Food fermentations: microorganisms with technological beneficial use

Assessing effectiveness of Komagataeibacter strains for producing surface-microstructured cellulose via guided assembly-based biolithography

In this study, a medical device made of surface microstructured bacterial cellulose was produced using cellulose-producing acetic acid bacteria wild-type strains in combination with guided assembly-based biolithography. The medical device aims at interfering with the cell's focal adhesion establishment and maturation around implantable devices placed in soft tissues by the symmetrical array on its surface. A total of 25 Komagataeibacter strains was evaluated over a three-step selection. In the first step, the ability of strains to produce a suitable bacterial cellulose layer with high production yield was examined, then nine strains, with a uniform and smooth layer of bacterial cellulose, were cultured in a custom-made silicone bioreactor and finally the characteristics of the symmetrical array of topographic features on the surface were analysed. Selected strains showed high inter and intra species variability in bacterial cellulose production. The devices obtained by K2G30, K1G4, DSM 46590 (Komagataeibacter xylinus), K2A8 (Komagataeibacter sp.) and DSM 15973^T (Komagataeibacter sucrofermentas) strains were pouched-formed with hexagonal surface pattern required for reducing the formation of fibrotic tissue around devices, once they are implanted in soft tissues. Our findings revealed the effectiveness of the selected Komagataeibacter wild-type strains in producing surface microstructured bacterial cellulose pouches for making biomedical devices.

Metabolomics Approaches for the Comprehensive Evaluation of Fermented Foods: A Review

Fermentation is an important process that can provide new flavors and nutritional and functional foods, to deal with changing consumer preferences. Fermented foods have complex chemical components that can modulate unique qualitative properties. Consequently, monitoring the small molecular metabolites in fermented food is critical to clarify its qualitative properties and help deliver personalized nutrition. In recent years, the application of metabolomics to nutrition research of fermented foods has expanded. In this review, we examine the application of metabolomics technologies in food, with a primary focus on the different analytical approaches suitable for food metabolomics and discuss the advantages and disadvantages of these approaches. In addition, we summarize emerging studies applying metabolomics in the comprehensive analysis of the flavor, nutrition, function, and safety of fermented foods, as well as emphasize the applicability of metabolomics in characterizing the qualitative properties of fermented foods.

Sourdough production: fermentation strategies, microbial ecology, and use of non-flour ingredients

Sourdough production is an ancient method to ferment flour from cereals for the manufacturing of baked goods. This review deals with the state-of-the-art of current fermentation strategies for sourdough production and the microbial ecology of mature sourdoughs, with a particular focus on the use of non-flour ingredients. Flour fermentation processes for sourdough production are typically carried out by heterogeneous communities of lactic acid bacteria and yeasts. Acetic acid bacteria may also occur, although their presence and role in sourdough production can be criticized. Based on the inoculum used, sourdough productions can be distinguished in fermentation processes using backslopping procedures, originating from a spontaneously fermented flour-water mixture (Type 1), starter culture-initiated fermentation processes (Type 2), and starter culture-initiated fermentation processes that are followed by backslopping (Type 3). In traditional recipes for the initiation and/or propagation of Type 1 sourdough productions, non-flour ingredients are often added to the flour-water mixture. These ingredients may be the source of an additional microbial inoculum and/or serve as (co-)substrates for fermentation. An example of the former is the addition of yoghurt; an example of the latter is the use of fruit juices. The survival of microorganisms transferred from the ingredients to the fermenting flour-water mixture depends on the competitiveness toward particular strains of the microbial species present under the harsh conditions of the sourdough ecosystem. Their survival and growth is also determined by the presence of the appropriate substrates, whether or not carried over by the ingredients added.

Impacts of manufacture processes and geographical regions on the microbial profile of traditional Chinese cheeses

The microbiota of cheese plays a critical role in determining its organoleptic and other physicochemical properties. Thus, assessing the composition of the cheese microbiota community would help promote the growth of desirable taxa and ultimately to optimize flavor, quality and safety. Here we measured microbial diversity, microbiota composition, short-chain fatty acids, and free amino acids in two traditional cheese-making strategies, Rushan and Rubing, processed in parallel from Lijiang, Eryuan, and Dengchuan of Yunnan province, China. We found distinct microbiota composition, and microbial diversity and richness in both Rushan and Rubing across all three regions, which were proportional to the scale of the cities where the cheeses were sampled. Furthermore, we found positive associations of Streptococcus and Acinetobacter with butyric acid, Phe and Tyr, which were negatively correlated with Lactococcus. For the first time, we provide evidence that environmental microbial contamination in cheese can be correlated with the manufacturing procedures and geographical regions. This should be paid more attention in upcoming cheese microbiota studies.

Role of Exposure to Lactic Acid Bacteria from Foods of Animal Origin in Human Health

Animal products, in particular dairy and fermented products, are major natural sources of lactic acid bacteria (LAB). These are known for their antimicrobial properties, as well as for their roles in organoleptic changes, antioxidant activity, nutrient digestibility, the release of peptides and polysaccharides, amino acid decarboxylation, and biogenic amine production and degradation. Due to their antimicrobial properties, LAB are used in humans and in animals, with beneficial effects, as probiotics or in the treatment of a variety of diseases. In livestock production, LAB contribute to animal performance, health, and productivity. In the food industry, LAB are applied as bioprotective and biopreservation agents, contributing to improve food safety and quality. However, some studies have described resistance to relevant antibiotics in LAB, with the concomitant risks associated with the transfer of antibiotic resistance genes to foodborne pathogens and their potential dissemination throughout the food chain and the environment. Here, we summarize the application of LAB in livestock and animal products, as well as the health impact of LAB in animal food products. In general, the beneficial effects of LAB on the human food chain seem to outweigh the potential risks associated with their consumption as part of animal and human diets. However, further studies and continuous monitorization efforts are needed to ensure their safe application in animal products and in the control of pathogenic microorganisms, preventing the possible risks associated with antibiotic resistance and, thus, protecting public health.

The safety of a Kluyveromyces lactis strain lineage for enzyme production

Kluyveromyces lactis is broadly considered as a safe yeast in food and a suitable organism for the production of food enzymes. The K. lactis enzyme production strains of DSM are used to produce a variety of enzymes, for example beta-galactosidase (lactase), chymosin and esterase. All of these production strains are derived from the same lineage, meaning they all originate from the same ancestor strain after classical mutagenesis and/or genetic engineering. Four different enzyme preparations produced with strains within this lineage were toxicologically tested. These enzyme preparations were nontoxic in repeated-dose oral toxicity studies performed in rats and were non-genotoxic in vitro. These studies confirm the safety of the DSM K. lactis strains as a production platform for food enzymes, as well as the safety of the genetic modifications made to these strains through genetic engineering or classical mutagenesis. The outcome of the toxicity studies can be extended to other enzyme preparations produced by any strain from this lineage through read across. Therefore, no new toxicity studies are required for the safety evaluation, as long as the modifications made do not raise safety concerns. Consequently, this approach is in line with the public ambition to reduce animal toxicity studies.

Tailor-made microbial consortium for Kombucha fermentation: Microbiota-induced biochemical changes and biofilm formation

Kombucha is a very distinct naturally fermented sweetened tea that has been produced for thousands of years. Fermentation relies on metabolic activities of the complex autochthonous symbiotic microbiota embedded in a floating biofilm and used as a backslop for successive fermentations. Here, we designed a tailor-made microbial consortium representative of the core Kombucha microbiota to drive this fermentation. Microbial (counts, metagenetics), physico-chemical (pH, density) and biochemical (organic acids, volatile compounds) parameters were monitored as well as biofilm formation by confocal laser scanning microscopy and scanning electron microscopy. While nine species were co-inoculated, four (Dekkera bruxellensis, Hanseniaspora uvarum, Acetobacter okinawensis and Liquorilactobacillus nagelii) largely dominated. Microbial activities led to acetic, lactic, succinic and oxalic acids being produced right from the start of fermentation while gluconic and glucuronic acids progressively increased. A distinct shift in volatile profile was also observed with mainly aldehydes identified early on, then high abundances of fatty acids, ketones and esters at the end. Correlation analyses, combining metabolomic and microbial data also showed a shift in species abundances during fermentation. We also determined distinct bacteria-yeast co-occurence patterns in biofilms by microscopy. Our study provides clear evidence that a tailor-made consortium can be successfully used to drive Kombucha fermentations.

Potential of Fermentation and Vacuum Packaging Followed by Chilling to Preserve Black Soldier Fly Larvae (Hermetia illucens)

Simple Summary

Insects are being produced at an industrial scale, mainly as feed ingredient to replace less sustainable protein sources in feed. Larvae of the black soldier fly (Hermetia illucens) are currently the most important species reared for this purpose. After production, it is necessary that the larvae be stored and transported in a stable way, i.e., without deterioration. In this study, we investigated fermentation and vacuum packaging technology as potential stabilisation techniques. Fermentation appears to be possible when the larvae are first blanched and pulverised, but bacterial endospores remain present and can potentially be dangerous if the conditions are not acidic enough. Vacuum packaging was tested as storage technique for living larvae, but their survival was lower than for living larvae packaged in air. Additionally, for killed larvae, vacuum packaging before chilling did not bring benefits over chilled storage alone. That was concluded from the fact that microbial counts were similar for larvae that were packaged in air or under vacuum during storage.

Abstract

Black soldier fly larvae (Hermetia illucens) are currently reared at an industrial scale, mainly as a feed ingredient. The logistic chain not only involves the production of larvae, but also stabilisation, storage, and transport. The aim of this work was to study fermentation and vacuum packaging of larvae as potential preservation technologies. For fermentation, blanched larvae were pulverised into a paste, and a starter culture, NaCl, and glucose were added. The mixture was fermented for 7 days at 35 °C and then stored for 14 days at 4 °C and pH and microbial counts were monitored. Vacuum packaging was applied to living, blanched and frozen larvae. After packaging, they were stored for 6–10 days at several temperatures and gas composition, survival (living larvae) and microbial counts (killed larvae) were recorded. Fermentation allows storage of pulverised larvae, but points to consider are a rapid pH reduction and the presence of bacterial endospores. Vacuum packaging did not bring added value over cooling alone. This was the case for all types of larvae investigated. Vacuum packaging is not considered as a valuable preservation technology to pursue for storage and transport of black soldier fly larvae.

Analysis of the Fungal Diversity and Community Structure in Sichuan Dark Tea During Pile-Fermentation

The fungi present during pile-fermentation of Sichuan dark tea play a pivotal role in the development of its aroma and physical characteristics. Samples of tea leaves were collected on days 0 (YC-raw material), 8 (W1-first turn), 16 (W2-second turn), 24 (W3-third turn), and 32 (W4-out of pile) during pile-fermentation. High-throughput sequencing revealed seven phyla, 22 classes, 41 orders, 85 families, 128 genera, and 184 species of fungi. During fermentation, the fungal diversity index declined from the W1 to W3 stages and then increased exponentially at the W4 stage. A bar plot and heatmap revealed that Aspergillus, Thermomyces, Candida, Debaryomyces, Rasamsonia, Rhizomucor, and Thermoascus were abundant during piling, of which Aspergillus was the most abundant. Cluster analysis revealed that the W4 stage of fermentation is critical for fungal growth, diversity, and the community structure in Sichuan dark tea. This study revealed the role of fungi during pile-fermentation in the development of the essence and physical characteristics of Sichuan dark tea. This study comes under one of the Sustainable Development Goals of United Nations Organization (UNO) to "Establish Good Health and Well-Being."

Glycolipid Biosurfactant Production from Waste Cooking Oils by Yeast: Review of Substrates, Producers and Products

Biosurfactants are a microbially synthesized alternative to synthetic surfactants, one of the most important bulk chemicals. Some yeast species are proven to be exceptional biosurfactant producers, while others are emerging producers. A set of factors affects the type, amount, and properties of the biosurfactant produced, as well as the environmental impact and costs of biosurfactant’s production. Exploring waste cooking oil as a substrate for biosurfactants’ production serves as an effective cost-cutting strategy, yet it has some limitations. This review explores the existing knowledge on utilizing waste cooking oil as a feedstock to produce glycolipid biosurfactants by yeast. The review focuses specifically on the differences created by using raw cooking oil or waste cooking oil as the substrate on the ability of various yeast species to synthesize sophorolipids, rhamnolipids, mannosylerythritol lipids, and other glycolipids and the substrate’s impact on the composition, properties, and limitations in the application of biosurfactants.

Update on Candida krusei, a potential multidrug-resistant pathogen

Although Candida albicans remains the main cause of candidiasis, in recent years a significant number of infections has been attributed to non-albicans Candida (NAC) species, including Candida krusei. This epidemiological change can be partly explained by the increased resistance of NAC species to antifungal drugs. C. krusei is a diploid, dimorphic ascomycetous yeast that inhabits the mucosal membrane of healthy individuals. However, this yeast can cause life-threatening infections in immunocompromised patients, with hematologic malignancy patients and those using prolonged azole prophylaxis being at higher risk. Fungal infections are usually treated with five major classes of antifungal agents which include azoles, echinocandins, polyenes, allylamines, and nucleoside analogues. Fluconazole, an azole, is the most commonly used antifungal drug due to its low host toxicity, high water solubility, and high bioavailability. However, C. krusei possesses intrinsic resistance to this drug while also rapidly developing acquired resistance to other antifungal drugs. The mechanisms of antifungal resistance of this yeast involve the alteration and overexpression of drug target, reduction in intracellular drug concentration and development of a bypass pathway. Antifungal resistance menace coupled with the paucity of the antifungal arsenal as well as challenges involved in antifungal drug development, partly due to the eukaryotic nature of both fungi and humans, have left researchers to exploit alternative therapies. Here we briefly review our current knowledge of the biology, pathophysiology and epidemiology of a potential multidrug-resistant fungal pathogen, C. krusei, while also discussing the mechanisms of drug resistance of Candida species and alternative therapeutic approaches.

Algae-Based Biorefinery as a Sustainable Renewable Resource

Algae are a large and diverse group of autotrophic organisms that are multicellular and single-celled and found in a variety of environments. Biofuel production and value-added chemicals produced through a sustainable process are represented by the biorefinery of algae. Algae are important because of the production of polysaccharides, lipids, pigments, proteins, and other compounds for pharmaceutical and nutritional applications. They can also be used as raw materials for biofuel production. Moreover, they are useful for wastewater treatment. All these factors have absorbed the attentions of researchers around the world. This review focuses specifically on the potentials, properties, and applications of algae as a sustainable renewable resource, which can be a good alternative to other sources due to their high biomass production, less land required for cultivation, and the production of valuable metabolites.

The forgotten role of food cultures

Fermentation is one of if not the oldest food processing technique, yet it is still an emerging field when it comes to its numerous mechanisms of action and potential applications. The effect of microbial activity on the taste, bioavailability and preservation of the nutrients and the different food matrices has been deciphered by the insights of molecular microbiology. Among those roles of fermentation in the food chain, biopreservation remains the one most debated. Presumably because it has been underestimated for quite a while, and only considered - based on a food safety and technological approach - from the toxicological and chemical perspective. Biopreservation is not considered as a traditional use, where it has been by design - but forgotten - as the initial goal of fermentation. The 'modern' use of biopreservation is also slightly different from the traditional use, due mainly to changes in cooling of food and other ways of preservation, Extending shelf life is considered to be one of the properties of food additives, classifying - from our perspective - biopreservation wrongly and forgetting the role of fermentation and food cultures. The present review will summarize the current approaches of fermentation as a way to preserve and protect the food, considering the different way in which food cultures and this application could help tackle food waste as an additional control measure to ensure the safety of the food.

New Insight into Bacterial Interaction with the Matrix of Plant-Based Fermented Foods

Microorganisms have been harnessed to process raw plants into fermented foods. The adaptation to a variety of plant environments has resulted in a nearly inseparable association between the bacterial species and the plant with a characteristic chemical profile. Lactic acid bacteria, which are known for their ability to adapt to nutrient-rich niches, have altered their genomes to dominate specific habitats through gene loss or gain. Molecular biology approaches provide a deep insight into the evolutionary process in many bacteria and their adaptation to colonize the plant matrix. Knowledge of the adaptive characteristics of microorganisms facilitates an efficient use thereof in fermentation to achieve desired final product properties. With their ability to acidify the environment and degrade plant compounds enzymatically, bacteria can modify the textural and organoleptic properties of the product and increase the bioavailability of plant matrix components. This article describes selected microorganisms and their competitive survival and adaptation in fermented fruit and vegetable environments. Beneficial changes in the plant matrix caused by microbial activity and their beneficial potential for human health are discussed as well.

Evaluation of the potential of protective cultures to extend the microbial shelf-life of chilled lamb meat

The use of protective cultures to inhibit spoilage bacteria is a promising natural preservation technique to extend the shelf-life of fresh meat. This study evaluated the effectiveness of six food-grade protective cultures (containing different combinations of Lactobacillus sakei, Pediococcus pentosaceus, Staphylococcus xylosus, and Staphylococcus carnosus) on naturally contaminated chill-stored (4 °C) lamb meat in different packaging systems. Only slight reductions of common meat spoilage bacteria Brochothrix thermosphacta, Pseudomonas spp., and Enterobacteriaceae were observed in culture-treated samples stored in modified atmosphere packaging (80% O₂:20% CO₂). Greater inhibitory effects were found in vacuum-packed lamb, with mixed cultures containing either L. sakei, S. carnosus, and S. xylosus or S. carnosus and L. sakei causing the most significant reductions. Protective cultures did not adversely affect meat color or pH. This study demonstrated the potential of protective cultures comprising lactic acid bacteria and coagulase-negative staphylococci in controlling microbial spoilage of lamb and, by inference, other types of meat as a natural solution for shelf-life extension.

Design of a New Fermented Beverage from Medicinal Plants and Organic Sugarcane Molasses via Lactic Fermentation

Functional beverages obtained using medicinal plants and fermented with lactic acid bacteria are gaining much interest from the scientific community, driven by the growing demand for food and beverages with beneficial properties. In this work, three different batches of medicinal plants and organic sugarcane molasses, named FB-lc, FB-sp and FB-lcsp, were prepared and fermented by using Lactobacillus acidophilus ATCC 43121, Bifidobacterium breve B632 and a mix of both strains’ culture, respectively. The three fermented beverages revealed a high level of polyphenols (expressed as gallic acid equivalent), ranging from 182.50 to 315.62 µg/mL. The highest content of flavonoids (152.13 µg quercetin equivalent/mL) and tannins (93.602 µg catechin equivalent/mL) was detected in FB-lcsp trial. The IR spectroscopy analysis showed a decrease in sugar (pyranose forms, D-glucopyranose and rhamnosides). In addition, the aromatic compounds of the fermented beverages, detected by GC-MS headspace analysis, showed twenty-four interesting volatile compounds, which could give positive aroma attributes to the flavor of the beverages. The highest antioxidant activity was observed in the beverage obtained by the mix culture strains. Accordingly, the production of these beverages can be further investigated for considering their well-being effects on human health.

Identification and characterization of extracellular enzymes secreted by Aspergillus spp. involved in lipolysis and lipid-antioxidation during katsuobushi fermentation and ripening

A mild-flavored soup stock made from katsuobushi is an important element of traditional Japanese cuisine and is the basic seasoning responsible for the taste. Fermented and ripened katsuobushi, known as karebushi, is manufactured by simmering skipjack tuna that is then smoke-dried, fermented, and ripened in a repeated molding process by five dominant Aspergillus species. Here, our aim was to characterize and identify the lipolytic enzymes secreted by the dominant Aspergillus species, especially A. chevalieri and A. pseudoglaucus, which are involved in hydrolyzing lipids during the molding process. The crude enzyme preparations from the five Aspergillus spp. cultivated on katsuobushi solid medium hydrolyzed triglycerides in fish oil, and more saturated and unsaturated fatty acids (C16:0, C16:1, C18:0, C18:1) were produced than major polyunsaturated fatty acids (C20:5, C22:6). On the basis of ion exchange chromatograms, the composition of the lipolytic enzymes was different in the five species. There was at least one active fraction with high hydrolytic activity toward fish oil in four of the Aspergillus spp., but not A. sydowii; the lipolytic enzyme secreted by A. sydowii had quite high activity toward the artificial substrate p-nitrophenyl butyrate, but low activity toward the natural oil. The lipolytic fractions from A. chevalieri and A. pseudoglaucus were further purified by hydrophobic interaction chromatography then gel-filtration chromatography; LC-MS-MS Mascot analysis identified a variety of lipolytic enzymes, including cutinase, esterase, phospholipase, and carboxyl esterase in the lipolytic fractions from these species. The identified enzymes had 30%-70% identity to previously reported or manually annotated lipases or esterases from taxa other than Aspergillus. The different lipolytic enzymes likely acted on triglycerides in the katsuobushi fish oil. Furthermore, catalase B and Cu/Zn superoxide dismutase, which limit oxidative damage of lipids, were also identified. These antioxidant enzymes may prevent lipid oxidation and rancidity as the lipolytic enzymes hydrolyze lipids during the long fermentation and ripening process. Umami and richness tastes tended to increase in extracts from culture of protease- and peptidase-producing A. sydowii. Our results will aid in the selection and application of desirable strains of Aspergillus species as starter cultures to improve the storage and quality of fermented and ripened karebushi.

Changes of fungal community and non-volatile metabolites during pile-fermentation of dark green tea

Fungal community and non-volatile metabolites changes during the pile-fermentation are key factors to organoleptic qualities of dark green tea. However, the correlation between fungal succession and non-volatile compounds has never been satisfactorily explained. The purpose of the present study was to investigate fungal succession and its correlation with flavor compounds by multi-omics. Illumina Miseq sequencing of ITS1 region was conducted to analyze the fungal succession, a total of 78 OTUs which consisted of one phyla, nine classes, 15 orders, 26 families, 37 genera were identified, with Ascomycota as dominant phyla. Cluster analysis and non-metric multidimensional scaling of samples demonstrated the distribution of OTUs in multi-dimensional space, the pile-fermentation process of dark green tea can be divided into four periods according to the generated trajectory of fungal population, S0, S1-S3, S4-S5, and S6. Aspergillus is the dominant genus. Penicillium, Cyberlindnera, Debaryomyces, Candida, Thermomyces, Rasamsonia, Thermoascus, and Byssochlamys appear in different periods. three alkaloids, seven catechins, nine amino acids, five organic acids, five flavones and flavonoid glycosides were identified by UPLC-QTOF-MS/MS, and the contents were all decreasing. Caffeine, EGC, EGCG, L-theanine, kaempferitrin, L-phenylalanine, gallic acid, and myricetin-3-O-galactoside are important ingredients which contribute to the flavor of dark green tea. This study demonstrated the fungal succession, non-volatile flavor compounds and their relationships during pile-fermentation of dark green tea, and provides new insights into evaluating pivotal role of fungal succession in the manufacturing process of dark green tea.

Why has the authorization of microbial biological control agents been slower in the EU than in comparable jurisdictions?

The aim of this study was to identify reasons why the authorization of microbial pest control agents is lengthier under regulatory frameworks of the European Union (EU) than in comparable jurisdictions. A main conclusion is that although the EU's regulatory processes have strong scientific foundations, the most appropriate scientific concepts, knowledge and expertise have not been applied in the safety assessment of microorganisms and biological control. Tradition and conceptual legacies from assessments of conventional chemical pesticides have likely contributed to this by steering the evaluations of microorganisms in less appropriate directions. According to our investigation, the current framework for microbial plant protection products complies poorly with the principles that legislation should have legal predictability, proportionality, and that it should be non-discriminative, for instance in comparison to corresponding regulations in comparable jurisdictions. We also found that existing possibilities to take non-safety and ethical considerations into account can probably be used more. To rationalize the EU's authorization of microbial control products, both the basic legislation and the evaluations of agents and products need stronger rooting in fundamental microbiological science. © 2020 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Critical Assessment of Mycotoxins in Beverages and Their Control Measures

Mycotoxins are secondary metabolites of filamentous fungi that contaminate food products such as fruits, vegetables, cereals, beverages, and other agricultural commodities. Their occurrence in the food chain, especially in beverages, can pose a serious risk to human health, due to their toxicity, even at low concentrations. Mycotoxins, such as aflatoxins (AFs), ochratoxin A (OTA), patulin (PAT), fumonisins (FBs), trichothecenes (TCs), zearalenone (ZEN), and the alternaria toxins including alternariol, altenuene, and alternariol methyl ether have largely been identified in fruits and their derived products, such as beverages and drinks. The presence of mycotoxins in beverages is of high concern in some cases due to their levels being higher than the limits set by regulations. This review aims to summarize the toxicity of the major mycotoxins that occur in beverages, the methods available for their detection and quantification, and the strategies for their control. In addition, some novel techniques for controlling mycotoxins in the postharvest stage are highlighted.

A systematic review to identify biomarkers of intake for fermented food products

Background

Fermented foods are ubiquitous in human diets and often lauded for their sensory, nutritious, and health-promoting qualities. However, precise associations between the intake of fermented foods and health have not been well-established. This is in part due to the limitations of current dietary assessment tools that rely on subjective reporting, making them prone to memory-related errors and reporting bias. The identification of food intake biomarkers (FIBs) bypasses this challenge by providing an objective measure of intake. Despite numerous studies reporting on FIBs for various types of fermented foods and drinks, unique biomarkers associated with the fermentation process (“fermentation-dependent” biomarkers) have not been well documented. We therefore conducted a comprehensive, systematic review of the literature to identify biomarkers of fermented foods commonly consumed in diets across the world.

Results

After title, abstract, and full-text screening, extraction of data from 301 articles resulted in an extensive list of compounds that were detected in human biofluids following the consumption of various fermented foods, with the majority of articles focusing on coffee (69), wine (69 articles), cocoa (62), beer (34), and bread (29). The identified compounds from all included papers were consolidated and sorted into FIBs proposed for a specific food, for a food group, or for the fermentation process. Alongside food-specific markers (e.g., trigonelline for coffee), and food-group markers (e.g., pentadecanoic acid for dairy intake), several fermentation-dependent markers were revealed. These comprised compounds related to the fermentation process of a particular food, such as mannitol (wine), 2-ethylmalate (beer), methionine (sourdough bread, cheese), theabrownins (tea), and gallic acid (tea, wine), while others were indicative of more general fermentation processes (e.g., ethanol from alcoholic fermentation, 3-phenyllactic acid from lactic fermentation).

Conclusions

Fermented foods comprise a heterogeneous group of foods. While many of the candidate FIBs identified were found to be non-specific, greater specificity may be observed when considering a combination of compounds identified for individual fermented foods, food groups, and from fermentation processes. Future studies that focus on how fermentation impacts the composition and nutritional quality of food substrates could help to identify novel biomarkers of fermented food intake.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12263-021-00686-4.

The International Scientific Association for Probiotics and Prebiotics (ISAPP) consensus statement on fermented foods

An expert panel was convened in September 2019 by The International Scientific Association for Probiotics and Prebiotics (ISAPP) to develop a definition for fermented foods and to describe their role in the human diet. Although these foods have been consumed for thousands of years, they are receiving increased attention among biologists, nutritionists, technologists, clinicians and consumers. Despite this interest, inconsistencies related to the use of the term 'fermented' led the panel to define fermented foods and beverages as "foods made through desired microbial growth and enzymatic conversions of food components". This definition, encompassing the many varieties of fermented foods, is intended to clarify what is (and is not) a fermented food. The distinction between fermented foods and probiotics is further clarified. The panel also addressed the current state of knowledge on the safety, risks and health benefits, including an assessment of the nutritional attributes and a mechanistic rationale for how fermented foods could improve gastrointestinal and general health. The latest advancements in our understanding of the microbial ecology and systems biology of these foods were discussed. Finally, the panel reviewed how fermented foods are regulated and discussed efforts to include them as a separate category in national dietary guidelines.

Functional role of yeasts, lactic acid bacteria and acetic acid bacteria in cocoa fermentation processes

Cured cocoa beans are obtained through a post-harvest, batchwise process of fermentation and drying carried out on farms in the equatorial zone. Fermentation of cocoa pulp-bean mass is performed mainly in heaps or boxes. It is made possible by a succession of yeast, lactic acid bacteria (LAB) and acetic acid bacteria (AAB) activities. Yeasts ferment the glucose of the cocoa pulp into ethanol, perform pectinolysis and produce flavour compounds, such as (higher) alcohols, aldehydes, organic acids and esters. LAB ferment the glucose, fructose and citric acid of the cocoa pulp into lactic acid, acetic acid, mannitol and pyruvate, generate a microbiologically stable fermentation environment, provide lactate as carbon source for the indispensable growth of AAB, and contribute to the cocoa and chocolate flavours by the production of sugar alcohols, organic acids, (higher) alcohols and aldehydes. AAB oxidize the ethanol into acetic acid, which penetrates into the bean cotyledons to prevent seed germination. Destruction of the subcellular seed structure in turn initiates enzymatic and non-enzymatic conversions inside the cocoa beans, which provides the necessary colour and flavour precursor molecules (hydrophilic peptides, hydrophobic amino acids and reducing sugars) for later roasting of the cured cocoa beans, the first step of the chocolate-making.

Microbial biopreservatives for controlling the spoilage of beef and lamb meat: their application and effects on meat quality

Biopreservation is a recognized natural method for controlling the growth of undesirable bacteria on fresh meat. It offers the potential to inhibit spoilage bacteria and extend meat shelf-life, but this aspect has been much less studied compared to using the approach to target pathogenic bacteria. This review provides comprehensive information on the application of biopreservatives of microbial origin, mainly bacteriocins and protective cultures, in relation to bacterial spoilage of beef and lamb meat. The sensory effect of these biopreservatives, an aspect that often receives less attention in microbiological studies, is also reviewed. Microbial biopreservatives were found to be able to retard the growth of the major meat spoilage bacteria, Brochothrix thermosphacta, Pseudomonas spp., and Enterobacteriaceae. Their addition did not have any discernible negative impact on the sensory properties of meat, whether assessed by human sensory panels or instrumental and chemical analyses. Although results are promising, the concept of biopreservation for controlling spoilage bacteria on fresh meat is still in its infancy. Studies in this area are still lacking, especially for lamb. Biopreservatives need more testing under conditions representative of commercial meat production, along with studies of any possible sensory effects, in order to validate their potential for large-scale industrial applications.

Multifunctional properties and safety evaluation of lactic acid bacteria and yeasts associated with fermented cereal doughs

Spontaneous cereal fermentations involve diverse lactic acid bacteria (LAB) and yeasts which may include multifunctional and safe or unsafe strains. This study assessed acidification ability, safety, antifungal activity and free amino acids release ability of LAB and yeasts previously isolated from spontaneously fermented cereal doughs in Benin. Fourteen LAB and thirteen yeast strains were studied in liquid media and/or in a model cereal dough prepared in laboratory conditions. Antifungal activity was assessed against Candida glabrata in liquid medium. Amino acids were determined by pre-column derivatization and separation with reversed-phase HPLC. Antimicrobial susceptibility was analysed by minimum inhibitory concentration determination. The acidification ability was higher for LAB compared to yeast strains. All LAB strains retarded the growth of C. glabrata Cg1 with the highest inhibition recorded for Weissella confusa Wc1 and Wc2. The highest free amino acid content was found in the doughs fermented with Pichia kudriavzevii Pk2 and Pk3. All the LAB strains were susceptible to ampicillin, chloramphenicol, erythromycin, but displayed phenotypic resistance to kanamycin, streptomycin and tetracycline. Positive PCR amplicon of resistance genes were detected in the following cases: 2 LAB strains were positive for kanamycin (aph(3)III), 5 strains were positive for streptomycin (aadA and/or strA and/or strB) and 3 strains were positive for tetracycline (tet (L) and/or tet (M)). For yeasts, most of the P. kudriavzevii strains were resistant to amphotericin B, fluconazole and itraconazole opposite to K. marxianus and Saccharomyces cerevisiae strains which were susceptible. The results obtained are valuable for selecting safe and multifunctional strains for cereal fermentation in West Africa.

Metataxonomic and metagenomic approaches for the study of undefined strain starters for cheese manufacture

Undefined strain starters are used for the production of many traditional and artisanal cheeses. Composition of undefined starters depends on several factors, and the diversity in strains and species significantly affects cheese quality and features. Culture-dependent approaches have long been used for the microbial profiling and functionalities of undefined cultures but underestimate their diversity due to culturability biases. Recently, culture-independent methods, based on high-throughput sequencing (HTS), have been preferred, with a significant boost in resolution power and sensitivity level. Amplicon targeted (AT) metagenomics, based on 16S rRNA sequencing, returned a larger microbiota diversity at genus and, sometimes, at species levels for artisanal starters of several PDO cheeses, but was inappropriate for populations with high strain diversity, and other gene targets were tested in AT approaches. Shotgun metagenomics (total DNA) and metatranscriptomics (total RNA), although are more powerful in depicting diversity and functionality of undefined cultures, have been rarely applied because of some limitations (e.g., high costs and laboriousness, need for bioinformatics skills). The advantages of HTS technologies are undoubted, but some hurdles need to be still overcame (e.g., resolution power, discrepancy between active and inactive cells, robust analytic pipelines, cost and time reduction for integrated approaches) so that HTS become routinary and convenient for defining complexity, microbial interactions (including host-phage relationships) and evolution in cheeses of undefined starters.

Fermentative Foods: Microbiology, Biochemistry, Potential Human Health Benefits and Public Health Issues

Fermented foods identify cultures and civilizations. History, climate and the particulars of local production of raw materials have urged humanity to exploit various pathways of fermentation to produce a wide variety of traditional edible products which represent adaptations to specific conditions. Nowadays, industrial-scale production has flooded the markets with ferments. According to recent estimates, the current size of the global market of fermented foods is in the vicinity of USD 30 billion, with increasing trends. Modern challenges include tailor-made fermented foods for people with special dietary needs, such as patients suffering from Crohn's disease or other ailments. Another major challenge concerns the safety of artisan fermented products, an issue that could be tackled with the aid of molecular biology and concerns not only the presence of pathogens but also the foodborne microbial resistance. The basis of all these is, of course, the microbiome, an aggregation of different species of bacteria and yeasts that thrives on the carbohydrates of the raw materials. In this review, the microbiology of fermented foods is discussed with a special reference to groups of products and to specific products indicative of the diversity that a fermentation process can take. Their impact is also discussed with emphasis on health and oral health status. From Hippocrates until modern approaches to disease therapy, diet was thought to be of the most important factors for health stability of the human natural microbiome. After all, to quote Pasteur, "Gentlemen, the microbes will have the last word for human health." In that sense, it is the microbiomes of fermented foods that will acquire a leading role in future nutrition and therapeutics.

Safety demonstration of a microbial species for use in the food chain: Weissella confusa

Due to their traditional use in food fermentation process for centuries, microbial food cultures are considered to have a safe history of use. A specific microbial risk assessment is therefore rarely conducted for fermented foods and their food cultures, inoculated or naturally present. Some of those food cultures have been also considered for their potential health effect as probiotic strain candidates, for which a specific safety demonstration process has been proposed by a joint expert report of FAO and WHO. The European Food Safety Authority (EFSA) Biohazard panel also provides an approach for evaluating the safety of a strain to be added in the food chain, the Qualified Presumption of Safety (QPS). Weissella confusa, former taxon Lactobacillus confusus, is a food culture characterized in the fermentation process of sourdough. Some strains have been recently proposed for their probiotic potential. The species is also documented in recent infection case reports. It is considered nevertheless to be opportunistic as underlying factors have been suggested to explain the infection. We report here the microbial risk assessment of the species, by studying a collection of 26 food and 17 clinical isolates of Weissella confusa. The phenotypic study, genomic characterization and bibliographical survey will allow us to conclude about the safety of the species and confirm its use for food fermentation and consider specific strains for demonstration of their respective health effects as probiotic candidates.

Recent advances in the intellectual property landscape of filamentous fungi

For centuries, filamentous fungi have been used in the making of food and beverages, and for decades for the production of enzymes and pharmaceuticals. In the last decades, the intellectual property (IP) landscape for fungal technology has seen an ever increasing upward trend, introducing new and promising applications utilising fungi. In this review, we highlight fungi-related patent applications published during the last 5 years (2015–2020), identify the key players in each field, and analyse future trends. New developments in the field of fungal technology include the increased use of filamentous fungi as a food source (mycoprotein), using fungi as biodegradable materials, in wastewater treatment, in integrated biorefineries and as biological pest agents. Biotechnology companies in Europe and the US are currently leading when it comes to the number of patents in these areas, but Asian companies and research institutes, in particular in China, are becoming increasingly important players, for example in pesticide formulation and agricultural practices.

Fermented-Food Metagenomics Reveals Substrate-Associated Differences in Taxonomy and Health-Associated and Antibiotic Resistance Determinants

Fermented foods have been the focus of ever greater interest as a consequence of purported health benefits. Indeed, it has been suggested that consumption of these foods helps to address the negative consequences of "industrialization" of the human gut microbiota in Western society. However, as the mechanisms via which the microbes in fermented foods improve health are not understood, it is necessary to develop an understanding of the composition and functionality of the fermented-food microbiota to better harness desirable traits. Here, we considerably expand the understanding of fermented-food microbiomes by employing shotgun metagenomic sequencing to provide a comprehensive insight into the microbial composition, diversity, and functional potential (including antimicrobial resistance and carbohydrate-degrading and health-associated gene content) of a diverse range of 58 fermented foods from artisanal producers from a number of countries. Food type, i.e., dairy-, sugar-, or brine-type fermented foods, was the primary driver of microbial composition, with dairy foods found to have the lowest microbial diversity. From the combined data set, 127 high-quality metagenome-assembled genomes (MAGs), including 10 MAGs representing putatively novel species of Acetobacter, Acidisphaera, Gluconobacter, Companilactobacillus, Leuconostoc, and Rouxiella, were generated. Potential health promoting attributes were more common in fermented foods than nonfermented equivalents, with water kefirs, sauerkrauts, and kvasses containing the greatest numbers of potentially health-associated gene clusters. Ultimately, this study provides the most comprehensive insight into the microbiomes of fermented foods to date and yields novel information regarding their relative health-promoting potential.IMPORTANCE Fermented foods are regaining popularity worldwide due in part to a greater appreciation of the health benefits of these foods and the associated microorganisms. Here, we use state-of-the-art approaches to explore the microbiomes of 58 of these foods, identifying the factors that drive the microbial composition of these foods and potential functional benefits associated with these populations. Food type, i.e., dairy-, sugar-, or brine-type fermented foods, was the primary driver of microbial composition, with dairy foods found to have the lowest microbial diversity and, notably, potential health promoting attributes were more common in fermented foods than nonfermented equivalents. The information provided here will provide significant opportunities for the further optimization of fermented-food production and the harnessing of their health-promoting potential.

Dynamic changes in the metabolite profile and taste characteristics of Fu brick tea during the manufacturing process

Fu brick tea is a typical post-fermentation tea known for its special flavor and health benefits. Liquid chromatography-mass spectrometry, and sensory evaluation with multivariate analysis were used to characterize the dynamic changes in metabolite profile and taste characteristics. Seventy-one compounds were identified as critical metabolites, catechins, flavonoids, phenolic acids, terpenoids and others. During the manufacturing process, these compounds exhibited sharp fluctuations in content, the intensities of astringency, bitterness, and sourness of the tea materials reduced greatly, but the mellow intensity increased sharply. Several catechins and phenolic acids were positively related to the 'astringent', 'bitter', and 'sour' tastes attributes. The fungal genera, Aspergillus, Candida, unclassified_o_Hypocreales, unclassified_o_Saccharomycetales and Wallemia and the bacterial genus, Klebsiella, were identified as core functional microorganisms linked to the metabolic variations during the process. Overall, these findings provided a more comprehensive understanding of the formation of the sensory characteristics in Fu brick tea during the manufacturing process.

Genetic Manipulation and Transformation Methods for Aspergillus spp

Species of the genus Aspergillus have a variety of effects on humans and have been considered industrial cell factories due to their prominent ability for manufacturing several products such as heterologous proteins, secondary metabolites, and organic acids. Scientists are trying to improve fungal strains and re-design metabolic processes through advanced genetic manipulation techniques and gene delivery systems to enhance their industrial efficiency and utility. In this review, we describe the current status of the genetic manipulation techniques and transformation methods for species of the genus Aspergillus. The host strains, selective markers, and experimental materials required for the genetic manipulation and fungal transformation are described in detail. Furthermore, the advantages and disadvantages of these techniques are described.

Fruits and fruit by-products as sources of bioactive compounds. Benefits and trends of lactic acid fermentation in the development of novel fruit-based functional beverages

Current awareness about the benefits of a balanced diet supports ongoing trends in humans towards a healthier diet. This review provides an overview of fruits and fruit-by products as sources of bioactive compounds and their extraction techniques, and the use of lactic acid fermentation of fruit juices to increase their functionality. Fruit matrices emerge as a technological alternative to be fermented by autochthonous or allochthonous lactic acid bacteria (LAB such as Lactiplantibacillus plantarum, Lacticaseibacillus rhamnosus, and other Lactobacillus species), and also as probiotic vehicles. During fermentation, microbial enzymes act on several fruit phytochemicals producing new derived compounds with impact on the aroma and the functionality of the fermented drinks. Moreover, fermentation significantly reduces the sugar content improving their nutritional value and extending the shelf-life of fruit-based beverages. The generation of new probiotic beverages as alternatives to consumers with intolerance to lactose or with vegan or vegetarian diets is promising for the worldwide functional food market. An updated overview on the current knowledge of the use of fruit matrices to be fermented by LAB and the interaction between strains and the fruit phytochemical compounds to generate new functional foods as well as their future perspectives in association with the application of nanotechnology techniques are presented in this review.

Brewing Characteristics of the Maltotriose-Positive Yeast Zygotorulaspora florentina Isolated from Oak

The use of wild yeasts in fermentation is becoming a viable option for the differentiation of beers. To achieve good fermentation rates and alcohol yields, however, such yeasts must have the ability to utilize the wort sugars maltose and maltotriose, a relatively rare trait amongst non-domesticated yeasts. Zygotorulaspora florentina is a species with the ability to utilize both sugars, and was evaluated here with respect to its brewing potential. The strain studied (VTT C-201041) was isolated from bark of an oak tree (Quercus robur) in Espoo, Finland. The fermentation performance of the strain was compared to that of two ale yeasts as well as the species type strain (VTT C-94199). Both Z. florentina strains fermented wort efficiently (apparent attenuation levels >77%). While the type strain had the highest yield, the Finnish strain produced more volatile aroma compounds. The species is capable of decarboxylating ferulic acid to produce the spice/clove-like compound 4-vinylguaiacol, which was present in beers at a concentration above the typical flavor threshold. The characteristic flavor of 4-vinylguaiacol was not however perceptible in taste trials, possibly due to the masking effect of other compounds. The potential of this species for industrial application is discussed, particularly in relation to its apparent ethanol sensitivity.

Genome-wide comparison of Carnobacterium maltaromaticum derived from diseased fish harbouring important virulence-related genes

Although Carnobacterium maltaromaticum has been used as a probiotic in fish, it was reported to cause disease for the first time in Korea. The objective of this study was to understand the differences between pathogenic and non-pathogenic strains. Pathogenicity was tested by challenging rainbow trout with C. maltaromaticum ATCC35586 and 18ISCm isolated from diseased fish, and DSM20342 isolated from a dairy product. We also compared 24 genomes of C. maltaromaticum strains plus the genome of our isolate 18ISCm sequenced in this study. Only the strains from diseased fish caused high mortality with severe histopathological changes. Although all strains shared more than 90% of Ko_id, wecC and xtmA were found only in strains from diseased fish. Interestingly, only strains from diseased fish harboured two wecC paralogs involved in the production of D-mannosaminuronic acid which is a major component of a well-known virulence factor, teichuronic acid. Two wecC paralogs of 18ISCm were increased when they were co-cultured with trout blood cells, suggesting that wecC genes might play a role in virulence. The results of this study show that strains isolated from diseased fish are different from strains derived from food in terms of pathogenicity to fish and the presence of virulence-related genes.

The potential use of the Penicillium chrysogenum antifungal protein PAF, the designed variant PAFopt and its γ-core peptide Pγopt in plant protection

The prevention of enormous crop losses caused by pesticide-resistant fungi is a serious challenge in agriculture. Application of alternative fungicides, such as antifungal proteins and peptides, provides a promising basis to overcome this problem; however, their direct use in fields suffers limitations, such as high cost of production, low stability, narrow antifungal spectrum and toxicity on plant or mammalian cells. Recently, we demonstrated that a Penicillium chrysogenum-based expression system provides a feasible tool for economic production of P. chrysogenum antifungal protein (PAF) and a rational designed variant (PAFopt ), in which the evolutionary conserved γ-core motif was modified to increase antifungal activity. In the present study, we report for the first time that γ-core modulation influences the antifungal spectrum and efficacy of PAF against important plant pathogenic ascomycetes, and the synthetic γ-core peptide Pγopt , a derivative of PAFopt , is antifungal active against these pathogens in vitro. Finally, we proved the protective potential of PAF against Botrytis cinerea infection in tomato plant leaves. The lack of any toxic effects on mammalian cells and plant seedlings, as well as the high tolerance to harsh environmental conditions and proteolytic degradation further strengthen our concept for applicability of these proteins and peptide in agriculture.

Comparative metagenomics and characterization of antimicrobial resistance genes in pasteurized and homemade fermented Arabian laban

The aim of this study was to investigate bacterial diversity and function in a fermented milk drink called laban, which is traditionally served in the Middle East, Africa, and Indian subcontinent. Pasteurized laban (LBP) and unpasteurized, homemade, raw laban (LBR) underwent 16S rRNA gene amplicon and shotgun sequencing to analyze their bacterial community, presence of antimicrobial resistance genes (ARGs), and metabolic pathways. This study highlighted relatively greater diversity in LBR bacterial populations compared to LBP, despite containing similar major taxa that consisted primarily of Firmicutes followed by Proteobacteria, Bacteroidetes, and Actinobacteria. The dominant species, Streptococcus thermophilus, was relatively more abundant in LBP (80.7%) compared to LBR (47.9%). LBR had increased diversity and higher relative abundance of several known probiotic bacteria, such as Streptococcus salivarius and Lactococcus lactis, whereas Lactobacillus acidophilus was detected at a higher abundance in LBP. Pathogens like Acinetobacter baumannii, Streptococcus pneumoniae, Streptococcus pyogenes, and Escherichia coli had lower abundance in LBP compared to LBR. Thirty-three ARGs were detected in LBR compared to nine in LBP and are responsible for resistance to 11 classes of antibiotics. A significant proportion of the metagenomes from both types of laban were assigned to housekeeping functions, such as amino acid metabolism, translation, membrane transport, and carbohydrate metabolism. LBR demonstrated increased diversity in probiotics and metabolic functions compared to LBP. However, the relatively high diversity of pathogenic and opportunistic bacteria and ARGs in LBR raises safety concerns and highlights the need for a more hygienic environment for the processing of homemade fermented dairy foods.

The Penicillium chrysogenum Q176 Antimicrobial Protein PAFC Effectively Inhibits the Growth of the Opportunistic Human Pathogen Candida albicans

Small, cysteine-rich and cationic antimicrobial proteins (AMPs) from filamentous ascomycetes promise treatment alternatives to licensed antifungal drugs. In this study, we characterized the Penicillium chrysogenum Q176 antifungal protein C (PAFC), which is phylogenetically distinct to the other two Penicillium antifungal proteins, PAF and PAFB, that are expressed by this biotechnologically important ascomycete. PAFC is secreted into the culture broth and is co-expressed with PAF and PAFB in the exudates of surface cultures. This observation is in line with the suggested role of AMPs in the adaptive response of the host to endogenous and/or environmental stimuli. The in silico structural model predicted five β-strands stabilized by four intramolecular disulfide bonds in PAFC. The functional characterization of recombinant PAFC provided evidence for a promising new molecule in anti-Candida therapy. The thermotolerant PAFC killed planktonic cells and reduced the metabolic activity of sessile cells in pre-established biofilms of two Candidaalbicans strains, one of which was a fluconazole-resistant clinical isolate showing higher PAFC sensitivity than the fluconazole-sensitive strain. Candidacidal activity was linked to severe cell morphology changes, PAFC internalization, induction of intracellular reactive oxygen species and plasma membrane disintegration. The lack of hemolytic activity further corroborates the potential applicability of PAFC in clinical therapy.

Effect of Lb. plantarum BFE 5092 Fermentation on Antinutrient and Oligosaccharide Composition of Whole Red Haricot Bean (Phaseolus vulgaris L)

Common beans are a leguminous plant of the genus Phaseolus. They are rich in protein, energy, and minerals. They confer a wide range of health benefits when consumed. Utilization of common bean has however been poor due to high antinutrient content that results in reduced nutrient digestibility and mineral bioavailability. Flatulence after consumption is also a huge deterrent to common bean consumption. Lactic acid fermentation is the most common form of food fermentation with the Lactobacilli spp dominating most spontaneous fermentations. The objective of this study was to determine the effect of lactic acid bacteria (LAB) on the antinutrient and flatulence causing oligosaccharide composition of red haricot bean. A factorial research design was used in the study. Red haricot beans were sorted and soaked for 15 h. The soaked beans were fermented in 2% salt-sugar solutions for 120 h. Experimental batch was inoculated with Lb. plantarum BFE 5092 (IF), and the control batch was spontaneously fermented (SF). Microbial growth and pH were monitored every 24 h during fermentation. After fermentation, the beans were dried and milled, and the flours were subjected to biochemical analysis. ANOVA was done using SPSS statistics 23. The pH decreased significantly (P < 0.05) from 6.06 to 3.9 in both batches at the end of fermentation. The LAB counts significantly increased (P < 0.05) in both batches, whereas coliform counts decreased significantly (P < 0.05). Fungi were not detected in both batches. Soaking lowered tannins and phytates and raffinose concentrations significantly but had no significant effect on stachyose concentration. At the end of 120 h of fermentation, the tannin content was 109.50 and 54.04 mg/100 g in IF and SF, respectively. Phytates were at 242.52 and 163.43 mg/100 g in IF and SF, respectively. Raffinose content was 32.85 and 32.58 mg/100 g in IF and SF, respectively, while stachyose content was 593.33 and 467.49 mg/100 g in IF and SF, respectively. This research showed that LAB is able to ferment soaked whole red haricot and lower the tannin, phytate, raffinose, and stachyose content significantly. Spontaneous fermentation lowered these antinutrients and oligosaccharides better than inoculation with Lb. plantarum BFE 5092.

Current Functionality and Potential Improvements of Non-Alcoholic Fermented Cereal Beverages

Fermentation continues to be the most common biotechnological tool to be used in cereal-based beverages, as it is relatively simple and economical. Fermented beverages hold a long tradition and have become known for their sensory and health-promoting attributes. Considering the attractive sensory traits and due to increased consumer awareness of the importance of healthy nutrition, the market for functional, natural, and non-alcoholic beverages is steadily increasing all over the world. This paper outlines the current achievements and technological development employed to enhance the qualitative and nutritional status of non-alcoholic fermented cereal beverages (NFCBs). Following an in-depth review of various scientific publications, current production methods are discussed as having the potential to enhance the functional properties of NFCBs and their safety, as a promising approach to help consumers in their efforts to improve their nutrition and health status. Moreover, key aspects concerning production techniques, fermentation methods, and the nutritional value of NFCBs are highlighted, together with their potential health benefits and current consumption trends. Further research efforts are required in the segment of traditional fermented cereal beverages to identify new potentially probiotic microorganisms and starter cultures, novel ingredients as fermentation substrates, and to finally elucidate the contributions of microorganisms and enzymes in the fermentation process.

Sheep and Goat Meat Processed Products Quality: A Review

Even though sheep and goat processed meat products are not as popular as pork, beef or poultry and are generally considered not as important, they have a very important role in meat consumption around the world. A concise review of the origin and type of the most important sheep and goat processed meat products produced in different countries and world regions is made. The manuscript also summarizes the most recent studies on sheep and goat processed meats on the physicochemical characterizations, sensory quality, microbiological quality and safety. Some conclusions and future trends in production, processing and commercial potentiality for sheep and goat processed meat products are discussed. Several possibilities exist to make them more diversified and appealing to the market. Processing meat from culled animals is an interesting way to value animals with low market acceptability. Some as fermented sausages, cured legs and pâtés have great commercial potential as highly acceptable consumer commodities. An interesting field of food research is the rediscovery of a new generation of goat and sheep meat products as functional foods that will respond to the constant innovation required by the meat industry. Everything related to food safety must be considered in the future.

Understanding the Biosynthetic Changes that Give Origin to the Distinctive Flavor of Sotol: Microbial Identification and Analysis of the Volatile Metabolites Profiles During Sotol (Dasylirion sp.) Must Fermentation

In northern Mexico, the distilled spirit sotol with a denomination of origin is made from species of Dasylirion. The configuration of the volatile metabolites produced during the spontaneous fermentation of Dasylirion sp. must is insufficiently understood. In this study, the aim was to investigate the composition of the microbial consortia, describe the variation of volatile metabolites, and relate such profiles with their particular flavor attributes during the fermentation of sotol (Dasylirion sp.) must. Ascomycota was the phylum of most strains identified with 75% of total abundance. The genus of fermenting yeasts constituted of 101 Pichia strains and 13 Saccharomyces strains. A total of 57 volatile metabolites were identified and grouped into ten classes. The first stage of fermentation was composed of diesel, green, fruity, and cheesy attributes due to butyl 2-methylpropanoate, octan-1-ol, ethyl octanoate, and butanal, respectively, followed by a variation to pungent and sweet descriptors due to 3-methylbutan-1-ol and butyl 2-methylpropanoate. The final stage was described by floral, ethereal-winey, and vinegar attributes related to ethyl ethanimidate, 2-methylpropan-1-ol, and 2-hydroxyacetic acid. Our results improve the knowledge of the variations of volatile metabolites during the fermentation of sotol must and their contribution to its distinctive flavor.

Spontaneously fermented traditional beverages as a source of bioactive compounds: an overview

Fermented food has been present throughout history, since fermentation not only helps preserving food, but also provides specific organoleptic characteristics typically associated to these foods. Most of the traditional fermented foods and artisanal beverages are produced by spontaneous generation, meaning no control of the microbiota, or the substrate used. Nevertheless, even not being standardized, they are an important source of bioactive compounds, such as antioxidant compounds, bioactive beeps, short chain fatty acids, amino acids, vitamins, and minerals. This review compiles a list of relevant traditional fermented beverages around the world, aiming to detail the fermentation process itself-including source of microorganisms, substrates, produced metabolites and the operational conditions involved. As well as to list the bioactive compounds present in each fermented food, together with their impact in the human health. Traditional fermented beverages from Mexico will be highlighted. These compounds are of high interest for the food, pharmaceutical and cosmetics industry. To scale-up the home fermentation processes, it is necessary to fully understand the microbiology and biochemistry behind these traditional products. The use of good quality raw materials with standardized methodologies and defined microorganisms, may improve and increase the production of the desirable bioactive compounds and open a market for novel functional products.