Quality Of Soy Sauce Research Articles

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.

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.

Synthesis, taste characteristics and taste mechanism of N-lactoyl leucine from soy sauce using sensory analysis and UPLC-MS/MS

Recently, amino acid derivatives gradually gained attention, but studies on N-lactoyl-leucine (Lac-Leu) and N-lactoyl-isoleucine (Lac-Ile) are limited. This study aims to explore the contributions of Lac-Leu and Lac-Ile to soy sauce. Lac-Leu and Lac-Ile were synthesized via enzymatic synthesis method catalyzed by Tgase. The mixed solutions containing Lac-Leu were found to have greater taste improvement than those containing Lac-Ile. Sensory evaluation indicated the sour, bitter, and astringent taste of Lac-Leu in water as well as its kokumi, astringent, and umami-enhancing taste in MSG solution. The taste threshold and umami-enhancing threshold of Lac-Leu measured by TDA and cTDA, respectively, were 0.08 mg/mL and 0.16 mg/mL. Molecular docking of Lac-Leu and Lac-Ile with the kokumi receptor CaSR and the umami receptors T1R1 and T1R3 indicated that Lac-Leu had higher affinities with receptors than Lac-Ile. These findings demonstrated the underlying contribution Lac-Leu made to soy sauce, indicating its potential to improve the flavor quality of soy sauce.

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.

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.

The key proteolytic enzyme analysis of industrial Aspergillus oryzae at solid-state koji fermentation with a local database extension

The productivity and flavor quality of soy sauce are partly determined by the proteolytic enzymes secreted by the industrial microbe Aspergillus oryzae, which break down proteins into peptides and amino acids. Because of how complicated it is to classify proteolytic enzymes and understand how they work, not much is known about what is in the profiles of proteolytic enzymes and which enzymes are most important to A. oryzae during solid-state fermentation. In this study, we collected industrial A. oryzae from Chinese and Japanese soy sauce production, both of which have excellent protein hydrolysis capability but have numerous genetic differences. We systematically analyzed the in vitro enzyme profiles of two industrial A. oryzae based on 4D label-free proteome sequencing technology. In addition, we constructed a local database of proteolytic enzymes from the Aspergillus genus, which helps us analyze the proteomics data more precisely. We found that 96 proteolytic enzymes are excreted by industrial A. oryzae, of which 27 are endopeptidases and 39 are exopeptidases. Based on the relative protein expression and transcription quantity, as well as the catalytic characteristics, we identified 27 potential key proteolytic enzymes associated with high protein breakdown efficiency at solid-state fermentation. Meanwhile, we proposed eight proteolytic enzymes with potential hydrolytic activity. This study deepens our understanding of the proteolytic enzyme profiles excreted by A. oryzae at solid state and provides our knowledge of the candidate key proteolytic enzymes during koji fermentation.

Efficient degradation of soybean protein B3 subunit in soy sauce by ultrasound-assisted prolyl endopeptidase and its primary mechanism.

Prolyl endopeptidase can partially degrade soybean protein B3 subunit and alleviate soy sauce secondary precipitate. In this study, the influences of ultrasound-assisted prolyl endopeptidase on the degradation of soybean protein B3 subunit of soy sauce and primary mechanism were investigated using SDS-PAGE, MALDI-TOF-MS, circular dichromatic spectrometer, fluorescence spectra, etc. Results showed that ultrasound-assisted prolyl endopeptidase enhanced 72% degradation rate of B3 subunit and reduced soy sauce secondary precipitate remarkably, meanwhile significantly increased content of organic taste compounds of soy sauce compared with control (p<0.05). Sonication markedly reduced percentage of α-helix and increased percentage of random coil, made hydrophobic amino acids inside prolyl endopeptidase exposed to its surface and enhanced its flexibility, which facilitated the binding of prolyl endopeptidase active center with B3 subunit and finally enhanced the latter's degradation rate and appearance quality of soy sauce. This work laid a foundation for solving soy sauce secondary precipitate.

Evaluation of the differences between low-salt solid-state fermented soy sauce and high-salt diluted-state fermented soy sauce in China: from taste-active compounds and aroma-active compounds to sensory characteristics.

The present study aimed to determine the components related to sensory properties in soy sauce and to characterize the differences between low-salt solid-state fermented soy sauce (LSFSS) and high-salt diluted-state fermented soy sauce (HDFSS). The taste and aroma active components of 18 commercially available soy sauces (eight types of LSFSS and 10 types of HDFSS) were characterized. The relationship between these compounds, soy sauce samples, and sensory properties was modeled by partial least squares regression. The analysis showed that the 11 taste-active components, including glutamic acid, glycine, alanine, threonine, malic acid, citric acid, tartaric acid, acetic acid, lactic acid, reducing sugar and salt, contributed greatly to the taste of soy sauce. In addition, umami, saltiness and sweetness are the characteristic tastes of HDFSS, whereas sourness and bitterness were the characteristic tastes of LSFSS. At the same time, seven aroma-active compounds, namely 4-ethyl-2-methoxyphenol, ethanol, 3-methyl-1-butanol, ethyl acetate, 2-phenethyl alcohol, 3-methyl thiopropanol and 2-ethyl-4-hydroxy-5-methylfuran-3-one, played a decisive role in the flavor of soy sauce. In addition, HDFSS presented the aroma attributes of smoky, alcoholic, floral, fruity and caramel-like, whereas LSFSS mainly presented sour and malty aroma attributes. The present study reveals new insight into the relationship between the chemical composition and sensory characteristics of soy sauce, which is of great significance for developing an objective measurement system and providing a theoretical basis to improve the sensory quality of soy sauce. © 2023 Society of Chemical Industry.

Improving protein utilization and fermentation quality of soy sauce by adding protease

Soy sauce is the most popular traditional fermented condiment in Asia. However, some proteins are unutilized during fermentation, causing resource waste. Therefore, this study aimed to improve protein utilization and fermentation quality by adding protease in the moromi. Firstly, Aspergillus oryzae (A. oryzae) endogenous proteases were found to play an important role in nitrogen element utilization, including increasing total nitrogen (TN), amino acid nitrogen (AAN), and relative protein expression. Secondly, among six exogenous proteases, neutral protease (NP) performed better both alone and synergistically with A. oryzae crude protease powder (CPP), because of the enhancement of small peptides and enzymatic effect. Importantly, adding NP increased AAN and TN by 7.45 % and 2.21 % respectively, as well as increasing peptides below 500 Da, Maillard peptides and the proportion of lactic to acetic acid, hence improving the umami and richness of soy sauce. Overall, adding NP could increase soy sauce protein utilization and fermentation quality.

Decoding the molecular basis for temperature control by metabolomics to improve the taste quality of soy sauce fermented in winter

This study aimed to explore the material basis of the temperature-controlled fermentation method (30 °C) to improve the taste quality of soy sauce fermented in winter under 200 tons industrial scale by quantitative description analysis (QDA), physicochemical and metabolomic analysis. Results showed that the taste of soy sauce fermented at controlled temperature (SSCT) was superior to that of soy sauce fermented at room temperature (SSRT), especially the intensity of umami, kokumi, and sweet. The contents of total nitrogen and amino acid nitrogen in SSCT were significantly higher. 49 non-volatile compounds (13 organic acids, 10 sugars, 9 sugar alcohols, 15 amino acids and 2 others) were identified by GC-MS derivatization, classified according to the taste characteristics and taste active value (TAV) was calculated. The total TAV of sweet and umami substances increased while the total TAVs of sour substances decreased for SSCT. Moreover, out of the 191 peptides/amino acids derivates detected by UPLC-MS/MS, where 34 compounds had large differences. Some umami compounds (Fru-Glu, Fru-Val and Fru-pGlu) and kokumi compounds (γ-Glu-Leu, γ-Glu-Ile) were significantly higher in SSCT. These results revealed the intrinsic reasons for the improved quality of temperature-controlled soy sauce and provided a theoretical basis for the exploration and industrial application of temperature control on soy sauce fermentation.

Effects of ultrasound combined with mild heat and potassium sorbate on Pichia membranaefaciens and the quality of soy sauce

AbstractThe aim of this study was to investigate the effects of ultrasound (US) combined with mild heat (T) and potassium sorbate (PS) on Pichia membranaefaciens in soy sauce and the quality of soy sauce. The maximum reduction of P. membranaefaciens was 5.34 ± 0.15 log after thermoultrasound (TS, 300 W, 10/3 s, 20 + 40 kHz, 60°C) + PS (0.1 mg/mL) treatment for 20 min. Physicochemical properties, including pH and total acid of soy sauce, did not change significantly after TS + PS treatment. Electronic nose analysis showed changes in the flavour of soy sauce after different treatments. A total of 122 and 125 volatile compounds were detected by SPME‐GCMS before and after TS + PS treatment respectively. T90 (soy sauce processed at 90°C) treatment decreased the content of the flavour compounds greatly, while TS + PS decreased the content of the flavour compounds slightly in soy sauce. TS + PS treatment inactivated P. membranaefaciens effectively in soy sauce and maintained and partially improved the sensory and flavour characteristics of soy sauce, which indicates that this combination technology has potential application in the commercial processing of soy sauce.

Effect of salt concentration on Chinese soy sauce fermentation and characteristics

The effect of salt concentration on soy sauce fermentation was studied. Four groups of soy sauce samples with 8%, 12%, 16%, and 20% salt concentrations were prepared and their physicochemical parameters, non-volatile metabolites (organic acids, free amino acids, and biogenic amines), volatile metabolites, and microbial abundance were analyzed during the whole fermentation. The sensory characteristics of the final products were also assessed. Salt concentration significantly affected the microbial abundance and metabolite profiles during soy sauce fermentation, resulting in different characteristics among samples. The RT-qPCR analysis showed that the microbial abundance in lower salted soy sauce was higher. Correspondingly, the accumulation of total acid and the decrease of reducing sugar were observed in lower salted soy sauce, aggravating the sourness of soy sauce. The levels of free amino acids and biogenic amines (detected by HPLC) in lower salted soy sauce were higher, resulting in a taste of umami but making unsafe soy sauce. Additionally, HS-SPME/GC-MS analysis showed that several distinctive volatile compounds were absent in lower salted soy sauce. Sensory evaluation revealed that the highest total score for the quality of soy sauce was obtained through fermentation under 16% salt concentration. This study helped deepen our understanding of the effect of salt on soy sauce fermentation and provide a theoretical data reference for low salt soy sauce development.

Characteristics of the soy sauce taste and koji enzyme profiles as affected by soybean traits

Soybean is the main raw material for soy sauce fermentation and has a significant impact on the quality of soy sauce. Understanding the impact of soybean traits on the soy sauce quality is important for the development of the industry. The present study compared the traits of 12 soybeans and the quality of their fermented kojis and soy sauces, revealing the differences in total sugar and protein content may be the key factors responsible for differences in soy sauce characteristics. On this basis, 6 representative soybeans including 3 high protein and low total sugar content soybeans (HPLS) and 3 low protein and high total sugar content soybeans (LPHS) were selected for further study. Results of the changes in enzyme activities during koji-making fermentation showed that neutral protease and beta-glucosidase activities were higher in HPLS kojis, while acid protease and xylanase activities were higher in LPHS kojis after 24 h of fermentation. Differences in enzyme activity further caused variations in the soy sauce quality and formed some correlations with soy sauce tastes, such as xylanase and umami (r = 0.885), kokumi (r = 0.916). The intensities of umami and kokumi were higher in LPHS soy sauces, which had a higher dipeptides content of X-Glu, X-Thr, X-Ser and Gly-X.

Microbial consortia and up-to-date technologies in global soy sauce production: A review

Soy sauce is an Oriental fermented condiment, and key ingredient in many Asian cuisines. As consumers around the world are becoming more adventurous with their eating choices and preferences, the demand for and popularity of Asian cuisines are increasing globally. The underlying basis of soy sauce fermentation is intricate microbial interactions which play a vital role in defining the quality, flavour, and smell of the resulting soy sauce. Traditional soy sauce fermentation consists of a two-step process: koji and moromi fermentation. Despite the presence of beneficial microorganisms in soy sauce, various harmful microorganisms can also be found during the koji or moromi step, thus resulting in soy sauce contamination. Therefore, studying the biodiversity and interactions of microorganisms is critical in ensuring soy sauce quality. The present review thus discusses in depth the various bacterial and fungal species that are either beneficial or harmful to soy sauce fermentation. The present review also discusses the advances in soy sauce fermentation such as the enhancement of gamma-aminobutyric acid (GABA) in soy sauce by microorganisms, the enhancement of soy sauce flavour by mixed starter culture, and by genome shuffling starter culture.

Near-infrared spectroscopy of Chinese soy sauce for quality evaluation

The feasibility of near-infrared (NIR) spectroscopy and partial least-squares regression (PLSR) was investigated for rapid prediction of the quality of Chinese soy sauce. Twenty-four soy sauce samples from eight common brands available in China were analyzed for the contents of various components that may affect the quality of soy sauce. Sensory evaluation was also conducted to determine the relationship between components and the sensory quality of soy sauce. Subsequently, NIR spectra (400–2500 nm) of the samples were obtained, and the raw spectra were subjected to different pretreatment methods. PLSR was performed on the raw and treated spectra to construct models using a calibration set. The performance of models was evaluated by comparing the determination coefficient of prediction (R2P) and root-mean-square error of prediction (RMSEP). The results showed that the models constructed using the moisture content (R2P of 0.825 and RMSEP of 1.73), amino acid nitrogen content (R2P of 0.785 and RMSEP of 0.071), and taste scores (R2P of 0.733 and RMSEP of 11.93) performed well, and the interactions between amino acid nitrogen content and taste of soy sauce were clarified. This study demonstrates that NIR spectroscopy can be used as a valid alternative method for rapid prediction of the sensory quality of soy sauce during processing.

Effect of Fortified Zygosaccharomyces rouxii on the Quality of Soy Sauce

Effect of Fortified Zygosaccharomyces rouxii on the Quality of Soy Sauce

Effects of amino acid composition of yeast extract on the microbiota and aroma quality of fermented soy sauce

Yeast extracts, of which amino acids are the main component, can be directly applied to improve the flavor of final soy sauce. In this study, the potential of commercial yeast extracts was explored from amino acid approach to enhance the flavor quality of soy sauce by shaping the core fermentation microbiota. Alkaline and neutral amino acids favored the competitive benefits of flavor-producing bacteria, while acidic amino acids promoted the stress resistance of the fermentation microbiota, especially the abundance of Lactobacillus, which increased to 18.03–23.78% and became the predominant microbiota. The mass ratio of neutral-nonpolar: neutral-polar: acidic: alkaline amino acids was 40: 18: 27: 15, which provided the optimal improvement of soy sauce aroma. The formulation and activated the metabolic pathways of 3-methyl-1-butyraldehyde, 3-methyl-1-butanol and 2-methyl-1-propanol through Leu and Ile, resulting in a 52.6% increase in malt-like aroma. This study provides a new idea for the regulation of soy sauce fermentation.

Identification of soy sauce using high-field asymmetric waveform ion mobility spectrometry combined with machine learning

Soy sauce, an important condiment, varies greatly in the brand, geographical distribution, and production processes. We investigated the potential of volatile organic compounds (VOCs) serving as an indicator of soy sauce quality to detect three regions and two production technologies of Chinese soy sauce. An analytical method named high-field asymmetric waveform ion mobility spectrometry (FAIMS) was utilized for acquiring sample data. Wavelet packet decomposition (WPD) and principal component analysis (PCA) were used to extract the features of FAIMS data. 4 machine learning models were trained using these features, and the optimal parameters were obtained by a grid search. The scatter plots of the optimal two features we selected showed that the different regions and production technologies of soy sauce had obvious clustering trends. For the identification of different regions and production technologies, the training score, test score, and average cross-validation score of the optimal model were all 100%. Furthermore, the learning curves indicated that the optimal model obtained good performance and had low prediction errors. It was concluded that FAIMS combined with a suitable machine learning algorithm can successfully classify different regions and production technologies of Chinese soy sauce.

Metabolic Features of Ganjang (a Korean Traditional Soy Sauce) Fermentation Revealed by Genome-Centered Metatranscriptomics.

ABSTRACTThe taste and quality of soy sauce, a fermented liquid condiment popular worldwide, is greatly influenced by microbial metabolism during fermentation. To investigate the fermentative features of ganjang (a Korean traditional soy sauce), ganjang batches using meju (fermented soybean) bricks and solar salts were prepared, and organic compounds, microbial communities, metagenomes, and metatranscriptomes of ganjang were quantitively analyzed during fermentation. Polymeric compound analysis in the ganjang treated with/without microbial inhibitors revealed that indigenous enzymes of meju bricks might be primarily responsible for degrading polymeric compounds. Through metagenome binning and microbe sequencing, 17 high-quality genome sequences representing all major ganjang microbiota were obtained, and their transcriptional expressions were quantitatively analyzed by mapping metatranscriptome reads normalized by spike-in RNA sequencing to the 17 genomes, which revealed that microbial metabolism might primarily occur while meju bricks are in the ganjang solution and decrease significantly after the removal of meju bricks. Metabolic pathways for carbohydrates, proteins, and lipids of the major ganjang microbiota were reconstructed, and their metabolic genes were transcriptionally analyzed, revealing that facultative lactic acid fermentation by Tetragenococcus was the major fermentation process active in the ganjang fermentation and that aerobic respiration by facultatively aerobic bacteria such as Chromohalobacter, Halomonas, and Marinobacter was also an important metabolic process during fermentation. Although the abundances of Fungi and the corresponding transcriptional expression levels were generally much lower than those of Bacteria, our analysis suggests that yeasts such as Debaryomyces and Wickerhamomyces might be in large part responsible for producing biogenic amines and flavors.IMPORTANCE The taste and quality of soy sauce, a popular fermented liquid condiment worldwide, is greatly influenced by microbial metabolism during fermentation. Spontaneous fermentation of ganjang (a Korean traditional soy sauce) in a nonsterile environment leads to the growth of diverse bacteria and fungi during fermentation, making it difficult to understand the mechanism of ganjang fermentation. Genome-centered metatranscriptomic analysis, combined with organic compound analysis, quantitative metagenome and metatranscriptome analyses, and metabolic pathway reconstruction and expressional analysis of the major ganjang microbiota during fermentation, would provide comprehensive insights into the metabolic features of ganjang fermentation.