Health benefits of fermented foods: microbiota and beyond

Consumption of the cell-free or heat-treated fractions of a pitched kefir confers some but not all positive impacts of the corresponding whole kefir

Introduction

Kefir consumption can have many metabolic health benefits, including, in the case of specific kefirs, improvements in plasma and liver lipid profiles. Our group has previously shown that these health benefits are dependent on the microbial composition of the kefir fermentation, and that a pitched kefir (PK1) containing specific traditional microbes can recapitulate the health benefits of a traditional kefir. In this study we investigated how different preparations of kefir impact cholesterol and lipid metabolism and circulating markers of cardiovascular disease risk and determine if freeze-drying impacts health benefits relative to past studies.

Materials and methods

Eight-week-old male and female C57Bl/6 mice were fed a high fat diet (40% kcal from fat) supplemented with one of 3 freeze-dried kefir preparations (whole kefir, cell-free kefir, or heat-treated kefir) for 8 weeks prior to analysis of plasma and liver lipid profiles, circulating cardiovascular disease (CVD) biomarkers, cecal microbiome composition, and cecal short-chain fatty acid levels. These groups of mice were compared to others that were fed a control low-fat diet, control high fat diet or high fat diet supplemented with milk, respectively.

Results

All kefir preparations lowered plasma cholesterol in both male and female mice, while only whole kefir lowered liver cholesterol and triglycerides. Plasma vascular cell adhesion molecule 1 (VCAM-1) was lowered by both whole kefir and heat-treated kefir in male mice but not females, while c-reactive protein (CRP) was unchanged across all high fat diet fed groups in males and females.

Conclusion

These results indicate that some of the metabolic benefits of consumption of this kefir do not require whole kefir while also indicating that there are multiple compounds or components responsible for the different benefits observed.

Non-Dairy Fermented Beverages Produced with Functional Lactic Acid Bacteria

At present, there is an increasing interest in beverages of non-dairy origin, as alternatives to those based on milk, but having similar health-promoting properties. Fermentation with specific bacteria or consortia may enhance the functionality of these products. In our study, selected lactic acid bacteria, that have been previously shown to possess functional properties (antimicrobial activity, probiotic potential), were used for the fermentation of wheat bran combined with root vegetables. Strains were investigated for their safety, while the obtained beverages were characterized in terms of microbial content, physical, chemical, nutritional, and functional properties. None of the strains harbors virulence genes, but all of them possess genes for survival at low pH, starch metabolism, and vitamin biosynthesis. Three strains (Lactiplantibacillus plantarum BR9, L. plantarum P35, and Lactobacillus acidophilus IBB801) and two substrates (5% wheat bran with 10% red beetroot/carrots) were selected based on a preliminary assessment of the beverage's sensory acceptability. These strains showed good growth and stability over time in the stored beverages. No enterobacteria were detected at the end of fermentations, while the final pH was, in most cases, below 3.5. Free phenolics, flavonoids, and DPPH scavenging effect increased during fermentation in all drinks, reaching 24h values that were much higher than in the unfermented substrates. Most of the obtained drinks were able to prevent the growth of certain pathogens, including Listeria monocytogenes ATCC 19111, Salmonella enterica ATCC 14028, Staphylococcus aureus ATCC 25923, and Escherichia coli ATCC 25922. The obtained beverages would combine the nutritiveness of the raw ingredients with the beneficial effect of fermentation (increasing shelf life, health-promoting effect, pleasant flavor, etc.). They would also fill a gap in the non-dairy probiotics sector, which is constantly increasing due to the increasing number of vegan people or people that cannot consume dairy products.

Consumers Respond Positively to the Sensory, Health, and Sustainability Benefits of the Rare Sugar Allulose in Yogurt Formulations

Increased added sugar consumption is associated with type II diabetes, metabolic syndrome, and cardiovascular disease. Low and no-calorie alternative sweeteners have long been used as an aid in the reduction of added sugar. Unfortunately, these alternative sweeteners often have notable sensory deficits when compared to sucrose. Furthermore, many alternative sweeteners have synthetic origins, while consumers are increasingly turning to foods from natural origins, and from more sustainable sources. Such sweeteners include the rare sugar allulose, which can be manufactured from common agricultural waste and dairy co-product streams, and is reported to have a sensory profile similar to sucrose. This study aimed to determine the influence of the rare sugar allulose on consumer perception of sweetened vanilla yogurt. Participants were recruited to evaluate 4 vanilla yogurts sweetened with either sucrose, allulose, stevia or sucralose, and to rate their liking of the samples overall, and for flavor, texture, and their purchase intent. Statistical analysis of hedonic data from 100 consumers suggested that allulose performed similarly to sucrose in liking and purchase intent, and superior to other sweeteners tested in this study, with fewer off-flavors. Moreover, when consumers were queried on their purchase intent after learning details on the sweetener for each formulation, allulose scored significantly higher than all other formulations in purchase intent. This study highlights the potential of the rare sugar allulose as a low calorie, zero glycemic index, natural and better tasting sugar replacement in sweetened yogurt.

Effects of Fermentation Time and Type of Tea on the Content of Micronutrients in Kombucha Fermented Tea

The fermented tea beverage Kombucha is obtained through a series of biochemical and enzymatic reactions carried out by symbiotic cultures of bacteria and yeasts (SCOBY). It contains organic acids, vitamins, amino acids, and biologically active compounds, notably polyphenols, derived mainly from tea. Kombucha exhibits a range of health-promoting properties, including antioxidant or detoxifying effects. This fermented beverage is traditionally brewed with black tea, but other types of tea are used increasingly, which may have significant implications in terms of chemical composition and health-promoting effects. In this preliminary study, we investigated the content of micronutrients (manganese (Mn), copper (Cu), iron (Fe), chromium (Cr) and zinc (Zn)) by the ICP-OES method in Kombucha prepared with black, red, green and white tea at different time points of fermentation (1, 7, 14 days). It should be noted that the composition of separate ingredients such as tea, leaven or sugar has not been studied. Kombucha had the highest content of zinc-0.36 mg/L to 2.08 mg/L, which accounts for between 3% and 26% of the RDA (Recommended Dietary Allowance) for adults, and the smallest amounts of chromium (0.03 mg/L to 0.09 mg/L), which however represents as much as between 75% and 232% of the RDA. It has been demonstrated that the type of tea as well as the day of fermentation have a significant effect on the concentrations of selected minerals. Kombucha can therefore supplement micronutrients in the human diet.

Serum and Urine Metabolites in Healthy Men after Consumption of Acidified Milk and Yogurt

The identification of molecular biomarkers that can be used to quantitatively link dietary intake to phenotypic traits in humans is a key theme in modern nutritional research. Although dairy products (with and without fermentation) represent a major food group, the identification of markers of their intake lags behind that of other food groups. Here, we report the results from an analysis of the metabolites in postprandial serum and urine samples from a randomized crossover study with 14 healthy men who ingested acidified milk, yogurt, and a non-dairy meal. Our study confirms the potential of lactose and its metabolites as markers of lactose-containing dairy foods and the dependence of their combined profiles on the fermentation status of the consumed products. Furthermore, indole-3-lactic acid and 3-phenyllactic acid are two products of fermentation whose postprandial behaviour strongly discriminates yogurt from milk intake. Our study also provides evidence of the ability of milk fermentation to increase the acute delivery of free amino acids to humans. Notably, 3,5-dimethyloctan-2-one also proves to be a specific marker for milk and yogurt consumption, as well as for cheese consumption (previously published data). These molecules deserve future characterisation in human interventional and observational studies.

Fermented Black Tea and Its Relationship with Gut Microbiota and Obesity: A Mini Review

Fermentation is one of the world’s oldest techniques for food preservation, nutrient enhancement, and alcohol manufacturing. During fermentation, carbohydrates such as glucose and starch are converted into other molecules, such as alcohol and acid, anaerobically through enzymatic action while generating energy for the microorganism or cells involved. Black tea is among the most popular fermented beverages; it is made from the dried tea leaves of the evergreen shrub plant known as Camellia sinensis. The adequate consumption of black tea is beneficial to health as it contains high levels of flavanols, also known as catechins, which act as effective antioxidants and are responsible for protecting the body against the development of illnesses, such as inflammation, diabetes, hypertension, cancer, and obesity. The prevalence of obesity is a severe public health concern associated with the incidence of various serious diseases and is now increasing, including in Malaysia. Advances in ‘omic’ research have allowed researchers to identify the pivotal role of the gut microbiota in the development of obesity. This review explores fermented black tea and its correlation with the regulation of the gut microbiota and obesity.

Two sides of the same coin: Meta-analysis uncovered the potential benefits and risks of traditional fermented foods at a large geographical scale

Traditional fermented foods, which are well-known microbial resources, are also bright national cultural inheritances. Recently, traditional fermented foods have received great attention due to their potential probiotic properties. Based on shotgun metagenomic sequencing data, we analyzed the microbial diversity, taxonomic composition, metabolic pathways, and the potential benefits and risks of fermented foods through a meta-analysis including 179 selected samples, as well as our own sequencing data collected from Hainan Province, China. As expected, raw materials, regions (differentiated by climatic zones), and substrates were the main driving forces for the microbial diversity and taxonomic composition of traditional fermented foods. Interestingly, a higher content of beneficial bacteria but a low biomass of opportunistic pathogens and antibiotic resistance genes were observed in the fermented dairy products, indicating that fermented dairy products are the most beneficial and reliable fermented foods. In contrast, despite the high microbial diversity found in the fermented soy products, their consumption risk was still high due to the enrichment of opportunistic pathogens and transferable antibiotic resistance genes. Overall, we provided the most comprehensive assessment of the microbiome of fermented food to date and generated a new view of its potential benefits and risks related to human health.

FDF-DB: A Database of Traditional Fermented Dairy Foods and Their Associated Microbiota

BACKGROUND

Fermented foods are attracting increasing interest due to their nutritional and health benefits, including a positive impact on gut microbiota exerted by their associated microbes. However, information relative to traditional fermented dairy products, along with their autochthonous microbiota, is still fragmented and poorly standardized. Therefore, our aim was to collect and aggregate data useful for obtaining a comprehensive overview translated in a classical database interface that can be easily handled by users.

METHODS

a preliminary inventory was built up by systematically collecting data from publicly available resources for the creation of a list of traditional dairy foods produced worldwide, including additional metadata useful for stratifying, and collapsing subgroups.

RESULTS

we developed the Fermented Dairy Food Database (FDF-DB), a feasible resource comprising 1852 traditional dairy foods (cheeses, fermented milks, and yogurt) for which microbial content and other associated metadata such as geographical indication label, country/region of origin, technological aspects were gathered.

CONCLUSIONS

FDF-DB is a useful and user-friendly resource where taxonomic information and processing production details converge. This resource will be of great aid for researchers, food industries, stakeholders and any user interested in the identification of technological and microbiological features characterizing traditional fermented dairy products.

Probiotic Property and Anti-Obesity Effect of Lactiplantibacillus plantarum KC3

Lactic acid bacteria are representative probiotics that have beneficial effects on humans. Nineteen strains among the 167 single strains from kimchi was selected and their physiological features were investigated. The selection of a strain was based on strong enzyme (lipase, α-amylase, and α-glucosidase) inhibitory activities and anti-obesity effects in the adipocytes. For the final selection, the strain Lactiplantibacillus plantarum KC3 was tested for its potential as a starter. To assess its functionality, a freeze-dried culture of L. plantarum KC3 was administered to a diet-induced obese mouse model receiving a high-fat diet. The animal group administered with L. plantarum KC3 showed significant body weight loss during the 12-week feeding period compared to the high-fat control group. This study investigated the physiological characteristics of selected strain and evaluated its potential as an anti-obesity probiotic in mice.

The Acute Effects of Milk Consumption on Systemic Inflammation after Combined Resistance and Plyometric Exercise in Young Adult Females

High-intensity/impact exercise elicits a transient increase in inflammatory biomarkers. Consuming nutrient-dense wholefoods, like milk, following exercise may modulate post-exercise inflammation and aid recovery. We examined the effect of post-exercise skim milk consumption (versus an isoenergetic, isovolumetric carbohydrate [CHO] drink) on acute exercise-induced inflammation in untrained females. Using a randomized crossover design, 13 healthy females (age = 20 ± 2.3 y; BMI = 21.0 ± 1.1 kg/m²) completed two bouts of combined resistance/plyometric exercise followed by either skim milk (MILK) or CHO at 5-min and 1 h post-exercise. Serum interleukin [IL]-1β, IL-6, IL-10, and tumor necrosis factor-alpha (TNF-α) concentrations were measured at pre-exercise, 15-min, 75-min, 24 h, and 48 h post-exercise. IL-6 increased 15-min post-exercise vs. all other timepoints (time effect, p = 0.017). Between 24 and 48 h, IL-10 decreased and increased in the MILK and CHO conditions, respectively (interaction, p = 0.018). There were no significant effects for IL-1β or TNF-α. Relative concentrations of IL-1β (p = 0.049) and IL-10 (p = 0.028) at 48 h post-exercise were lower in MILK vs. CHO. Milk post-exercise did not influence the absolute concentration of pro-inflammatory cytokines; however, there were divergent responses for the anti-inflammatory cytokine, IL-10, and milk reduced the relative inflammatory response at 48 h (vs. CHO) for IL-1β and IL-10. This demonstrates the potential for milk to modulate inflammation post-exercise in this sample.

Microbial and metabolic characterization of organic artisanal sauerkraut fermentation and study of gut health-promoting properties of sauerkraut brine

Sauerkraut is a traditionally fermented cabbage, and recent evidence suggests that it has beneficial properties for human health. In this work, a multi-disciplinary approach was employed to characterize the fermentation process and gut health-promoting properties of locally produced, organic sauerkraut from two distinct producers, SK1 and SK2. 16S rRNA metataxonomics showed that bacterial diversity gradually decreased as fermentation progressed. Differences in sauerkraut microbiota composition were observed between the two producers, especially at the start of fermentation. Lactic acid bacteria (LAB) dominated the microbiota after 35 days, with Lactiplantibacillus being the dominant genus in both sauerkraut products, together with Leuconostoc and Paucilactobacillus in SK1, and with Pediococcus, Levilactibacillus, and Leuconostoc in SK2. LAB reached between 7 and 8 Log CFU/mL brine at the end of fermentation (35 days), while pH lowering happened within the first week of fermentation. A total of 220 LAB strains, corresponding to 133 RAPD-PCR biotypes, were successfully isolated. Lactiplantibacillus plantarum and Lactiplantibacillus pentosus accounted for 67% of all SK1 isolates, and Lactiplantibacillus plantarum/paraplantarum and Leuconostoc mesenteroides represented 72% of all the isolates from SK2. ¹H-NMR analysis revealed significant changes in microbial metabolite profiles during the fermentation process, with lactic and acetic acids, as well as amino acids, amines, and uracil, being the dominant metabolites quantified. Sauerkraut brine did not affect trans-epithelial electrical resistance through a Caco-2 cell monolayer as a measure of gut barrier function. However, significant modulation of inflammatory response after LPS stimulation was observed in PBMCs-Caco-2 co-culture. Sauerkraut brine supported a robust inflammatory response to endotoxin, by increasing TNF-α and IL-6 production while also stimulating the anti-inflammatory IL-10, therefore suggesting positive resolution of inflammation after 24 h and supporting the potential of sauerkraut brine to regulate intestinal immune function.

Antimicrobial potentials of natural products against multidrug resistance pathogens: a comprehensive review

Antibiotic resistance is one of the critical issues, describing a significant social health complication globally. Hence, the discovery of novel antibiotics has acquired an increased attention particularly against drug-resistant pathogens. Natural products have served as potent therapeutics against pathogenic bacteria since the glorious age of antibiotics of the mid 20th century. This review outlines the various mechanistic candidates for dealing with multi-drug resistant pathogens and explores the terrestrial phytochemicals isolated from plants, lichens, insects, animals, fungi, bacteria, mushrooms, and minerals with reported antimicrobial activity, either alone or in combination with conventional antibiotics. Moreover, newly established tools are presented, including prebiotics, probiotics, synbiotics, bacteriophages, nanoparticles, and bacteriocins, supporting the progress of effective antibiotics to address the emergence of antibiotic-resistant infectious bacteria. Therefore, the current article may uncover promising drug candidates that can be used in drug discovery in the future.

Fermented Minor Grain Foods: Classification, Functional Components, and Probiotic Potential

Fermented minor grain (MG) foods often have unique nutritional value and functional characteristics, which are important for developing dietary culture worldwide. As a kind of special raw material in fermented food, minor grains have special functional components, such as trace elements, dietary fiber, and polyphenols. Fermented MG foods have excellent nutrients, phytochemicals, and bioactive compounds and are consumed as a rich source of probiotic microbes. Thus, the purpose of this review is to introduce the latest progress in research related to the fermentation products of MGs. Specific discussion is focused on the classification of fermented MG foods and their nutritional and health implications, including studies of microbial diversity, functional components, and probiotic potential. Furthermore, this review discusses how mixed fermentation of grain mixtures is a better method for developing new functional foods to increase the nutritional value of meals based on cereals and legumes in terms of dietary protein and micronutrients.

Novel Candidate Microorganisms for Fermentation Technology: From Potential Benefits to Safety Issues

Fermentation is one of the oldest known production processes and the most technologically valuable in terms of the food industry. In recent years, increasing nutrition and health awareness has also changed what is expected from fermentation technology, and the production of healthier foods has started to come a little more forward rather than increasing the shelf life and organoleptic properties of foods. Therefore, in addition to traditional microorganisms, a new generation of (novel) microorganisms has been discovered and research has shifted to this point. Novel microorganisms are known as either newly isolated genera and species from natural sources or bacterial strains derived from existing bacteria. Although novel microorganisms are mostly studied for their use in novel food production in terms of gut-microbiota modulation, recent innovative food research highlights their fermentative effects and usability, especially in food modifications. Herein, Clostridium butyricum, Bacteroides xylanisolvens, Akkermansia muciniphila, Mycobacterium setense manresensis, and Fructophilic lactic acid bacteria (FLAB) can play key roles in future candidate microorganisms for fermentation technology in foods. However, there is also some confusion about the safety issues related to the use of these novel microorganisms. This review paper focuses on certain novel candidate microorganisms for fermentation technology with a deep view of their functions, benefits, and safety issues.

Optimization of nutritional and sensory properties of fermented oat-based composite beverage

Oat (Avena sativa) is well-known for its nutritional value and health-promoting properties. There are only a few oat-based value-added products on the market in Ethiopia, and this study attempted to develop a new product that is both nutritionally enhanced and sensory acceptable, therefore, the objective of this study was to optimize the nutritional and sensory properties of a beverage made from oat, lupine (Lupinus albus), stinging nettle (Urtica simensis), and premix. D-optimal mixture experimental design was used to generate 11 runs applying the following constraints: 60–70% toasted oat, 10–25% roasted and soaked de-bittered white lupine, 5–15% boiled stinging nettle leaves, and 10% premix (flour of toasted black cardamom (2.8%), malted wheat (2.8%), pumpkin (2.6%), spiced chili peppers (1.1%), and table salt (0.7%). Statistical model evaluation and optimization were carried out using Minitab 19 software. The nutritional composition of the product was assessed, and results show that increasing the proportion of oat flour in the blend resulted in a significant (p < 0.05) increase in fat, carbohydrate, gross energy, and mineral contents (Fe, Zn). An increase in lupine flour increased crude protein, crude fiber, gross energy, phytate, tannin, oxalate, and antinutrient to mineral molar ratios. In contrast increased in stinging nettle leaf powder increased the ash and beta-carotene contents. Sensory of 11 composite sample beverages and control (90% oat plus 10% premix) were also carried out by 50 untrained panelists. Consequently, eight responses were optimized: protein, fat, Fe, Zn, beta-carotene, taste, appearance, and overall acceptability. The optimal blending ratio obtained was 70% oats, 11.3% lupine, 8.7% stinging nettle flour, and 10.0% premix. The study's findings suggested that the optimal combination of these traditionally processed ingredients in a beverage can be considered a valuable food with the potential to improve diet quality.

Bacterial diversity of traditional fermented food, Idli by high thorough-put sequencing

The bacterial composition of naturally fermented Indian food, Idli was studied by high-throughput Illumina amplicon sequencing at different taxonomic levels. Metagenomic investigation revealed fold change with respect to some of the phylotypes in 06th to 12th h of fermentation, suggesting the synergistic mode of nutrition. After 12th h fermentation, bacterial populations were stabilized towards 15th h fermentation. The bacterial phyla found as Firmicutes, Fusobacteria, Proteobacteria, Actinobacteria, Bacteroidetes and others in various proportions with respective to fermentation time. Among these Firmicutes and Proteobacteria were the predominant bacterial associates in this product. Initially at 0th h time interval Firmicutes (7%) and Proteobacteria (93%) were present adequately in the product which has been changed to Firmicutes (68%), Proteobacteria (31%) at the end of the fermentation (15th h). Phylum Firmicutes represented various major genus such as Lactococcus, Weissella, Lactobacillus, Enterococcus, Bacillus and Macrococcus whereas Proteobacteria revealed the presence of Enterobacter, Erwinia, Serratia, Pseudoalteromonas, Vibrio and Klebsiella genus. Co-occurrence and Co-exclusion network were developed to ensure the positive and negative association in the eubacterial genus detected in entire batter fermentation event. Some genera like Weissella, Lactococcus and Enterococcus are showing increase in abundances in auxiliary succession events can be established for starter culture development.

Supplementary material

The online version contains supplementary material available at 10.1007/s13197-022-05421-4.

Red Beetroot Fermentation with Different Microbial Consortia to Develop Foods with Improved Aromatic Features

The European culinary culture relies on a wide range of fermented products of plant origin, produced mostly through spontaneous fermentation. Unfortunately, this kind of fermentations is difficult to standardize. Therefore, the use of commercial starter cultures is becoming common to achieve more stable, reproducible, and predictable results. Among plant-based fermentation processes, that of the red beet (Beta vulgaris L. var. conditiva) is scarcely described in the scientific literature. In this work, we compared different types of fermentation methods of beetroot and evaluated the processes' micro-biological, physico-chemical, structural, and volatilome features. A multi-variate analysis was used to match the production of specific VOCs to each starter and to define the correlations between the process variables and volatilome. Overall, the results showed a successful lactic acid fermentation. The analysis of the volatilome clearly discriminated the metabolic profiles of the different fermentations. Among them, the sample fermented with the mixture was the one with the most complex and diversified volatilome. Furthermore, samples did not appear softened after fermentation. Although this work had its weaknesses, such as the limited number of samples and variety, it may pave the way for the standardization of artisanal fermentation procedures of red beetroot in order to improve the quality and safety of the derived food products.

Fermented foods and cardiometabolic health: Definitions, current evidence, and future perspectives

Unhealthy diets contribute to the increasing burden of non-communicable diseases. Annually, over 11 million deaths worldwide are attributed to dietary risk factors, with the vast majority of deaths resulting from cardiometabolic diseases (CMDs) including cardiovascular disease (∼10 million) and type II diabetes (∼339,000). As such, defining diets and dietary patterns that mitigate CMD risk is of great public health importance. Recently, the consumption of fermented foods has emerged as an important dietary strategy for improving cardiometabolic health. Fermented foods have been present in the human diet for over 10,000 years, but knowledge on whether their consumption benefits human health, and the molecular and microbiological mechanisms underpinning their purported health benefits, is relatively nascent. This review provides an overview of the definitions of fermented foods, types and qualities of fermented foods consumed in Europe and globally, possible mechanisms between the consumption of fermented foods and cardiometabolic health, as well as the current state of the epidemiological evidence on fermented food intake and cardiometabolic health. Finally, we outline future perspectives and opportunities for improving the role of fermented foods in human diets.

Microbes of traditional fermentation processes as synthetic biology chassis to tackle future food challenges

Microbial diversity is magnificent and essential to almost all life on Earth. Microbes are an essential part of every human, allowing us to utilize otherwise inaccessible resources. It is no surprise that humans started, initially unconsciously, domesticating microbes for food production: one may call this microbial domestication 1.0. Sourdough bread is just one of the miracles performed by microbial fermentation, allowing extraction of more nutrients from flour and at the same time creating a fluffy and delicious loaf. There are a broad range of products the production of which requires fermentation such as chocolate, cheese, coffee and vinegar. Eventually, with the rise of microscopy, humans became aware of microbial life. Today our knowledge and technological advances allow us to genetically engineer microbes - one may call this microbial domestication 2.0. Synthetic biology and microbial chassis adaptation allow us to tackle current and future food challenges. One of the most apparent challenges is the limited space on Earth available for agriculture and its major tolls on the environment through use of pesticides and the replacement of ecosystems with monocultures. Further challenges include transport and packaging, exacerbated by the 24/7 on-demand mentality of many customers. Synthetic biology already tackles multiple food challenges and will be able to tackle many future food challenges. In this perspective article, we highlight recent microbial synthetic biology research to address future food challenges. We further give a perspective on how synthetic biology tools may teach old microbes new tricks, and what standardized microbial domestication could look like.

Prebiotics enhance persistence of fermented-food associated bacteria in in vitro cultivated fecal microbial communities

It is well established that the gastrointestinal (GI) microbiota plays a major role in human health. Dietary interventions, and consumption of fermented foods that contain live microbes, in particular, are among the approaches being investigated to modulate the GI microbiota and improve health. However, the persistence of fermented food-associated bacteria (FAB) within the GI tract is typically limited by host factors that limit colonization and competition with autochthonous microbes. In this research, we examined if the addition of prebiotics, dietary substrates that are selectively metabolized by microbes to improve health, would enhance the persistence of FAB. We evaluated the persistence of bacteria from three live microbe-containing fermented foods—kefir, sausage, and sauerkraut—in fecal microbial communities from four healthy adults. Fecal communities were propagated in vitro and were inoculated with fermented food-associated microbes from kefir, sausage, or sauerkraut at ~10⁷ CFU/mL. Communities were diluted 1:100 every 24 h into fresh gut simulation medium to simulate microbial community turnover in the GI tract. We measured the persistence of Lactobacillaceae from fermented foods by quantitative PCR (qPCR) and the persistence of other FAB through 16S rRNA gene sequencing. FAB were unable to persist in vitro, reaching undetectable levels within 96 h. Addition of prebiotics, including xylooligosaccharides and a mixture of fructooligosaccharides and galactooligosaccharides enhanced the persistence of some species of FAB, but the level of persistence varied by fecal donor, fermented food, and prebiotic tested. Addition of prebiotics also increased the relative abundance of Bifidobacterium species, which most likely originated from the fecal microbiota. Collectively, our results support previous in vivo studies demonstrating the transient nature of FAB in the GI tract and indicate that consumption of prebiotics may enhance their persistence.

Differential Amino Acid Uptake and Depletion in Mono-Cultures and Co-Cultures of Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus in a Novel Semi-Synthetic Medium

The mechanistic understanding of the physiology and interactions of microorganisms in starter cultures is critical for the targeted improvement of fermented milk products, such as yogurt, which is produced by Streptococcus thermophilus in co-culture with Lactobacillus delbrueckii subsp. bulgaricus. However, the use of complex growth media or milk is a major challenge for quantifying metabolite production, consumption, and exchange in co-cultures. This study developed a synthetic medium that enables the establishment of defined culturing conditions and the application of flow cytometry for measuring species-specific biomass values. Time courses of amino acid concentrations in mono-cultures and co-cultures of L. bulgaricus ATCC BAA-365 with the proteinase-deficient S. thermophilus LMG 18311 and with a proteinase-positive S. thermophilus strain were determined. The analysis revealed that amino acid release rates in co-culture were not equivalent to the sum of amino acid release rates in mono-cultures. Data-driven and pH-dependent amino acid release models were developed and applied for comparison. Histidine displayed higher concentrations in co-cultures, whereas isoleucine and arginine were depleted. Amino acid measurements in co-cultures also confirmed that some amino acids, such as lysine, are produced and then consumed, thus being suitable candidates to investigate the inter-species interactions in the co-culture and contribute to the required knowledge for targeted shaping of yogurt qualities.

Enhancement of nutritional, sensory and storage stability by lactic fermentation of Auricularia auricula

BACKGROUND

Auricularia auricula is of important nutritional value, although its utilization or consumption are mainly under the original form with no further processing. Indeed, its liquid or other fermented products contribute to improved digestion and absorption of nutrients.

RESULTS

The present study used Lactiplantibacillus plantarum to ferment A. auricula juice after an initial processing comprising superfine grinding and high-pressure homogenization. The content of probiotic bacteria in the juice of A. auricula reached 8.48 log colony-forming units mL^-1 after 24 h of fermentation under 37 °C, with the addition of 3% carbon and 0.3% nitrogen source. Meanwhile, the antioxidant activity was increased approximately two-fold, as well as the enriched volatile flavors, both effectively cover up the unwelcoming earthy smell of A. auricula. Furthermore, the storage stability was also strengthened up to 28 days.

CONCLUSION

In summary, the introduced fermentation process not only realized the purpose of improving the nutritional value of A. auricula, but also effectively upgraded the sensory evaluation of A. auricula products. © 2022 Society of Chemical Industry.

Melanoidins present in traditional fermented foods and beverages

Traditional fermented foods and beverages (TFFB) are an important dietary component consumed in large quantities worldwide. Currently, much attention has been focused on the health benefits of TFFB. Melanoidins, a class of bioactive substance produced in the final stage of the Maillard reaction, not only have a significant impact on sensory properties of TFFB but also contribute to the health effects. Melanoidins formed in the fermentation system with a long reaction time at low temperature could be different from those obtained from high-temperature, short-duration roasted systems due to the multiple formative stages and involvement of microorganisms and enzymes. In this paper, the current state of knowledge regarding the formation, distribution, extraction and purification, physicochemical properties, structure characteristics, and biological activities of TFFB melanoidins are comprehensively reviewed, with predominant focus on TFFB that are typically brown like douchi, miso, cheonggukjang, soy sauce, huangjiu (Chinese rice wine), beer, vinegar, and sweet wine. The current challenges and prospective recommendations for the research of melanoidins in fermented systems are also presented. In future, people should pay more attention to the basic research on TFFB melanoidins, especially purification methods and formation mechanisms, further substantiation of health properties of TFFB melanoidins in vivo, and development of specific melanoidins to fulfill technological, productive, or health needs of consumers.

Dairy-Based Probiotic-Fermented Functional Foods: An Update on Their Health-Promoting Properties

Numerous studies have shown a link between the consumption of fermented dairy foods and improved health outcomes. Since the early 2000s, especially probiotic-based fermented functional foods, have had a revival in popularity, mostly as a consequence of claims made about their health benefits. Among them, fermented dairy foods have been associated with obesity prevention and in other conditions such as chronic diarrhea, hypersensitivity, irritable bowel syndrome, Helicobacter pylori infection, lactose intolerance, and gastroenteritis which all are intimately linked with an unhealthy way of life. A malfunctioning inflammatory response may affect the intestinal epithelial barrier’s ability to function by interfering with the normal metabolic processes. In this regard, several studies have shown that fermented dairy probiotics products improve human health by stimulating the growth of good bacteria in the gut at the same time increasing the production of metabolic byproducts. The fermented functional food matrix around probiotic bacteria plays an important role in the survival of these strains by buffering and protecting them from intestinal conditions such as low pH, bile acids, and other harsh conditions. On average, cultured dairy products included higher concentrations of lactic acid bacteria, with some products having as much as 109/mL or g. The focus of this review is on fermented dairy foods and associated probiotic products and their mechanisms of action, including their impact on microbiota and regulation of the immune system. First, we discussed whey and whey-based fermented products, as well as the organisms associated with them. Followed by the role of probiotics, fermented-product-mediated modulation of dendritic cells, natural killer cells, neutrophils, cytokines, immunoglobulins, and reinforcement of gut barrier functions through tight junction. In turn, providing the ample evidence that supports their benefits for gastrointestinal health and related disorders.

Functional Characteristics of Lactic Acid Bacteria In Vitro Isolated from Spontaneously Fermented Sour Porridge with Broomcorn Millet in Northwestern Shanxi Province of China

Eighteen strains of lactic acid bacteria were isolated from spontaneously fermented sour porridge with broomcorn millet in Northwestern Shanxi Province of China, and their probiotic characteristics were investigated in vitro. Survival rates under gastrointestinal conditions, cholesterol reduction, antibacterial capabilities, antioxidant activities, and safety assessments were examined. Results showed that five strains were selected as probiotics and identified as Levilactobacillusbrevis. Strain L10 exhibited excellent probiotic characteristics, with an 86% survival rate under pH 2.0 for 2 h, 80% survival rate in 0.3% bile salt for 6 h, the highest survival rate (78%) in simulated gastrointestinal juice for 3 h, the highest hydrophobicity (42% to xylene and 39% to hexadecane), the highest aggregation (39% auto-aggregation and 10.4–18.13% co-aggregation), relative higher cholesterol reduction rate (80%), the highest antibacterial activities, the highest antioxidant activity, sensitive to most antibiotics tested, without hemolytic and hydrolyze gelatinase activity and could not produce biogenic amine. Therefore, strain L10 could be applied to functional foods.

Chemical Composition of Kombucha

Kombucha is a fermented sweetened tea with a mixed fermenting culture of yeast and acetic acid bacteria. While the history of kombucha is not completely clear, it is now available around the world and has shown an increase in availability and demand in the United States market. The proponents of kombucha consumption tout the varied health benefits it can provide. The final kombucha flavor and composition is a function of both the initial tea used and the fermentation process. While the ascribed benefits are varied and numerous, the number of direct studies has been limited. This review focuses on the current state of understanding of the chemical composition and the potential health effects both positive and negative reported in the literature.

Antihypertensive Activity of Milk Fermented by Lactiplantibacillus plantarum SR37-3 and SR61-2 in L-NAME-Induced Hypertensive Rats

Probiotic fermented milk can lower the incidence rate of hypertension and is beneficial to the regulation of the intestinal microecology. However, the underlying molecular mechanism remains elusive. Here, we evaluated the role of the gut microbiota and its metabolites in the antihypertensive effect of milk fermented by the Lactiplantibacillus plantarum strains SR37-3 (PFM-SR37-3) and SR61-2 (PFM-SR61-2) in Ng-nitro-L-arginine methyl ester induced hypertensive rats. The results showed that PFM-SR37-3 and PFM-SR61-2 intervention significantly lowered the blood pressure (BP) of NG-nitro-L-arginine methyl ester induced hypertensive rats and attenuated renal injury. In particular, long-term administration of PFM inhibited a progressive elevation in SBP (170.22 ± 8.40 and 133.28 ± 6.09 by model group and PFM-SR37-3 treated model group, respectively, at the end of the 4 weeks; p < 0.01 PFM-SR37-3 treated model group versus model group) and DBP (133.83 ± 5.91 and 103.00 ± 6.41 by model group and PFM-SR37-3 treated model group, respectively, at the end of the 4 weeks; p < 0.01 PFM-SR37-3 treated model group versus model group). PFM-SR37-3 and PFM-SR61-2 reshaped the gut microbiome and metabolome, and especially regulated the metabolic levels of L-phenylalanine, L-methionine and L-valine in the intestine and blood circulation. The analysis of the target organ’s aortic transcriptome indicated that the protective effects of PFM-SR37-3 and PFM-SR61-2 were accompanied by the modulation of the BP circadian rhythm pathway, which was conducive to cardiovascular function. Vascular transcriptomic analysis showed that circadian rhythm and AMPK might be potential targets of hypertension. In addition, the ACE inhibition rates of Lactiplantibacillus plantarum SR37-3 and Lactiplantibacillus plantarum SR61-2 in vitro were 70.5% and 68.9%, respectively. Our research provides new insights into novel and safe options for hypertension treatment.

Acetic Acid Bacteria in Sour Beer Production: Friend or Foe?

Beer is the result of a multistep brewing process, including a fermentation step using in general one specific yeast strain. Bacterial presence during beer production (or presence in the beer itself) is considered as bad, since bacteria cause spoilage, produce off-flavors, and/or turbidity. Although most problems in the past related to lack of hygiene and/or cleaning, bacteria do still cause problems nowadays. Despite this negative imago, certain bacteria play an irreplaceable role during fermentation and/or maturation of more unique, funky, and especially refreshing sour beers. The term sour beers or sours is not restricted to one definition but covers a wide variety of beers produced via different techniques. This review proposes an uncluttered sour beer classification scheme, which includes all sour beer production techniques and pays special attention to the functional role of acetic acid bacteria. Whereas their oxidation of ethanol and lactate into acetic acid and acetoin usually spoils beer, including sour beers, organoleptically, a controlled growth leads to a desirable acidic flavor in sour beers, such as lambic-style, lambic-based, and red-brown acidic ales.

16S ribosomal RNA-depletion PCR and its application in cause analysis of yogurt package shrinkage

Fermentative bacteria, the main microbiota in yogurt, interfere with the detection of unintended bacterial contaminants. The removal of fermentative bacteria and enrichment of unintended bacterial contaminants is a challenging task in bacterial detection. The present study developed a new 16S rRNA-depletion PCR for such enrichment and detection. Specifically, a single-guide RNA was designed and synthesized based on the 16S rRNA sequence of Streptococcus thermophilus, with the highest DNA abundance in the yogurt. The CRISPR-Cas9 system was used to specifically cleave and remove the genomic DNA of the fermentative bacteria, followed by PCR amplification. This method improved the detection sensitivity, simplified the operation steps, and reduced the detection cost of PCR analysis. We also used the 16S rRNA-depletion PCR to amplify and detect the unintended bacterial contaminants in yogurts with shrunken packages and analyzed the underlying reasons to prevent this issue of product quality.

Nutritional components as mitigators of cellular senescence in organismal aging: a comprehensive review

The process of cellular senescence is rapidly emerging as a modulator of organismal aging and disease. Targeting the development and removal of senescent cells is considered a viable approach to achieving improved organismal healthspan and lifespan. Nutrition and health are intimately linked and an appropriate dietary regimen can greatly impact organismal response to stress and diseases including during aging. With a renewed focus on cellular senescence, emerging studies demonstrate that both primary and secondary nutritional elements such as carbohydrates, proteins, fatty acids, vitamins, minerals, polyphenols, and probiotics can influence multiple aspects of cellular senescence. The present review describes the recent molecular aspects of cellular senescence-mediated understanding of aging and then studies available evidence of the cellular senescence modulatory attributes of major and minor dietary elements. Underlying pathways and future research directions are deliberated to promote a nutrition-centric approach for targeting cellular senescence and thus improving human health and longevity.

Long-Duration Space Travel Support Must Consider Wider Influences to Conserve Microbiota Composition and Function

The microbiota is important for immune modulation, nutrient acquisition, vitamin production, and other aspects for long-term human health. Isolated model organisms can lose microbial diversity over time and humans are likely the same. Decreasing microbial diversity and the subsequent loss of function may accelerate disease progression on Earth, and to an even greater degree in space. For this reason, maintaining a healthy microbiome during spaceflight has recently garnered consideration. Diet, lifestyle, and consumption of beneficial microbes can shape the microbiota, but the replenishment we attain from environmental exposure to microbes is important too. Probiotics, prebiotics, fermented foods, fecal microbiota transplantation (FMT), and other methods of microbiota modulation currently available may be of benefit for shorter trips, but may not be viable options to overcome the unique challenges faced in long-term space travel. Novel fermented food products with particular impact on gut health, immune modulation, and other space-targeted health outcomes are worthy of exploration. Further consideration of potential microbial replenishment to humans, including from environmental sources to maintain a healthy microbiome, may also be required.

Combined Toxicity Evaluation of Ochratoxin A and Aflatoxin B1 on Kidney and Liver Injury, Immune Inflammation, and Gut Microbiota Alteration Through Pair-Feeding Pullet Model

Ochratoxin A (OTA) and aflatoxin B1 (AFB1) are often co-contaminated, but their synergistic toxicity in poultry is limitedly described. Furthermore, the traditional ad libitum feeding model may fail to distinguish the specific impact of mycotoxins on the biomarkers and the indirect effect of mildew on the palatability of feed. A pair-feeding model was introduced to investigate the specific effect and the indirect effect of the combined toxicity of OTA and AFB1, which were independent and dependent on feed intake, respectively. A total of 180 one-day-old pullets were randomly divided into 3 groups with 6 replicates, and each replicate contained 10 chicks. The control group (Group A) and the pair-feeding group (Group B) received the basal diet without mycotoxin contamination. Group C was administrated with OTA- and AFB1-contaminated feed (101.41 μg/kg of OTA + 20.10 μg/kg of AFB1). The scale of feeding in Group B matched with the feed intake of Group C. The trial lasted 42 days. Compared with the control group, co-contamination of OTA and AFB1 in feed could adversely affect the growth performance (average daily feed intake (ADFI), body weight (BW), average daily weight gain (ADG), feed conversion ratio (FCR), and shank length (SL)), decrease the relative weight of the spleen (p < 0.01), and increase the relative weight of the kidney (p < 0.01). Moreover, the reduction of feed intake could also adversely affect the growth performance (BW, ADG, and SL), but not as severely as mycotoxins do. Apart from that, OTA and AFB1 also activated the antioxidative and inflammation reactions of chicks, increasing the level of catalase (CAT), reactive oxygen species (ROS), and interleukin-8 (IL-8) while decreasing the level of IL-10 (p < 0.01), which was weakly influenced by the feed intake reduction. In addition, OTA and AFB1 induced histopathological changes and apoptosis in the kidney and liver as well as stimulated the growth of pernicious bacteria to cause toxic effects. There were no histopathological changes and apoptosis in the kidney and liver of the pair-feeding group. The combined toxicity of OTA and AFB1 had more severe effects on pullets than merely reducing feed supply. However, the proper reduction of the feed intake could improve pullets’ physical health by enriching the bacteria Lactobacillus, Phascolarctobacterium, Bacteroides, Parabacteroides, and Barnesiella.

Health-Promoting and Therapeutic Attributes of Milk-Derived Bioactive Peptides

Milk-derived bioactive peptides (BAPs) possess several potential attributes in terms of therapeutic capacity and their nutritional value. BAPs from milk proteins can be liberated by bacterial fermentation, in vitro enzymatic hydrolysis, food processing, and gastrointestinal digestion. Previous evidence suggested that milk protein-derived BAPs have numerous health-beneficial characteristics, including anti-cancerous activity, anti-microbial activity, anti-oxidative, anti-hypertensive, lipid-lowering, anti-diabetic, and anti-osteogenic. In this literature overview, we briefly discussed the production of milk protein-derived BAPs and their mechanisms of action. Milk protein-derived BAPs are gaining much interest worldwide due to their immense potential as health-promoting agents. These BAPs are now used to formulate products sold in the market, which reflects their safety as natural compounds. However, enhanced commercialization of milk protein-derived BAPs depends on knowledge of their particular functions/attributes and safety confirmation using human intervention trials. We have summarized the therapeutic potentials of these BAPs based on data from in vivo and in vitro studies.

Physical activity enhances fecal lactobacilli in rats chronically drinking sweetened cola beverage

Overweight and obesity have been linked with increased intake of sugar-sweetened beverages. On the other hand, physical activity has been known to lead to weight loss. Therefore, we hypothesized that exercise might influence the Lactobacillus population in fecal microbiota as their changed abundance is often associated with shifts in the physical activity and diet. In our experiment, Wistar rats were allocated into groups with normal feed or added sugar-sweetened beverages with or without access to a running wheel. Interestingly, only a combination of physical activity and sweetened beverage intake was associated with a significant increase in fecal lactobacilli abundance, suggesting a connection between exercise and a rise in lactobacilli abundance. Moreover, physical activity has improved weight-related parameters and led to increased plasma and mRNA adiponectin levels. Ghrelin and leptin plasma levels were unaltered. Taken together, our results demonstrate that effect of physical activity on adiposity even during unhealthy feeding patterns is accompanied by increased lactobacilli abundance in the fecal microbiota population.

Microbiomes Associated With the Surfaces of Northern Argentinian Fruits Show a Wide Species Diversity

The fiber, vitamin, and antioxidant contents of fruits contribute to a balanced human diet. In countries such as Argentina, several tropical fruits are witnessing a high yield in the harvest season, with a resulting surplus. Fruit fermentation using autochthonous starter cultures can provide a solution for food waste. However, limited knowledge exists about the microbiota present on the surfaces of fruits and the preceding flowers. In the present exploratory study, the microbiomes associated with the surfaces of tropical fruits from Northern Argentina, such as white guava, passion fruit and papaya were investigated using a shotgun metagenomic sequencing approach. Hereto, one sample composed of 14 white guava fruits, two samples of passion fruits with each two to three fruits representing the almost ripe and ripe stage of maturity, four samples of papaya with each two to three fruits representing the unripe, almost ripe, and ripe stage of maturity were processed, as well as a sample of closed and a sample of open Japanese medlar flowers. A considerable heterogeneity was found in the composition of the fruits’ surface microbiota at the genus and species level. While bacteria dominated the microbiota of the fruits and flowers, a small number of the metagenomic sequence reads corresponded with yeasts and filamentous fungi. A minimal abundance of bacterial species critical in lactic acid and acetic acid fermentations was found. A considerable fraction of the metagenomic sequence reads from the fruits’ surface microbiomes remained unidentified, which suggested that intrinsic species are to be sequenced or discovered.

The Role of Milk on Children's Weight Status: An Epidemiological Study among Preadolescents in Greece

Milk consumption contributes greatly to children's diet, playing a pivotal role in the development and structure of bones and the functioning of the musculoskeletal system and the heart. This study investigated the association between the type of milk and childhood overweight/obesity. In the school period 2014-2016, 1728 students aged 10-12 years and their parents participated. The measurement and classification of their weight status were performed through the criteria of the International Obesity Task Force. Among others, the type of milk consumption was recorded. Four categories of the type of milk children consumed were classified (white milk, chocolate milk, both types of milk, and no milk at all). Children consuming only white milk were 33.1% less likely to be overweight/obese in comparison with children who were not consuming milk at all [OR (95% CI): 0.669 (0.516, 0.867), p = 0.002]. The consumption of chocolate milk showed a protective role against childhood overweight/obesity although its association was not consistently significant. This study highlights the significant contribution of milk (and particularly of white milk) consumption to weight management, and thus its promotion should be consistently encouraged. More studies are needed to shed light on the effects of different dairy foods on weight status in childhood.

Essential Factors for a Healthy Microbiome: A Scoping Review

Recent discoveries of the purpose and potential of microbial interactions with humans have broad implications for our understanding of metabolism, immunity, the host−microbe genetic interactions. Bioavailability and bioaccessibility of phytonutrients in foods not only enrich microbial diversity in the lower human gastrointestinal tract (GIT) but also direct the functioning of the metagenome of the microbiota. Thus, healthy choices must include foods that contain nutrients that satisfy both the needs of humans and their microbes. Physical activity interventions at a moderate level of intensity have shown positive effects on metabolism and the microbiome, while intense training (>70% VO2max) reduces diversity in the short term. The microbiome of elite endurance athletes is a robust producer of short-chain fatty acids. A lifestyle lacking activity is associated with the development of chronic disease, and experimental conditions simulating weightlessness in humans demonstrate loss of muscle mass occurring in conjunction with a decline in gut short-chain fatty acid (SCFA) production and the microbes that produce them. This review summarizes evidence addressing the relationship between the intestinal microbiome, diet, and physical activity. Data from the studies reviewed suggest that food choices and physical fitness in developed countries promote a resource “curse” dilemma for the microbiome and our health.

Microbiome Research as an Effective Driver of Success Stories in Agrifood Systems – A Selection of Case Studies

Increasing knowledge of the microbiome has led to significant advancements in the agrifood system. Case studies based on microbiome applications have been reported worldwide and, in this review, we have selected 14 success stories that showcase the importance of microbiome research in advancing the agrifood system. The selected case studies describe products, methodologies, applications, tools, and processes that created an economic and societal impact. Additionally, they cover a broad range of fields within the agrifood chain: the management of diseases and putative pathogens; the use of microorganism as soil fertilizers and plant strengtheners; the investigation of the microbial dynamics occurring during food fermentation; the presence of microorganisms and/or genes associated with hazards for animal and human health (e.g., mycotoxins, spoilage agents, or pathogens) in feeds, foods, and their processing environments; applications to improve HACCP systems; and the identification of novel probiotics and prebiotics to improve the animal gut microbiome or to prevent chronic non-communicable diseases in humans (e.g., obesity complications). The microbiomes of soil, plants, and animals are pivotal for ensuring human and environmental health and this review highlights the impact that microbiome applications have with this regard.

Lactobacillus acidophilus, L. plantarum, L. rhamnosus, and L. reuteri Cell-Free Supernatants Inhibit Candida parapsilosis Pathogenic Potential upon Infection of Vaginal Epithelial Cells Monolayer and in a Transwell Coculture System In Vitro

Vulvovaginal candidiasis (VVC) is a common clinical condition with symptoms and signs of vaginal inflammation in the presence of Candida species. At least one episode of VVC is experienced in up to 75% of women in the reproductive age group during their lifetime, and 5% to 8% of such women suffer from the chronic form. Most cases of VVC are still caused by C. albicans. However, the incidence of VVC cases by non-albicans Candida (NAC) species, such as C. parapsilosis, is continuously increasing. Despite the prevalence of VVC from NAC, little is known about these species and almost nothing about the mechanisms that trigger the VVC. Lactobacillus spp. are the most widely before represented microorganisms in the vaginal microbiota of healthy women. Here, cell-free supernatants (CFS) obtained from L. acidophilus, L. plantarum, L. rhamnosus, and L. reuteri were assessed for their effect on C. parapsilosis virulence traits. Moreover, we assessed if such an effect persisted even after the removal of the CFS (CFS preincubation effect). Moreover, a transwell coculture system was employed by which the relevant antifungal effect was shown to be attributable to the compounds released by lactobacilli. Our results suggest that lactobacilli can work (i) by reducing C. parapsilosis virulence traits, as indicated by the reduced fungal proliferation, viability, and metabolic activity, and (ii) by improving epithelial resistance to the fungus. Overall, these data suggest that, in the context of the vaginal microbiota, the lactobacilli may play a role in preventing the onset of mucosal C. parapsilosis infection. IMPORTANCE The incidence of VVC by non-albicans Candida (NAC) species, such as C. parapsilosis, is increasing. Treatment failure is common in NAC-VVC because some species are resistant or poorly susceptible to the antifungal agents normally employed. Research on C. parapsilosis's pathogenic mechanisms and alternative treatments are still lacking. C. albicans triggers the VVC by producing hyphae, which favor the loss of epithelial tolerance. Differently, C. parapsilosis only produces pseudohyphae. Hence, different virulence factors may trigger the VVC. Likewise, the therapeutic options could also involve different fungal targets. Substantial in vitro and in vivo studies on the pathogenicity mechanisms of C. parapsilosis are lacking. The data presented here ascribe a novel beneficial role to different Lactobacillus spp., whose CFS provides a postbiotic-like activity against C. parapsilosis. Further studies are needed to unravel the mechanisms involved in the bioactivities of such compounds, to better understand the role of single postbiotics in the CFS.

Probiotics, Prebiotics, Synbiotics, and Fermented Foods as Potential Biotics in Nutrition Improving Health via Microbiome-Gut-Brain Axis

Biological, social, and psychological practices greatly affect the dietary intake of people; as a result, health-related complexities occur. Functional food and supplements have become popular due to their nutraceutical benefits, which make different choices of fermented food and beverages available to people. This review describes the characteristics of probiotics, prebiotics, post- and paraprobiotics, and their role in nutrition and in the sustainability of health. Currently, several synbiotic supplements have attracted consumers in the nutraceutical market to offer a number of health benefits, which are complementary mixtures of selected characterized probiotic cultures and prebiotic substrates. Traditional fermented foods consumed in different cultures are different than probiotics and symbiotic preparations, though these could be considered potential biotics in nutrition. Fermented foods are part of a staple diet in several countries and are cost-effective due to their preparation using seasonal raw materials available from local agriculture practices. Intake of all biotics discussed in this article is intended to improve the population of beneficial microbiota in the gut, which has proved important for the microbiome–gut–brain axis, influencing the activity of vagus nerve.

Bioactive metabolites in functional and fermented foods and their role as immunity booster and anti-viral innate mechanisms

Live microorganisms in the fermented foods termed probiotics and their secondary metabolites with bioactive potential were considered as potential anti-viral capabilities through various mechanisms. Given the importance of functional and fermented foods in disease prevention, there is a need to discuss the contextualization and deep understanding of the mechanism of action of these foods, particularly considering the appearance of coronavirus (COVID-19) pandemic, which is causing health concerns and increased social services globally. The mechanism of probiotic strains or their bioactive metabolites is due to stimulation of immune response through boosting T-lymphocytes, cytokines, and cell toxicity of natural killer cells. Proper consumption of these functional and fermented foods may provide additional antiviral approaches for public benefit by modulating the immune functions in the hosts.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13197-022-05528-8.

African cereal fermentations: A review on fermentation processes and microbial composition of non-alcoholic fermented cereal foods and beverages

Africa has a rich tradition of cereal fermentations to produce diverse products including baked goods, porridges, non-alcoholic beverages and alcoholic beverages. Diversity also relates to the choice of the fermentation substrates, which include wheat, maize, teff, sorghum and millet, and the fermentation processes that are used in food production. For fermentation processes that are used in baking and brewing, it is well established that the composition of fermentation microbiota and thus the impact of fermentation on product quality is determined by the choice of fermentation conditions. This link has not been systematically explored for African cereal fermentations. This review therefore aims to provide an overview on the diversity of African fermented cereal products, and to interrogate currently available literature data with respect to the impact of fermentation substrate and fermentation processes on the assembly of fermentation microorganisms and product quality.

Metapath Aggregated Graph Neural Network and Tripartite Heterogeneous Networks for Microbe-Disease Prediction

More and more studies have shown that understanding microbe-disease associations cannot only reveal the pathogenesis of diseases, but also promote the diagnosis and prognosis of diseases. Because traditional medical experiments are time-consuming and expensive, many computational methods have been proposed in recent years to identify potential microbe-disease associations. In this study, we propose a method based on heterogeneous network and metapath aggregated graph neural network (MAGNN) to predict microbe-disease associations, called MATHNMDA. First, we introduce microbe-drug interactions, drug-disease associations, and microbe-disease associations to construct a microbe-drug-disease heterogeneous network. Then we take the heterogeneous network as input to MAGNN. Second, for each layer of MAGNN, we carry out intra-metapath aggregation with a multi-head attention mechanism to learn the structural and semantic information embedded in the target node context, the metapath-based neighbor nodes, and the context between them, by encoding the metapath instances under the metapath definition mode. We then use inter-metapath aggregation with an attention mechanism to combine the semantic information of all different metapaths. Third, we can get the final embedding of microbe nodes and disease nodes based on the output of the last layer in the MAGNN. Finally, we predict potential microbe-disease associations by reconstructing the microbe-disease association matrix. In addition, we evaluated the performance of MATHNMDA by comparing it with that of its variants, some state-of-the-art methods, and different datasets. The results suggest that MATHNMDA is an effective prediction method. The case studies on asthma, inflammatory bowel disease (IBD), and coronavirus disease 2019 (COVID-19) further validate the effectiveness of MATHNMDA.