Riboflavin-overproducing lactobacilli for the enrichment of fermented soymilk: insights into improved nutritional and functional attributes

Characterization of a symbiotic beverage based on water-soluble soybean extract fermented by Lactiplantibacillus plantarum ATCC 8014

The health benefits of functional foods are associated with consumer interest and have supported the growth of the market for these types of foods, with emphasis on the development of new formulations based on plant extracts. Therefore, the present study aimed to characterize a symbiotic preparation based on water-soluble soy extract, supplemented with inulin and xylitol and fermented by Lactiplantibacillus plantarum ATCC 8014. Regarding nutritional issues, the symbiotic formulation can be considered a source of fiber (2 g/100 mL) and proteins (2.6 g/100 mL), and it also has a low-fat content and low caloric value. This formulation, in terms of microbiological aspects, remained adequate to legal standards after storage for 60 days under refrigeration and also presented an adequate quantity of the aforementioned probiotic strain, corresponding to 9.11 Log CFU.mL-1. These viable L. plantarum cells proved to be resistant to simulated human gastrointestinal tract conditions, reaching the intestine at high cell concentrations of 7.95 Log CFU.mL-1 after 60 days of refrigeration. Regarding sensory evaluation, the formulation showed good acceptance, presenting an average overall impression score of 6.98, 5.98, and 5.16, for control samples stored for 30 and 60 days under refrigeration, respectively. These results demonstrate that water-soluble soy extract is a suitable matrix for fermentation involving L. plantarum ATCC 8014, supporting and providing data on the first steps towards the development of a symbiotic functional food, targeting consumers who have restrictions regarding the consumption of products of animal origin, diabetics, and individuals under calorie restrictions.

Potential neuroprotective benefits of plant-based fermented foods in Alzheimer's disease: an update on preclinical evidence

Alzheimer's disease (AD) currently lacks effective treatments, making its prevention a critical focus. While accumulating evidence supports that plant-based fermented foods may contribute to AD prevention, the neuroprotective effect of plant-based fermented foods on AD has not been comprehensively reviewed. In this study, we conducted a systematic review of preclinical studies on the efficacy of plant-based fermented foods in AD. The literature search was based on databases including PubMed, Embase, Web of Science, and Scopus. The PICO approach was employed for report inclusion, and each report was assessed for risk of bias using the SYRCLE's RoB tool. From the analysis of 25 retrieved reports, we extracted essential details, including bibliographic information, animal models and characteristics, sources of plant-based fermented foods, dosages, administration routes, durations, and outcome measures. Our findings indicate that plant-based fermented foods may positively impact acute and long-term cognitive function, as well as beta-amyloid-mediated neurodegeneration. This review sheds light on the potential neuroprotective benefits of plant-based fermented foods for various AD-related aspects, including oxidative stress, synaptotoxicity, neuroinflammation, tau hyperphosphorylation, dysfunctional amyloidogenic pathways, and cognitive deficits, as observed in rodent models of AD. However, the small number of studies obtained from our literature search and the finding that many of them were of moderate methodological quality suggest the need for further investigation to substantiate the beneficial potential of this class of functional food for the management of AD.

Significance of Soy-Based Fermented Food and Their Bioactive Compounds Against Obesity, Diabetes, and Cardiovascular Diseases

Soybean-based fermented foods are commonly consumed worldwide, especially in Asia. These fermented soy-products are prepared using various strains of Bacillus, Streptococcus, Lactobacillus, and Aspergillus. The microbial action during fermentation produces and increases the availability of various molecules of biological significance, such as isoflavones, bioactive peptides, and dietary fiber. These dietary bio active compounds are also found to be effective against the metabolic disorders such as obesity, diabetes, and cardiovascular diseases (CVD). In parallel, soy isoflavones such as genistein, genistin, and daidzin can also contribute to the anti-obesity and anti-diabetic mechanisms, by decreasing insulin resistance and oxidative stress. The said activities are known to lower the risk of CVD, by decreasing the fat accumulation and hyperlipidemia in the body. In addition, along with soy-isoflavones fermented soy foods such as Kinema, Tempeh, Douchi, Cheonggukjang/Chungkukjang, and Natto are also rich in dietary fiber (prebiotic) and known to be anti-dyslipidemia, improve lipolysis, and lowers lipid peroxidation, which further decreases the risk of CVD. Further, the fibrinolytic activity of nattokinase present in Natto soup also paves the foundation for the possible cardioprotective role of fermented soy products. Considering the immense beneficial effects of different fermented soy products, the present review contextualizes their significance with respect to their anti-obesity, anti-diabetic and cardioprotective roles.

Biochemical Composition, Antioxidant Capacity and Protective Effects of Three Fermented Plants Beverages on Hepatotoxicity and Nephrotoxicity Induced by Carbon Tetrachloride in Mice

Functional beverages play an essential role in our modern life and contribute to nutritional well-being. Current efforts to understand and develop functional beverages to promote health and wellness have been enhanced. The present study aimed to investigate the production of three fermented plants beverages (FPBs) from aromatic and medicinal plants and to evaluate the fermented product in terms of physio-biochemical composition, the aromatic compounds, antioxidant activity, and in vivo protective effects on hepatotoxicity and nephrotoxicity induced by carbon tetrachloride (CCl4). The results showed that the fermented beverage NurtBio B had the highest levels of polyphenols, flavonoids, and tannins; 242.3 ± 12.4 µg GAE/mL, 106.4 ± 7.3 µg RE/mL and 94.2 ± 5.1 µg CE/mL, respectively. The aromatic profiles of the fermented beverages showed thirty-one interesting volatile compounds detected by GC-MS headspace analyses such as benzaldehyde, Eucalyptol, Fenchone, 3-Octadecyne, Estragole, and Benzene propanoic acid 1-methylethyl ester. In addition, the fermentation process was significantly improved, indicating its great potential as a functional food with both strong antioxidant activity and good flavor. In vivo administration of CCl4 in mice induced hepatotoxicity and nephrotoxicity by a significant rise in the levels of serum liver and kidney biomarkers. The protective effects of the FPBs showed that they significantly restored the majority of these biological parameters to normal levels, along with increase antioxidant enzyme activities, as well as an improvement of histopathological changes, suggesting their protective effects.

Nutritional and potential health benefits of fermented food proteins

BACKGROUND

Protein fermentation continues to gain popularity as a result of several factors, including the cost-effectiveness of the process and the positive correlation of fermented protein consumption, with a reduced risk of developing diet-related diseases such as diabetes and cardiovascular disorders, as well as their enhanced nutritional and techno-functional properties. Nonetheless, the nutritional and health benefits of food protein fermentation such as enhanced nutrient bioavailability, reduced antinutritional factors (ANFs) and enriched bioactive peptides (BAPs) are often overlooked. The present study reviewed recent work on the influence of protein fermentation on nutrition and health. In total, 322 eligible studies were identified on the Scopus and Google Scholar databases out of which 69 studies were evaluated based on our inclusion criteria.

RESULTS

Fermented protein ingredients and products show reduced ANF content, enhanced digestibility and bioavailability, and increased antioxidant and other biological activities, such as probiotic, prebiotic, angiotensin-converting enzyme inhibitory and antihypertensive properties. In addition, co-products in protein fermentation such as BAPs possess and could contribute additional sensory and flavor properties, degrade toxins, and reduce allergens in foods.

CONCLUSION

Thus, fermentation is not only a method for food preservation, but also serves as a means for producing functional food products for consumer health promotion and nutrition enrichment. © 2023 Society of Chemical Industry.

Aroma characteristics of flaxseed milk via GC-MS-O and odor activity value calculation: Imparts and selection of different flaxseed varieties

Currently, the effect of varieties on the flavor and stability of flaxseed milk remains unknown. Therefore, this study was conducted to investigate the effects of different varieties on the stability, sensory, and aromas of flaxseed milk. 51 volatile compounds were identified in flaxseed milk using Stir Bar Sorptive Extraction-Gas Chromatography-Olfactometry-Mass Spectrometry (SBSE-GC-O-MS). Among them, 1-octen-3-ol, 2-methoxy-4-vinylphenol, and 2,3,5-trimethylpyrazine contributed higher relative odor active values (ROAV), resulted in the fruity, roasted, sweet, and cucumber in flaxseed milk. Isovaleraldehyde (green notes) was not detected in XHZM. However, other compounds such as 1-nonanol (floral), γ-nonanolactone and γ-octanoic lactone (coconut milk) had higher concentrations, causing a better sensory evaluation. Additionally, its stability was relatively good. The orthogonal partial least-squares regression (OPLS) model and VIP values showed that eight compounds were responsible for the sensory differences from different varietals. The study provided references to selection and understanding flavor composition basis of flaxseed milk.

Biotechnological Potential and Safety Evaluation of Dextran- and Riboflavin-Producing Weisella cibaria Strains for Gluten-Free Baking

Gluten consumption causes several immunological and non-immunological intolerances in susceptible individuals. In this study, the dextran-producing Weissella cibaria BAL3C-5 and its derivative, the riboflavin-overproducing strain BAL3C-5 C120T, together with a commercial bakery yeast, were used to ferment gluten-free (GF)-doughs obtained from corn and rice flours at two different concentrations and supplemented with either quinoa, buckwheat, or chickpea to obtain laboratory-scale GF bread. The levels of dextran, riboflavin, and total flavins were determined in the fermented and breads. Both strains grew in fermented doughs and contributed dextran, especially to those made with corn plus quinoa (~1 g/100 g). The highest riboflavin (350-150 µg/100 g) and total flavin (2.3-1.75 mg/100 g) levels were observed with BAL3C-5 C120T, though some differences were detected between the various doughs or breads, suggesting an impact of the type of flour used. The safety assessment confirmed the lack of pathogenic factors in the bacterial strains, such as hemolysin and gelatinase activity, as well as the genetic determinants for biogenic amine production. Some intrinsic resistance to antibiotics, including vancomycin and kanamycin, was found. These results indicated the microbiological safety of both W. cibaria strains and indicated their potential application in baking to produce GF bread.

Hermetia illucens Fermented with Lactobacillus plantarum KCCM12757P Alleviates Dextran Sodium Sulfate-Induced Colitis in Mice

Inflammatory bowel disease (IBD) can severely affect humans and animals and is difficult to treat. Black soldier fly (Hermetia illucens; Hi) larvae (BSFL) are a sustainable source of protein. However, no studies exist on the antioxidant and anti-inflammatory functions of BSFL or fermented BSFL with respect to IBD. In this study, riboflavin-producing Lactobacillus plantarum KCCM12757P was isolated from a fish farm tank, and in conjunction with hot water-extracted Hi (HeHi) (termed HeHi_Lp), was used to determine optimal fermentation conditions to increase vitamin B2 concentration. This in vivo study investigated the therapeutic effects and mechanistic role of HeHi_Lp in chronic colitis-induced murine models. Histological changes, inflammatory cytokine levels, and intestinal barrier function were explored. Gut microbial communities and gene expression in the nuclear factor (NF)-κB signaling pathway were also studied. HeHi_Lp remarkably reduced the disease activity index, inflammatory cytokine (inducible nitric oxide synthase, cyclooxygenase 2, tumor necrosis factor α, interleukin (IL-6 and IL-1β) levels, and increased body weight and colon length. HeHi_Lp administration significantly raised zonula occludens 1, occludin and claudin 1 and improved the composition of the gut microbiota and beneficial intestinal bacteria. These results suggest that HeHi_Lp can be used as a dietary supplement in pet food to alleviate colitis.

Phenotypic and genomic analyses of bacteriocin-producing probiotic Enterococcus faecium EFEL8600 isolated from Korean soy-meju

Enterococcus faecium is a prevalent species found in fermented soybean products, known for its contributions to flavor development and inhibition of pathogenic microorganisms during fermentation. This study aims to provide comprehensive phenotypic and genomic evidence supporting the probiotic characteristics of E. faecium EFEL8600, a bacteriocin-producing strain isolated from Korean soy-meju. Phenotypic analysis revealed that EFEL8600 produced a peptide with inhibitory activity against Listeria monocytogenes, estimated to be 4.6 kDa, corresponding to the size of enterocins P or Q. Furthermore, EFEL8600 exhibited probiotic traits, such as resilience in gastrointestinal conditions, antioxidant and anti-inflammatory activities, and protection of the intestinal barrier. Safety assessments demonstrated no hemolytic and bile salt deconjugation activities. Genomic analysis revealed the presence of several genes associated with probiotic characteristics and bacteriocin production, while few deleterious genes with a low likelihood of expression or transferring were detected. Overall, this study highlights E. faecium EFEL8600 as a potent anti-listeria probiotic strain suitable for use as a starter culture in soymilk fermentation, providing potential health benefits to consumers.

Development of a Fermented Beverage with Chlorella vulgaris Powder on Soybean-Based Fermented Beverage

The area of functional beverages made from plant-based or non-dairy milk is one of the fastest-growing sectors in the world. The microalgae Chlorella vulgaris is a source of functional ingredients, with a large spectrum of healthy compounds, such as canthaxanthins, astaxanthins, peptides, and oleic acid. The study aimed to investigate the suitability of C. vulgaris biomass as a substrate for Lactobacillus fermentum and Lactobacillus rhamnosus development and fermentation in vegetal soy beverages and to evaluate the fermented product in terms of bacterial viability, antioxidant capacity, and in vitro bio-accessibility. During fermentation, a bacterial concentration of 8.74 log10 CFU/mL was found in the soy beverage with C. vulgaris and L. rhamnosus, and 8.71 log10 CFU/mL in beverage with C. vulgaris and L. fermentum. Polyphenol content and dietary antioxidant capacity significantly improved after fermentation soy drinks. On the other hand, through the digestibility of the beverages, the bacterial viability significantly decreased. To comprehend the components responsible for the efficient delivery of bacteria across the gastrointestinal tract, further investigation is required on probiotic encapsulation methods.

Unveiling of dietary and gut-microbiota derived B vitamins: Metabolism patterns and their synergistic functions in gut-brain homeostasis

Nutrition-gut cross-talk holds a vital position in sustaining intestinal function, and micronutrient metabolism has emerged as the foremost metabolic pathway to preserve gut homeostasis. Among micronutrients, B vitamins have evolved prior to DNA/RNA and are known for their vital roles for major evolutionary transitions in extant organisms. Despite their universal requirement and critical role, not all the three domains of life are endowed with a natural ability for de novo B vitamins synthesis. The human gut microbiome constitutes prototrophs and auxotroph which are entirely dependent on dietary intake and gut microbial production of B vitamins. The syntrophic metabolism involving cross-feeding of B vitamins and community-wide exchange between commensal bacteria elicit important changes in the diversity and composition of the human gut microbiome. Hereto, we discuss the B-vitamins sharing among prototrophic and auxotrophic gut bacteria, their absorption in small intestine and transport in distal gut, functional role in relation to the gut homeostasis and symptoms linked to their deficiency. We also briefly explore their potential involvement as psychobiotics in brain energetic metabolism (kynurenines/tryptophan pathway) for neurological functions and highlight their deficiency related malfunctioning.

Harmful compounds of soy milk: characterization and reduction strategies

Soymilk is a plant based product which is a rich source of nutrients. However, various harmful compounds including allergens, anti-nutritional factors, and biogenic amines (BAs) exist in soybeans that may be transferred into soymilk. These compounds cause difficulties for consumers from mild to severe symptoms. Soymilk production is considered as a critical step in quantity of harmful compounds in final product. Common steps in soy milk manufacturing include soaking, grinding, and heating process. Allergens contents could be decreased by heating alone or in combination with structural modifiers and fermentation. BAs could be reduced by optimizing fermentation process and using suitable strains, especially BAs degradable types. Soaking, grinding and heating of soybeans in water are considered as effective methods for inactivation of antinutritional factors. Isoflavones are soy phytochemicals, which potentially leads to breast cancer in some women, can be converted to less bioavailable forms during processing. Other treatments such as high hydrostatic pressure and irradiation are also effective in harmful compounds reduction. Combination of the processes is more effective in harmful compounds removal. Considering the increasing trends in soymilk consumption, this review is focused on introduction of harmful compounds in soymilk and investigating the effects of processing condition on their concentration.

Functionalization of soy residue (okara) by enzymatic hydrolysis and LAB fermentation for B2 bio-enrichment and improved in vitro digestion

The utilization of major edible soy-waste (okara) remains a challenge due to its poor digestion, nutritional imbalance (lack of B-vitamins), and undesirable off-flavors. Herein, fresh okara was enzymatically hydrolyzed and then fermented using the B2-overproducing Lactiplantibacillus plantarum UFG169 strain. SEM micrographs showed the microporous and honeycombed structures on the surface of okara. The off-flavors were reduced, and the essential amino acids content was significantly increased in fermented okara. The higher β-glucosidase activity, increased aglycone isoflavones, and in situ riboflavin (B2) were associated with the enhanced antioxidant potential of the fermented okara. The in vitro digestion of okara resulted in reduced particle size, higher protein digestibility, improved aggregation, lower protein molecular chains, and increased polyphenols. Overall, our study indicated the improved nutrition and digestibility of B2 bio-enriched okara.

A statistical optimization by response surface methodology for the enhanced production of riboflavin from Lactobacillus plantarum–HDS27: A strain isolated from bovine milk

In the present study, Lactobacillus plantarum-HDS27 strain isolated from bovine milk was used for the enhanced production of riboflavin. Production medium was optimized by one factor at a time with different parameters. Statistical optimization by Response surface methodology (RSM), central composite design was used to optimize variables such as pH, temperature, glucose, and yeast extract. The present study reveals the maximum riboflavin production by one factor at a time was obtained under the culture conditions; glucose, yeast extract, pH 6, the temperature at 40°C, and 3% of inoculum size. In RSM, analysis of variance for the responses was calculated. Among the tested variables, pH, yeast extract, and temperature showed significant impact on riboflavin production. Maximum amount of yeast extract in production medium resulted in increased riboflavin production. The riboflavin production after 24 h with the optimal condition was found to be 12.33 mg/L. It was found proximate to the expected value (12.29 mg/L) achieved by the RSM model. The yield of riboflavin was increased to 3.66-fold after 24 h with the optimized parameters. The current research, emphasizes that the Lactobacillus plantarum–HDS27 could be an excellent strain for the large-scale industrial production of riboflavin.

Spontaneous Riboflavin-Overproducing Limosilactobacillus reuteri for Biofortification of Fermented Foods

Riboflavin-producing lactic acid bacteria represent a promising and cost-effective strategy for food biofortification, but production levels are typically insufficient to support daily human requirements. In this study, we describe the novel human isolate Limosilactobacillus reuteri AMBV339 as a strong food biofortification candidate. This strain shows a high natural riboflavin (vitamin B2) overproduction of 18.36 μg/ml, biomass production up to 6 × 10¹⁰ colony-forming units/ml (in the typical range of model lactobacilli), and pH-lowering capacities to a pH as low as 4.03 in common plant-based (coconut, soy, and oat) and cow milk beverages when cultured up to 72 h at 37°C. These properties were especially pronounced in coconut beverage and butter milk fermentations, and were sustained in co-culture with the model starter Streptococcus thermophilus. Furthermore, L. reuteri AMBV339 grown in laboratory media or in a coconut beverage survived in gastric juice and in a simulated gastrointestinal dialysis model with colon phase (GIDM-colon system) inoculated with fecal material from a healthy volunteer. Passive transport of L. reuteri AMBV339-produced riboflavin occurred in the small intestinal and colon stage of the GIDM system, and active transport via intestinal epithelial Caco-2 monolayers was also demonstrated. L. reuteri AMBV339 did not cause fecal microbiome perturbations in the GIDM-colon system and inhibited enteric bacterial pathogens in vitro. Taken together, our data suggests that L. reuteri AMBV339 represents a promising candidate to provide riboflavin fortification of plant-based and dairy foods, and has a high application potential in the human gastrointestinal tract.

Riboflavin Bioenriched Soymilk Alleviates Oxidative Stress Mediated Liver Injury, Intestinal Inflammation, and Gut Microbiota Modification in B2 Depletion-Repletion Mice

Epidemiological evidence emphasizes that ariboflavinosis can lead to oxidative stress, which in turn may mediate the initiation and progression of liver injury and intestinal inflammation. Although vitamin B₂ has gained worldwide attention for its antioxidant defense, the relationship between B₂ status, oxidative stress, inflammatory response, and intestinal homeostasis remains indistinct. Herein, we developed a B₂ depletion-repletion BALB/c mice model to investigate the ameliorative effects of B₂ bioenriched fermented soymilk (B₂FS) on ariboflavinosis, accompanied by oxidative stress, inflammation, and gut microbiota modulation in response to B₂ deficiency. In vivo results revealed that the phenotypic ariboflavinosis symptoms, growth rate, EGRAC status, and hepatic function reverted to normal after B₂FS supplementation. B₂FS significantly elevated CAT, SOD, T-AOC, and compromised MDA levels in the serum, simultaneously up-regulated Nrf2, CAT, and SOD2, and down-regulated Keap1 gene in the colon. The histopathological characteristics revealed significant alleviation in the liver and intestinal inflammation, confirmed by the downregulation of inflammatory (IL-1β and IL-6) and nuclear transcription (NF-κB) factors after B₂FS supplementation. B₂FS also increased the abundance and diversity of gut microbiota, increased the relative abundance of Prevotella and Absiella, as well as decreased Proteobacteria, Fusobacteria, Synergistetes, and Cyanobacteria in strong conjunction with antioxidant, anti-inflammatory properties, and gut homeostasis along with the remarkable increase in cecal SCFAs content. We hereby reveal that B₂FS can effectively alleviate deleterious ariboflavinosis associated with oxidative stress mediated liver injury, chronic intestinal inflammation, and gut dysbiosis in the B₂ depletion-repletion mice model via activation of the Nrf2 signaling pathway.

Functional bacterial cultures for dairy applications: towards improving safety, quality, nutritional and health benefit aspects

Traditionally, fermentation was used to preserve the shelf life of food. Currently, in addition to favouring food preservation, well standardized and controlled industrial processes are also aimed at improving the functional characteristics of the final product. In this regard, starter cultures have become an essential cornerstone of food production. The selection of robust microorganisms, well adapted to the food environment, has been followed by the development of microbial consortia that provide some functional characteristics, beyond their acidifying capacity, achieving safer, high‐quality foods with improved nutritional and health‐promoting properties. In addition to starters, adjunct cultures and probiotics, which normally do not have a relevant role in fermentation, are added to the food in order to provide some beneficial characteristics. This review focuses on highlighting the functional characteristics of food starters, as well as adjunct and probiotic cultures (mainly lactic acid bacteria and bifidobacteria), with a specific focus on the synthesis of metabolites for preservation and safety aspects (e.g. bacteriocins), organoleptic properties (e.g. exopolysaccharides), nutritional (e.g. vitamins) and health improvement (e.g. neuroactive molecules). Literature reporting the application of these functional cultures in the manufacture of foods, mainly those related to dairy production, such as cheeses and fermented milks, has also been updated.

Functional relevance and health benefits of soymilk fermented by lactic acid bacteria

The growing interest of consumers towards nutritionally enriched, and health promoting foods, provoke interest in the eventual development of fermented functional foods. Soymilk is a growing trend that can serve as a low-cost non-dairy alternative with improved functional and nutritional properties. Soymilk acts as a good nutrition media for the growth and proliferation of the micro-organism as well as for their bioactivities. The bioactive compounds produced by fermentation of soymilk with lactic acid bacteria (LAB) exhibit enhanced nutritional values, and several improved health benefits including antihypertensive, antioxidant, antidiabetic, anticancer and hypocholesterolaemic effects. The fermented soymilk is acquiring a significant position in the functional food industry due to its increased techno-functional qualities as well as ensuring the survivability of probiotic bacteria producing diverse metabolites. This review covers the important benefits conferred by the consumption of soymilk fermented by LAB producing bioactive compounds. It provides a holistic approach to obtain existing knowledge on the biofunctional attributes of fermented soymilk, with a focus on the functionality of soymilk fermented by LAB.

A single change in the aptamer of the Lactiplantibacillus plantarum rib operon riboswitch severely impairs its regulatory activity and leads to a vitamin B2 - overproducing phenotype

Manufacturing of probiotics and functional foods using lactic acid bacteria (LAB) that overproduce vitamin B₂ has gained growing interest due to ariboflavinosis problems affecting populations of both developing and affluent countries. Two isogenic Lactiplantibacillus plantarum strains, namely a riboflavin‐producing parental strain (UFG9) and a roseoflavin‐resistant strain (B2) that carries a mutation in the FMN‐aptamer of the potential rib operon riboswitch, were analysed for production and intra‐ and extracellular accumulation of flavins, as well as for regulation of the rib operon expression. Strain B2 accumulated in the medium one of the highest levels of riboflavin+FMN ever reported for LAB, exceeding by ~ 25 times those accumulated by UFG9. Inside the cells, concentration of FAD was similar in both strains, while that of riboflavin+FMN was ~ 8‐fold higher in B2. Mutation B2 could decrease the stability of the aptamer’s regulatory P1 helix even in the presence of the effector, thus promoting the antiterminator structure of the riboswitch ON state. Although the B2‐mutant riboswitch showed an impaired regulatory activity, it retained partial functionality being still sensitive to the effector. The extraordinary capacity of strain B2 to produce riboflavin, together with its metabolic versatility and probiotic properties, can be exploited for manufacturing multifunctional foods.

Probiotic Potential of a Novel Vitamin B2-Overproducing Lactobacillus plantarum Strain, HY7715, Isolated from Kimchi

Vitamin B2, also known as riboflavin, is essential for maintaining human health. The purpose of this study was to isolate novel lactic acid bacteria that overproduce vitamin B2 and to validate their potential as probiotics. In this study, Lactobacillus plantarum HY7715 (HY7715) was selected among lactic acid bacteria isolated from Kimchi. HY7715 showed a very high riboflavin-producing ability compared to the control strain due to the high expression of ribA, ribB, ribC, ribH, and ribG genes. HY7715 produced 34.5 ± 2.41 mg/L of riboflavin for 24 h without consuming riboflavin in the medium under optimal growth conditions. It was able to produce riboflavin in an in vitro model of the intestinal environment. In addition, when riboflavin deficiency was induced in mice through nutritional restriction, higher levels of riboflavin were detected in plasma and urine in the HY7715 administration group than in the control group. HY7715 showed high survival rate in simulated gastrointestinal conditions and had antibiotic resistance below the cutoff MIC value suggested by the European Food Safety Authority; moreover, it did not cause hemolysis. In conclusion, HY7715 could be considered a beneficial probiotic strain for human and animal applications, suggesting that it could be a new alternative to address riboflavin deficiency.

Effects of okara and vitamin B2 bioenrichment on the functional properties and in vitro digestion of fermented soy milk

Due to highly nutritious and well-known prebiotic nature, okara (soy by-product) can improve the physiological benefits of probiotic consumption by enhancing the physicochemical stability and bioavailability of bacteria and metabolites, partially in food matrices and then in gastrointestinal tract. Initially, vitamin B₂ producing probiotic Lactobacillus plantarum UFG10 was immobilized with 4% okara for soy milk fermentation. SEM micrographs showed firm adherence of UFG10 to okara surface depicting efficient immobilization. Soy milk fermented with okara immobilized UFG10 showed enhanced β-glucosidase activity, stimulating the biotransformation of isoflavones from glucosides (daidzin, from 27.78 to 9.84 μg/mL; genistin, from 32.58 to 8.33 μg/mL) to aglycones (daidzein, from 0.19 to 30.84 μg/mL; genistein, from 1.42 to 33.10 μg/mL) and higher B₂ production (1.53 μg/mL, 12 h) confirmed by HPLC. Okara addition and B₂ enrichment could yield relatively higher antioxidant strength than control soy milk. PLSR correlation revealed the effects of okara and B₂ on the functional properties of soy milk. After okara immobilization, soy milk showed higher soy protein digestibility after in vitro digestion for 225 min, higher aggregation, and lower protein molecular chains, qualitatively confirmed with Atomic force microscope. Okara immobilized bacterial cells exhibited relatively greater resistance up to 55.1% (p < 0.05) in simulated GIT, indicating okara as an ideal substrate for an efficient immobilization which ultimately improved the fate of soy B₂ and protein bioaccessibility and functional products such as isoflavones for micro structural design of soy milk with improved nutrition and digestibility.

Fermented Soy Products: Beneficial Potential in Neurodegenerative Diseases

Fermented soybean products, such as cheonggukjang (Japanese natto), doenjang (soy paste), ganjang (soy sauce), and douchi, are widely consumed in East Asian countries and are major sources of bioactive compounds. The fermentation of cooked soybean with bacteria (Bacillus spp.) and fungi (Aspergillus spp. and Rhizopus spp.) produces a variety of novel compounds, most of which possess health benefits. This review is focused on the preventive and ameliorative potential of fermented soy foods and their components to manage neurodegenerative diseases, including Alzheimer's and Parkinson's diseases.

Recent update on lactic acid bacteria producing riboflavin and folates: application for food fortification and treatment of intestinal inflammation

Lactic acid bacteria (LAB), widely used as starter cultures for the fermentation of a large variety of food, can improve the safety, shelf life, nutritional value and overall quality of the fermented products. In this regard, the selection of strains delivering health-promoting compounds is now the main objective of many researchers. Although most LAB are auxotrophic for several vitamins, it is known that certain strains have the capability to synthesize B-group vitamins. This is an important property since humans cannot synthesize most vitamins, and these could be obtained by consuming LAB fermented foods. This review discusses the use of LAB as an alternative to fortification by the chemical synthesis to increase riboflavin and folate concentrations in food. Moreover, it provides an overview of the recent applications of vitamin-producing LAB with anti-inflammatory/antioxidant activities against gastrointestinal tract inflammation. This review shows the potential uses of riboflavin and folates producing LAB for the biofortification of food, as therapeutics against intestinal pathologies and to complement anti-inflammatory/anti-neoplastic treatments.