Comparison of Physicochemical Characteristics and Microbial Quality between Commercially Available Organic and Conventional Japanese Soy Sauces

The article aims to compare the properties and quality of two types of organic Japanese soy sauce from the market, declared by manufacturers as koikuchi, and tamari, both conventional and organic, along with an attempt to determine the differentiating factors using modern statistical methods. The amino acid profile showed the highest proportions were glutamic acid and aspartic acid. Tamari sauces could be distinguished from koikuchi by an elevated content of glutamic acid and alanine, while conventional and organic products differed the most in the shares of arginine, aspartic acid, and serine. The total polyphenol content was higher in conventional soy sauces and better antioxidant properties were found in koikuchi. Organic tamari sauces were characterized by higher antioxidant capacities and total flavonoid content. The volatile profile showed a significant difference between organic and conventional sauces. The research did not confirm that the quality of sauces declared as organic was significantly enhanced, and the overall quality of all tested sauces was high, both in terms of microbiological safety and physicochemical parameters.