## 3 Results and Discussion  
### Physicochemical Characteristics of Japanese Sauces  
Throughout this publication, we refer to manufacturers' declarations specifying the type of sauce when analyzing and discussing the results. The lowest value of density characterized the sauce TS_O (Table 1). The significantly higher value was observed for TS_C and KS_O, and the highest density was detected for conventional koikuchi sauce. The results of dry weight correspond to high moisture content (over 69% \(w/v\)) and are comparable to results of different studies (65% [21] and 60% [22]). The differences can be caused by the boiling time and amounts of protein and starch in soy sauce [23]. However, in our data, there is no correlation between protein content and dry weight of the product. The pH values of traditional koikuchi shoyu and tamari shoyu should be 4.7 and 4.8 [24]. The significantly lower pH value of KS_O and TS_C (Table 1) can be explained by the higher content of organic acids as a result of the different microflora and enzymatic activities during the fermentation process of products. Several studies have pointed out that the organic acid contents (lactic acid, formic acid, and citric acid) in handcrafted tamari are higher than in koikuchi shoyu [22]. However, common industrial practice is the addition of vinegar or spirit vinegar to the final product, which corrects pH and enhances the preservation effect. Koikuchi shoyu (KS) sauces are made with the same quantity of soybeans and wheat, and have a strong aroma and a deep reddish-brown color. Tamari shoyu-style products (TS) are made with a large number of soybeans and 10% or less wheat. The information available on the packaging provided information about the manufacturer, raw material composition, energy, and nutritional value. However, the information about the percentage share of raw materials of soya and wheat is not labeled. The quality of naturally brewing soy sauces depends on microorganisms, which play a crucial role in koji and moromi fermentation processes. They secrete enzymes hydrolyzing starch, proteins, and lipids, into saccharides, peptides, free amino acids, and volatiles [25]. However, the flavor and color development during the production process is also attributed to non-enzymatic Maillard reactions occurring between reducing sugars and amino acids, and to other reactions such as lipid oxidation, esterification, or degradation of amino acids [26]. Japanese have developed the craft of using mold as a carrier of hydrolytic enzymes, which is significantly different from the use of malt in the European tradition. _A. oryzae_ and _A. sojae_ are the most popular for use in the koji step; however, _A. sojae_ is more recommended. The genome sequencing of _A. oryzae_ showed higher \(\alpha\)-amylase productivity [27], which results in higher carbohydrate consumption (caused by high \(\alpha\)-amylase activity), and consequently can slow the moromi fermentation [1]. _A. sojae_ characterizes the higher activity of endopolygalacturonase. The immersion of koji in the saline solution creates a moromi, while enzymatic activities remain to digest the ingredients in the raw materials. This process occurs in parallel with the growth in halophilic microorganisms in the moromi marsh [28]. Halophilic lactic acid bacteria (LAB) and yeast play a key role in the moromi stage [25]. The dominant yeast species are Tetragonococcus halophilus, Zygosaccharomyces rouxii, Candida etchellsi, and Candida versatilis [24; 29; 30; 31]. LAB populations include strains of Lactococcus, Lactobacillus, Leuconstoc, Weissella, and