Soy Sauce Shoyu

Defatted soy meal is used as a starting material in the production of this seasoning sauce (Fig. 16.7). The meal is moistened, then mixed with roasted and crushed wheat and heated in an autoclave for 45 min. The mix ratio in Japan is fixed at 1 1, while in China it varies up to 4 1. Increasing the amount of soy decreases the quality of the endproduct. The mix, with a water content of 26%, is then inoculated with Aspergillus oryzae and Aspergillus soyae. Initial incubation is at 30 °C for 24 h and then at 40 °C for an additional 48 h. This fermentation starter, called koji , is then salted to 18% by addition of 22.6% NaCl solution. Inoculation with Lactobacillus delbrueckii and with Hansenula yeast species results in lactic acid fermentation, which proceeds under gentle aeration in order to prevent the growth 

During fermentation the microorganisms produce extracellular hydrolases which decompose the main components of the raw material proteins, carbohydrates and nucleic acids. Soy sauce contains 1.5% N (of which 60% corresponds to amino-N) and 4.4% reducing sugar. The N-containing fraction consists of 40-50% amino acids (glutamic acid predominates at 1.2% of the product), 40-50% peptides, 10-15% ammonia and less than 1% protein. In addition, soy sauce contains by-products of microorganism 

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Soy Sauce (Shoyu). Production of soy sauce is a two-step process in which a mixture of boiled soybeans and cmshed roasted wheat is first... 

When Japanese rice wine (sake) is kept under unsuitable conditions, it develops an off-flavor with a burnt or soy-sauce (shoyu)-like odor. Takahashi al.(12) identified the main component as sotolon before our identification, and they claimed that the sotolon concentration was between 140-430 ppb in aged sake. This concentration is much higher than the threshold value of sotolon, and its aroma character would change from sugary to herbal or curry-like. The high sotolon content in aged sake could be a reason for the off-flavor defect. The formation of sotolon in aged... 

Japan has a long tradition in the fermentation industry to produce rice wine sake and a variety of fermented foodstuffs such as fermented soy sauce shoyu . Before introduction of modern science and technology at the end of the last century, engineer s guilds in the brewing manufacturers had established a sophisticated system of rational technologies, even empirically. The best example is the sake brewing process, in which saccharification of rice starch by amylases... 

Identified by Tressl et al. (1978a) as ethylfuraneol (a rather misleading name) with concentrations of 8 ppm in a roasted arabica, 2 in a robusta and 4 in an arabusta. Semmelroch et al. (1995) identified it as the 5-ethyl-2-methyl compound (1.101), with a concentration of 17.3 ppm in a roasted arabica and 14.3 ppm in a robusta (stable isotope dilution assay) it was later noted under the tautomeric forms, 2(5)-ethyl-5(2)-methyl (1.101a,b), by Grosch (1998b). Until 1991, it was said to exist only in soy sauce (shoyu) by Sasaki et al. (1991), the error perhaps arising from the trivial name ethylfuraneol . 

Kataoka, S. Functional effects of Japanese style fermented soy sauce (shoyu) and its components./. Biosci. Bioeng. 2005> 100, 227-234. 

In traditional fermented foods in Asia such as soy sauce (shoyu), fermented soybean-barley miso) in Japan, and pickles such as kimchi in Korea and tsukemono in Japan, various organic acids, such as acetic acid, lactic acid, and citric acid, are detected by chemical and liquid chromatographic analyses. The largest amount of lactic acid is contained in Japanese pickles, tsukemono, followed by acetic, citric, formic, mahc, and glutamic acids (Tomomatsu et al. 1972). More than 13 species of lactic acid bacteria and 10 species of yeast isolated from six kinds of tsukemono were identified by 16S rRNA sequence analysis (Asada and Ueno 2009). However, no acetic acid bacteria were detected. By cultivatiOTi of isolated yeast strains, acetic acid, citric acid, and succinic acid were detected in the fermentation broth. However, more careful experiments would be required to conclude that the special yeast can form acetic acid. 

Recent work has shown the presence of pyrazine and 2,6-dimethylpyrazine in leek (75), pyrazine and alkylpyrazines in the volatile constituents of tamarind (76), five alkylpyrazines in soong-neung (extract of cooked and roasted rice) (77) and in shoyu (soy sauce) (78), and alkylpyrazines in white bread (79). Murray and Whitfield (80) have examined vegetable tissue for 2-isopropyl-, 2is-butyl-, and 2-isobutyl-3-methoxypyrazines and observed at least one of these compounds in 23 of the 27 samples studied. 2-Methylpyrazine and 2,5- and 2,6-dimethylpyrazines have been determined in black tobacco and in the smoke of nonfilter cigarettes made from these tobaccos (81). 

Nunomura N., Sasaki M., Asao Y. and Yokotsuka T. (1976) Isolation and identification of 4-hydroxy-2(or 5)-ethyl-5(or 2)-methyl-3(2//)-furanone, as a flavor component in shoyu (soy sauce). Agric. Biol Chem. 40, 491-5. 

Soy sauce is a dark-brown liquid extracted from the fermented mixture of soybeans and wheat. Due to its salty taste and sharp flavor, it is served as an all-purpose seasoning for thousands of years. The product is known zsjiangyou (Mandarin) or chiangyu (Cantonese) in China, meaning oil from jiang shoyu in Japan tao-yu in Indonesia and tayo in the Philippines. Among all fermented soyfoods, soy sauce is now the widest-accepted product, not only in Far East but also in Western countries. 

Traditionally, soy sauce is made by fermentation as described above however, soy sauce can also be made by acid hydrolysis. The resulting product is known as chemical soy sauce, or protein chemical hydrolysate. In this process, defatted soy products or other proteinous materials are first hydrolyzed by heating with 18% HCl for 8—12 h. After hydrolysis, the hydrolysate is neutralized with sodium carbonate and filtered to remove the insoluble materials. The resulting product (chemical soy sauce) is a clear dark-brown liquid. However, chemical soy sauce does not possess the flavor and odor of fermented shoyu. Therefore, to improve its quality, chemical soy sauce is often blended with fermented shoyu to become a semi-chemical product before being sold. 

Fukushrma, D. (1989). Industrialization of fermented soy sauce production centering around Japanese shoyu. In K. H. Steinkraus (Ed.), Industrialization of indigenous fermented foods (pp. 1-88). New York, Basel Marcel Dekker, Inc. 

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