Recent progress and advances in soy sauce production technologies: A review

Soy sauce is a traditional condiment that, because of its documented health benefits, is becoming increasingly ubiquitous. It is produced in a two-stage fermentation process consisting of a solid-state fermentation or koji involving mold, followed by brine fermentation or moromi involving halophilic bacteria and salt-tolerant yeasts. Efforts have been made to tackle the present limitations facing this industry, including the long fermentation time, the high salt concentrations, and the generated by-products with the use of genetic engineering such as genome shuffling, mutagenesis, enzyme alteration, mixed starter cultures, and gamma-aminobutyric acid-generating microorganisms. This analysis offers an overview of the latest technologies employed in the soy sauce industry, explaining the various conventional and alternative feedstocks used, the manufacturing processes, the microbial community, and their main role. The transition of soy sauce from a standard condiment to a potential functional food will also be explored. Novelty impact statement Soy sauce is a traditional food condiment that is currently transitioning into a functional food. With rapid advancements in food science, this review covers recent progress and advances in soy sauce production technologies. In addition, it also reviews strategies to resolve long fermentation time, high salt content, and utilization of soy sauce residues to value-added biodiesel.