Dietary and circulating branched chain amino acids are unfavorably associated with body fat measures among Chinese adults.

Animal studies showed a detrimental effect of dietary branched chain amino acids (BCAAs) on metabolic health, while epidemiological evidence on dietary BCAAs and obesity is limited and inconclusive. We hypothesized that high dietary and circulating BCAAs are unfavorably associated with obesity in community-dwelling adults. We evaluated the 1-year longitudinal associations of dietary BCAA intake and circulating BCAAs with body fat measures. Body weight, height, and circumferences of the waist (WC) and hip (HC) were measured at baseline and again after 1-year. Body composition and liver fat [indicated by controlled attenuation parameter (CAP)] were also assessed after 1-year. Serum BCAA concentrations at baseline were quantified by liquid chromatography mass spectrometry. Diet was collected using 4 quarterly 3-day recalls during the 1-year. The correlation coefficients between dietary and serum BCAAs were 0.12 (P = .035) for total dietary BCAAs, and ranged from -0.02 (soy foods, P = .749) to 0.18 (poultry, P = .001). Total dietary BCAA intake was associated with increase in body weight (ß = 0.044, P = .022) and body mass index (BMI, ß = 0.047, P = .043). BCAAs from animal foods were associated with increase in HC, while BCAAs from soy foods were associated with weight gain and higher CAP (all P < .05). Serum BCAAs were associated with higher WC, HC, BMI, body fat mass, visceral fat level, and CAP (all P < .05). These results support that dietary and circulating BCAAs are positively associated with the risk of obesity. More cohort studies with validated dietary assessment tools and long-term follow-up among diverse populations are needed to confirm our findings.

Flavor Perception and Formation Mechanism of Empty Cup Aroma in Soy Sauce Aroma Type Baijiu.

The research focused on the distinctive empty cup aroma, with the aim of identifying the key aroma compounds and the formation mechanism of empty cup aroma in soy sauce aroma type baijiu (SSB). The lasting times of SSB is significantly longer than that of other types of baijiu, with an average duration of 28 days. Key compounds such as 2,3-dimethyl-5-ethylpyrazine, phenylethyl alcohol, p-cresol, sotolon, benzeneacetic acid were identified in empty cup aroma due to their highest flavor dilution factor. Molecular dynamics (MD) simulation was performed to study the mechanism of empty cup aroma on the liquid-gas interface and solid-gas interface. The results revealed the existence of hydrogen bonding and van der Waals forces between sotolon and lactic acid, a representative nonvolatile compound, which are speculated to be an important reason for the empty cup aroma.

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.

Whole genome sequencing of the poly-γ-glutamic acid-producing novel Bacillus subtilis Tamang strain, isolated from spontaneously fermented kinema.

Kinema, a traditional fermented soybean food from the Himalayas, is well-liked for its sticky texture and flavourful umami taste. Among 175 bacterial strains from spontaneously fermented kinema samples, Bacillus subtilis Tamang strain stood out for its high stickiness and viscosity. The strain's Poly-γ-glutamic acid (γ-PGA) contains various groups of glutamic acid and has a molecular weight of 660 kDa. It demonstrates the ability to solubilize iron, preserve ferritin in Caco-2 cells, and exhibit antibacterial properties. The genome of B. subtilis Tamang is devoid of plasmid elements but does feature nine insert elements. Noteworthy is the presence of unique secondary metabolites with potential antimicrobial effects, such as amyloliquecidin GF610, bogorol A, and thermoactinoamide A. A total of 132 carbohydrate-active enzymes (CAZy) were identified, hinting at possible prebiotic characteristics. The genome analysis revealed genes responsible for γ-PGA production via the capBCA complex. Furthermore, genes associated with fibrinolytic activity, taste enhancement, biopeptides, immunomodulators, and vitamins like B12 and K2 were found, along with probiotics and various health benefits. The genetic material for L-asparaginase production, known for its anti-cancer properties, was also detected, as well as CRISPR-Cas systems. The absence of virulence factors and antimicrobial resistance genes confirms the safety of consuming B. subtilis Tamang as a food-grade bacterium.

Efficacy and mechanisms of rotating algal biofilm system in remediation of soy sauce wastewater.

This study investigated the efficacy of the rotating algal biofilm (RAB) for treating soy sauce wastewater (SW) and its related treatment mechanisms. The RAB system demonstrated superior nutrient removal (chemical oxygen demand, ammonium nitrogen, total nitrogen, and phosphorus for 92 %, 94 %, 91 %, and 82 %, respectively) and biofilm productivity (14 g m-2 d-1) at optimized 5-day harvest time and 2-day hydraulic retention time. This was mainly attributed to the synergistic interactions within the algae-fungi (Apiotrichum)-bacteria (Acinetobacter and Rhizobia) consortium, which effectively assimilated certain extracellular polymeric substances into biomass to enhance algal biofilm growth. Increased algal productivity notably improved protein and essential amino acid contents in the biomass, suggesting a potential for animal feed applications. This study not only demonstrates a sustainable approach for managing SW but also provides insight into the nutrient removal and biomass conversion, offering a viable strategy for large-scale applications in nutrient recovery and wastewater treatment.

Bioconversion of lignans in flaxseed cake by fermented tofu microbiota and isolation of Enterococcus faecium strain ZB26 responsible for converting secoisolariciresinol diglucoside to enterodiol.

Human intestinal microbiota plays a crucial role in converting secoisolariciresinol diglucoside, a lignan found in flaxseed, to enterodiol, which has a range of health benefits: antioxidative, antitumor, and estrogenic/anti-estrogenic effects. Given the high secoisolariciresinol diglucoside content in flaxseed cake, this study investigated the potential of co-fermenting flaxseed cake with fermented soybean product to isolate bacterial strains that effectively convert secoisolariciresinol diglucoside to enterodiol in a controlled environment (in vitro). The co-fermentation process with stinky tofu microbiota significantly altered the lignan, generating 12 intermediate lignan metabolites as identified by targeted metabolomics. One particular promising strain, ZB26, demonstrated an impressive ability to convert secoisolariciresinol diglucoside. It achieved a conversion rate of 87.42 ± 0.33%, with secoisolariciresinol and enterodiol generation rates of 94.22 ± 0.51% and 2.91 ± 0.03%, respectively. Further optimization revealed, under specific conditions (0.5 mM secoisolariciresinol diglucoside, pH 8, 30 °C for 3 days), ZB26 could convert an even higher percentage (97.75 ± 0.05%) of the secoisolariciresinol diglucoside to generate secoisolariciresinol (103.02 ± 0.16%) and enterodiol (3.18 ± 0.31%). These findings suggest that the identified strains ZB26 have promising potential for developing functional foods and ingredients enriched with lignans.

A new method based on dispersive solid phase microextraction with commercial MOFs coupled to LC-MS/MS for the determination of isoflavones in soy drinks.

For the first time, a method based on dispersive solid phase microextraction (D-µSPE) using commercial metal-organic frameworks coupled to liquid chromatography-triple quadrupole tandem mass spectrometry (LC-MS/MS) has been proposed for the determination of isoflavones in soy drinks. The use of commercial sorbents simplifies the sample treatment procedure and allows their application to routine analysis. Optimization of the parameters involved in the microextraction process was carried out using a Box-Behnken experimental design. Under the optimized conditions, the limits of detection ranged between 2 and 7 µg L-1; the intra-day and inter-day precision were <10 and 20%, respectively, and the recoveries were in the range of 61-120%. No significant matrix effect was found, which allowed the use of external standard calibration method. The method was successfully applied to the determination of isoflavones in commercial soy milk samples.

The effect of a fermented soy beverage among patients with localized prostate cancer prior to radical prostatectomy.

BACKGROUND: Fermented soy products have shown to possess inhibitory effects on prostate cancer (PCa). We evaluated the effect of a fermented soy beverage (Q-Can®), containing medium-chain triglycerides, ketones and soy isoflavones, among men with localized PCa prior to radical prostatectomy. METHODS: We conducted a placebo-controlled, double-blind randomized trial of Q-Can®. Stratified randomization (Cancer of the Prostate Risk Assessment (CAPRA) score at diagnosis) was used to assign patients to receive Q-Can® or placebo for 2-5 weeks before RP. Primary endpoint was change in serum PSA from baseline to end-of-study. We assessed changes in other clinical and pathologic endpoints. The primary ITT analysis compared PSA at end-of-study between randomization arms using repeated measures linear mixed model incorporating baseline CAPRA risk strata. RESULTS: We randomized 19 patients, 16 were eligible for analysis of the primary outcome. Mean age at enrollment was 61, 9(56.2%) were classified as low and intermediate risk, and 7(43.8%) high CAPRA risk. Among patients who received Q-Can®, mean PSA at baseline and end-of-study was 8.98(standard deviation, SD 4.07) and 8.02ng/mL(SD 3.99) compared with 8.66(SD 2.71) to 9.53ng/mL(SD 3.03), respectively, (Difference baseline - end-of-study, p = 0.36). There were no significant differences in Gleason score, clinical stage, surgical margin status, or CAPRA score between treatment arms (p > 0.05), and no significant differences between treatment arms in end-of-study or change in lipids, testosterone and FACT-P scores (p > 0.05). CONCLUSIONS: Short exposure to Q-Can® among patients with localized PCa was not associated with changes in PSA levels, PCa characteristics including grade and stage or serum testosterone. Due to early termination from inability to recruit, study power, was not achieved.

Fermented Yak-Kong using Bifidobacterium animalis derived from Korean infant intestine effectively relieves muscle atrophy in an aging mouse model.

Yak-Kong (YK) is a small black soybean widely cultivated in Korea. It is considered to have excellent health functionality, as it has been reported to have better antioxidant efficacy than conventional black or yellow soybeans. Since YK has been described as good for the muscle health of the elderly in old oriental medicine books, this study sought to investigate the effect of fermented YK with Bifidobacterium animalis subsp. lactis LDTM 8102 (FYK) on muscle atrophy. In C2C12 mouse myoblasts, FYK elevated the expression of MyoD, total MHC, phosphorylated AKT, and PGC1α. In addition, two kinds of in vivo studies were conducted using both an induced and normal aging mouse model. The behavioral test results showed that in the induced aging mouse model, FYK intake alleviated age-related muscle weakness and loss of exercise performance. In addition, FYK alleviated muscle mass decrease and improved the expression of biomarkers including total MHC, myf6, phosphorylated AKT, PGC1α, and Tfam, which are related to myoblast differentiation, muscle protein synthesis, and mitochondrial generation in the muscle. In the normal aging model, FYK consumption did not increase muscle mass, but did upregulate the expression levels of biomarkers related to myoblast differentiation, muscle hypertrophy, and muscle function. Furthermore, it mitigated age-related declines in skeletal muscle force production and functional limitation by enhancing exercise performance and grip strength. Taken together, the results suggest that FYK has the potential to be a new functional food material that can alleviate the loss of muscle mass and strength caused by aging and prevent sarcopenia.

Fermented dietary fiber from soy sauce residue exerts antidiabetic effects through regulating the PI3K/AKT signaling pathway and gut microbiota-SCFAs-GPRs axis in type 2 diabetic mellitus mice.

The gut plays a crucial role in the development and progression of metabolic disorders, particularly in relation to type 2 diabetes mellitus (T2DM). While a high intake of dietary fiber is inversely associated with the risk of T2DM, the specific effects of various dietary fibers on T2DM are not fully understood. This study investigated the anti-diabetic properties of fermented dietary fiber (FDF) derived from soy sauce residue in T2DM mice, demonstrating its ability to lower blood glucose levels and ameliorate insulin resistance. Our findings revealed that FDF could enhance hepatic glucose metabolism via the IRS-1/PI3K/AKT/mTOR pathway. Additionally, the anti-diabetic effect of FDF was correlated with alterations in gut microbiota composition in T2DM mice, promoting a healthier gut environment. Specifically, FDF increased the abundance of beneficial flora such as Dubosiella, Butyricimonas, Lachnospiraceae_NK4A136_group, Lactobacillus and Osillibacter, while reducing harmful bacteria including Bilophila, Parabacteroides and Enterorhabdus. Further analysis of microbial metabolites, including short-chain fatty acids (SCFAs) and bile acids (BAs), provided evidence of FDF's regulatory effects on cecal contents in T2DM mice. Importantly, FDF treatment significantly restored the G-protein-coupled receptors (GPRs) expression in the colon of T2DM mice. In conclusion, our study suggests that the anti-diabetic effects of FDF are associated with the regulation of both the liver-gut axis and the gut microbiota-SCFAs-GPRs axis.

Highly efficient production of 2-phenylethanol by wild-type Saccharomyces bayanus strain.

2-Phenylethanol (2-PE) is a highly valuable aromatic alcohol utilized in fragrance, cosmetics and food industries. Due to the toxic by-products from chemical synthesis and the low productivity of the extraction method, bioproduction of 2-PE by yeast is considered promising. In this study, a wild-type Saccharomyces bayanus L1 strain producing 2-PE was isolated from soy sauce mash. Transcriptional analysis showed that 2-PE was synthesized via the Ehrlich pathway and Shikimate pathway in S. bayanus L1. By improving the fermentation conditions in shaking flasks, the maximum 2-PE titer reached 4.2 g/L with a productivity of 0.058 g/L/h within 72 h. In fed-batch fermentation, S. bayanus L1 strain produced 6.5 g/L of 2-PE within 60 h, achieving a productivity of 0.108 g/L/h. These findings suggest that S. bayanus L1 strain is an efficient 2-PE producer, paving the way for highly efficient 2-PE production.

A comparative study on the nutritional composition, protein structure and effects on gut microbiota of 5 fermented soybean products (FSPs).

In this study, we conducted an analysis of the differences in nutrient composition and protein structure among various fermented soybean products and their impacts on the gut microbiota of rats. Conventional physicochemical analysis was employed to analyze the fundamental physicochemical composition of the samples. Additionally, we utilized high-performance liquid chromatography and ELISA techniques to quantify the presence of antinutritional compounds. Fourier infrared spectroscopy was applied to delineate the protein structure, while 16 s rRNA gene sequencing was conducted to evaluate alterations in gut microbiota abundance. Subsequently, KEGG was utilized for metabolic pathway analysis. Our findings revealed that fermented soybean products improved the nutritional profile of soybeans. Notably, Douchi exhibited the highest protein content at 52.18 g/100 g, denoting a 26.58 % increase, whereas natto showed a 24.98 % increase. Douchi and natto demonstrated the most substantial relative amino acid content, comprising 50.86 % and 49.04 % of the total samples, respectively. Moreover, the levels of antinutritional factors markedly decreased post-fermentation. Specifically, the α-helix content in doujiang decreased by 13.87 %, while the random coil content in soybean yogurt surged by 132.39 %. Rats that were fed FSP showcased notable enhancements in gut microbiota and associated metabolic pathways. A strong correlation was observed between nutrient composition, protein structure, and gut microbiota abundance. This study furnishes empirical evidence supporting the heightened nutritional attributes of FSPs.

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.

Characterization and correlations of dominant microorganisms and volatile compounds in fermentation process of Yangjiang douchi.

BACKGROUND: Yangjiang douchi (YD) is a traditional fermented soybean product, which is popular in Chinese cuisine for its unique flavor. However, due to its high salt content and unstable flavor, its competitiveness in the international market is gradually weakening. Microorganisms have a key role in the production process of YD because it is a fermented food but the effect of microorganisms on the volatile compounds of YD is also not currently clear. RESULTS: In this paper, aroma compounds and microbial diversity in different fermentation stages of YD were analyzed using gas chromatography-mass spectrometry/olfactometry (GC-MS/O) and IlluminaMiseq system sequencing. A total of 78 aroma-active compounds were detected throughout the fermentation process and they influenced the formation of flavor in YD. Fungi flora were relatively single in YD, and bacteria were rich and varied. A total of 418 species of bacteria were present during fermentation, with unclassified_Staphylococcus, Staphylococcus_kloosii, and Bacillus_velezensis_Bacillus predominating. There were 25 species of fungi at the species level, and Aspergillus minisclerotigenes (OTU 4) played a dominant role in the whole fermentation process. CONCLUSION: Staphylococcus and Bacillus in the bacterial genus were strongly correlated with most flavor compounds detected, and A. minisclerotigenes in the fungi were more relevant to flavor compounds. This research provides a theoretical basis for the enhancement of the flavor of traditional fermented douchi in China. © 2024 Society of Chemical Industry.

Improved analysis of 230 pesticide residues in three fermented soy products by using automated one-step accelerated solvent extraction coupled with GC-MS/MS.

Consumer concerns over healthy diets are increasing as a result of the toxicity and persistence of pesticide residues in foodstuffs. Developing sensitive and high-throughput monitoring techniques for these trace residues is seen as an essential step in ensuring food safety. An automatic and sensitive multi-residue analytical method was developed and validated for the simultaneous determination of 230 compounds, including pesticides and their hazardous metabolites, in fermented soy products. The method included preparing the sample using on-line extraction and clean-up system based on accelerated solvent extraction (ASE), then determining the analytes using GC-MS/MS techniques. The homogenized samples (soy sauce, douchi, and sufu) were automatically extracted at 80 °C and 10.3 MPa and at the same time, in situ cleaned by 300 mg of primary secondary amine (PSA) combined with 20 mg of hydroxylated multi-walled carbon nanotubes in an extraction cell. The method obtained excellent calibration linearity (r > 0.9220) and a satisfactory analysis of the targeted compounds, which were evaluated with matrix-matched calibration standards over the range of 5-500 µg L-1. The limit of detections (LODs) of analytes were in the range of 0.01-1.29 µg kg-1, 0.01-1.39 µg kg-1, and 0.01-1.34 µg kg-1 in soy sauce, douchi, and sufu, respectively. The limit of quantifications (LOQs), which defined as the lowest spiking level, were set at 5.0 µg kg-1. The recoveries were within 70-120 % for over 95 % of the analytes, and the relative standard deviations (RSDs) were below 13.6 %. Moreover, a positive detection rate of 47 % were obtained when the proposed method was used on 15 real fermented soy products. These results suggested that the developed high-throughput method is highly feasible for monitoring of these target analytes in trace level.

Starter molds and multi-enzyme catalysis in koji fermentation of soy sauce brewing: A review.

Soy sauce is a traditional fermented food produced from soybean and wheat under the action of microorganisms. The soy sauce brewing process mainly involves two steps, namely koji fermentation and moromi fermentation. In the koji fermentation process, enzymes from starter molds, such as protease, aminopeptidase, carboxypeptidase, l-glutaminase, amylase, and cellulase, hydrolyze the protein and starch in the raw ingredients to produce short-chain substances. However, the enzymatic reactions may be diminished after being subjected to moromi fermentation due to its high NaCl concentration. These enzymatically hydrolyzed products are further metabolized by lactic acid bacteria and yeasts during the moromi fermentation process into organic acids and aromatic compounds, giving soy sauce a unique flavor. Thus, the starter molds, such as Aspergillus oryzae, Aspergillus sojae, and Aspergillus niger, and their secreted enzymes play crucial roles in soy sauce brewing. This review comprehensively covers the characteristics of the starter molds mainly used in soy sauce brewing, the enzymes produced by starter molds, and the roles of enzymes in the degradation of raw material. We also enumerate current problems in the production of soy sauce, aiming to offer some directions for the improvement of soy sauce taste.

Evaluation of Menopausal Syndrome Relief and Anti-Obesity Efficacy of the Korean Fermented Food Doenjang: A Randomized, Double-Blind Clinical Trial.

Foods that help improve menopausal syndrome are being studied worldwide. Doenjang is a traditional Korean fermented soybean food with potential health benefits for menopausal women. In this clinical trial using Doenjang, we aimed to compare the effectiveness of traditional Doenjang and commercial Doenjang in menopausal women. Furthermore, we compared whether Doenjang has a better effect if the number of beneficial microbes is higher. The analyses included the following groups: traditional Doenjang containing either a high dose (HDC; n = 18) or low dose (LDC; n = 18) of beneficial microbes and commercial Doenjang (CD; n = 20). The Kupperman index and hematological changes were examined before and after the use of Doenjang pills. The effects of Doenjang on obesity and body composition were studied before and after ingestion. Lastly, the microorganisms and short-chain fatty acid changes in the stool were compared. The Kupperman index decreased after Doenjang consumption in all three groups, with the greatest decrease in the LDC group. Only the groups that took traditional Doenjang pills exhibited reduced LDL cholesterol. No changes in obesity and inflammation-related indicators were observed. The number of Firmicutes, associated with obesity, decreased in the CD group but the numbers of Bacteroidetes increased in the HDC and CD groups. Thus, traditional Doenjang is more effective in alleviating menopausal syndrome than commercial Doenjang. Further research on the anti-obesity effect or changes in microbiomes and short-chain fatty acids in feces is needed.

The association between soyfoods or soybean products consumption and executive functioning among Chinese adolescents: A cross-sectional multicenter study.

BACKGROUND: The association of soyfoods or soybean products with executive functions in the brain has been less well studied. In this study, we investigated the consumption of soyfoods or soybean products and its association with executive functions in Chinese adolescents. METHODS: A three-stage stratified whole group sampling method was used to investigate the consumption of soyfoods or soybean products and executive functions among 1643 Chinese adolescents aged 13-15 years. One-way ANOVA and chi-square test were used to compare the basic conditions and executive functions of adolescents with different soyfoods or soybean products consumption. Linear regression analysis and logistic regression analysis were used to analyze the association between soyfoods or soybean products and executive functions. RESULTS: The proportions of Chinese adolescents with soyfoods or soybean products consumption ≤0 time/week, 1-3 time/week, and ≥4 time/week were 41.14 %, 46.80 %, and 12.05 %, respectively. Logistic regression analysis showed that with adolescents with soyfoods or soybean products consumption ≥4 time/week as a reference, adolescents with ≤0 time/week were less likely to have executive dysfunction in inhibiting functional (OR = 17.523, 95 % CI: 7.501, 40.938), 2back (OR = 3.384, 95 % CI: 1.729, 6.623), and switching functional (OR = 7.846, 95 % CI: 3.300, 18.657), were at higher risk of executive dysfunction (P < 0.001). CONCLUSION: Chinese adolescents' consumption of soyfoods or soybean products is inadequate and has a positive association with executive functions. The consumption of soyfoods or soybean products among Chinese adolescents should be increased in the future.

Research advancements in the maintenance mechanism of Sporidiobolus pararoseus enhancing the quality of soy sauce during fermentation.

Soy sauce is a traditional condiment that undergoes microbial fermentation of various ingredients to achieve its desired color, scent, and flavor. Sporidiobolus pararoseus, which is a type of Rhodocerevisiae, shows promising potential as a source of lipids, carotenoids, and enzymes that can enrich the taste and color of soy sauce. However, there is currently a lack of systematic and comprehensive studies on the functions and mechanisms of action of S. pararoseus during soy sauce fermentation. In this review, it is well established that S. pararoseus produces lipids that are abundant in unsaturated fatty acids, particularly oleic acid, as well as various carotenoids, such as ß-carotene, torulene, and torularhodin. These pigments are synthesized through the mevalonic acid pathway and possess remarkable antioxidant properties, acting as natural colorants. The synthesis of carotenoids is stimulated by high salt concentrations, which induces oxidative stress caused by NaCl. This stress further activates crucial enzymes involved in carotenoid production, ultimately leading to pigment formation. Moreover, S. pararoseus can produce high-quality enzymes that aid in the efficient utilization of soy sauce substrates during fermentation. Furthermore, this review focused on the impact of S. pararoseus on the color and quality of soy sauce and comprehensively analyzed its characteristics and ingredients. Thus, this review serves as a basis for screening high-quality oleaginous red yeast strains and improving the quality of industrial soy sauce production through the wide application of S. pararoseus.

Characterization and in vitro digestibility of soybean tofu: Influence of the different kinds of coagulant.

This study explored the effect of diverse coagulants (glucono-δ-lactone (GDL), gypsum (GYP), microbial transglutaminase (MTGase), and white vinegar (WVG)) on microstructure, quality, and digestion properties of tofu. The four kinds of tofu were significantly different in their structure, composition, and digestibility. Tofu coagulated with MTGase had the highest springiness and cohesiveness while GDL tofu had the highest enthalpy (6.54 J/g). However, the WVG and GYP groups outperformed others in terms of thermodynamic, and digestion properties. The WVG group exhibited the highest nitrogen release (84.3%), water content, denaturation temperature, and the highest free-SH content but the lowest S-S content. Compared to WVG, the GYP group had the highest ash content, hardness, and chewiness. Results demonstrated that the tofu prepared by WVG and GYP show high digestibility. Meanwhile, the former has better thermal properties and the latter has better texture properties.