Saccharomyces cerevisiae from Brazilian kefir-fermented milk: An in vitro evaluation of probiotic properties

Study and characterization of a product based on a vegetable extract of quinoa fermented with water kefir grains

This work aimed to study and characterize a product based on vegetable extract of quinoa (WVEQ) fermented with water kefir grains. The effect of sucrose concentration (SC), inulin concentration (IC), and xanthan gum (XG) concentration were evaluated using a central composite design (CCD) 23. They were subsequently characterized regarding cellular growth of the grains, beverage yield, pH, soluble solids, carbon dioxide (CO2) production, lactic acid, and ethanol production. Therefore, for the final stage, two formulations (F1 and F8) of the CCD were chosen to be characterized in terms of proximate composition, microbiological composition of the kefir culture, analysis of organic compounds, sensory analysis, and enzymatic and microbiological characterization before and after simulation of in vitro gastrointestinal digestion. In the two chosen products, one can see that fermentation optimized the bioavailability of proteins due to the high proteolytic activity of the microorganisms in kefir and the increase in lipid content. In identifying microorganisms, there was a prevalence of Saccharomyces sp. yeasts. In the sensory analysis, the F8 formulation showed better results than the F1 formulation. In vitro, gastrointestinal digestion showed reduced lactic acid bacteria and yeast and increased acetic acid bacteria in the liquid phase for both formulations. In the enzymatic profile, there was a reduction in all enzymes analyzed for both formulations, except for amylase in F1, which went from 14.05 U/mL to 39.41 U/mL. Therefore, it is concluded that using WVEQ as a substrate for the product appears to be a viable alternative with nutritional and technological advantages for serving a specific market niche.

Identification, characterization and optimization of culture medium conditions for organic acid-producing lactic acid bacteria strains from Chinese fermented vegetables

Lactic acid bacteria (LAB) are widely exploited in fermented foods and are gaining attention for novel uses due to their safety as biopreservatives. In this study, several organic acid-producing LAB strains were isolated from fermented vegetables for their potential application in fermentation. We identified nine novel strains belonging to four genera and five species, Lactobacillus plantarum PC1-1, YCI-2 (8), YC1-1-4B, YC1-4 (4), and YC2-9, Lactobacillus buchneri PC-C1, Pediococcus pentosaceus PC2-1 (F2), Weissella hellenica PC1A, and Enterococcus sp. YC2-6. Based on the results of organic acids, acidification, growth rate, antibiotic activity and antimicrobial inhibition, PC1-1, YC1-1-4B, PC2-1(F2), and PC-C1 showed exceptional biopreservative potential. Additionally, PC-C1, YC1-1-4B, and PC2-1(F2) recorded higher (p < 0.05) growth by utilizing lower concentrations of glucose (20 g/L) and soy peptone (10 g/L) as carbon and nitrogen sources in optimized culture conditions (pH 6, temperature 32 °C, and agitation speed 180 rpm) at 24hr and acidification until 72hr in batch fermentation, which suggests their application as starter cultures in industrial fermentation.

Identification of four autochthonous yeasts from the intestines of goldfish, Carassius auratus with potential probiotic properties and their effects on the most common fish bacterial pathogens

In aquaculture, probiotic yeasts have gained particular interest because of their numerous health benefits for farmed fish. Many autochthonous yeasts have been isolated and identified from fish species with potential probiotic characteristics. In the present study, four autochthonous yeast strains were identified and characterized from the intestinal tracts of 16 healthy goldfish, Carassius auratus. Their in vitro probiotic properties were examined in terms of cell surface hydrophobicity, co-aggregation, and tolerability to different pH values and bile salt concentrations. These strains were identified by culture characters and sequence analysis of ITS (Internal Transcribed Spacer) gene regions. Four strains, namely Cutaneotrichosporon jirovecii isolate jpn01, Debaryomyces nepalensis isolate jpn02, Blastobotrys proliferans isolate jpn05, and Diutina catenulata isolate jpn06, were identified and added to the NCBI GenBank with accession numbers defined as MT584874.1, MT584873.1, MT649918.1, and MT501155.1, respectively. Results demonstrated the capability of these strains to co-aggregate with several fish-associated bacterial pathogens such as Lactococcus garvieae, Vagococcus salmoninarum, Vibrio anguillarum, Yersinia ruckeri, and Aeromonas hydrophila. Only the jpn05 strain did not co-aggregate with A. hydrophila. All identified yeast isolates could grow and tolerate low pH conditions (pH 2.0) and bile salt concentrations (up to 1.5%). Of interest, the hydrophobicity (%) of the yeast isolates was 80%, 94.0%, 80.6%, and 66.4% for jpn01, jpn02, jpn05, and jpn06 isolates, respectively. In this context, our data provide important in vitro evidence for the potential probiotic features of the yeast isolates. These strains could be considered candidate probiotic yeasts; however, their application in aquaculture nutrition necessitates further in vivo assays.

Biocontrol of Pathogen Microorganisms in Ripened Foods of Animal Origin

Ripened foods of animal origin comprise meat products and dairy products, being transformed by the wild microbiota which populates the raw materials, generating highly appreciated products over the world. Together with this beneficial microbiota, both pathogenic and toxigenic microorganisms such as Listeria monocytogenes, Salmonella enterica, Staphylococcus aureus, Clostridium botulinum, Escherichia coli, Candida spp., Penicillium spp. and Aspergillus spp., can contaminate these products and pose a risk for the consumers. Thus, effective strategies to hamper these hazards are required. Additionally, consumer demand for clean label products is increasing. Therefore, the manufacturing sector is seeking new efficient, natural, low-environmental impact and easy to apply strategies to counteract these microorganisms. This review gathers different approaches to maximize food safety and discusses the possibility of their being applied or the necessity of new evidence, mainly for validation in the manufacturing product and its sensory impact, before being implemented as preventative measures in the Hazard Analysis and Critical Control Point programs.

Diversity of fermentative yeasts with probiotic potential isolated from Thai fermented food products

This research aimed to evaluate the diversity of yeasts recovered from fermented foods gathered from some areas of Northeastern Thailand. The fermented food items included Pla-som, Nham-pla, Kem-buknud, Isan-sausage, Pla-ra, Mhum-neu, Mhum-Khai-pla, Nham-neu, Nham-mu, Kung-joom, Som-pla-noi, and Poo-dong. Their probiotic characteristics were also investigated. A total of 103 yeast isolates of nine genera were identified using 28S rDNA sequencing. The yeast genera were Candida (20.3%), Diutina (2.9%), Filobasidium (1.0%), Kazachstania (33.0%), Pichia (3.9%), Saccharomyces (1.0%), Starmerella (28.2%), Torulaspora (2.9%), and Yarrowia (6.8%). Based on probiotic characteristic analysis of ten selected yeast strains, Kazachstania bulderi KKKS4-1 showed the strongest probiotic characteristics in terms of hemolytic activity, antimicrobial activity against pathogenic bacteria, tolerance to low pH and bile salt and hydrophobicity. Isolated yeasts with probiotic characteristics may be useful in fermented food and animal feed production to improve their nutritional values.

Ameliorative Effect of Saccharomyces cerevisiae JKSP39 on Fusobacterium nucleatum and Dextran Sulfate Sodium-Induced Colitis Mouse Model

The aim of this study was to evaluate the ability of the Saccharomyces cerevisiae strain with probiotic properties isolated from Tibetan kefir grains to ameliorate Fusobacterium nucleatum (Fn) infection and dextran sulfate sodium (DSS) treatment-induced murine model of colitis. The tolerance to simulated gastrointestinal conditions, hydrophobicity test, autoaggregation assay, and the antioxidant effect of strains was used to screen one strain with colonization and probiotic potential. The murine model of colitis was established by giving 10⁹ cfu Fn 3 weeks by intragastric administration and 3% DSS in water 1 week before sacrifice. The results indicated that S. cerevisiae JKSP39 (SC) possessed optimal probiotic characteristics in vitro. Supplementation with SC increased the body weight and the expression of anti-inflammatory cytokines (IL-4 and IL-10), while decreasing the disease activity index score and expression of proinflammatory cytokines (TNF-α, IL-6, and IL-17F) in mice undergoing experimental colitis as compared with the colitis model group. Additionally, tight junction proteins and the number of goblet cells per crypt were significantly increased in the SC group, which indicated that the gut barrier was well repaired. The mechanism of SC ameliorating Fn-DSS-induced colitis could be related to the decreased levels of reactive oxygen species (myeloperoxidase, total superoxide dismutase, catalase, H₂O₂, and malondialdehyde) in the colon, the inhibition of endoplasmic reticulum stress, and the regulation of gut microbiota.

Lactobacillus kefiranofaciens JKSP109 and Saccharomyces cerevisiae JKSP39 isolated from Tibetan kefir grain co-alleviated AOM/DSS induced inflammation and colorectal carcinogenesis

This study aimed to investigate the alleviative effects of Lactobacillus kefiranofaciens JKSP109 (LK) and Saccharomyces cerevisiae JKSP39 (SC) isolated from Tibetan kefir grain on colon inflammation and colorectal carcinogenesis. Azoxymethane (AOM) and dextran sulfate sodium (DSS) were used to establish a mouse model of colorectal cancer (CRC). The treatment group mice were administered with LK, SC, or the combination of LK and SC for five days per week from the day of receiving AOM. The composition of the gut microbiota was assessed using internal transcribed spacer 2 and 16S rRNA gene high-throughput sequencing. Furthermore, the biomarkers associated with gut barrier integrity, inflammation, regulators of cell proliferation, and apoptosis were evaluated. The results showed that the administration of LK, SC, and their combination increased the body weights and decreased the disease activity index (DAI) score and tumor multiplicity. As compared to the CRC model group, the three treatment groups positively regulated the gut microbiota. Meanwhile, the three treatments also enhanced the gut barrier, decreased the expression of proinflammatory cytokines and oncocyte proliferation indicators, and increased the expression of terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL)-positive tumor epithelial cells and content of short chain fatty acids in fecal samples. All these results indicated that the LK and SC alleviated the inflammation and colorectal carcinogenesis in AOM/DSS-induced CRC mouse models, and the majority of tested indexes in the combination group were superior to single strain groups.

Assessment of Yeasts as Potential Probiotics: A Review of Gastrointestinal Tract Conditions and Investigation Methods

Probiotics are microorganisms (including bacteria, yeasts and moulds) that confer various health benefits to the host, when consumed in sufficient amounts. Food products containing probiotics, called functional foods, have several health-promoting and therapeutic benefits. The significant role of yeasts in producing functional foods with promoted health benefits is well documented. Hence, there is considerable interest in isolating new yeasts as potential probiotics. Survival in the gastrointestinal tract (GIT), salt tolerance and adherence to epithelial cells are preconditions to classify such microorganisms as probiotics. Clear understanding of how yeasts can overcome GIT and salt stresses and the conditions that support yeasts to grow under such conditions is paramount for identifying, characterising and selecting probiotic yeast strains. This study elaborated the adaptations and mechanisms underlying the survival of probiotic yeasts under GIT and salt stresses. This study also discussed the capability of yeasts to adhere to epithelial cells (hydrophobicity and autoaggregation) and shed light on in vitro methods used to assess the probiotic characteristics of newly isolated yeasts.

Metagenomic analysis of microflora structure and functional capacity in probiotic Tibetan kefir grains

Tibetan kefir grains (TKGs) are distinctive and complex mixtures with protein-lipid-polysaccharide matrices and multiple microorganism species. The objective of this study was to evaluate the microflora composition, probiotic species and functional genes within TKGs. Metagenomic analysis was used to evaluate communities of three TKGs, revealing the presence of 715 species, with Lactobacillus kefiranofaciens as the most dominant species. The relative abundances of acetic acid bacteria and yeast significantly differed among the three TKGs (acetic acid bacteria: p < 0.01; yeast: p < 0.05), and the dominant yeast species also varied across three TKGs. Lactobacillus helveticus was the most abundant listed probiotic species, and its abundance did not significantly differ across three TKGs. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis revealed that ko01501 was the most abundant pathway that related to human disease. There are 16 different KOs (KEGG Orthology) in the ko01501 pathway were annotated in TKGs, which helps to resist β-lactam. This study provided a new insight into the microbial community structures and the presence of probiotic species within TKGs and provides a foundation for further targeted studies.

Supplementation of kefir ameliorates azoxymethane/dextran sulfate sodium induced colorectal cancer by modulating the gut microbiota

The aim of this study was to investigate the efficacy of kefir on colorectal cancer (CRC) via regulating the microbiota structure in the colon using the azoxymethane/dextran sulfate sodium (AOM/DSS) induced CRC mouse model. Mice in the treatment group were orally administered with milk or kefir. The gut microbiota composition was assessed by internally transcribed spacer 2 (ITS2) and 16S rRNA high-throughput sequencing. Furthermore, the biomarkers associated with the gut barrier, inflammation, and cell proliferation regulators were evaluated. The results indicated that the size and the amount of tumor were decreased and the immunity regulators (TNF-α, IL-6, and IL-17a) and oncocyte proliferation indicator (Ki67, NF-κB, and β-catenin) were all decreased. Increased short chain fatty acids (SCFAs) lowered the pH in the colon and helped enhance the intestinal barrier. The Firmicutes/Bacteroidetes ratio and Ascomycota/Basidiomycota ratio were decreased at the phylum level; the relative abundance of probiotics was increased and the pathogenic bacterium (Clostridium sensu stricto, Aspergillus and Talaromyces) were decreased after supplementation of kefir. Consequently, kefir could regulate the gut microbiota composition and ameliorate AOM/DSS induced colorectal cancer.

Dose-Dependent Beneficial Effects of Tryptophan and Its Derived Metabolites on Akkermansia In Vitro: A Preliminary Prospective Study

Akkermansia muciniphila, a potential probiotic, has been proven to lessen the effects of several diseases. As established, the relative abundance of Akkermansia is positively correlated with tryptophan metabolism. However, the reciprocal interaction between tryptophan and Akkemansia is still unclear. Herein, for the first time, the possible effects of tryptophan and its derived metabolites on A. muciniphila were preliminarily investigated, including growth, physiological function, and metabolism. Obtained results suggested that 0.4 g/L of tryptophan treatment could significantly promote the growth of A. muciniphila. Notably, when grown in BHI with 0.8 g/L of tryptophan, the hydrophobicity and adhesion of A. muciniphila were significantly improved, potentially due to the increase in the rate of cell division. Furthermore, A. muciniphila metabolized tryptophan to indole, indole-3-acetic acid, indole-3-carboxaldehyde, and indole-3-lactic acid. Indoles produced by gut microbiota could significantly promote the growth of A. muciniphila. These results could provide a valuable reference for future research on the relationship between tryptophan metabolism and A. muciniphila.

In Vitro Properties of Potential Probiotic Indigenous Yeasts Originating from Fermented Food and Beverages in Taiwan

Probiotics are live microorganisms that may be able to help prevent and treat some illnesses. Most probiotics on the market are bacterial, primarily Lactobacillus. Yeast are an inevitable part of the microbiota of various fermented foods and beverages and have several beneficial properties that bacteria do not have. In this study, yeast strains were isolated from fermented food and beverages. Various physiological features of the candidate probiotic isolates were preliminarily investigated, including bile salt and acid tolerance, cell surface hydrophobicity, autoaggregation, antioxidant activity, and β-galactosidase activity. Several yeast strains with probiotic potential were selected. Overall, Kluyveromyces marxianus JYC2614 adapted well to the bile salt and acid tolerance test; it also had favorable autoaggregation and good cell-surface hydrophobicity. Klu. marxianus JYC2610 grew well according to the bile salt and acid tolerance test and performed well regarding cell surface hydrophobicity and β-galactosidase activity. Selected yeast species can survive in a gastrointestinal environment and should be further evaluated in vivo as probiotics in the future. Our findings should encourage further studies on the application of the strains in this study as food and feed supplements.

Potential Probiotic Strains of Saccharomyces and Non-Saccharomyces: Functional and Biotechnological Characteristics

Due to the evident demand for probiotic microorganisms, a growing number of scientific studies have involved the preliminary selection of new strains, but deeper studies for knowing specific functional and biotechnological properties are needed. In the present work, twenty yeasts (Saccharomyces and non-Saccharomyces) with potential probiotic characteristics, selected in previous works, were evaluated. The following assays were realized: adhesion to Caco-2/TC7 cells, prebiotic metabolisms, assimilation of cholesterol, enzymatic and antioxidant activity, and antifungal resistance. In addition, the effect of ultrasonic treatment was evaluated for attenuating the cultures before their possible incorporation into a food or supplement. In all of the cases, the unique commercial probiotic yeast (S. boulardii CNM I-745) was used as positive control. Results show different capabilities depending on the property studied. In general, no Saccharomyces yeasts were better in the adhesion to Caco cells, prebiotic metabolism, and presented higher variability of enzymatic activities. The ones related to cholesterol assimilation and antioxidant capability did not show a marked trend, and with respect to the attenuation process, the Saccharomyces yeasts were more resistant. For selecting the potential probiotic yeasts with better balance among all characteristics, a principal component analysis (PCA) was carried out. The most promising yeasts for use as health-promoting probiotics are Hanseniaspora osmophila 1056 and 1094, Lachancea thermotolerans 1039, and S. cerevisiae 3 and 146.

Anti-Biofilm Activity of Cell-Free Supernatant of Saccharomyces cerevisiae against Staphylococcus aureus

Staphylococcus aureus is one of the most common microorganisms and causes foodborne diseases. In particular, biofilm-forming S. aureus is more resistant to antimicrobial agents and sanitizing treatments than planktonic cells. Therefore, this study aimed to investigate the anti-biofilm effects of cell-free supernatant (CFS) of Saccharomyces cerevisiae isolated from cucumber jangajji compared to grapefruit seed extract (GSE). CFS and GSE inhibited and degraded S. aureus biofilms. The adhesion ability, auto-aggregation, and exopolysaccharide production of CFS-treated S. aureus, compared to those of the control, were significantly decreased. Moreover, biofilm-related gene expression was altered upon CFS treatment. Scanning electron microscopy images confirmed that CFS exerted anti-biofilm effects against S. aureus. Therefore, these results suggest that S. cerevisiae CFS has anti-biofilm potential against S. aureus strains.

Investigation into In Vitro and In Vivo Caenorhabditis elegans Models to Select Cheese Yeasts as Probiotic Candidates for their Preventive Effects against Salmonella Typhimurium

The design of multiscale strategies integrating in vitro and in vivo models is necessary for the selection of new probiotics. In this regard, we developed a screening assay based on the investigation of the potential of yeasts from cheese as probiotics against the pathogen Salmonella Typhimurium UPsm1 (ST). Two yeasts isolated from raw-milk cheese (Saccharomyces cerevisiae 16, Sc16; Debaryomyces hansenii 25, Dh25), as well as S. cerevisiae subspecies boulardii (CNCM I-1079, Sb1079), were tested against ST by applying in vitro and in vivo tests. Adherence measurements to Caco-2 and HT29-MTX intestinal cells indicated that the two tested cheese yeasts presented a better adhesion than the probiotic Sb1079 as the control strain. Further, the Dh25 was the cheese yeast most likely to survive in the gastrointestinal tract. What is more, the modulation of the TransEpithelial Electrical Resistance (TEER) of differentiated Caco-2 cell monolayers showed the ability of Dh25 to delay the deleterious effects of ST. The influence of microorganisms on the in vivo model Caenorhabditis elegans was evaluated by measuring the longevity of the worm. This in vivo approach revealed that this yeast increased the worm’s lifespan and protected it against ST infection, confirming that this in vivo model can be useful for screening probiotic cheese yeasts.

Health beliefs towards kefir correlate with emotion and attitude: A study using an emoji scale in Brazil

Emojis can be used to explore food-evoked emotions in order to provide information that can support the product development and marketing decisions. This study aimed to evaluate consumers' acceptance, purchase intent and emotional responses to milk beverages, with and without kefir added, before and after these consumers were informed about the products' composition (0%, 15%, 30% and 50% m/v) and health claims toward kefir (blind and informed tests, respectively). Emotional responses were assessed by emoji use within a RATA questionnaire in order quantify the perceived significance of the emojis chosen. In the informed test, the consumers' perception of the sensory attributes of the milk beverages, such as their perception of an acid taste in added kefir beverages was shown to have changed. Overall, participants attributed significantly higher acceptance and purchase intent scores to added kefir beverages after they had been informed on its health benefits. In addition, expressions of positive emotion increased when participants were exposed to stimuli related to health benefits of kefir (15%, 30% and 50% m/v), while negative expressions of emotion decreased. The provided information of kefir modified valence and arousal in subjects, and it can be said that to 30% of kefir can be added to yogurt without compromising its sensory acceptability. Thus, health benefits alone cannot improve product acceptance, since participants found a 50% addition of kefir to be unpleasant when tasted during a blind test. Mixed beverages may present a probiotic beverage alternative for consumers who dislike kefir milk, but want to include it in their diets. The implications of liking and purchase intent and how they are linked to emotions are discussed in this paper as well.

Probiotic properties and fatty acid composition of the yeast Kluyveromyces lactis M3. In vivo immunomodulatory activities in gilthead seabream (Sparus aurata)

The aim of this study was to analyze the probiotic potential, fatty acid composition and immunostimulant activities of Kluyveromyces lactis M3 isolated from a hypersaline sediment. For this purpose, K. lactis M3 resistance to different pH, salinities and bile, as well as its antioxidant capability were assayed. Furthermore, total fatty acid composition of the yeast was determined where the dominant fatty acids were palmitic, palmitoleic, oleic and linoleic acids. K. lactis M3 showed no cytotoxic effects on peripheral blood leukocytes. During an in vivo experiment in gilthead seabream (Sparus aurata), dietary K. lactis M3 supplemented at 0.55 or 1.1% of the basal diet enhanced bactericidal activity against Vibrio parahaemolyticus N16, V. harveyi Lg 16/00, and V. anguillarum CECT 43442 compared to fish fed commercial diet (control group). Finally, nitric oxide production, peroxidase activity and skin mucus lectin union levels strongly increased in fish fed K. lactis M3 with respect to the control group. The results suggested that the yeast K. lactis M3 had exhibited high antioxidant capability, and its dietary administration at 0.55 or 1% basal diet had immunostimulant activity for gilthead seabream. For all these reasons, it should be considered an appropriate probiotic candidate for the aquaculture fish industry.

The life and times of yeasts in traditional food fermentations

Yeasts are eukaryotic microorganisms which have a long history in the biotechnology of food production, as they have been used since centuries in bread-making or in the production of alcoholic beverages such as wines or beers. Relative to this importance, a lot of research has been devoted to the study of yeasts involved in making these important products. The role of yeasts in other fermentations in association with other microorganisms - mainly lactic acid bacteria - has been relatively less studied, and often it is not clear if yeasts occurring in such fermentations are contaminants with no role in the fermentation, spoilage microorganisms or whether they actually serve a technological or functional purpose. Some knowledge is available for yeasts used as starter cultures in fermented raw sausages or in the production of acid curd cheeses. This review aimed to summarize the current knowledge on the taxonomy, the presence and potential functional or technological roles of yeasts in traditional fermented plant, dairy, fish and meat fermentations.

Identification and Evaluation of Probiotic Potential in Yeast Strains Found in Kefir Drink Samples from Malaysia

Kefir drink is a source of probiotic microorganism with remarkable functional and technological properties. The objective of this work is to isolate yeast strains from Malaysian kefir drink and evaluate them for probiotic potentials. In the present study, nine strains of probiotic yeast were isolated from a Malaysian kefir drink and identified according to their 16S rDNA sequences. Furthermore, their probiotic potential was evaluated. The probiotic properties were tested for aspects of antibiotic susceptibility, antimicrobial activity, and gastrointestinal condition tolerance (pH and temperature). Five isolated strains, M3, Y5, Y9, Y11 and A1, showed good tolerance towards low pH condition while three strains, A1, M1, and M3, showed antimicrobial activity against E. coli, P. aeruginosa, and Salmonella sp. Most isolates were resistant to penicillin, streptomycin, and ampicillin, and grew well at human body temperature. The result of this test indicates that the yeast strains isolated from Malaysian kefir drink have excellent potential for use as probiotics in various products. Lastly, kefir milk is one of the excellent source of probiotic yeast strains and could be used as a new yeast probiotic formulation or in food supplements.

The potential use of probiotic and beneficial bacteria in the Brazilian dairy industry

Scientific studies demonstrate the importance of intestinal microbiota to human health and how probiotic microorganisms can positively affect health when administered regularly and in adequate amounts. Probiotic bacteria can be part of fermented products and their functional importance is associated mainly with their metabolism. They are thought to benefit individuals to maintain their health and also to strengthen resistance against various types of diseases. The acceptance of probiotic cultures and products by consumers increased when these bacteria were marketed as natural cultures that help in digestion and health. Considering this, the food industry has an increasing demand for new candidates as probiotic cultures, and the dairy industry has a particular interest for fermented milks and other dairy products, since these are the most common food vehicles for probiotic cultures. Therefore, the dairy industries are increasingly seeking to improve their products with these beneficial bacteria. However, the legal peculiarities and excess of control agencies in Brazil makes the registration of these products and the collection of data very complex. Prospective analysis suggests that probiotic foods have the potential to effect a considerable expansion of the dairy industry, allowing the dairy sector to grow and for these products to be increasingly sought by consumers globally. For this, not only actions on research and innovation are necessary, but also official clarifications on the claims for considerations of microbiological security and functionality of these products. This review aims to elucidate important probiotic research regarding the isolation and characterization of beneficial cultures in Brazil, and to demonstrate the relevance of the dairy chain as a potential source of novel cultures for the development of new probiotic products to expand the Brazilian dairy industry.

Enhancement of anti-tubercular activity and biomass of fermented food associated Staphylococcus hominis strain MANF2 using Taguchi orthogonal array and Box-Behnken design

The prime focus of the present investigation was to optimize statistically the anti-tubercular activity and biomass of fermented food associated Staphylococcus hominis strain MANF2 using Taguchi orthogonal array (OA) and Box-Behnken design (BBD). The anti-tubercular activity of strain MANF2 was determined against Mycobacterium tuberculosis H37Rv using luciferase reporter phase assay. Among varied media examined, the isolate exhibited impressive anti-tubercular activity with paramount relative light unit reduction of >90% in de Man Rogose Sharpe (MRS) broth. Primarily, the anti-tubercular activity and biomass of strain MANF2 were estimated in MRS broth by optimizing eight diversified parameters using one factor at a time (OFAT) method after working out a series of experiments. The most significant contributing factors selected through OFAT tool were optimized using Taguchi approach with a standard OA layout of L18 (2² × 3⁶). Results demonstrated the significant (P ≤ 0.05) influence of pH, temperature, yeast extract, magnesium sulphate, and glycerol on response variables. These controlled variables were further optimized using BBD matrix at N = 46 by second-order polynomial equation. The fermentation medium of pH 6.5 constituting yeast extract (0.5% w/v), magnesium sulphate (0.1% w/v), and glycerol (1.5% v/v), being further incubated at 30 °C showed enhanced anti-tubercular activity (98.7%) and approximately 4 fold increment in the bacterial biomass yield (8.3 mg/mL) with respect to traditional OFAT method. Three-dimensional response plots of the quadratic model showed interdependent interaction between the significant variables. In conclusion, the present study revealed the first report on the optimization of anti-tubercular activity and biomass of S. hominis via Taguchi OA as well as BBD design, and thus, paved a path for its proficient applications in pharmaceutical industries as dynamic mycobactericidal agent in future.