Salzreduzierte Sojasauce (Genen-Shoyu, bio?, roh?)

Soy sauce or shoyu, in Japanese, is a liquid seasoning that is currently used in cooking worldwide. The varieties of soy sauce that are produced depend on the various types and ratios of raw materials used, the microorganisms employed and the conditions of fermentation [21, 79]. Many other sauces that are produced in China and Southeast Asia are made from Wsh or grain, and they resemble shoyu visually. However, these sauces are not categorized as soy sauce. Shoyu was Wrst made, according to legend, by a Buddhist bishop, Kakushin, at Yuasa, Wakayama, Japan, in 1254. Traditional soy sauce is produced in wooden tanks by static fermentation for 1 to 2years. However, nowadays, most soy sauce is produced in computer-controlled systems, from the cooking of raw materials to bottling. Moistened soybeans are cooked at high pressure and high temperature, while wheat is roasted and ground. Then almost the same amounts, by weight, of soybeans and wheat are mixed with a small amount of seed koji mold, A. oryzae or Aspergillus sojae [31]. The mash, which contains koji, NaCl [15–17% (w/v)] and water, is called moromi, and is fermented in large enamel or stainless tanks for 6–8months at room temperature or higher. The moromi also contains halotolerant lactobacilli, for example, Pedicoccus soyae nov. sp. [60] or Tetragenococcus halophilus, and halotolerant yeasts, such as Zygosaccharomyces rouxii and Candida famata [61]. Other microorganisms, such as Aureobasidium pullulans [62] and Metschnikowia koreensis [63], which contribute to the production of polyols from starch, have also been isolated from the mash. Finally, the aged moromi is pressed and the liquid exudate is pasteurized to yield soy sauce. Soy sauce promotes the secretion of gastric juice in humans [32]. It contains certain bioactive components in addition to its taste components, such as amino acids and polyols [56–58] and aromatic compounds, and various biological activities of soy sauce have been reported. Such activities include anticarcinogenic activities, as indicated by inhibition of benzopyrene-induced forestomach neoplasia [6, 15, 20] and antimicrobial activity against Shigella Xexneri, Salmonella typhi, S. paratyphi, S. enteritidis, Vibrio cholera [2], and Escherichia coli O157:H7 [37]. Soy sauce also has antioxidant activity [3, 34]. It contains 4hydroxy-2(or 5)-ethyl-5(or 2)-methyl–3(2H)-furanone [45] and related compounds as Xavor components [20], and these compounds have potent antioxidant and anticarcinogenic activity. Soy sauce also exhibits anti-platelet aggregation activity, which may be due to -carbolines [72]. Soy sauce decreases blood pressure [17], and inhibition by soy sauce of an angiotensin I-converting enzyme has been demonstrated [26]. IsoXavone derivatives from soy sauce can inhibit the activity of histidine decarboxylases, which produce histamine, a mediator of inXammation, allergy and the secretion of gastric acid [27, 28]. Such active compounds are formed during digestion of soybeans and wheat and by the enzymatic reactions that occur during fermentation. During fermentation and subsequent aging of soy sauce, the proteins in soybeans and wheat are completely digested to short peptides and amino acids by microbial proteolytic enzymes, and none of the allergens present in the raw materials are present in soy sauce [52, 73]. About 1% (w/v) of the polysaccharides originating from the cell walls of soybeans are present in soy sauce and these polysaccharides have potent antiallergic activities both in vitro and in vivo [30]. The oral administration of polysaccharides from soy sauce was shown to be eVective as a treatment for patients with allergic rhinitis. Thus, soy sauce is not only a traditional seasoning but also a functional seasoning. The daily consumption of soy sauce in Japan has been estimated to be close to 30ml per person 

Narratives Review

DOI: 10.1007/s10295-008-0362-5

Study: weak evidence

According to connoisseurs, the shoyu bouquet has more than two hundred constituent, which result from the lenghty fermentation process. For the sauce to acquire this complexity takes 12 to 24 months by traditional production methos. The basic ingredients used are soybeans, wheat, spring water, koji, and seas salt. The wheat is first roasted and cracked. The soybeans are soaked in water and steamed. Both are then mixed together, an the whole is inoculated ith koji mold, a fermentation starter. Ober the next 40 hours, the koji multiply in the mixture. The sweet-smelling brew is then combined with salted spring water and left to feremnt in a wooden barrel for up to one year. While the high salt content prevents unwanted bacteria from growing in the barrel, proteins are broken down into amino acids, and starch into sugars, alcohol, and organic acids. These give shoyu its rich flavor and hundreds of aromatic compounds. Fermentation also increases the nutritional benefits uf shoyu. The bacteria synthezize enzymes and vitamins, including vitamnin B12 and create a more usable amino-acid balance. After fermentation and aging, the mixture is pressed to seperate the liquid, shoyu, from the mash. The shoyu is filtered and then heat--treated, to stop the fermentation, sterilize the shoyu, and add an extra flavor component-a sort of caramelized flavor. Today advanced refrigeration and transportation technologies in Japan allow the producers to distribute non-heat-treated shoyu, called kijoyu or namashoyu, which is still biologically active. Unpasteurized shoyu has a distinctive robust, natural flavor that some people prefer. Much of the shoyu made by large manufacturers is produced in a shortened, more automated way. Fermentation is done in termerture-sontrolled tanks, so production time can be reduced to only four to five months. This results in shoyu whith less flavor than traditionally made soy sauce.

A japanese kithen uses three types of shoyu, which differ in color, flavor and degree of saltiness. the most widely available, both in Japan and overseas, is koikuchi shoyu. This type is also called simply shoyu, the name I use in this book. Koichuchi shoyu has a dark brown color, rich flavor and compley aroma. The salt content of koikuchi shoyu is 17 to 18%; that is , 1 tabespoonn contain over 1/2 teaspoon salt. Koikuchi shoyu is used with all types of ingridients- poultry, meat, fish, and vegetables- and in all types of preperations-sauces, soups, and braised and stir-fried dishes. Koichuchi shoyu gives food a dark brown and rich flavor. 
The second type of Japanese soy sauce is usukuchi shoyu, "light-colored soy sauce ". To produce light colored shoyu, the wheat is more lightly roasted, and more salt is added to slow the fermentation. A small amount of mirin, sweet rice wine, may also be added. The resulting shoyu is lighter in color, less strongly flavored, and slightly higher in salt content thant regular shoyu, about 19 %. Because of these charcteristic, usukuchi shoyu is used in recipes where a refined color and weak flavor are required.
The third kind of soy sauce, tamari, is traditonally produced in only three Japanes prefectures. Aichi, Gifu and Mie. Tamari is made nearly entirely from soybeands, and only a very small amount of water is adde to the fermentating mixture. After 20 month of fermentation, tamari is thicker than the other types, dark brown in color, rich in bean flavor, and about as salty as regular shoyu. Unlike the two other types of shoyu, tamari is prefered as a condiment of flavor enhancer rather than as a basic cooking ingridient. Tamari may also be added to dishes at the end of the cooking process. 

At the beginning of the twentieth century, the Japanese chemist Kikunae Ikeda identified the glutamate ion as inducing a novel taste quality that he proposed was a signal for protein, analogous to sweetnes being a signal fo energy or calories. He described this novel quality as "the peculiar taste we feel as umami (meaning, according to the translator, meaty, brothy, or savory)". He calle sthis taste umami. Subsequent studies further identified the ribonucleotides 5'-inosinate and 5'-guanylates as synergistic enhancers of this novel taste, altough for humans and some other species, they may not produce a taste on their own. Beginning in the late 1960s and 70s, additional researchers also proposed umami as a novel fifth basic taste. This idea gained momentum from a scientif meeting held in 1985 and the publication of the proceedings Umami: A Basic Taste. The evidence used to support the proposal that umami was the fifth basic taste at the time sonsisted primarly of human sensory studies and animal model studies of behavior and physiology.
The discory in the 1990s and 2000s of specific taste receptors responsive to amino acids gave substanial impetus to the idea that umami might be the fifth basic taste. Yet even the proponents of umami as basic taste acknowledge that it differs significally from classic fou : it is more subtle, which may account for it no being identified historically or in most traditional cultures, and unlike the other appetitive taste qualities, swwt and salty, relatively pure solutions of monosodium glutamate are very rare in natrue and are not palatable for hman adults or infants. Moreover, unlike sweet, salty and bitter, the perceptual quality of umami for humans does not directly signal the presence of purporte nutrient, proteins (which gernally have no taste), or even amino acis. Indeed, many umami-rich foods are not naturally high in protein.

There are five types of shoyu based on the different characteristics of color, viscosity, taste, and aroma. These are koikuchi shoyu, usukuchi shoyu, tamari shoyu, saishikomi shoyu, and shiro shoyu (Fukushima 1981, 1985, 1989; Yokotsuka 1981, 1986; Flegel 1988). The regular type for daily use in Japan is koikuchi shoyu. The different characteristics are yielded primarily due to the different raw material composition of soybeans and wheat, and the fermentation process used.

Book: weak evidence

Nährstofftabellen?

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Melanoidins, generated during the Maillard reaction in soy sauce fermentation, have potential health benefits due to its excellent bioactivity. This study aimed to investigate the antioxidant contributions and structural characteristics of melanoidins in soy sauce. Five molecular weight fractions (1–3 kDa, 3–10 kDa, 10–30 kDa, 30–50 kDa, and >50 kDa) were isolated and their composition was analyzed. Results showed that soy sauce melanoidins mainly comprised proteins, sugars, and phenolic compounds. Antioxidant activities of the melanoidins were influenced by their molecular weights and structures. The >50 kDa melanoidins fraction contributed the most to the overall antioxidant activities of soy sauce. The total contributions of melanoidins to the antioxidant activities of soy sauce ranged from 34.21% to 75.03%. Spectroscopic analyses indicated that the antioxidant activities were positively correlated with the presence of conjugated structures and active functional groups (i.e., C=C, C=O, N-H, O-H) in melanoidins. This study provides new insights into the health-promoting properties of soy sauce melanoidins and offers theoretical support for the development of soy sauce as a functional food.

Experimentelle Studie in wissenschaftlichem Journal

DOI: 10.3390/foods14162787

Study: weak evidence

Soy sauce is consumed not only because of its color and flavor but also because of  its health benefits. Soy sauce exhibits antioxidant (Hsiao et al., 2013),  antihyperuricemic (Li et al., 2017), antimicrobial, anticarcinogenic, anticataract, and  antiplatelet activities (Kataoka, 2005). This product contains many antioxidant  substances, including soy isoflavones, melanoidins, furan ketones, phenolic acids, organic acids, peptides, and β-carbolines (Li et al., 2017).

Experimentelle Interventionsstudie in wissenschaftlichem Journal

DOI: 10.1016/j.lwt.2018.01.008

Study: weak evidence

Although soybean is a rich source of plant protein, its nutritive values are concealed by the anti-nutritive properties. Fermentation not only reduces the toxins but it leads to the production of several beneficial compounds such as peptides. Peptides in fermented soybean products exhibit bioactive properties such as ACEinhibitory, antioxidant, antitumor, antidiabetic and antimicrobial property. The bioactive peptides produced during fermentation are produced either by starter culture or by hydrolysis of soybean proteins. Studies on the bioactive peptides in fermented soybean products responsible for such properties will result in their application in preparation of functional food and food supplements. Also, specific starter cultures are responsible for the production of specific peptides, and the same is applicable with the specific strains of culture. From the studies till date, it can be concluded that peptides are one of the promising health promoting components in fermented soybeans products. Future studies on other health benefits and characterization of bioactive peptides in fermented soybean can lead to its application as pharmaceuticals with specific health benefits and functional foods to fight against degenerative diseases to replace the synthetic drugs which have surplus side effects.

Narrativer Review in wissenschaftlichem Journal

DOI: 10.1016/j.tifs.2016.01.010

Study: weak evidence

The antioxidative potency of soy sauce is often linked to polyphenols, melanoidins, free amino acids and low molecular weight peptides, which play roles in diminishing oxidative damage by clearing free radicals and reactive oxygen species.

The phenolic molecules identified in soy sauce are classified as simple isoflavones, furanones, pyranones and phenolic acids. In particular, the presence of 4-ethylguaiacol, catechol, daidzein and 4-ethylphenol is responsible for the antioxidative activity of soy sauce. 

The products of the Maillard reaction produce the antioxidant characteristics in soy sauce. Among them, melanoidins were the major substances of brown color products in soy sauce and showed strong antioxidant activities (Wang et al., 2007).

Amino acids and small peptides are the main fractions of total nitrogen in soy sauce, and both accounted for 45% of the total nitrogen. A total of 31 free amino acids were detected in the soy sauce sample. The predominant free amino acids in the fermented soy sauce were proline (8.4%), leucine (7.78%) and aspartic acid (7.13%), in descending order (Lin et al., 2016). Free amino acids had effective ABTS and DPPH radical-scavenging activities and metal-ion chelating capacities. 

Shoyu effectively inhibited ACE activity, thereby regulating the blood pressure in SHRs and in Dahl salt–sensitive rats (Nakahara et al., 2010). Several ACE inhibitory peptides, including Ala-Trp, Gly-Trp, Ala-Tyr, Ser-Tyr, Gly-Tyr, Ala-Phe, Val-Pro, Ala-Ile, and Val-Gly, were identified in shoyu, and nicotianamine, an ACE inhibitory compound, was also isolated from shoyu (Nakahara et al., 2010).

Anti-inflammatory and immunomodulatory components

The immune regulation and anti-inflammation of soy sauce polysaccharides (SPS) have been reported in multiple studies (Table 1). 

4.5. Anticancer components: Soy sauce is also reported to have anticancer effects 

Narrativer Review in wissenschaftlichem Journal 

DOI: 10.1016/j.foodres.2022.111575

Study: weak evidence

Soy sauce, commonly called shoyu, is made from soy bean, wheat and salt.9 Soy bean is the primary ingredient. Other ingredients and additives of soy sauce are salt, alcohol, amino acid, glucose and sugar. Shoyu is made by brewing soybean; there were some brewing process stages, koji, moromi and raw soy sauce.9 Soybean change koji at first stage, then koji change moromi. At last stage, moromi change raw soy sauce. Beneficial effects of soy sauce are hypolipidaemia,13 improvement of anaemia,14 promotive secretion of gastric juice,15 anti-allergic, inhibitory allergic reactions16 etc., whereas it is well-known that some people suffered irritation or dermatitis or cellulites after using shoyu in the past. It is possible that the process of brewing soy sauce is what generates the adverse effects: soy sauce allergy, histamine poisoning, soy allergy, wheat allergy, etc. Soy bean and wheat are major allergens of food allergy; major allergens of soybean are Gly mBD 30k8 and Gly mBD 28k17 which were measured using ELISA.8 Soy sauce and fermented foods are considered hypoallergenic foods and any allergens were not detected1 because these allergens degrade during fermentation.1,18 Shoyu-flavones are produced during fermentation and shoyu-flavones inhibit histidine decarboxylase, which results in the production of histamine.19 Histamine is made during the brewing process of soy sauce.12,20 We noted allergy of soy sauce and histamine poisoning and investigated the volume of histamine in some kinds of soy sauce. The results were interesting in that histamines were detected in the sauces made from soybeans and broad beans,but not in the sauces made from millet (awa), barnyard grass and fish. The colours of sauces that contained histamine were deep. We suspected that one cause of the patient symptoms was histamine poisoning and then we studied it with prick test using soy sauce with nine volunteers. If histamine poisoning causes cellulites or dermatitis around the lip, the results of prick test to all volunteers must be positive. In fact, volunteers had negative reactions by prick test after using soy sauce as positive reactions to soy sauce in four patients were not caused by histamine poisoning. These four patients did not develop any histamine poisonings after eating histamine-contained foods11,12 or histamine-releasing foods (additives, citrus fruit, strawberries, chocolate, tomatoes, peanut, etc.)12 or some ingredients and additives of soy sauce (salt, alcohol, amino acid, glucose and sugar). These four patients did not have any allergy of ingredients or additives in sauce from the results of prick test or after eating meal; they had allergy of some products in sauce during brewing. At this time, although patients were female, the relationship between gender and soy sauce allergy is not definite. It is speculated that soy sauce allergy is caused by substances raised during fermentation. It was difficult to detect what allergen, a generative product of soy sauce, causes their allergic reactions. As soy sauce is consumed globally, the number of patients having soy sauce allergy or histamine poisoning of soy sauce could increase. The manufactures and companies of soy sauce should educate or acquaint with people not only about the advantageous effects but also about histamine poisoning or allergic reactions.

Fallserie

DOI: 10.1111/j.1468-3083.2009.03512.x

Study: weak evidence

"In spite of the key role of sodium chloride in the human body, the World Health Organization has recommended reduction of its consumption up to 5 g (or 2 g of Na) per day as the maximum level of intake (consumed as common salt), as its high consumption has been associated with raised blood pressure and adverse cardiovascular health consequences in the world population."

DOI: 10.1016/B978-0-444-59562-1.00026-8

Book: moderate evidence

"However over consumption of salt through the diet is related to increased risk of hypertension, cardiovascular diseases, and renal insufficiency. 1 , 3 , 6 , 10 The World Health Organization recommended level of less than 5 g of salt intake per day in adults. 11 Thus, considering the substantial role that salt taste plays in food acceptance/choice, 5 , 6 the food industry is looking for ways to reduce or replace salt in processed foods. 4 , 5 , 6 , 12 , 13 Along with the search for salt substitutes, 4 , 5 , 7 , 14 actual research focuses on approaches that rely on modification or manipulation of salt taste."

Senosrische Interventionsstudie

DOI: 10.1002/jsfa.11953

Study: moderate evidence

"Almost all populations are consuming too much sodium. The global mean intake of adults is 4310 mg/day sodium (equivalent to 10.78 g/day salt) (1). This is more than double the World Health Organization recommendation for adults of less than 2000 mg/day sodium (equivalent to < 5 g/day salt)." "The primary health effect associated with diets high in sodium is raised blood pressure, increasing the risk of cardiovascular diseases, gastric cancer, obesity, osteoporosis, Meniere’s disease, and kidney disease. An estimated 1.89 million deaths each year are associated with consuming too much sodium (2)." eat mostly fresh, minimally processed foods choose low-sodium products (less than 120mg/100g sodium) cook with little or no added sodium/salt use herbs and spices to flavour food, rather than salt limit the use of commercial sauces, dressings and instant products limit the consumption of processed foods remove the saltshaker/container from the table."

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The human body, predestined to salt conservation by the evolution, could not adapt to increased salt intake. This discrepancy is reflected in the growing number of people affected by salt-sensitive hypertension and cardiovascular (CV) diseases, putting tremendous pressure on the healthcare system [5]. Conventionally volume expansion arising from salt consumption had been explained solely by the interplay between sodium homeostasis and the extracellular space. Having seen its beneficial effects, sodium restriction has become an auxiliary therapy in a number of diseases involving volume overload (e.g., hypertension, kidney diseases, CV diseases, liver cirrhosis). Since high salt intake has long been considered a key risk factor of hypertension, several associations, organizations have made recommendations regarding daily sodium intake. According to the proposals of the World Health Organization (WHO) and the American Heart Association for normal, healthy adults, daily sodium intake should not exceed the level of 2.0 g/day or 2.3 g/day, respectively [6, 7]. Since children have a lower need for sodium, their daily dietary sodium intake is different from that of adults.

DOI: 10.1007/s00467-019-04387-4

Book: moderate evidence

Soya sauce - 1,64

Sauce, barbeque 2,09

Chili Sauce 1,94

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Soy sauce, glass bottle - United Kingdom of Great Britain and Northern Ireland - Live footprint: 1.23 kg CO₂e/kg 

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Nr. 14 auf S. 13

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thylcarbamat ist zwar nur mässig akuttoxisch, in vitro wurde jedoch seine mutagene Wirkung belegt. 2007 stufte die IARC (International Agency for Research on Cancer) die Substanz als "wahrscheinlich krebserregend für den Menschen" ein.

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The average water footprint for 330 ml of soy sauce was 200 litter. 

The scope of the study only focuses on one-unit stock of a particular brand located in Kuala Kangsar, Perak in Malaysia. 

Ökologische Ressourcenanalyse

DOI: 10.26480/jwbm.01.2020.01.04

The total water footprint of soy sauce production is 1.986,35 L/kg with fraction of green water (78,43%), blue water (21,4%) and gray water (0,17%). 

The raw material of soy sauce are soybean, brown sugar and salt. There are 3 main stage in the process of soy sauce production is boiling and drying soybean, fermentation process and mixing and cooking soy sauce.

"The water footprint of soy sauce production consist 2 part, there are soybean crop stage and soy sauce process production."

Ökologische Ressourcenanalyse

DOI: 10.1051/e3sconf/20183108018

"Originating in China over 2,500 years ago, soy sauce is a traditional seasoning in Eastern Asia that has become a favorite around the world due to its unique umami taste."

"Soy sauce is traditionally produced by mixing steamed and presoaked-soybean with roasted wheat flour, usually at a ratio of 4:1 for Chinese style or 1:1 for Japanese style, followed by fermentation using A. oryzae or A. sojae to produce Koji, which is then mixed with sodium chloride at 16-18% w/v and water to continue fermentation as moromi (mash) (Kataoka, 2005; Feng et al., 2013; Guidi and Gloria, 2012). During the moromi production stage, the predominant microbial community switches from filamentous fungi to halotolerant LAB and yeast. Added brine inhibits the growth of molds and favors the growth of the halotolerant LAB, naturally present in the mash (Yong and Wood, 1976). LAB including Weissella, Lactobacillus, Streptococcus, and Tetragenococcus have all been detected in moromi mash. The low pH, due to lactic acid production by LAB, provides a perfect niche for acidophilic yeast such as Zygosaccharomyces rouxii, Candida etchellsii (or Candida nodaensis) and C. versatilis (Tanaka et al., 2012). Moromi yeasts improve the quality of soy sauce by producing alcohol and volatile flavor compounds (Wah et al., 2013). Moromi is fermented and aged for several months at room temperature. High temperature is avoided, as while it speeds the fermentation process, it usually compromises the flavor of soy sauce. The aged moromi is finally filtered and pasteurized to yield soy sauce."

Narratives Review

DOI: 10.1016/j.biotechadv.2018.12.001

Study: weak evidence

"In ancient China, about 2200 years ago, soy sauce was developed as a way to preserve food—due to its salt content—and also to enhance the flavor of the modest, vegetarian Buddhist diet since salt at that moment was an expensive commodity. (2) Nowadays, soy sauce is used as a food product rather than a food preservative."

"Soy sauce—also called jiangyou in Chinese, shoyu in Japanese, and soya sauce in British English"

Narrativer Review in wissenschaftlichem Journal

DOI: 10.1021/acs.jafc.0c04274

Study: weak evidence

The brewing of traditional soy sauce involves a two-stage primary fermentation process, a short-term solid-state fermentation (koji) followed by long-term liquid-state fermentation (moromi) (Yee et al., 2021). The microorganisms in the koji fermentation step, mainly members of the Aspergillus genus (A. oryzae or A. sojae), produce enzymes that breakdown soybean and wheat into simple molecules used for the development of halophilic bacteria including lactic acid bacteria (LAB), Bacillus species, and yeasts during the moromi stage with 18%–20% salt content. The mash is allowed to ferment for 1 month to 4 years of maturation to finally produce soy sauce (Det-udom, Gilbert, et al., 2019; Harada et al., 2017). Apart from fermentation, soy sauce can also be made via chemical hydrolyzation by adding hydrochloric acid to hydrolyze the soybean protein to shorten the production time from several months to 1–3 days. Although this method is cheaper and faster, the soy sauce quality is unsatisfactory because of the insufficient aromatic and flavor substances as well as the presence of some undesirable compounds that are lacking in naturally fermented soy sauce, including carcinogens such as 3-chloropropane-1,2-diol (3-MCPD) and 1,3-dichloropropanol (1,3- DCP; Lee et al., 2006; Liu, 2012; Luh, 1995). Despite the favorable image of soy sauce in terms of nutrition and health benefits as well as its recent production progress, several limitations need to be resolved. For instance, numerous attempts have been made to reduce the considerable fermentation time during the moromi stage using genetic engineering approaches as well as cell and enzyme immobilization without altering the quality of the final product (Devanthi & Gkatzionis, 2019). Furthermore, the high salt content in soy sauce is a cause of concern due to health impacts such as hypertension and renal dysfunction. Thus, driven by industry and the World Health Organization recommendation to reduce the dietary intake of sodium salt, the amount in soy sauce has been reduced to ~8%–11%. However, salt is a critical element in the fermentation of soy sauce because it regulates microbial and organoleptic properties; thus, its reduction will not only cause microbiological safety concerns but could also compromise the final product quality (Devanthi, Linforth, El Kadri, et al., 2018; Devanthi, Linforth, Onyeaka, et al., 2018; Hoang et al., 2016). Another concern is the by-products generated during manufacturing, including ethyl carbamate (EC), a Group 2A carcinogen formed by arginine-consuming bacteria in the moromi mash.

Narrativer Review in wissenschaftlichem Journal 

DOI: 10.1111/jfpp.15799

Study: weak evidence

"The demand for low-salt soy sauce has increased due to health concerns related to high sodium intakes, such as hypertension and renal dysfunction. The WHO recommends a limitation of daily sodium intake to 2 g, which is equivalent to 5 g of salt (World Health Organization, 2012). Meanwhile, the daily consumption of soy sauce per person in Japan is 30 mL (Kobayashi, 2013), while the per capita daily consumption in Indonesia is 10–15 mL (Sasaki & Nunomura, 2003). Due to high NaCl content in soy sauce, the consumption of 1 tablespoon (15 mL) of soy sauce can contribute to 38% of the Recommended Daily Intake (RDI) of sodium. Therefore, the production of soy sauce with low salt content without decreasing its quality has become a challenge for the industry."

"The high salt concentration is used in soy sauce production to create anaerobic conditions in moromi, prevent putrefaction of the autolysate, and inhibit the growth of spoilage microorganisms (Luo, Ding, Chen, & Wan, 2009; Muramatsu, Sano, Uzuka, & Company, 1993). It is also important to the organoleptic properties of soy sauce, including texture and aroma (Song et al., 2015a)."

"Other studies focused on reducing the amount of salt used during moromi fermentation. This approach was shown to benefit the soy sauce production by accelerating the fermentation (Goh, Lai, Abas, & Tan, 2017; Hoang et al., 2016; Muramatsu et al., 1993; van der Sluis, Tramper, & Wijffels, 2001). High salt content in moromi can slow down the microbial metabolic activity, therefore a minimum period of 6 months is needed to complete fermentation. In order to accelerate the fermentation process while maintaining quality, low NaCl concentration can be combined with some physical treatments. Muramatsu et al. (1993) have successfully shortened the soy sauce production process by lowering NaCl content in moromi to 4.6% and autolyzing the koji prior to moromi fermentation with high temperature. This treatment was performed to obtain soy sauce with chemical composition and flavor similar to the traditional one. A recent study by Hoang et al. (2016) has demonstrated a significant reduction in reduced-salt (NaCl 10%) moromi fermentation time to 4.6 days by conducting the fermentation process at high temperature (40.7 °C)."

"In addition to fermentation pattern and organoleptic quality, NaCl reduction also raises a microbiological safety concern. Chiou (1999) demonstrated that partial substitution of NaCl with ethanol could prevent the growth of pathogenic and spoilage microorganisms. However, the use of ethanol could limit the growth of desirable microorganisms."

"The reduction of salt in soy sauce demands the development of robust starter cultures that are stable and active towards the environmental perturbation. Therefore, the soy sauce production process can be modified, such as by lowering the salt concentration during the moromi stage, without compromising the flavor quality."

Narratives Review

DOI: 10.1016/j.foodres.2019.03.010

Study: weak evidence