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Abstract This review paper explores the history, cultural significance, and functional characteristics of soybean paste (doenjang) in Korean cuisine. In particular, it covers its origins, cultural importance, production methods, functionalities, and associated risks. This review delves into the nutritional and functional aspects of fermented soybean products, focusing on compounds in soybean paste linked to health benefits, such as anticancer, anti-obesity, anti-diabetic, and antithrombotic properties. The key bioactive compounds identified in soybean paste include total phenols, total flavonoids, γ-Aminobutyric acid, vitamin B group, and vitamin E. These compounds are primarily produced through microbial fermentation, which enhances their biological activity. Additionally, the review addresses potential risks such as biogenic amines, aflatoxins, Bacillus cereus contamination, and high sodium levels, and suggests methods for mitigating these risks. By synthesizing current research, this paper aims to provide a comprehensive understanding of the physiological compounds in soybean paste and their health benefits. It also highlights the need for strategies to reduce associated risks.

Cheonggukjang (CGJ) is a traditional food, made by the fermentation of beans, and it has different recipes for different regions in Korea. However, it has anti-inflammatory, anti-cancer, and anti-obesity effects, and is known to affect changes in the intestinal microbiota. In this study, we investigated the immune-enhancing effects of four type CGJs (one commercial and three transitional CGJs). In the cyclophosphamide (CP)-treated immunosuppressed rat, oral administration of CGJs for 4 weeks was used to investigate weight of body and immune organ, change of microbiota, blood and serum parameters, inflammation pathways (MAPKs and NFκB) and histology of spleen. It showed an immunity-enhancing effect through increase Bacteroidetes in gut, the recovery of complete blood count, levels of cytokines and IgG, activation of inflammatory pathways, and histology of spleen. In conclusion, these results show that the intake of a commercial brand CGJ, and traditional CGJs can maintain or promote the body's immunity.

The mechanisms underlying chronic inflammatory diseases remain unclear. Therefore, researchers have explored the mechanisms underlying colitis using diverse materials. Recently, there has been an increasing interest in fermented products and bioconversion materials, their potential efficacy is being actively studied. Gochujang, a traditional Korean fermented product, is crafted by blending fermented Meju powder, gochu (Korean chili) powder, glutinous rice, and salt. In our study, we explored the effectiveness of Gochujang (500 mg/kg; Cheongju and Hongcheon, Korea) in dextran sulfate sodium (DSS)-induced colitis mice model. Gochujang was orally administered for 2 weeks, followed by the induction of colitis using 3% DSS in the previous week. During our investigation, Gochujang variants (TCG22-25, Cheongju and TCG22-48, Hongcheon) did not exhibit significant inhibition of weight reduction (p = 0.061) but notably (p = 0.001) suppressed the reduction in large intestine length in DSS-induced colitis mice. In the serum from colitis mice, TCG22-48 demonstrated reduced levels of the inflammatory cytokines interleukin (IL)-6 (p = 0.001) and tumor necrosis factor (TNF)-α (p = 0.001). Additionally, it inhibited the phosphorylation of Erk (p = 0.028), p38, and NF-κB (p = 0.001) the inflammatory mechanism. In our study, TCG22-25 demonstrated a reduction in the IL-6 level (p = 0.001) in serum and inhibited the phosphorylation of p38 and NF-κB (p = 0.001). Histological analysis revealed a significant (p = 0.001) reduction in the pathological score of the large intestine from TCG22-25 and TCG22-48. In conclusion, the intake of Gochujang demonstrates potent anti-inflammatory effects, mitigating colitis by preventing the large intestine length reduction of animals with colitis, lowering serum levels of TNF-α and IL-6 cytokines, and inhibiting histological disruption and inflammatory mechanism phosphorylation.

Hyperlipidemia, characterized by elevated cholesterol, lipids, and triglycerides in the bloodstream, is linked to hepatic oxidative damage. Doenjang, a traditional Korean condiment made from fermented soybeans, is known for its health benefits, yet its anti-hyperlipidemic effects remain understudied. Our study aimed to assess the hypolipidemic and hepatic protective effects of Doenjang on male ICR mice fed a high-fat cholesterol diet for 8 weeks. Mice were divided into three groups: the normal diet (ND), the high-fat cholesterol diet (HD), and the Doenjang-supplemented HD diet (DS) group. Doenjang supplementation significantly regulated total cholesterol, triglycerides, LDL cholesterol, and HDL cholesterol levels compared to the HD group. It also downregulated lipogenic genes, including PPARγ, FAS, and ACC, and positively influenced the cholesterol metabolism-related genes HMGCR and LXR. Moreover, Doenjang intake increased serum glutathione levels, activated oxidative stress defense genes (NRF2, SOD, GPx1, and CAT), positively modulated inflammation genes (NF-kB and IL6) in hepatic tissue, and reduced malondialdehyde levels. Our findings highlight the effectiveness of traditional Doenjang in preventing diet-induced hyperlipidemia and protecting against hepatic oxidative damage.

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.

Fungal diseases including anthracnose, stem rot, blight, wilting, and root rot of crops are caused by phytopathogens such as Colletotrichum species, Sclerotinia sclerotiorum, Phytophthora species, and Fusarium oxysporum and F. solani which threaten the production of chili pepper. In this study, to identify biological control agents (BCAs) of phytopathogenic fungi, potentially useful Bacillus species were isolated from the field soils. We screened out five Bacillus strains with antagonistic capacity that are efficiently inhibiting the growth of phytopathogenic fungi. Bacillus species were characterized by the production of extracellular enzymes, siderophores, and indole-3-acetic acid (IAA). Furthermore, the influence of bacterial strains on the plant growth promoting activity and seedling vigor index were assessed using Brassica juncea as a model plant. Inoculation with Bacillus subtilisSRCM 121379 significantly increased the length of B. juncea shoots and roots by 45.6% and 52.0%, respectively. Among the bacterial isolates, Bacillus subtilisSRCM 121379 showed the superior enzyme activities, antagonistic capacity and plant growth promoting effects. Based on the experimental results, Bacillus subtilisSRCM 121379 (GenBank accession no. NR027552) was finally selected as a BCA candidate.

Cheonggukjang is a traditional Korean fermented soybean food with potential health benefits. For this reason, Cheonggukjang is consumed in the form of pills in addition to being used as a food ingredient. There are few clinical studies that have evaluated changes in various health indicators through blood and stool tests before and after consumption of Cheonggukjang. In this study, symptoms and hematological changes were analyzed before and after the intake of traditional Cheonggukjang pills containing high-dose (n = 19) or low-dose (n = 20) beneficial bacteria and commercial Cheonggukjang pills (n = 20). Anti-obesity effects and body composition changes were determined before and after Cheonggukjang consumption. Lastly, the changes in microorganisms and short-chain fatty acids in the stool were compared. No changes in obesity and inflammation-related indicators were observed before and after Cheonggukjang consumption. The Firmicutes/Bacteroidetes ratio, associated with obesity, decreased in all three groups after Cheonggukjang consumption, but no statistical significance was indicated. Cheonggukjang contained various BAs, but they did not adversely affect symptoms and hematological changes in the participants. BAs generated during the manufacturing process of Cheonggukjang did not have any adverse effects in this randomized, double-blind clinical trial. Further research is needed in future concerning the anti-obesity effect or regarding changes in the microbiome and short-chain fatty acids in feces.

Traditionally made doenjang (TMD) produced by the long-term fermentation of soybeans with salt may improve symptoms of estrogen deficiency. We aimed to evaluate the effects of four TMD types, containing low and high amounts of Bacillus species and biogenic amines (HBHA, HBLA, LBHA, and LBLA), on energy, glucose, and lipid metabolism, by altering the gut microbiota in estrogen-deficient ovariectomized (OVX) rats. Their mechanisms were also examined. The OVX rats were divided into the control, cooked soybean (CSB), HBHA, LBHA, HBLA, and LBLA groups. Sham-operated rats were the normal control group. Serum 17β-estradiol concentrations were similar among all OVX groups. Tail skin temperatures, which are indicative of hot flashes, were higher in the control than the HBHA and HBLA groups and were similar to the normal control group. Weight gain and visceral fat mass were lower in the TMD and CSB intake groups but not as low as in the normal control group. Lean body mass showed a trend opposite to that of visceral fat in the respective groups. The hepatic triglyceride content decreased with the TMD intake compared to the control and CSB groups. mRNA expressions of the peroxisome proliferator-activated receptor-γ (PPAR-γ) and carnitine palmitoyltransferase-1 in the TMD and CSB groups were as high as in the normal control group, and the PPAR-γ mRNA expression was more elevated in the HBLA group than in the normal control group. The morphology of the intestines improved in the TMD groups compared to the control, and the HBHA and HBLA groups showed an enhanced improvement compared to the CSB group. The HBHA, HBLA, and LBHA groups increased the α-diversity of the cecal microbiota compared to the control. Akkermenia and Lactobacillus were higher in the HBLA and LBLA groups compared to the control. The expression of the estrogen, forkhead box proteins of the class-O subgroup, and insulin-signaling pathways were lower in the control group, and HBHA and HBLA prevented their decrement. In conclusion, long-term treatment with TMD containing high amounts of Bacillus potentially improves estrogen deficiency symptoms more than unfermented soybeans.

Abstract Increasing evidence indicates that alterations in gut microbiota are associated with mammalian development and physiology. The gut microbiota has been proposed as an essential player in metabolic diseases including brain health. This study aimed to determine the impact of probiotics on degenerative changes in the gut microbiota and cognitive behavior. Assessment of various behavioral and physiological functions was performed using Y-maze tests, wheel running tests, accelerated rotarod tests, balance beam tests, and forced swimming tests (FSTs), using adult mice after 50 weeks of administering living probiotic bacterium Lactobacillus fermentum strain JDFM216 or a vehicle. Immunomodulatory function was investigated using immune organs, immune cells and immune molecules in the mice, and gut microbiota was also evaluated in their feces. Notably, the L. fermentum JDFM216-treated group showed significantly better performance in the behavior tests (P

Abstract Background Allium hookeri is widely consumed as a vegetable and herbal medicine in Asia. A. hookeri has been reported anti-inflammatory, anti-obesity, osteoblastic, anti-oxidant, and anti-diabetic effects in animal studies. We investigated the anti-diabetic effects of A. hookeri aqueous extract (AHE) in the Korean subjects. Methods Prediabetic subjects (100 ≤ fasting plasma glucose (FPG)

Staphylococcus aureus is a significant pathogen that can source a variety of illness worldwide. In this announcement, we report here the complete genome sequence of S. aureus strain JDFM SA01, isolated from a milk filter collected from Korean dairy farm. The final complete genome assembly consists of one circular chromosome (2,748,925 bp) with an overall GC content of 32.9% and one circular plasmid sequence (24,655 bp) with a GC content of 28.7%.

Colorectal cancer (CRC) is the third most common type of cancer and is caused by multiple factors. Chronic inflammation, known to cause inflammatory bowel disease (IBD), is closely associated with CRC. Cheonggukjang (CJ), a traditional Korean fermented soybean, is a functional food with anti-inflammatory effects in the intestines, but its anti-cancer effects have not yet been explored. In this study, we investigated the cancer-protective effects of cheonggukjang in an azoxymethane/DSS (AOM/DSS)-induced colitis-associated colorectal cancer (CAC) mouse model. The CJ alleviated AOM/DSS-induced pathological symptoms such as colonic shortening, increased spleen weight, tumor formation, and histological changes. It also modulated pro-inflammatory and anti-inflammatory cytokine levels via the suppression of NF-κB and inflammatory mediator signaling pathways. Furthermore, the CJ improved intestinal integrity by regulating mucin-associated and tight junction proteins. In addition, it suppressed tumor growth by regulating apoptosis and proliferation. These results highlight the anti-tumor effects of CJ in an AOM/DSS-induced CAC mouse model.

Brown spot and sheath rot of rice are caused by fungal pathogens such as Curvularia lunata, Cochliobolus miyabeanus, and Sarocladium oryzae, and cause losses such as reduced rice yield and quality, which is an enormous problem with serious long-term effects. To search biological control agents of phytopathogenic fungi, five kinds of useful Bacillus-like isolates which are excellent in extracellular enzyme activity and produce siderophore were selected from paddy soil of Sunchang in Korea. The selected isolates were tested for excellent antifungal activity against three of the phytopathogenic fungi that frequently occur in rice, and JSRB 177 strain had the most excellent antifungal activity. Based on the experimental results, JSRB 177 is finally selected as a candidate for biological control and identified to Bacillus subtilis through 16S rRNA sequence analysis. In addition, physiological characteristics of JSRB 177 confirmed by analysis of carbohydrate fermentation patterns and enzyme production ability. Based on the above results, JSRB 177 is expected to be used as a biological control agent for the rice pathogenic fungi. In the future, further studies related to industrialization such as port test and establishment of mass production process are needed.

Kochujang shows anti-obesity effects in cell and animal models. Kochujang is traditionally prepared via slow fermentation or commercially using Aspergillus oryzae. We analyze the anti-obesity effects of two types of Kochujang in overweight and obese adults. The analyses included the following groups: traditional Kochujang containing either a high-dose (HTK; n = 19), or a low-dose of beneficial microbes (LTK; n = 18), and commercial Kochujang (CK; n = 17). Waist circumference decreased significantly in the HTK and CK groups. Total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, and triglyceride levels decreased in the HTK and LTK groups. Visceral fat is significantly reduced in the HTK group. The population of beneficial microorganisms in stool samples increased in all groups. Consumption of Kochujang reduces visceral fat content and improves the lipid profile, which can be enhanced by enrichment with beneficial microbes. These results suggest that Kochujang has the potential for application in obesity prevention.

Menopause increases the osteoporosis risk, to which phytoestrogen intake can be beneficial. This study hypothesized that mulberry vinegar had a preventive effect on osteoporosis by decreasing osteoclastic activity. The hypothesis was tested in ovariectomized (OVX) rats and RANKL-differentiated osteoclast cells. OVX rats were given 0(OVX-CON), 0.5(OVX-MVL), 1(OVX-MVM), and 2(OVX-MVH) fermented mulberry vinegar (MV) mL/kg body weight (BW) daily for 12 weeks. Sham-operated rats had no MV supplementation (Normal-CON). The osteoporosis-related biomarkers were measured, and Micro-CT determined the bone mass of the femur. RANKL-differentiated Raw 264.7 cells were treated with MV (0–100 μg/mL). The cell viability, osteoporosis-related mRNA expression, and protein contents were measured. MV contained Acetobacter pasteurianus (7.31 log CFU/mL), citric acid (106 mg/mL), lactic acid (19.2 mg/mL), acetic acid (15.0 mg/mL), and rutin (0.36 mg/mL). OVX-MVM elevated the serum 17β-estradiol concentration similar to the Normal-CON group, but it did not prevent the decrease in uterine weight. OVX-MVM prevented the increase in osteoclastic-related parameters, including cathepsin K(CtsK), receptor activator of NF-κB ligand (RANKL), and tartrate-resistant acid phosphatase (TRAP) in the circulation. OVX-MVH also lowered C-telopeptide of type Ⅰ collagen as much as the Normal-CON group (p < 0.05). By contrast, OVX-MVH increased the serum osteoprotegerin concentration, an inhibitor of osteoclasts, better than the Normal-CON group (p < 0.05). These changes were integrated to alter the bone mineral density (BMD) in Micro-CT analysis: OVX-MVM and OVX-MVH prevented BMD decrease after OVX as much as the Normal-CON. In RANKL-differentiated osteoclast cells, the MV treatment for 24 and 48 h decreased RANKL-induced differentiation in osteoclast cells dose-dependently up to 100 µg/mL. Its decrease was related to inhibiting the TRAP activity and reducing TRAP-positive multinucleated cells during the five-day administration of RANKL. MV treatments also decreased mRNA expression of osteoclast-related genes (TRAP, Ctsk, OSCAR, and NFATc1). MV suppressed the protein contents of NFATc1 and c-FOS-related osteoclast. In conclusion, MV intake (1 mg/kg bw) protected against BMD loss mainly by inhibiting the osteoclastic activity (RANKL/RANK/TRAP) in OVX rats. MV may develop as a functional food for anti-osteoporosis in menopausal women.

Inflammatory bowel disease (IBD) is a chronic inflammatory disease, and the incidence of IBD is increasing every year owing to changes in dietary structure. Although the exact pathogenesis of IBD is still unclear, recent evidence suggests that gut dysbiosis is closely associated with IBD pathogenesis. Cheonggukjang is a traditional Korean fermented soybean paste produced using traditional and industrial methods, and contains probiotics, which affect the gut microbiota composition. However, the protective effect of Cheonggukjang against IBD is unknown. In this study, we investigated the bacterial community structure of traditional and commercial Cheonggukjang samples, as well as the protective effect of Cheonggukjang on a dextran sulfate sodium (DSS)-induced colitis mouse model. Traditional and commercial Cheonggukjang were found to contain various type of useful probiotics in their bacterial community structure. Cheonggukjang reduced the progression of DSS-induced symptoms, such as body weight loss, colonic shortening, disease activity index, and histological changes. Further, Cheonggukjang improved the intestinal epithelial barrier integrity on DSS-induced colitis mice. In addition, Cheonggukjang suppressed the expression of proinflammatory cytokines and inflammatory mediators through the inactivation of NF-κB and MAPK signaling pathways. These results indicate that Cheonggukjang exerts protective effects against DSS-induced colitis, suggesting its possible application as a functional food for improving inflammatory diseases.

Atopic dermatitis (AD) is a chronic inflammatory skin disease that is associated with intestinal microflora. Since specific probiotics may have better efficacy for AD, we determined the efficacy of Pediococcus acidilactici SRCM102024 (PA) for treating AD in HaCaT cells and NC/Nga mice and explored the mechanism of action. AD-like pathology was induced in HaCaT cells and the dorsal skin of Nc/Nga mice by local exposure to 2,4-dinitrochlorobenzene (DNCB). In AD-lesion induced mice, PA in low-, medium- and high-dosages (5 × 10E6, 5 × 10E7 and 5 × 10E8 CFU/kg bw, respectively) and dexamethasone (3 mg/kg bw, positive-control) were orally administered for 5 weeks. The clinical AD severity, serum immunoglobulin E (IgE) and TNF-α, gene expressions of interleukin (IL)-4, IL-13, and TNF-α and gut microflora were measured. PA treatment (100–300 CFU/mL) dose-dependently increased cell survival in DNCB-induced HACAT cells. PA reduced the relative mRNA expression of PAR-2, TNF-α, IL-4 and IL-13 in the cells. In dorsal skin of Nc/Nga mice applied with DNCB, PA dose-dependently attenuated erythema, hemorrhage, edema, excoriation, dryness and scratching behavior and PA-H improved the clinical symptoms similar to the positive-control. PA-M and PA-H treatment significantly prevented the disturbance of the dorsal skin tissues and decreased the inflammatory cellular infiltrate of mast cells, compared to the control. PA dose-dependently reduced serum IgE and TNF-α concentrations and the mRNA expression of TNF-α, IL-4, and IL-13 in dorsal skin. In gut microflora, relative counts of Lactobacillales, Butyricicoccus and Ruminococcus were decreased in the AD-control compared to the positive-control and the PA-M and PA-H prevented their decrease. However, the positive-control increased serum AST and ALT activities, indicating liver damage as an adverse effect. In conclusion, oral treatment of PA (human equivalent 1 × 10E9-1 × 10E10) relieved the AD symptoms by dose-dependently preventing over-activation of the immune response. Oral PA intake may be a safe and effective alternative therapy for AD.

Abstract Here, we examined the functionality of Lactobacillus fermentum strain JDFM216, a newly isolated probiotic bacterium, using a Caenorhabditis elegans model. We determined bacterial colonization in the intestinal tract of C. elegans by plate counting and transmission electron microscopy and examined the survival of C. elegans using a solid killing assay. In addition, we employed DNA microarray analysis, quantitative real time-polymerase chain reaction, and immunoblotting assays to explore health-promoting pathways induced by probiotic bacteria in C. elegans. Initially, we found that the probiotic bacterium L. fermentum strain JDFM216 was not harmful to the C. elegans host. Conditioning with JDFM216 led to its colonization in the nematode intestine and enhanced resistance in nematodes exposed to food-borne pathogens, including Staphylococcus aureus and Escherichia coli O157:H7. Interestingly, this probiotic strain significantly prolonged the life span of C. elegans. Whole-transcriptome analysis and transgenic worm assays revealed that the health-promoting effects of JDFM216 were mediated by a nuclear hormone receptor (NHR) family and PMK-1 signaling. Taken together, we described a new C. elegans-based system to screen novel probiotic activity and demonstrated that preconditioning with the probiotic L. fermentum strain JDFM216 may positively stimulate the longevity of the C. elegans host via specific pathway.

Traditionally made Kochujang (TMK) is a long-term fermented soybean and rice mixture with red pepper and salts. The ambient bacteria in rice straw and nutrient components of Kochujang influence the bacteria community. We aimed to investigate the bacterial composition and quality of TMK from different provinces of Korea: Chungcheung (CC), Jeolla (JL), Kyungsang (KS), and GeongGee plus Kangwon (GK) provinces, and Jeju island (JJ). Furthermore, Bacillus spp. isolated from TMK were studied to have anti-cerebrovascular disease activity and probiotic properties. Seventy-three TMK samples from different regions were collected to assess the biogenic amine contents, bacteria composition using next-generation methods, and bacterial functions using Picrust2. Bacillus spp. was isolated from the collected TMK, and their antioxidant, fibrinolytic, and angiotensin I conversion enzyme (ACE) inhibitory activities and probiotic properties were examined. KS TMK had lower sodium contents than the other TMK. There were no significant differences in histamine and tyramine contents among the TMK samples in different provinces. The predominant bacteria in TMK was Bacillus spp., but KS included much less Bacillus spp. and higher Enterococcus and Staphylococcus than the other TMK. Gene expression related to lipopolysaccharide biosynthesis was higher in KS TMK than the other TMK in Picrust2. The predominant Bacillus spp. isolated from TMK was B. subtilis and B. velezensis. B. subtilis SRCM117233, SRCM117245, and SRCM117253 had antioxidant activity, whereas B. subtilis had higher fibrinolytic activity than other Bacillus spp. Only B. velezensis SRCM117254, SRCM117311, SRCM117314, and SRCM117318 had over 10% ACE inhibitory activity. In conclusion, KS had less Bacillus related to lower sodium contents than the other TMK. The specific strains of B. subtilis and B. velezensis had antioxidant, fibrinolytic, and ACE inhibitory activity, and they can be used as a starter culture to produce better quality controlled Kochujang with anti-cerebrovascular disease activities.

Since doenjang quality depends on the bacterial composition, which ambient bacteria in the environment and production conditions influence, a complete understanding of the bacteria community in traditionally madetraditionally made doenjang (TMD) from different regions is needed. We aimed to investigate the bacteria composition and quality of TMD in the following areas: Chonbuk (CB), Chonnam (CN), Kyungsang (KS), Kangwon (KW), Chungchung (CC) provinces, and Jeju island (JJ) of Korea. Twenty-nine TMD samples from different regions were used to assess biogenic amine contents, bacteria composition using next-generation methods, and metabolic functions of the bacteria using Picrust2. Bacillus spp. were isolated, and their antioxidant and fibrinolytic activities were determined. Most TMD contained high amounts of beneficial bacteria (Bacillus, Lactobacillus, Pediococcus and Weissella). However, some KS samples contained harmful bacteria (Cronobacter, Proteus and Acinetobacter) and less beneficial B. velezensis bacteria. There was no similarity among the regional groups, and each TMD showed a different bacteria composition. Shannon index, α-diversity index, was lower in TMD from JJ and CB than the other areas, but there was no β-diversity among TMD from the six area groups. Picrust2 analysis revealed that the functional potential for arachidonic acid metabolism was lowest in JJ and CN, that for supporting insulin action was highest in KS and JJ, and that for carbohydrate digestion and absorption was lowest in CB and JJ among all groups (p < 0.05) according to the Kyoto Encyclopedia of Genes and Genomes Orthology. Histamine contents were lower in CN and CC, and tyramine contents did not differ significantly. B. velezensis, B. subtilis, B. licheniformis, B. siamensis, and B. amyloliquefaciens were isolated from TMD. None of the isolated Bacillus spp. contained the B. cereus gene. B. subtilis from CN had the highest fibrinolytic activity, and B. velezensis from CB had the highest antioxidant activity. In conclusion, TMD mainly contained various Bacillus spp., and the predominant one was B. velezensis, which had antioxidant and fibrinolytic activity regardless of the regional origin.

Fermented soybean paste is an indigenous food for use in cooking in East and Southeast Asia. Korea developed and used its traditional fermented foods two thousand years ago. Chungkookjang has unique characteristics such as short-term fermentation (24–72 h) without salt, and fermentation mostly with Bacilli. Traditionally fermented chungkookjang (TFC) is whole cooked soybeans that are fermented predominantly by Bacillus species. However, Bacillus species are different in the environment according to the regions and seasons due to the specific bacteria. Bacillus species differently contribute to the bioactive components of chungkookjang, resulting in different functionalities. In this review, we evaluated the production process of poly-γ-glutamic acid (γ-PGA)-rich chungkookjang fermented with specific Bacillus species and their effects on memory function through the modulation of brain insulin resistance, neuroinflammation, and the gut–microbiome–brain axis. Bacillus species were isolated from the TFC made in Sunchang, Korea, and they included Bacillus (B.) subtilis, B. licheniformis, and B. amyloliquefaciens. Chungkookjang contains isoflavone aglycans, peptides, dietary fiber, γ-PGA, and Bacillus species. Chungkookjangs made with B. licheniformis and B. amyloliquefaciens have higher contents of γ-PGA, and they are more effective for improving glucose metabolism and memory function. Chungkookjang has better efficacy for reducing inflammation and oxidative stress than other fermented soy foods. Insulin sensitivity is improved, not only in systemic organs such as the liver and adipose tissues, but also in the brain. Chungkookjang intake prevents and alleviates memory impairment induced by Alzheimer’s disease and cerebral ischemia. This review suggests that the intake of chungkookjang (20–30 g/day) rich in γ-PGA acts as a synbiotic in humans and promotes memory function by suppressing brain insulin resistance and neuroinflammation and by modulating the gut–microbiome–brain axis.

Many fermented foods are known to have beneficial effects on human and animal health, offering anti-aging and immunomodulatory benefits to host. Microorganisms contained in the fermented foods are known to provide metabolic products possibly improving host health. However, despite of a number of studies on the functional effects of the fermented foods, isolation and identification of the effective bacterial strains in the products are still in progress. The objective of this study was to isolate candidate functional strains in various Korean traditional fermented foods, including ganjang, gochujang, doenjang, and jeotgal, and evaluate their beneficial effects on the host, using Caenorhabditis elegans as a surrogate animal model. Among the 30 strains isolated, five Bacillus spp. were selected that increased the expression level of pmk-1, an innate immune gene of C. elegans. These strains extended the nematode lifespan and showed intestinal adhesion to the host. Based on the bioinformatic analyses of whole genome sequences and pangenomes, the five strains of Bacillus subtilis were genetically different from the strains found in East Asian countries and previously reported strains isolated from Korean fermented foods. Our findings suggest that the newly isolated B. subtilis strains can be a good candidate for probiotic with further in-depth investigation on health benefits and safety.

We evaluated whether long-term consumption of black carrot (BC), black carrot fermented with Aspergillus oryzae (FBAO) and Lactobacillus plantarum (FBLP) extracts improved cognitive dysfunction and glucose homeostasis in type 2 diabetic rats with dementia. Male diabetic rats received hippocampal CA1 infusions of 3.6 nmol amyloid-β (25–35; AD) or amyloid-β (35–25, non-plaque forming; Normal) per day, for two weeks. AD rats received either 2% lyophilized BC, FBAO, and FBLP or dextrin (AD-CON) for 8 weeks. FBAO and FBLP, rich in aglycated anthocyanins, suppressed amyloid-β deposition in the hippocampus and potentiated insulin signalling, compared to the BC and the control. FBAO and FBLP had better cognitive function and less visceral fat mass than BC. FBLP most effectively improved both whole body and hepatic insulin resistance and first phase insulin secretion and insulin sensitivity in the hyperglycaemic state. Thus, FBLP and FBAO (1 g/kg bw/day; 0.5–1 mg cyanidin and malvidin aglycone/kg bw/day) may have the potent efficacy for improving cognitive function by preventing hippocampal insulin resistance.

Background: Studies in animals have demonstrated the antiallergenic properties of Chongkukjang (CKJ), a traditional Korean food made by fermentation of soybean with Bacillus subtilis. CKJ might therefore be used as an ingredient in a functional food designed to suppress allergies. The purpose of this study was to investigate the effect of CKJ on histamine-induced skin wheal response in healthy participants. Methods: A randomized, double-blind, placebo-controlled trial was conducted. Sixty participants (48 women and 12 men) were randomly assigned to one of two groups: One group received 35 g CKJ daily for 12 weeks, and the other received a placebo at the same dosing frequency. A skin prick test with histamine (10 mg/mL) was conducted on the ventral forearm 10 cm from the elbow, and assessed 15 minutes later. Outcomes included measurement of efficacy [skin wheal response, immunoglobulin E (IgE), histamine, interferon-gamma, interleukin-4, eosinophil, and eosinophil cationic protein (ECP)], and safety (adverse events, laboratory test results, electrocardiogram, anthropometric values, and vital signs). Results: Fifty-five participants (28 in the CKJ group and 27 in the placebo group) completed the study. After 12 weeks of supplementation, participants in the CKJ group showed a significant reduction in histamine-induced skin wheal areas compared with placebo group (p