Lactic Acid Fermentation of Cereals and Pseudocereals: Ancient Nutritional Biotechnologies with Modern Applications

Contributions of Gamma-Aminobutyric Acid (GABA) Produced by Lactic Acid Bacteria on Food Quality and Human Health: Current Applications and Future Prospects

The need to increase food safety and improve human health has led to a worldwide increase in interest in gamma-aminobutyric acid (GABA), produced by lactic acid bacteria (LABs). GABA, produced from glutamic acid in a reaction catalyzed by glutamate decarboxylase (GAD), is a four-carbon, non-protein amino acid that is increasingly used in the food industry to improve the safety/quality of foods. In addition to the possible positive effects of GABA, called a postbiotic, on neuroprotection, improving sleep quality, alleviating depression and relieving pain, the various health benefits of GABA-enriched foods such as antidiabetic, antihypertension, and anti-inflammatory effects are also being investigated. For all these reasons, it is not surprising that efforts to identify LAB strains with a high GABA productivity and to increase GABA production from LABs through genetic engineering to increase GABA yield are accelerating. However, GABA's contributions to food safety/quality and human health have not yet been fully discussed in the literature. Therefore, this current review highlights the synthesis and food applications of GABA produced from LABs, discusses its health benefits such as, for example, alleviating drug withdrawal syndromes and regulating obesity and overeating. Still, other potential food and drug interactions (among others) remain unanswered questions to be elucidated in the future. Hence, this review paves the way toward further studies.

Bacterial Degradation of Antinutrients in Foods: The Genomic Insight

Antinutrients, also known as anti-nutritional factors (ANFs), are compounds found in many plant-based foods that can limit the bioavailability of nutrients or can act as precursors to toxic substances. ANFs have controversial effects on human health, depending mainly on their concentration. While the positive effects of these compounds are well documented, the dangers they pose and the approaches to avoid them have not been discussed to the same extent. There is no dispute that many ANFs negatively alter the absorption of vitamins, minerals, and proteins in addition to inhibiting some enzyme activities, thus negatively affecting the bioavailability of nutrients in the human body. This review discusses the chemical properties, plant bioavailability, and deleterious effects of anti-minerals (phytates and oxalates), glycosides (cyanogenic glycosides and saponins), polyphenols (tannins), and proteinaceous ANFs (enzyme inhibitors and lectins). The focus of this study is on the possibility of controlling the amount of ANF in food through fermentation. An overview of the most common biochemical pathways for their microbial reduction is provided, showing the genetic basis of these phenomena, including the active enzymes, the optimal conditions of action, and some data on the regulation of their synthesis.

Wholegrain triticale sourdough: Effects of triticale:Wheat flour ratio and hydration level on bread quality

Triticale (×Triticosecale) is a hybrid between wheat (Triticum spp.) and rye (Secale cereale), producing higher grain yields than wheat in challenging environments. Triticale grain is also highly nutritious. Thus, the potential of triticale grain for an expanded range of food applications should be explored. Sourdough bread has unique functional and nutritional properties, but understanding the effects of partial substitution of triticale for wheat flour and varying levels of dough moisture content on sourdough quality requires further research. The aim of this study was to evaluate the wholegrain flour of contrasting triticale cultivars in comparison to that of a common wheat cultivar in commercial sourdough breadmaking. Two triticale cultivars (Goanna and Hawkeye, selected from a panel of Australian genotypes) and one wheat cultivar (Scout) were grown in a field trial in northern NSW, Australia. Differences in quantitative texture and color parameters of the dough and sourdough bread resulting from (1) substitution of commercial wholemeal wheat flour with different proportions of wholegrain triticale or wholegrain wheat (Scout) flour (0%, 60%, 70%, 80%, and 90%) and (2) varying the amount of water included in the dough preparation (70%, 80%, 90%, and 100 g water/100 g flour) were determined. Replacement of wholemeal wheat flour with 60% wholegrain Goanna flour (protein content 12.76%; c.f. 11.50% for Hawkeye, 12.40% for Scout), and addition of 100 g water/100 g flour in the dough preparation gave the highest quality sourdough bread based on specific volume, texture, and color parameters and had similar properties to the control made from wheat alone.

Screening of Lactic Acid Bacteria Strains for Potential Sourdough and Bread Applications: Enzyme Expression and Exopolysaccharide Production

Twenty-eight strains of lactic acid bacteria (LAB) were characterized for the ability to express enzymes of interest (including protease, xylanase, α-amylase, laccase, and glucose oxidase) as well as the ability to produce exopolysaccharide (EPS). The screening of enzyme capability for all LAB strains proceeded in a progressive 3-stage manner that helps to profile the efficiency of LAB strains in expressing chosen enzymes (Stage 1), highlights the strains with affinity for flour as the substrate (Stage 2), and discerns strains that can adapt well in a simulated starter environment (Stage 3). The theoretical ability of LAB to express these enzymes was also assessed using Basic Local Alignment Search Tool (BLAST) analysis to identify the underlying genes in the whole genome sequence. By consolidating both experimental data and information obtained from BLAST, three LAB strains were deemed optimal in expressing enzymes, namely, Lb. delbrueckii subsp. bulgaricus (RBL 52), Lb. rhamnosus (RBL 102), and Lb. plantarum (ATCC 10241). Meanwhile, EPS-producing capabilities were observed for 10 out of 28 LAB strains, among which, Lactococcus lactis subsp. diacetylactis (RBL 37) had the highest total EPS yield (274.15 mg polysaccharide/L culture) and produced 46.2% polysaccharide with a molecular mass of more than 100 kDa.

Bio-functional and prebiotics properties of products based on whole grain sorghum fermented with lactic acid bacteria

BACKGROUND

Products fermented with lactic acid bacteria based on whole grain flours of red or white sorghum (Sorghum bicolor (L.) Moench) added with malted sorghum flour, or with skim milk (SM) were developed. Composition, protein amino acid profile, total acidity, pH, prebiotic potential, and bio-functional properties after simulation of gastrointestinal digestion were evaluated.

RESULTS

In all cases, a pH of 4.5 was obtained in approximately 4.5 h. The products added with SM presented higher acidity. Products made only with sorghum presented higher total dietary fiber, but lower protein content than products with added SM, the last ones having higher lysine content. All products exhibited prebiotic potential, white sorghum being a better ingredient to promote the growth of probiotic bacteria. The addition of malted sorghum or SM significantly increased the bio-functional properties of the products: the sorghum fermented products added with SM presented the highest antioxidant (ABTS•+ inhibition, 4.7 ± 0.2 mM Trolox), antihypertensive (Angiotensin converting enzyme-I inhibition, 57.3 ± 0.5%) and antidiabetogenic (dipeptidyl-peptidase IV inhibition, 31.3 ± 2.1%) activities, while the products added with malted sorghum presented the highest antioxidant (reducing power, 1.6 ± 0.1 mg ascorbic acid equivalent/mL) and antidiabetogenic (α-amylase inhibition, 38.1 ± 0.9%) activities.

CONCLUSION

The fermented whole grain sorghum-based products could be commercially exploited by the food industry to expand the offer of the three high-growth markets: gluten-free products, plant-based products (products without SM), and functional foods. © 2023 Society of Chemical Industry.

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

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

What are the main obstacles to turning foods healthier through probiotics incorporation? a review of functionalization of foods by probiotics and bioactive metabolites

Functional foods are gaining significant attention from people all over the world. When added to foods, probiotic bacteria can turn them healthier and confer beneficial health effects, such as improving the immune system and preventing cancer, diabetes, and cardiovascular disease. However, adding probiotics to foods is a challenging task. The processing steps often involve high temperatures, and intrinsic food factors, such as pH, water activity, dissolved oxygen, post-acidification, packaging, and cold storage temperatures, can stress the probiotic strain and impact its viability. Moreover, it is crucial to consider these factors during food product development to ensure the effectiveness of the probiotic strain. Among others, techniques such as microencapsulation and lyophilization, have been highlighted as industrial food functionalization strategies. In this review, we present and discuss alternatives that may be used to functionalize foods by incorporating probiotics and/or delivering bioactive compounds produced by probiotics. We also emphasize the main challenges in different food products and the technological characteristics influencing them. The knowledge available here may contribute to overcoming the practical obstacles to food functionalization with probiotics.

Microbial Phytases: Properties and Applications in the Food Industry

Microbial phytases are enzymes that break down phytic acid, an anti-nutritional compound found in plant-based foods. These enzymes which are derived from bacteria and fungi have diverse properties and can function under different pH and temperature conditions. Their ability to convert phytic acid into inositol and inorganic phosphate makes them valuable in food processing. The application of microbial phytases in the food industry has several advantages. Firstly, adding them to animal feedstuff improves phosphorus availability, leading to improved nutrient utilization and growth in animals. This also reduces environmental pollution by phosphorus from animal waste. Secondly, microbial phytases enhance mineral bioavailability and nutrient assimilation in plant-based food products, counteracting the negative effects of phytic acid on human health. They can also improve the taste and functional properties of food and release bioactive compounds that have beneficial health effects. To effectively use microbial phytases in the food industry, factors like enzyme production, purification, and immobilization techniques are important. Genetic engineering and protein engineering have enabled the development of phytases with improved properties such as enhanced stability, substrate specificity, and resistance to degradation. This review provides an overview of the properties and function of phytases, the microbial strains that produce them, and their industrial applications, focusing on new approaches.

Fermented Kamut Sprout Extract Decreases Cell Cytotoxicity and Increases the Anti-Oxidant and Anti-Inflammation Effect

Kamut sprouts (KaS) contain several biologically active compounds. In this study, solid-state fermentation using Saccharomyces cerevisiae and Latilactobacillus sakei was used to ferment KaS (fKaS-ex) for 6 days. The fKaS-ex showed a 26.3 mg/g dried weight (dw) and 46.88 mg/g dw of polyphenol and the β-glucan contents, respectively. In the Raw264.7 and HaCaT cell lines, the non-fermented KaS (nfKaS-ex) decreased cell viability from 85.3% to 62.1% at concentrations of 0.63 and 2.5 mg/mL, respectively. Similarly, the fKaS-ex decreased cell viability, but showed more than 100% even at 1.25 and 5.0 mg/mL concentrations, respectively. The anti-inflammatory effect of fKaS-ex also increased. At 600 µg/mL, the fKaS-ex exhibited a significantly higher ability to reduce cytotoxicity by suppressing COX-2 and IL-6 mRNA expressions as well as that for IL-1β mRNA. In summary, fKaS-ex exhibited significantly lower cytotoxicity and increased anti-oxidant and anti-inflammatory properties, indicating that fKaS-ex is beneficial for use in food and other industries.

Applicable Strains, Processing Techniques and Health Benefits of Fermented Oat Beverages: A Review

Based on the high nutrients of oat and the demand of health-conscious consumers for value-added and functional foods, fermented oat beverages have great market prospects. This review summarizes the applicable strains, processing techniques and health benefits of fermented oat beverages. Firstly, the fermentation characteristics and conditions of the applicable strains are systematically described. Secondly, the advantages of pre-treatment processes such as enzymatic hydrolysis, germination, milling and drying are summarized. Furthermore, fermented oat beverages can increase the nutrient content and reduce the content of anti-nutritional factors, thereby reducing some risk factors related to many diseases such as diabetes, high cholesterol and high blood pressure. This paper discusses the current research status of fermented oat beverages, which has academic significance for researchers interested in the application potential of oat. Future studies on fermenting oat beverages can focus on the development of special compound fermentation agents and the richness of their taste.

Recent advances in modified poly (lactic acid) as tissue engineering materials

As an emerging science, tissue engineering and regenerative medicine focus on developing materials to replace, restore or improve organs or tissues and enhancing the cellular capacity to proliferate, migrate and differentiate into different cell types and specific tissues. Renewable resources have been used to develop new materials, resulting in attempts to produce various environmentally friendly biomaterials. Poly (lactic acid) (PLA) is a biopolymer known to be biodegradable and it is produced from the fermentation of carbohydrates. PLA can be combined with other polymers to produce new biomaterials with suitable physicochemical properties for tissue engineering applications. Here, the advances in modified PLA as tissue engineering materials are discussed in light of its drawbacks, such as biological inertness, low cell adhesion, and low degradation rate, and the efforts conducted to address these challenges toward the design of new enhanced alternative biomaterials.

The Contribution of Scalded and Scalded-Fermented Rye Wholemeal Flour to Quality Parameters and Acrylamide Formation in Semi-Wheat-Rye Bread

The aim of this study was to evaluate the influence of scalded (Sc) and scalded-fermented (FSc) (with Lactiplantibacillus paracasei No. 244 strain) rye wholemeal flour on the quality parameters and acrylamide formation in semi-wheat-rye bread. To that purpose, 5, 10 and 15% of Sc and FSc were used for bread production. Results showed that scalding increased fructose, glucose and maltose content in rye wholemeal. Lower concentrations of free amino acids were found in Sc when compared with rye wholemeal, but fermentation of Sc increased the concentrations of some amino acids (on average by 1.51 times), including gamma aminobutyric acid (GABA, by 1.47 times). Addition of Sc and FSc had a significant influence (p ≤ 0.05) on bread shape coefficient, mass loss after baking and most bread colour coordinates. Most of the breads with Sc or FSc showed lower hardness after 72 h of storage compared with the control (i.e., without Sc or FSc). FSc improved bread colour and flavour, as well as overall acceptability. Breads with 5 and 10% of Sc had a similar level of acrylamide to the control, while its level in breads with FSc was higher (on average, 236.3 µg/kg). Finally, different types and amounts of scald had varying effects on the quality of the semi-wheat-rye bread. FSc delayed staling and improved sensory properties and acceptability, as well as the GABA level of wheat-rye bread, while the same level of acrylamide as was seen in control bread could be reached when using between 5 and 10% of scalded rye wholemeal flour.

Nutritional and bioactive characteristics of buckwheat, and its potential for developing gluten‐free products: An updated overview

In the present era, food scientists are concerned about exploiting functional crops with nutraceutical properties. Buckwheat is one of the functional pseudocereals with nutraceutical components used in the treatment of health-related diseases, malnutrition, and celiac diseases. As a preferred diet as a gluten-free product for celiac diseases, buckwheat is a good source of nutrients, bioactive components, phytochemicals, and antioxidants. The general characteristics and better nutritional profile of buckwheat than other cereal family crops were highlighted by previous investigations. In buckwheats, bioactive components like peptides, flavonoids, phenolic acids, d-fagomine, fagopyritols, and fagopyrins are posing significant health benefits. This study highlights the current knowledge about buckwheat and its characteristics, nutritional constituents, bioactive components, and their potential for developing gluten-free products to target celiac people (1.4% of the world population) and other health-related diseases.

Investigating the Probiotic Properties and Antimicrobial Activity of Lactic Acid Bacteria Isolated from an Iranian Fermented Dairy Product, Kashk

In the present study, kashk samples were collected from two regions of Iran, the Fars (Abadeh) and Razavi Khorasan (Kalat) provinces. Fifteen bacteria were isolated and physiological and biochemical assays were performed. After identification to the genus level, eight isolates were identified as lactic acid bacteria (LAB) and subjected to molecular identification and probiotic properties assays. The results revealed that the isolates were Enterococcus faecium KKP 3772 (KF1), Enterococcus faecium C1 (KF2), Pediococcus pentosaceus H11 (KF3), Pediococcus pentosaceus VNK-1 (KK4), Lactococcus lactis RSg (KK1), Enterococcus faecalis P190052 (KK2), Enterococcus mundtii CECT972T (KK3), and Lactiplantibacillus plantarum PM411 (KK5). Only the numbers of L. lactis RSg (KK1) and Lpb. Plantarum PM411 (KK5) decreased to below 9 Log CFU/mL after acidic conditions (pH = 3) and showed weak antibacterial activity. Enterococcus mundtii CECT972T (KK3) and E. faecium C1(KF2) were highly susceptible to bile salts, while P. pentosaceus VNK-1 (KK4) and P. pentosaceus H11 (KF3) showed the highest resistance. All of the isolates were resistant to tetracycline and sensitive to chloramphenicol and gentamicin. The antimicrobial activity of P. pentosaceus VNK-1 (KK4) and P. pentosaceus H11 (KF3) was higher than other isolates and consequently, their inhibition zones were larger. The adhesion capabilities of LAB isolates to intestinal epithelial cells were evaluated by examining the auto-aggregation factor and cell surface hydrophobicity. The highest and lowest cell surface hydrophobicity and auto-aggregation were obtained from P. pentosaceus VNK-1 (KK4) and E. mundtii CECT972T (KK3), respectively. In general, P. pentosaceus VNK-1 (KK4) and P. pentosaceus H11 (KF3) have shown better probiotic properties as compared to other isolates.

Lactate drives cellular DNA repair capacity: Role of lactate and related short-chain fatty acids in cervical cancer chemoresistance and viral infection

The characteristic feature of a cancer microenvironment is the presence of a highly elevated concentration of L-lactate in the tumor niche. The lactate-rich environment is also maintained by commensal mucosal microbiota, which has immense potential for affecting cancer cells through its receptoric and epigenetic modes of action. Some of these lactate activities might be associated with the failure of anticancer therapy as a consequence of the drug resistance acquired by cancer cells. Upregulation of cellular DNA repair capacity and enhanced drug efflux are the most important cellular mechanisms that account for ineffective radiotherapy and drug-based therapies. Here, we present the recent scientific knowledge on the role of the HCA1 receptor for lactate and lactate intrinsic activity as an HDAC inhibitor in the development of an anticancer therapy-resistant tumor phenotype, with special focus on cervical cancer cells. In addition, a recent study highlighted the viable role of interactions between mammalian cells and microorganisms in the female reproductive tract and demonstrated an interesting mechanism regulating the efficacy of retroviral transduction through lactate-driven modulation of DNA-PKcs cellular localization. To date, very few studies have focused on the mechanisms of lactate-driven enhancement of DNA repair and upregulation of particular multidrug-resistance proteins in cancer cells with respect to their intracellular regulatory mechanisms triggered by lactate. This review presents the main achievements in the field of lactate impact on cell biology that may promote undesirable alterations in cancer physiology and mitigate retroviral infections.

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.

Role of lactic acid bacteria and yeasts in sourdough fermentation during breadmaking: Evaluation of postbiotic-like components and health benefits

Sourdough (SD) fermentation is a traditional biotechnological process used to improve the properties of baked goods. Nowadays, SD fermentation is studied for its potential health effects due to the presence of postbiotic-like components, which refer to a group of inanimate microorganisms and/or their components that confer health benefits on the host. Some postbiotic-like components reported in SD are non-viable microorganisms, short-chain fatty acids, bacteriocins, biosurfactants, secreted proteins/peptides, amino acids, flavonoids, exopolysaccharides, and other molecules. Temperature, pH, fermentation time, and the composition of lactic acid bacteria and yeasts in SD can impact the nutritional and sensory properties of bread and the postbiotic-like effect. Many in vivo studies in humans have associated the consumption of SD bread with higher satiety, lower glycemic responses, increased postprandial concentrations of short-chain fatty acids, and improvement in the symptoms of metabolic or gastrointestinal-related diseases. This review highlights the role of bacteria and yeasts used for SD, the formation of postbiotic-like components affected by SD fermentation and the baking process, and the implications of functional SD bread intake for human health. There are few studies characterizing the stability and properties of postbiotic-like components after the baking process. Therefore, further research is necessary to develop SD bread with postbiotic-related health benefits.

Changes in the content of glucosinolates, polyphenols and carotenoids during lactic-acid fermentation of cruciferous vegetables: a mini review

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Cruciferous vegetables as fermented products has been used since ancient times.

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During fermentation of cruciferous vegetables complete fermentation of glucosinolates occur.

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Fermentation decrease the content of complex polyphenols, while increase the content of polyphenols in free form.

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Carotenoid content decrease during fermentation of cruciferous vegetables.

Cruciferous vegetables are considered functional foods because of their content of health-related compounds. They are grown and consumed in various cultures around the world. Fermentation as a preservation method for cruciferous vegetables has been used since ancient times. This process results in fermented products that have a unique flavour and odour, high bioactivity, and a distinctly different phytochemical profile than raw vegetables. In this mini review, we summarize data on changes in phytochemical content during lactic-acid fermentation of various cruciferous vegetables. The main focus was on the changes in the group of glucosinolates, polyphenols and carotenoids.

Effect of Fermentation on the Biochemical Parameters Antioxidant Capacity and Dispersed Composition of Plant Beverages Based on Barley and Hemp Seeds

Enzymatic processes play a key role in the production of grain-containing food due to their effect on the nutritional properties, rheological characteristics, and contribution to improving the functional and antioxidant proprieties. Eight samples of beverages based on barley grain and hemp seeds were produced (control beverages and beverages fermented by bifidobacteria and propionic acid bacteria). It was found that lactic acid accumulated during fermentation alongside a gradual shift in the pH level in the acidic direction. A comparative analysis of the DPPH activity revealed the highest values for barley-based beverages, ranging from 71.0 to 100.7%, while for the hemp seed-based beverages, the DPPH activity was 64.1–97.9%. The maximum values of DPPH activity were observed during fermentation with a combination of bifidobacteria and propionic acid bacteria concentrates. The highest concentration of polyphenolic compounds and flavonoids was found in barley-based beverages fermented with Propionibacterium freudenreichii (1.26 mg GAE/g and 0.11 mg EQ/g) and a combination of Propionibacterium freudenreichii and Bifidobacterium longum (1.24 mg GAE/g and 0.14 mg EQ/g). Studies have shown an increase in the nutrient content for fermented beverages compared to the control samples. The barley-based beverages exhibited the largest average dynamic particle diameter, and all beverage samples showed a more uniform particle size distribution after microbial fermentation.

The Complex Role of Lactic Acid Bacteria in Food Detoxification

Toxic ingredients in food can lead to serious food-related diseases. Such compounds are bacterial toxins (Shiga-toxin, listeriolysin, Botulinum toxin), mycotoxins (aflatoxin, ochratoxin, zearalenone, fumonisin), pesticides of different classes (organochlorine, organophosphate, synthetic pyrethroids), heavy metals, and natural antinutrients such as phytates, oxalates, and cyanide-generating glycosides. The generally regarded safe (GRAS) status and long history of lactic acid bacteria (LAB) as essential ingredients of fermented foods and probiotics make them a major biological tool against a great variety of food-related toxins. This state-of-the-art review aims to summarize and discuss the data revealing the involvement of LAB in the detoxification of foods from hazardous agents of microbial and chemical nature. It is focused on the specific properties that allow LAB to counteract toxins and destroy them, as well as on the mechanisms of microbial antagonism toward toxigenic producers. Toxins of microbial origin are either adsorbed or degraded, toxic chemicals are hydrolyzed and then used as a carbon source, while heavy metals are bound and accumulated. Based on these comprehensive data, the prospects for developing new combinations of probiotic starters for food detoxification are considered.

Engineered Biofilm: Innovative Nextgen Strategy for Quality Enhancement of Fermented Foods

Microbial communities within fermented food (beers, wines, distillates, meats, fishes, cheeses, breads) products remain within biofilm and are embedded in a complex extracellular polymeric matrix that provides favorable growth conditions to the indwelling species. Biofilm acts as the best ecological niche for the residing microbes by providing food ingredients that interact with the fermenting microorganisms' metabolites to boost their growth. This leads to the alterations in the biochemical and nutritional quality of the fermented food ingredients compared to the initial ingredients in terms of antioxidants, peptides, organoleptic and probiotic properties, and antimicrobial activity. Microbes within the biofilm have altered genetic expression that may lead to novel biochemical pathways influencing their chemical and organoleptic properties related to consumer acceptability. Although microbial biofilms have always been linked to pathogenicity owing to its enhanced antimicrobial resistance, biofilm could be favorable for the production of amino acids like l-proline and L-threonine by engineered bacteria. The unique characteristics of many traditional fermented foods are attributed by the biofilm formed by lactic acid bacteria and yeast and often, multispecies biofilm can be successfully used for repeated-batch fermentation. The present review will shed light on current research related to the role of biofilm in the fermentation process with special reference to the recent applications of NGS/WGS/omics for the improved biofilm forming ability of the genetically engineered and biotechnologically modified microorganisms to bring about the amelioration of the quality of fermented food.

Lactic acid bacteria: isolation-characterization approaches and industrial applications

The current state-of-art research pertaining to lactic acid bacteria (LAB) calls for the screening and isolation of robust LAB strains to achieve holistic exploitation of LAB and their metabolites of marketable importance. Hence it is imperative to comprehend LAB sources, growth requisites, isolation and characterization strategies necessary for featured cataloging and appropriate culturing. This review comprehensively describes various growth media and biomasses used for supporting LAB sustenance, assay procedures needed for the isolation and characterization of LAB strains, and their application in diverse sectors. The various industrial patents and their summarized claims about novel LAB strains isolated and identified, methods and media (used for detection/screening, isolation, adaptation, culturing, preservation, growth improvement), the techniques and/or methodologies supporting LAB fermentation, and applications of produced industrial metabolites in various market scenarios are detailed.

A Review on Factors Influencing the Fermentation Process of Teff (Eragrostis teff) and Other Cereal-Based Ethiopian Injera

Fermented foods and beverages are the product of the enzymaticcally transformed food components which are acived by different microorganisms. Fermented foods have grown in popularity in recent years because of their alleged health benefits. Biogenic amines, bioactive peptides, antinutrient reduction, and polyphenol conversion to physiologically active chemicals are all possible health benefits of fermentation process products. In Ethiopian-fermented foods, which are mostly processed using spontaneous fermentation process. Injera is one of the fermented food products consumed in all corners of the country which sourdough fermentation could be achieved using different LAB and yeast strains. Moreover, the kind and concentration of the substrate and the type of microbial flora, as well as temperature, air supply, and pH, all influence the fermentation process of injera. This review article gives an overview of factors influencing the fermentation process of teff ('Eragrostis tef.') and other cereal-based Ethiopian injera.

Ingredients, Processing, and Fermentation: Addressing the Organoleptic Boundaries of Plant-Based Dairy Analogues

Consumer interest and research in plant-based dairy analogues has been growing in recent years because of increasingly negative implications of animal-derived products on human health, animal wellbeing, and the environment. However, plant-based dairy analogues face many challenges in mimicking the organoleptic properties of dairy products due to their undesirable off-flavours and textures. This article thus reviews fermentation as a viable pathway to developing clean-label plant-based dairy analogues with satisfactory consumer acceptability. Discussions on complementary strategies such as raw material selection and extraction technologies are also included. An overview of plant raw materials with the potential to be applied in dairy analogues is first discussed, followed by a review of the processing steps and innovative techniques required to transform these plant raw materials into functional ingredients such as plant-based aqueous extracts or flours for subsequent fermentation. Finally, the various fermentation (bacterial, yeast, and fungal) methodologies applied for the improvement of texture and other sensory qualities of plant-based dairy analogues are covered. Concerted research efforts would be required in the future to tailor and optimise the presented wide diversity of options to produce plant-based fermented dairy analogues that are both delicious and nutritionally adequate.

Overview of fermentation process: structure-function relationship on protein quality and non-nutritive compounds of plant-based proteins and carbohydrates

Demands for high nutritional value-added food products and plant-based proteins have increased over the last decade, in line with the growth of the human population and consumer health awareness. The quality of the plant-based proteins depends on their digestibility, amino acid content, and residues of non-nutritive compounds, such as phenolic compounds, anti-nutritional compounds, antioxidants, and saponins. The presence of these non-nutritive compounds could have detrimental effects on the quality of the proteins. One of the solutions to address these shortcomings of plant-based proteins is fermentation, whereby enzymes that present naturally in microorganisms used during fermentation are responsible for the cleavage of the bonds between proteins and non-nutritive compounds. This mechanism has pronounced effects on the non-nutritive compounds, resulting in the enhancement of protein digestibility and functional properties of plant-based proteins. We assert that the types of plant-based proteins and microorganisms used during fermentation must be carefully addressed to truly enhance the quality, functional properties, and health functionalities of plant-based proteins.Supplemental data for this article is available online at here. show.

Fermentation of Cereals and Legumes: Impact on Nutritional Constituents and Nutrient Bioavailability

Fermented food products, especially those derived from cereals and legumes are important contributors to diet diversity globally. These food items are vital to food security and significantly contribute to nutrition. Fermentation is a process that desirably modifies food constituents by increasing the palatability, organoleptic properties, bioavailability and alters nutritional constituents. This review focuses on deciphering possible mechanisms involved in the modification of nutritional constituents as well as nutrient bioavailability during the fermentation of cereals and legumes, especially those commonly consumed in developing countries. Although modifications in these constituents are dependent on inherent and available nutrients in the starting raw material, it was generally observed that fermentation increased these nutritive qualities (protein, amino acids, vitamins, fats, fatty acids, etc.) in cereals and legumes, while in a few instances, a reduction in these constituents was noted. A general reduction trend in antinutritional factors was also observed with a corresponding increase in the nutrient bioavailability and bioaccessibility. Notable mechanisms of modification include transamination or the synthesis of new compounds during the fermentation process, use of nutrients as energy sources, as well as the metabolic activity of microorganisms leading to a degradation or increase in the level of some constituents. A number of fermented products are yet to be studied and fully understood. Further research into these food products using both conventional and modern techniques are still required to provide insights into these important food groups, as well as for an overall improved food quality, enhanced nutrition and health, as well as other associated socioeconomic benefits.

Developing lactic acid bacteria starter cultures for wholemeal rye flour bread with improved functionality, nutritional value, taste, appearance and safety

Starter cultures composed of lactic acid bacteria (LAB) were developed based on the genotypic and phenotypic characterisation of isolates belonging to dominant groups of bacteria in spontaneous rye wholemeal sourdoughs. Combinations of strains have been evaluated on an industrial scale in the sourdough fermentation process. Wholemeal rye bread was prepared using sourdoughs obtained with 3 new starter cultures, and compared to bread made using the commercial culture (LV2). All newly developed cultures used for the preparation of wholemeal rye bread allowed to obtain better quality products as compared to the LV2 based bread. The best results were obtained when the culture containing Lactiplantibacillus plantarum 2MI8 and exopolysaccharide (EPS)-producing Weissella confusa/cibaria 6PI3 strains was applied. The addition of yeast during sourdough breads production, especially the one prepared from mentioned above starter culture, significantly improved their organoleptic properties, their volume and crumb moisture was increased, and also the crumb acidity and hardness was reduced. Fermentation of rye wholemeal dough, especially without the yeast addition, resulted in a significant reduction in the content of higher inositol phosphates as compared to the applied flour, which is associated with improved bioavailability of minerals. The results of this study prove that the investigated new starter cultures can be successfully applied in wholemeal rye bread production.

Enriching Lactobacilli from Fermented Pulse Dal Flour-Analyzing its Efficacy in Utilizing Carbohydrates and Production of α-galactosidase Enzyme During Pigeon Pea Fermentation

Pigeon peas are an excellent source of carbohydrates, proteins and other nutrients. Many traditional fermented foods are prepared from cereals and combinations of cereals and pulses that usually contain Lactic acid bacteria (LAB), Bacillus, Enterococcus and yeast. Lactobacillus can be used as a starter culture for such fermentation using pulses, as very few reports are available on fermented pulse-based products. Hence, pulse dal flour was used as a source for isolation of Lactobacillus to maintain their functionality, growth characteristics and activity during food processing. In this study, we investigated the potential of lactobacilli from fermented pigeon pea to utilize carbohydrates, the ability to degrade non-digestible oligosaccharides and the production of the α-galactosidase enzyme. Lactobacillus isolated from six different pulse dal flour grew well during fermentation with carbohydrates in mMRS medium. Among Lactobacillus species, only Lactobacillus brevis displayed the highest α-galactosidase activity (1.24 U/ml), where raffinose was added as the sole carbohydrate source in the medium. The isolate was further tested in pigeon pea fermentation, where it showed maximum activity (1.86 U/ml) and complete hydrolysis of non-digestible oligosaccharides was observed. Overall, usage of Lactobacilli could be an excellent opportunity to design and develop a novel pulse-based fermented product contributing to beneficial bioactive compounds and improving the properties of food.

Leuconostoc mesenteroides and Pediococcus pentosaceus Non-Alcoholic Pearl Millet Beverage Enriched with Moringa oleifera Leaf Powder: Nutritional and Sensory Characteristics

Non-alcoholic cereal beverages (NACB) are usually produced through uncontrolled fermentation driven by a cocktail of bacteria resulting in final product variability. Hence, to commercialise fermented traditional cereal beverages bioburden microbial cultures are required. This investigation aimed to evaluate the physicochemical, nutritional, and sensory characteristics of NACB produced using pure cultures of Leuconostoc mesenteroides and Pediococcus pentosaceus. Pearl millet extract (PME) pasteurised at 85 °C for 15 min and cooled to 40 °C was inoculated with Leuconostoc mesenteroides and Pediococcus pentosaceus at 0.050% and 0.025% (1:0.5), respectively, and fermented at 37 °C for 18 h, referred to as plain non-alcoholic pearl millet beverage (PNAPMB). Moringa supplemented non-alcoholic pearl millet beverage (MSNAPMB) was produced following the same method as PNAPMB but a 4% moringa leaf extract powder was added before hydration of the pearl millet powder. The traditional non-alcoholic pearl millet beverage (TNAPMB) was prepared by mixing water and pearl millet flour (1:1.25; PMF:Water) and hydrated for 3 h at 25 °C. The mixture was divided into ¼ slurry which was mixed with sprouted rice flour (SRF) and ¾ portion that was gelatinised with 1 L of boiling water and cooled to 40 °C. The two portions were mixed and fermented at 37 °C for 18 h, followed by sieving, dilution with water (1:0.5, filtrate:water), and pasteurization for 15 min at 85 °C. The growth of lactic acid bacteria, pH, total titratable acidity (TTA), and sugar in PNAPMB and MSNAPMB were determined at 3 h intervals during fermentation. The final beverages were also analysed for proximate, colour and metabolites. The lactic acid bacteria were significantly (p < 0.05) affected by the fermentation period and increased from 3.32 to 7.97 log CFU/mL (pH 4.14) and 3.58 to 8.38 log CFU/mL (pH 3.65) for PNAPMB and MSNAPMB, respectively. The total titratable acidity significantly (p < 0.05) increased from 0.14 to 0.22% and from 0.17 to 0.38% in PNAPMB and MSNAPMB, respectively. The protein, total fat, moisture total sugar, and carbohydrates differed significantly (p < 0.05) among the samples. PNAPMB was preferred by a consumer panel followed by MSNAPMB and TNAPMB. Volatile compounds with beneficial anti-inflammatory and anti-pathogenic properties were identified in the beverages. Innovative fermentation of pearl millet extract using purified bioburden cultures was possible and the added Moringa oleifera leaf powder improved the nutritional quality of the resulting beverage.

Recent developments and knowledge in pseudocereals including technological aspects

Amaranth, buckwheat, quinoa, and less known, canihua are the most important pseudocereals. Their high nutritional value is well recognized and they are increasingly used for the development of a wide range of starch-based foods, which has been fostered by intensified research data performed in recent years. In addition to health driven motivations, also environmental aspects like the ongoing climate change are an important stimulus to increase agricultural biodiversity again. As pseudocereals are botanically classified as dicotyledonous plants their chemical, physical and processing properties differ significantly from the monocotyledonous cereals. Most important factors that need to be addressed for processing is their smaller seed kernel size, their specific starch structure and granule architecture, their gluten-free protein, but also their dietary fibre and secondary plant metabolites composition. This review gives a condensed overview of the recent developments and gained knowledge with special attention to the technological and food processing aspects of these pseudocereals.

Ancient Wheat Species: Biochemical Profile and Impact on Sourdough Bread Characteristics—A Review

In recent years, the attention of farmers, bakers and consumers towards ancient wheat species has been increasing. Low demands of pedo-climatic growth factors, the suitability for organic cultivation along with their high nutritional quality and their content in pro-health compounds make them extremely attractive for bakers and modern consumers, equally. On the other hand, in recent years, sourdough has gained attention due to its ability to produce new functionally active molecules with higher bioaccessibility and thus to produce bread with enhanced nutritional quality. This paper highlights the relevant nutritional profile of einkorn, spelt, emmer and Khorasan which could lead to bread with improved textural, sensorial, microbial and nutritional characteristics through sourdough fermentation. The ancient wheat species could be used as promising substitutes for common wheat flour for the design of innovative types of bread, even for special needs.

Effect of solid state fermentation on proximate composition, antinutritional factors and in vitro protein digestibility of maize flour

Cereals including maize generally have limiting amino acids particularly lysine. In most cases, spontaneous fermentation is used to improve the nutritional profiles of maize-based products. However, in such fermentation, biological risks including the presence of pathogenic microorganisms, chemical contaminants, and toxic compounds of microbial origin such as mycotoxins pose a health risk. The aim of this study was, therefore, to improve the nutritional properties of maize flour by reducing antinutritional factors through microbial fermentation by strains of Lactobacillus plantarum and Saccharomyces cerevisiae and their cocultures. A factorial experimental design was used to evaluate the effect of fermentation setups and time on proximate composition, antinutritional factors, and in vitro digestibility of proteins in maize flour. During 48 h of fermentation, protein content was improved by 38%, 55%, 49%, and 48%, whereas in vitro protein digestibility improved by 31%, 40%, 36%, and 34% for natural, Lactobacillus plantarum, Saccharomyces cerevisiae, and their coculture-fermented maize flour, respectively. The highest improvement in protein content and its digestibility was observed for Lactobacillus plantarum strain-fermented maize flour. Phytate, tannin and trypsin inhibitor activity were reduced significantly (p < .05) for natural, Lactobacillus plantarum, Saccharomyces cerevisiae, and coculture-fermented maize flour. The highest reduction of phytate (66%), tannin (75%), and trypsin inhibitor (64%) was observed for coculture-fermented maize flour. The two strains and their cocultures were found feasible for fermentation of maize flour to improve its nutritional profiles more than the conventional fermentation process.

Biosynthesis of γ-aminobutyric acid by lactic acid bacteria in surplus bread and its use in bread making

AIMS

The aim of this study was to investigate the effectiveness of bread as substrate for γ-aminobutyric acid (GABA) biosynthesis, establishing a valorization strategy for surplus bread, repurposing it within the food chain.

METHODS AND RESULTS

Surplus bread was fermented by lactic acid bacteria (LAB) to produce GABA. Pediococcus pentosaceus F01, Levilactobacillus brevis MRS4, Lactiplantibacillus plantarum H64 and C48 were selected among 33 LAB strains for the ability to synthesize GABA. Four fermentation experiments were set up using surplus bread as such, added of amylolytic and proteolytic enzymes, modifying the pH or mixed with wheat bran. Enzyme-treated slurries led to the release of glucose (up to 20 mg g^-1 ) and free amino acid, whereas the addition of wheat bran (30% of bread weight) yielded the highest GABA content (circa 800 mg kg^-1 of dry weight) and was the most suitable substrate for LAB growth. The selected slurry was ultimately used as an ingredient in bread making causing an increase in free amino acids.

CONCLUSIONS

Besides the high GABA concentration (148 mg kg^-1 dough), the experimental bread developed in this study was characterized by good nutritional properties, highlighting the efficacy of tailored bioprocessing technologies as means to mitigate food wastage.

SIGNIFICANCE AND IMPACT OF STUDY

Our results represent a proof of concept of effective strategies to repurpose food industry side streams.

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.

Non-Alcoholic Pearl Millet Beverage Innovation with Own Bioburden: Leuconostoc mesenteroides, Pediococcus pentosaceus and Enterococcus gallinarum

The appropriate solution to the problem of quality variability and microbial stability of traditional non-alcoholic pearl millet fermented beverages (NAPMFB) is the use of starter cultures. However, potential starter cultures need to be tested in the production process. We aimed to identify and purify bioburden lactic acid bacteria from naturally fermented pearl millet slurry (PMS) and assess their effectiveness as cultures for the production of NAPMFB. Following the traditional Kunun-zaki process, the PMS was naturally fermented at 37 °C for 36 h. The pH, total titratable acidity (TTA), lactic acid bacteria (LAB), total viable count (TVC) and the soluble sugar were determined at 3 h interval. The presumptive LAB bacteria were characterized using a scanning electron microscope, biochemical tests and identified using the VITEK 2 Advanced Expert System for microbial identification. The changes in pH and TTA followed a non-linear exponential model with the rate of significant pH decrease of 0.071 h⁻¹, and TTA was inversely proportional to the pH at the rate of 0.042 h⁻¹. The Gompertz model with the mean relative deviation modulus, 0.7% for LAB and 2.01% for TVC explained the variability in microbial growth during fermentation. The LAB increased significantly from 6.97 to 7.68 log cfu/mL being dominated by Leuconostoc, Pediococcus, Streptococcus and Enterococcus with an optimum fermentation time of 18 h at 37 °C and 4.06 pH. L. mesenteroides and P. pentosaceus created an acidic environment while E. gallinarum increased the pH of the pearl millet extract (PME). Innovative NAPMFB was produced through assessment of LAB from PMS to PME fermented with L. mesentoroides (0.05%) and P. pentosaceus (0.025%) for 18 h, thereby reducing the production time from the traditional 24 h.

Fermentation as a tool for increasing food security and nutritional quality of indigenous African leafy vegetables: the case of Cucurbita sp

Sub-Saharan region is often characterized by food and nutrition insecurity especially "hidden hunger" which results from inadequate micronutrients in diets. African indigenous leafy vegetables (AILVs) can represent a valid food source of micronutrients, but they often go to waste resulting in post-harvest losses. In an attempt to prolong AILVs shelf-life while enhancing their nutritional quality, fermentation was studied from a microbiological and nutritional point of view. Pumpkin leaves (Cucurbita sp.) were spontaneously fermented using the submerged method with 3% NaCl and 3% sucrose. Controls were set up, consisting of leaves with no additions. During fermentation, samples of both treatments were taken at 0, 24, 48, 72 and 168 h to monitor pH and characterize the microbial population through culture-based and molecular-based analyses. Variations between fresh and treated leaves in B-group vitamins, carotenoids, polyphenols, and phytic acid were evaluated. Data revealed that the treatment with addition of NaCl and sucrose hindered the growth of undesired microorganisms; in controls, unwanted microorganisms dominated the bacterial community until 168 h, while in treated samples Lactobacillaceae predominated. Furthermore, the content in folate, β-carotene and lutein increased in treated leaves compared to the fresh ones, while phytic acid diminished indicating an amelioration in the nutritional value of the final product. Thus, fermentation could help in preserving Cucurbita sp. leaves, avoiding contamination of spoilage microorganisms and enhancing the nutritional values.

Microbial Resources, Fermentation and Reduction of Negative Externalities in Food Systems: Patterns toward Sustainability and Resilience

One of the main targets of sustainable development is the reduction of environmental, social, and economic negative externalities associated with the production of foods and beverages. Those externalities occur at different stages of food chains, from the farm to the fork, with deleterious impacts to different extents. Increasing evidence testifies to the potential of microbial-based solutions and fermentative processes as mitigating strategies to reduce negative externalities in food systems. In several cases, innovative solutions might find in situ applications from the farm to the fork, including advances in food matrices by means of tailored fermentative processes. This viewpoint recalls the attention on microbial biotechnologies as a field of bioeconomy and of ‘green’ innovations to improve sustainability and resilience of agri-food systems alleviating environmental, economic, and social undesired externalities. We argue that food scientists could systematically consider the potential of microbes as ‘mitigating agents’ in all research and development activities dealing with fermentation and microbial-based biotechnologies in the agri-food sector. This aims to conciliate process and product innovations with a development respectful of future generations’ needs and with the aptitude of the systems to overcome global challenges.

Bioactive Properties of Breads Made with Sourdough of Hull-Less Barley or Conventional and Pigmented Wheat Flours

Functional and nutritional properties of baked goods can be enhanced by the use of sourdough fermentation, which is defined as a mixture of water and flour fermented by lactobacilli (LAB) and yeasts. Previous data highlighted the ability of sourdoughs obtained with selected LAB strains and commercial flour to produce bioactive peptides equipped with antioxidant and anti-inflammatory properties. More recently, it has been proven that choosing the most suitable combination of selected LAB and high-functional-value flours greatly increase the amount of low-molecular-weight antioxidant compounds responsible for improving the nutritional value of the products. This work aimed to isolate bioactive peptides both from sourdoughs and baked breads obtained with pigmented wheat and barley and a selected combination of LABs. Soluble water extracts were obtained, and low-molecular-weight peptides were isolated. Antioxidant activity was detected by assaying the intracellular ROS production in stressed cultured macrophages, treated with peptides. Moreover, anti-inflammatory activity, highlighted by NFkB pathway inhibition and by COX2 reduction in stressed cells, was demonstrated for peptides obtained from breads. The results allowed the conclusion that the combination of flours and LAB used in the present manuscript led to the production of bakery products with beneficial effects on oxidative and inflammatory status.

Lscβ and lscγ, two novel levansucrases of Pseudomonas syringae pv. actinidiae biovar 3, the causal agent of bacterial canker of kiwifruit, show different enzymatic properties

Bacterial canker disease caused by Pseudomonas syringae pv. actinidiae (Psa) biovar 3 involved all global interest since 2008. We have found that in Psa3 genome, similarly to other P. syringae, there are three putative genes, lscα, lscβ and lscγ, coding for levansucrases. These enzymes, breaking the sucrose moiety and releasing glucose can synthetize the fructose polymer levan, a hexopolysaccharide that is well known to be part of the survival strategies of many different bacteria. Considering lscα non-coding because of a premature stop codon, in the present work we cloned and expressed the two putatively functional levansucrases of Psa3, lscβ and lscγ, in E. coli and characterized their biochemical properties such as optimum of pH, temperature and ionic strength. Interestingly, we found completely different behaviour for both sucrose splitting activity and levan synthesis between the two proteins; lscγ polymerizes levan quickly at pH 5.0 while lscβ has great sucrose hydrolysis activity at pH 7.0. Moreover, we demonstrated that at least in vitro conditions, they are differentially expressed suggesting two distinct roles in the physiology of the bacterium.

Traditional Bulgarian Dairy Products: Ethnic Foods with Health Benefits

The reported health effects of fermented dairy foods, which are traditionally manufactured in Bulgaria, are connected with their microbial biodiversity. The screening and development of probiotic starters for dairy products with unique properties are based exclusively on the isolation and characterization of lactic acid bacterial (LAB) strains. This study aims to systematically describe the LAB microbial content of artisanal products such as Bulgarian-type yoghurt, white brined cheese, kashkaval, koumiss, kefir, katak, and the Rhodope's brano mliako. The original technologies for their preparation preserve the valuable microbial content and improve their nutritional and probiotic qualities. This review emphasises the features of LAB starters and the autochthonous microflora, the biochemistry of dairy food production, and the approaches for achieving the fortification of the foods with prebiotics, bioactive peptides (ACE2-inhibitors, bacteriocins, cyclic peptides with antimicrobial activity), immunomodulatory exopolysaccharides, and other metabolites (indol-3-propionic acid, free amino acids, antioxidants, prebiotics) with reported beneficial effects on human health. The link between the microbial content of dairy foods and the healthy human microbiome is highlighted.

The combined effect of fermentation of lactic acid bacteria and in vitro digestion on metabolomic and oligosaccharide profile of oat beverage

Oat (Avena sativa L.) is widely appreciated for its beneficial properties for human health, which have led to the introduction of more food products on the market, including oat beverages. The fibre components found in the oat are recognized for their beneficial effects, despite other bioactive compounds with healthy properties being present. This work aimed to evaluate the metabolites profile of a commercial oat beverage, either fermented with lactic bacteria or not, following in vitro gastro-intestinal digestion. UHPLC-QTOF untargeted metabolomics allowed investigation of the bioaccessibility of health-related metabolites from the oat beverage at the intestinal level. The results identified flavonoids, phenolic acids (avenanthramides), amino acids and steroids as the major classes of compounds. In particular, after in vitro digestion, amino acids, peptides, and phenolic acids showed the highest increases. The co-fermentation of oat milk by Lactobacillus spp. and Bifidobacterium spp. strains decreased the levels of both lignans and phytic acid, while increased the levels of some polyphenols like avenanthramides. Furthermore, fermentation by microorganisms increased the bioaccessibility of specific amino acids, vitamins, and polyphenols (flavonoids and phenolic acids). Interestingly, despite lacking a significant part of beta-glucans, the HPAEC-PAD profiling of our oat beverage evidenced that the fermentation process did not alter the oligosaccharides profile, thus preserving its prebiotic potential. The phytochemical profile of oat milk was shown to have a functional potential. Nonetheless, the fermentation by bacterial strains changed the profile of metabolites during in vitro digestion, thus offering an interesting option in the future development of cereal-based beverages.

Production and Characterization of a Novel Gluten-Free Fermented Beverage Based on Sprouted Oat Flour

This study investigates the use of sprouted oat flour as a substrate to develop a novel gluten-free beverage by fermentation with a probiotic (Lactobacillus plantarum WCFS1) starter culture. Physicochemical, microbiological, nutritional and sensory properties of sprouted oat fermented beverage (SOFB) were characterized. After fermentation for 4 h, SOFB exhibited an acidity of 0.42 g lactic acid/100 mL, contents of lactic and acetic acids of 1.6 and 0.09 g/L, respectively, and high viable counts of probiotic starter culture (8.9 Log CFU/mL). Furthermore, SOFB was a good source of protein (1.7 g/100 mL), β-glucan (79 mg/100 mL), thiamine (676 μg/100 mL), riboflavin (28.1 μg/100 mL) and phenolic compounds (61.4 mg GAE/100 mL), and had a high antioxidant potential (164.3 mg TE/100 mL). Spoilage and pathogenic microorganisms were not detected in SOFB. The sensory attributes evaluated received scores higher than 6 in a 9-point hedonic scale, indicating that SOFB was well accepted by panelists. Storage of SOFB at 4 °C for 20 days maintained L. plantarum viability and a good microbial quality and did not substantially affect β-glucan content. SOFB fulfils current consumer demands regarding natural and wholesome plant-based foods.

Valorization of Vegetable Food Waste and By-Products Through Fermentation Processes

There is a general interest in finding new ways of valorizing fruit and vegetable processing by-products. With this aim, applications of industrial fermentation to improve nutritional value, or to produce biologically active compounds, have been developed. In this sense, the fermentation of a wide variety of by-products including rice, barley, soya, citrus, and milling by-products has been reported. This minireview gives an overview of recent fermentation-based valorization strategies developed in the last 2 years. To aid the designing of new bioprocesses of industrial interest, this minireview also provides a detailed comparison of the fermentation conditions needed to produce specific bioactive compounds through a simple artificial neural network model. Different applications reported have been focused on increasing the nutritional value of vegetable by-products, while several lactic acid bacteria and Penicillium species have been used to produce high purity lactic acid. Bacteria and fungi like Bacillus subtilis, Rhizopus oligosporus, or Fusarium flocciferum may be used to efficiently produce protein extracts with high biological value and a wide variety of functional carbohydrates and glycosidases have been produced employing Aspergillus, Yarrowia, and Trichoderma species. Fermentative patterns summarized may guide the production of functional ingredients for novel food formulation and the development of low-cost bioprocesses leading to a transition toward a bioeconomy model.