off-flavors, as the fungal broth serves only as a nutrient source and is completely transformed during bacterial fermentation.

The fungal fermentation broth serves dual purposes: it is both the product of the first fermentation stage and the substrate for the second fermentation stage. The system is self-sufficient, using its own output as input for the next stage, thereby producing nucleic acids without requiring external yeast extracts that would introduce off-flavors.