Soy Sauce Fermentation Research Articles

The effect of adding Gracilaria on flavor and quality of low-salt fermented soy sauce

With the increasing awareness of health, there are higher expectations of customers for the unique flavor, umami, and nutritional value of soy sauce. To explore the potential application of edible seaweed in soy sauce, this study utilized high nutritional value seaweeds to ferment soy sauce and investigated the effects of the addition of Gracilaria on the physicochemical properties and flavor substances of soy sauce. The contents of amino acid nitrogen and total nitrogen in Gracilaria soy sauce were 0.8 g/100g and 1.4 g/100g, respectively, which were higher than those in traditional soy sauce. The free amino acid content of Gracilaria soy sauce (17.82 mg/g) was 1.35 times higher than that of traditional soy sauce, the organic acids content of Gracilaria soy sauce (15.78 mg/mL) was 1.12 times higher than that of traditional soy sauce. Compared with traditional soy sauce, the addition of Gracilaria promoted the accumulation of pyrazines and acids in soy sauce, which contributed to the seafood-like flavor. In general, the addition of Gracilaria to ferment soy sauce can improve the quality and give it a unique flavor. This study can provide a reference for improving the quality and flavor diversity of soy sauce by using seaweed as a fermentation substrate.

Differences in taste and material basis of soybean and defatted soybean fermented soy sauces and influence factors

Soybean and defatted soybean have been widely used as protein materials in soy sauce fermentation. Defatted soybean is welcomed by the industry for lower costs and higher level of protein. It has been revealed that defatted soybean fermented soy sauce (SS-DS) has a less appealing flavor than whole soybean fermented soy sauce (SS-HS). But the taste differences in molecular basis between the two remain unexplored. In this study, quantitative descriptive analysis (QDA) demonstrated SS-HS had a more harmonious and palatable taste, while SS-DS exhibit a more bitter taste. 9 organic acids, 15 sugars and sugar alcohols, 17 amino acids, 31 peptides and 12 Amadori compounds in soy sauce were detected by gas chromatography-mass spectrometer combined with derivatization (Der-GC-MS) and ultra-performance liquid chromatography quadrupole time-of flight mass spectrometry (UPLC-Q-TOF-MS). Sixteen compounds with taste active value (TAV) higher than 1 were identified as key substances. Further, it was found that lipid composition played an important role in taste difference between SS-HS and SS-DS, especially phospholipids. This paper determined the taste difference basis between SS-HS and SS-DS, and clarified the role of lipids in formation of these differences, which provided a theoretical reference for the flavor regulation in soy sauce industry.

Influence of spatial and temporal diversity and succession of microbial communities on physicochemical properties and flavor substances of soy sauce

In this study, the influence and relationship between the microbial structure composition at different spatial locations during soy sauce fermentation and the quality of soy sauce were investigated. Within 3–7 days of fermentation, the abundance of Chromohalobacter in the surface and upper layers of moromi was initially high but subsequently decreased. In contrast, Tetragenococcus exhibited low abundance on the surface of moromi at the beginning of fermentation but emerged as the absolute dominant bacteria by the end of the fermentation process. Throughout the fermentation period of 3–42 days, Staphylococcus and Bacillus were the predominant bacterial genera observed at the bottom of the moromi. In addition, Halanaerobium was the dominant bacterial genus in the crude soy sauce layer throughout the fermentation process. Tetragenococcus and Zygosaccharomyces were strongly positively correlated with total acid and ammonia nitrogen. Bacillus and Staphylococcus were significantly negatively correlated with the salt content.

Mechanistic insights into soy sauce flavor enhancement via Co-culture of Limosilactobacillus fermentum and Zygosaccharomyces rouxii

For years, the intricate interactions between microorganisms in fermented food have played a key role in enhancing flavor. Our previous study highlighted that co-culture of Limosilactobacillus fermentum (L. fermentum) and Zygosaccharomyces rouxii (Z. rouxii) could enhance the flavor improvement capability of Z. rouxii in soy sauce fermentation, but the mechanism has been understudied. In this study, gas chromatography-mass spectrometry (GC-MS), GC-MS combined with derivatization (Der-GC-MS) and metabolite addition experiments were employed to elucidate their interaction. The first reason for the enhanced flavor of co-culture was that L. fermentum itself could produce the caramel-like compounds, such as HDMF and 2-furanmethanol. Another important reason was the commensality interaction between L. fermentum and Z. rouxii, where L. fermentum not only grew vigorously, but also significantly promoted the growth of Z. rouxii, mitigating the inhibitory effects of acetic acid on Z. rouxii. Further validation revealed that the metabolites of L. fermentum could stimulate the reproduction of Z. rouxii and increase the synthesis of aroma compounds such as phenylethyl acetate and ethyl acetate. Notably, glycerin and lactic acid emerged as pivotal metabolites facilitating enhanced aroma production. This study offers valuable insights for advancing flavor regulation techniques in soy sauce production.

Similarity recognition approach to identify zero-added MSG soy sauce using stable isotopes and amino acid profiles

Seasonings such as naturally fermented soy sauce without added monosodium glutamate (MSG), are currently a growth market in China. However, fraudulent and mislabeled zero-added MSG soy sauce may cause a risk of excessive MSG intake, increasing food safety issues for consumers. This study investigates stable carbon and nitrogen isotopes and 16 amino acids in typical Chinese in-market soy sauces and uses a similarity method to establish criteria to authenticate MSG addition claims. Results reveal most zero-added MSG soy sauces had lower δ13C values (−25.2 ‰ to −17.7 ‰) and glutamic acid concentrations (8.97 mg mL−1 to 34.76 mg mL−1), and higher δ15N values (−0.27 ‰ +0.95 ‰) and other amino acid concentrations than added-MSG labeled samples. A combined approach, using isotopes, amino acids, similarity coefficients and uncertainty values, was evaluated to rapidly and accurately identify zero-added MSG soy sauces from MSG containing counterparts.

Co-culture of Tetragenococcus halophilus and Zygosaccharomyces rouxii to improve microbiota and metabolites in secondary fortified fermented soy sauce

This study employed metagenomics and metabolomics to evaluate the impact of Tetragenococcus halophilus and Zygosaccharomyces rouxii on microbiota composition and metabolite profiles in secondary fortified fermented soy sauce. The Co-culturing of T. halophilus T10 and Z. rouxii QH-1(T1Z) enriched microbial diversity and promoted the proliferation of functional species, thereby enhancing biomarker species. Annotations matched from EggNOG, KEGG, and CAZy databases underscored the significance of carbohydrate and amino acid metabolism in moromi. Sample T1Z enhanced the metabolism by increasing the abundance and catalytic efficiency of the relevant enzymes, resulting in increases of 3.94%, 2.69%, and 11.14%, respectively, with total nitrogen, amino acid nitrogen, and free amino acids. It introduced 11 volatile compounds and increased the alcohol content by 13.65%, and the aldehyde content by 49.28%, while also suppressing the accumulation of ammonium nitrogen and biogenic amines. Metabolic pathway analysis identified Staphylococcus gallinarum, Mammaliicoccus sciuri, and certain Bacillus species, especially B. parathracis, B. velezensis, and B. subtilis, as principal contributors to carbohydrate and amino acid metabolism. These findings offer insight into microbial strain selection for industrial fermentation and provide a foundation for optimizing the process through co-culture bioaugmentation to enhance and underscore the potential of modern microbial techniques in traditional practices.

Identification of fermented soy sauce and blended soy sauce based on dielectric spectra

A new method based on dielectric properties has been developed to distinguish blended soy sauce from fermented soy sauce. Fifty samples of pure fermented soy sauce and blended soy sauce with different contents of hydrolyzed vegetable protein (HVP) were prepared. The dielectric constant and dielectric loss factor of all soy sauce samples in the 30 MHz–3000 MHz frequency range were measured using an impedance analyzer. The sample set was divided into a correction set and a prediction set using the joint x-y distances (SPXY) algorithm, and the partial least squares (PLS) and support vector machine (SVM) models were adopted to distinguish the different samples. The effects of selecting characteristic variables on model prediction using the full spectra (FS), principal component analysis (PCA), and successive projection algorithm (SPA) were compared. Results indicate that the discriminant effect of the PLS model was better than that of the SVM model overall. The SPA–PLS model had the best predictive performance among the six developmental models. The correlation coefficients of the correction set and prediction set were 0.9205 and 0.9096, respectively. The root mean square error of the calibration set was 1.3699 and that of the prediction set was 1.5950. The study demonstrated that the combination of dielectric spectra and stoichiometry can be utilized to determine whether soy sauce has been adulterated.

Effects of yeast variations and fermentation time on the physicochemical characteristics and sensory quality of sorghum soy sauce

Abstract Soy sauce is a traditional salty liquid condiment produced by fermenting soybeans. However, the increasingly high price of soybeans on the market has led to the need for alternative substitutes to the raw material for making soy sauce. Sorghum (Sorghum bicolor (L.) Moench.) is a cereal crop that is widely grown in Indonesia and has high carbohydrate and protein content but has yet to be utilized optimally, so sorghum has the potential to be used as a functional. The sensory quality of soy sauce is affected by the fermentation process. This research aims to analyze the effect of adding yeast variations and fermentation time on the physicochemical and sensory quality characteristics of sorghum soy sauce. The research method used a wholly randomized factorial design with three repetitions. The first factor is yeast variations, which use two levels, Rhizopus oligosporus and Saccharomyces cerevisiae. The second factor is the fermentation time, with four levels, namely 7, 11, 15, and 19 days. The resulting soy sauce is then analyzed for protein content, acidity, viscosity, and sensory analysis using the attributes of taste, color, and flavor. The data obtained was processed with SPSS software using two-way ANOVA and Least Significant Difference (LSD) if the results obtained had a significant effect. The research results showed that the use of various types of yeast has a substantial impact on the protein content, viscosity, and flavor attributes of sorghum soy sauce. Meanwhile, fermentation time treatment had a significant effect on acidity and color. Overall, the best treatment was obtained by adding Saccharomyces cerevisiae with a fermentation time of 11 days, resulting in a protein content of 1.32%, acidity of 4.60, and viscosity of 3.11 cp. Sensory analysis showed that the best treatment was soy sauce fermentation using Rhizopus oligosporus for 11 days, which obtained a taste attribute value of 3.24, flavor value of 2.21, and color value of 3.96.

Optimisation of fermentation conditions for the production of gamma-aminobutyric acid (GABA)-rich soy sauce

This study addresses the challenge of enhancing gamma-aminobutyric acid (GABA) content in soy sauce through optimized fermentation condition. Using a multiple starter culture, consisting of Aspergillus oryzae strain NSK, Bacillus cereus strain KBC and Tetragenococcus halophilus strain KBC, the incubation conditions including the percentage of bacterial inoculum (10, 15 and 20 %), pH (3, 5 and 7) and agitation speed (100, 150 and 200 rpm) were optimized through Response Surface Methodology (RSM). Under the optimal conditions (20 % inoculum, pH 7 and stirring at 100 rpm), the multiple starter culture generated 128.69 mg/L of GABA after 7 days and produced 239.08 mg/L of GABA after 4 weeks of fermentation, which is 36 % higher than under non-optimized conditions (153.48 mg/L). Furthermore, sensory analysis revealed high consumer acceptance of the fermented soy sauce than the control (soy sauce without any treatment and additional bacteria) and commercial soy sauce. Consumers indicated that the starter culture offered an improved umami taste and reduced bitter, sour and salty flavours compared to the commercial product. Under optimal fermentation conditions determined by RSM statistical analysis, the multiple starter culture is able to produce high levels of GABA and is more likely to be accepted by consumers. The findings of this research have the potential to impact the food sector by offering a functional soy sauce with added health benefits and also being well-received by consumers.

Anti-Inflammatory Effect of Korean Soybean Sauce (Ganjang) on Mice with Induced Colitis.

Inflammatory bowel disease (IBD), characterized by chronic inflammation of the gut, is caused by several factors. Among these factors, microbial factors are correlated with the gut microbiota, which produces short-chain fatty acids (SCFAs) via anaerobic fermentation. Fermented foods are known to regulate the gut microbiota composition. Ganjang (GJ), a traditional fermented Korean soy sauce consumed worldwide, has been shown to exhibit antioxidant, anticancer, anti-colitis, and antihypertensive activities. However, its effects on the gut microbiota remain unknown. In the present study, we aimed to compare the anti-inflammatory effects of GJ manufactured using different methods and investigate its effect on SCFA production in the gut. To evaluate the anti-inflammatory effects of GJ in the gut, we performed animal experiments using a mouse model of dextran sulfate sodium (DSS)-induced colitis. All GJ samples attenuated DSS-induced colitis symptoms, including reduced colonic length, by suppressing the expression of inflammatory cytokines. In addition, GJ administration modulated SCFA production in the DSS-induced colitis model. Overall, GJ exerted anti-inflammatory effects by reducing DSS-induced symptoms via regulation of inflammation and modulation of SCFA levels in a DSS-induced colitis model. Thus, GJ is a promising fermented food with the potential to prevent IBD.

Exploring changes in key aroma-active compounds of soy sauce due to different fermentation processes

In this study, two extraction methods combined with gas chromatography-olfactometry-mass spectrometry (GC×GC-O-MS) were used to investigate the sensory characteristics of high-salt dilute fermented soy sauce (HDFSS), and molecular sensory methods were used to characterize its aroma. Among them, 3-methylthiopropanal had the highest odor activity value (OAV) in HDFSS, and acetic acid had the highest content in HDFSS. The results showed that the concentrations of benzyl alcohol, phenethyl alcohol, 1-octen-3-ol, maltol, and 1-hydroxy-2-propanone did not vary significantly in the HDFSS of different fermentation processes. The Y2 HDFSS produced in the koji-making fermentation system 2 had higher concentrations of 3-methyl-1-butanol (malt) and 3-methylthiopropanal (roasted potato). Additionally, it received high aroma scores in the sensory evaluation. Finally, by conducting aroma reconstitution and omission experiments on HDFSS from two different fermentation processes, the key aroma-active compounds, such as phenethyl alcohol, maltol, and guaiacol, were identified.

Identification and Free Radical Scavenging Activity of Oligopeptides from Mixed-Distillate Fermented Baijiu Grains and Soy Sauce Residue.

This study aimed to explore the potential antioxidant activity and mechanism of oligopeptides from sauce-aroma Baijiu. The oligopeptides of Val-Leu-Pro-Phe (VLPF), Pro-Leu-Phe (PLF), Val-Gly-Phe-Cys (VGFC), Leu-Tyr-Pro (LYP), Leu-Pro-Phe (LPF), and Phe-Thr-Phe (FTF) were identified by liquid chromatography-mass spectrometry (LC-MS) from the mixed-distillate of Baijiu fermented grains and soy sauce residue (MDFS). The antioxidant mechanism of these oligopeptides on scavenging DPPH•, ABTS•+, and hydroxide radicals was investigated, respectively. Among them, VGFC had the strongest potential antioxidant activity, which was responsible for its hydrogen bonds with these radicals with high affinity. The binding energies between VGFC and these radicals were -1.26 kcal/mol, -1.33 kcal/mol, and -1.93 kcal/mol, respectively. Additionally, free radicals prefer to bind the oligopeptide composed of hydrophobic amino acid residues such as Leu, Val, Phe, and Pro, thus being scavenged for exerting antioxidant activity. It provided a new idea for the development and utilization of bioactive oligopeptides in sauce-aroma Baijiu.

Exploring the core microorganisms and mechanisms responsible for biogenic amines production during soy sauce fermentation

Hazardous levels of biogenic amines (BA) are frequently detected in soy sauce. However, the microorganisms and mechanisms responsible for BA formation in soy sauce are not well understood. In this study, we investigated the dynamic changes and metabolic pathways of BAs during soy sauce fermentation via metabolome and metagenomic analyses. Spermidine and putrescine were the main BAs detected during koji making, while putrescine, tyramine, phenylethylamine, and histamine were dominant during moromi fermentation. PCA analysis revealed that the soy sauce fermentation process could be divided into five representative stages based on the dynamics of BAs. Metagenomic analysis uncovered that a total of 15 genera were mainly involved in BAs formation, particularly, histamine was principally produced by Klebsiella, and Bacillus was the major tyramine-synthesizing bacteria. Correlation analysis showed that pH increase inhibited the spermidine production during koji making, whereas elevated NaCl concentration facilitated the phenylethylamine formation during moromi fermentation. Co-occurrence network analysis unveiled the associations between the BA-producing microorganisms and other genera. Overall, these results have improved our understanding of the mechanism of BA formation during soy sauce fermentation and guided the development of fermentation agents capable of degrading BA in industrial manufacture soy sauce production.

Investigation of the Physicochemical Properties and its Correlation during Koji-Moromi Fermentation Stage of Production Soy Sauce Naturally Brewed in Central Java, Indonesia

Soy sauce, a widely consumed condiment, undergoes intricate physicochemical transformations during its natural fermentation process. This research delved into the analysis of physical and chemical properties in naturally brewed soy sauce, aiming to elucidate the impact of fermentation stages (Koii, earlier moromi, final moromi, soy sauce product) and sample variations on these properties. Parameters such as pH, total acid, total soluble solids, and water activity (aw) were assessed. Additionally, chemical attributes were analyzed, including total nitrogen, crude protein, formol nitrogen, and sodium chloride (NaCl) content. The correlation between physical and chemical properties during the fermentation stages was determined using the principal component analysis (PCA) method. The fermentation process significantly affected soy sauce's physical and chemical properties. Key factors include total dissolved solids, water activity, total acids, salt, total nitrogen, crude protein, and formol nitrogen, which display distinct patterns. These fluctuations were primarily driven by microbial activity and enzymatic hydrolysis, and total nitrogen, crude protein, and formol nitrogen play pivotal roles in characterizing soy sauce quality. Remarkably, total acid content and pH values exhibited significant variations that deviate from expected correlations due to weak acids. Samples C and D were deemed the most suitable out of the five tested, aligning better with quality standards for soy sauce. This study sheds light on the complex physicochemical changes during soy sauce fermentation, emphasizing the impact of raw materials and microbial processes on its properties.

Metabolic behavior of Aspergillus oryzae in salt-reduced soy sauce and its regulation for the brewing process

Soy sauce fermentation process initiates with the involvement of Aspergillus oryzae, which serves as the primary beneficiary in salt-reduced fermentation (SRF) process. This investigation aimed to scrutinize the metabolic activities of A. oryzae in salt-reduced soy sauce and examine its subsequent impacts on the microecology and flavor profile. SRF amplified the central carbon and protein metabolism of A. oryzae, leading to improved substrate utilization efficiency, which in turn facilitated the colonization of Lactobacillus and the maintenance of a co-occurrence equilibrium within the microbiota. Consequently, Ascomycetes established a fundamental module for aroma generation, exhibiting robust interconnections. SRF facilitated A. oryzae in supplying amino acid precursors vital to produce phenylacetaldehyde derivatives. Furthermore, SRF prompted an up-regulation of the β-oxidation pathway in A. oryzae, effectively suppressing the generation of undesirable fatty rancidity odor (fatty aldehyde) derived from fatty acids. These metabolic characteristics of A. oryzae play a pivotal role in enhancing the quality of salt-reduced soy sauce.

Polysaccharide intercellular adhesin and proper phospholipid composition are important for aggregation in Tetragenococcus halophilus SL10.

Aggregating strains of Tetragenococcus halophilus tend to be trapped during soy sauce mash-pressing process and are, therefore, critical for clear soy sauce production. However, the precise molecular mechanism involved in T. halophilus aggregation remains elusive. In previous studies, we isolated a number of aggregating strains, including T. halophilus AB4 and AL1, and showed that a cell surface proteinaceous aggregation factor is responsible for their aggregation phenotype. In the present study, we explored the role of polysaccharide intercellular adhesin (PIA) in aggregate formation in T. halophilus SL10, isolated from soy sauce. SL10 exhibited similar aggregation to AB4 and AL1 but formed a non-uniform precipitate with distinctive wrinkles at the bottom of the test tube, unlike AB4 and AL1. Insertion sequence mutations in each gene of the ica operon diminished aggregation and PIA production, highlighting the critical role of IcaADBC-mediated PIA production in T. halophilus aggregation. Furthermore, two non-aggregating cardiolipin synthase (cls) gene mutants with intact ica operon did not produce detectable PIA. Phospholipid composition analysis in cls mutants revealed a decrease in cardiolipin and an increase in phosphatidylglycerol levels, highlighting the association between phospholipid composition and PIA production. These findings provide evidence for the pivotal role of cls in PIA-mediated aggregation and lay the foundation for future studies to understand the intricate networks of the multiple aggregation factors governing microbial aggregation.IMPORTANCEAggregation, commonly observed in various microbes, triggers biofilm formation in pathogenic variants and plays a beneficial role in efficient food production in those used for food production. Here, we showed that Tetragenococcus halophilus, a microorganism used in soy sauce fermentation, forms aggregates in a polysaccharide intercellular adhesin (PIA)-mediated manner. Additionally, we unveiled the relationship between phospholipid composition and PIA production. This study provides evidence for the presence of aggregation factors in T. halophilus other than the proteinaceous aggregation factor and suggests that further understanding of the coordinated action of these factors may improve clarified soy sauce production.

Insights into the Biogenic Amine-Generating Microbes during Two Different Types of Soy Sauce Fermentation as Revealed by Metagenome-Assembled Genomes

Insights into the Biogenic Amine-Generating Microbes during Two Different Types of Soy Sauce Fermentation as Revealed by Metagenome-Assembled Genomes

Dynamic changes in metabolomics and flavoromics during industrial scale fermentation of Chinese traditional soy sauce

Flavor substances are crucial to the quality of soy sauce and closely related to the intermediate metabolites. This study systematically explored the dynamic changes in physicochemical characteristics, metabolomics and flavoromics during traditional Chinese soy sauce fermentation. The results indicated that the amino acid nitrogen gradually increased to 0.95 g/100 mL on the 13th day and then stabilized, and the changes of reducing sugars increased to 66.40 mg/mL on the 7th day and then slowly decreased. A total of 90 volatile compounds and 1172 non-volatile metabolites were detected. In the early fermentation period (1–7 day), alcohols, aldehydes and ketones were the main volatile compounds, but as fermentation proceeded, phenols and esters gradually accumulated. The total content of volatile compounds, mainly alcohols and phenols, reached the highest value on the 23rd day. Non-volatile metabolites were mainly amino acids, organic acids, lipids and carbohydrates, and the content and types of varied with fermentation time. KEGG analysis indicates there were significant changes in the proline and arginine metabolism in the middle and late periods (7–28 day) compared to the early fermentation period. Correlation analysis indicating a delicate balance between the transformation of metabolites and the formation of volatile compounds in traditional Chinese soy sauce.

A Method of Reducing Salt Content in Fermented Soy Sauce Improves Its Flavor and Quality.

Most commercially available soy sauce is fermented by high-salt liquid-state (HS) fermentation, which has an excessive salt content and a long fermentation period. In this study, a new salt-reduced fermentation (SR) soy sauce technology involving multiple strains of bacteria was developed to reduce consumers' salt intake. The SR soy sauce was found to have an amino acid nitrogen content of 8.40 g/L and over 80 kinds of flavor substances, which were significantly higher than those of low-salt solid-state fermented soy sauce and approximately equal to HS soy sauce. Compared with HS soy sauce, the salt content of the SR soy sauce was reduced by 59.2%, achieving the salt reduction goal. The proportion of umami amino acids in SR soy sauce reached 32.0% of the total level, enhancing SR soy sauce's quality. Hence, the new fermentation process can decrease salt content and shorten fermentation time.

Exploring correlations between soy sauce components and the formation of thermal contaminants during low-salt solid-state fermentation

Soy sauce is a traditional seasoning in Asia and provides a unique flavor to food. However, some harmful Maillard reaction products (MRPs) were inevitably formed during the manufacturing process. Fermentation is a critical step of soy sauce manufacturing and has a significant impact on MRPs formation. Therefore, this study investigated the formation of some characteristic MRPs (e.g., furan, carboxymethyl lysine (CML), 5-hydroxymethylfurfural (5-HMF), α-dicarbonyl compounds) and their correlation with major quality indicators (e.g., free amino acids, reducing sugar, total acid, ammonia nitrogen, total nitrogen, non-salt soluble solids) in low-salt solid-state fermentation soy sauce (LSFSS). The result showed that the levels of furan, CML, and 5-HMF continue to increase during the fermentation process, reaching a maximum after sterilization. Further testing using Person correlation showed that the formation of furan, CML, and 5-HMF in LSFSS was positively correlated with glucose, fructose, α-dicarbonyl compounds, and most of the amino acids, while it was negatively correlated with sucrose and methionine. Among them, the contribution of lysine, valine, isoleucine, leucine, and arginine to furan formation has rarely been reported. Our results provide a good theoretical basis for the control of MRPs during LSFSS fermentation.