In vitro probiotic evaluation of phytase producing Lactobacillus species isolated from Uttapam batter and their application in soy milk fermentation

Potential of γ-Aminobutyric Acid-Producing Leuconostoc mesenteroides Strains Isolated from Kimchi as a Starter for High-γ-Aminobutyric Acid Kimchi Fermentation

γ-Aminobutyric acid (GABA)-producing Leuconostoc mesenteroides K1501 and K1627, isolated from kimchi, exhibited the highest GABA production in 1% monosodium glutamic acid. Both strains showed high survival rates of approximately 87% in artificial gastric juice (pH 3.0) and >80% in 0.1% artificial bile salt fluid. The survival rate was approximately 28% in 0.3% artificial bile salt fluid and 0% in 0.5% artificial bile salts. Both strains showed excellent adhesion to intestinal epithelial cells (>99%). Furthermore, it was observed that growth was not inhibited at 2% salt concentration; however, it was slightly retarded at salt concentrations of 3% and 4%. Moreover, L. mesenteroides K1501 and K1627 inhibited the growth of certain species of Lactobacillus, whose presence in kimchi fermentation is undesirable. Therefore, L. mesenteroides K1501 and K1627 have the potential to be used as starter organisms for functional GABA-rich kimchi.

Alpha-amylase and alphaglucosidase inhibitory properties, beta-galactosidase activity, and probiotic potential of lactic acid bacteria and bifidobacteria from Apis mellifera intermissa and its products

The present study aimed to evaluate the probiotic potential, α-amylase and α-glucosidase inhibitory effects, and β-galactosidase production of 19 non haemolytic lactic acid bacteria and bifidobacteria previously identified and isolated from honey bee gastrointestinal tract (BGIT) of Apis mellifera intermissa, honey, propolis and bee bread. The isolates were screened according to their high resistance to lysozyme and potent antibacterial activity. Our results indicated that among the 19 isolates, Limosilactobacillus fermentum BGIT_E12.2, Lactiplantibacillus plantarum BGIT_EC13, Limosilactobacillus fermentum BGIT_EC5.1 and Bifidobacterium asteroides BGIT_OB8, isolated from BGIT exhibited a good tolerance to 100 mg/mL lysozyme (> 82%), excellent tolerance to 0.5% bile salt [survival rate (SR) ≥ 83.19% ± 0.01], and a high SR (≥ 80.0%) under gastrointestinal tract conditions. The auto-aggregation ability was high (auto-aggregation index ranging from 67.14 ± 0.16 to 92.8% ± 0.03) for L. fermentum BGIT_E12.2, L. plantarum BGIT_EC13, and B. asteroides BGIT_OB8, and moderate for L. fermentum BGIT_EC5.1 (39.08% ± 0.11). Overall, the four isolates showed moderate co-aggregation capacity with pathogenic bacteria. They exhibited from moderate to high hydrophobicity towards toluene and xylene. The safety assessment revealed that the four isolates lacked gelatinase and mucinolytic activities. Also, they were susceptible to ampicillin, clindamycin, erythromycin, and chloramphenicol. Interestingly, the four isolates showed α-glucosidase and α-amylase inhibitory activities ranging from 37.08 ± 0.12 to 57.57% ± 0.1 and from 68.30 ± 0.09 to 79.42% ± 0.09, respectively. Moreover, L. fermentum BGIT_E12.2, L. plantarum BGIT_EC13, L. fermentum BGIT_EC5.1 isolates exhibited β-galactosidase activity over a wide range of 52.49 ± 0.24-746.54 ± 0.25 Miller Units. In conclusion, our findings suggest that the four isolates could be potential candidates for probiotics with interesting functional properties.

Lactiplantibacillus argentoratensis and Candida tropicalis Isolated from the Gastrointestinal Tract of Fish Exhibited Inhibitory Effects against Pathogenic Bacteria of Nile Tilapia

Nile tilapia is one of the most consumed farmed fish in the world. The outbreak of pathogenic bacterial diseases causes high mortality rates and economic losses in Nile tilapia farming. Antibiotic administrations are commonly utilized to inhibit and prevent bacterial infections. However, antibiotics are expensive and cause serious concerns for antibiotic resistance in fish that can be potentially transferred to humans. As an alternative solution, probiotics can be used to prevent infection of pathogenic bacteria in fish. In this work, both bacteria and yeast were isolated from fish gastrointestinal tracts and their inhibitory activity against Nile tilapia pathogenic bacteria was evaluated, as well as other probiotic properties. In this study, 66 bacteria and 176 acid tolerant yeasts were isolated from fish gastrointestinal tracts. Of all isolated microorganisms, 39 bacterial and 15 yeast isolates with inhibitory effect against pathogens were then examined for their probiotic properties (acidic and bile salt resistance, adhesion potential, and biofilm formation), formation of antibacterial factor survival rate under simulated gastrointestinal fluid, and safety evaluation. AT8/5 bacterial isolate demonstrated probiotic properties and the highest inhibition against all 54 tested pathogens while YON3/2 yeast isolate outperformed the inhibitory effect among all yeast isolates. These two probiotic isolates were further identified by 16S rDNA and the D1/D2 domain of 26S rDNA sequence analysis for bacterial and yeast identification, respectively. AT8/5 and YON3/2 showed the highest similarity to Lactiplantibacillus argentoratensis and Candida tropicalis, respectively. This is the first report on isolated L. argentoratensis and C. tropicalis with antipathogenic bacteria of Nile tilapia properties. Collectively, AT8/5 and YON3/2 could be potentially used as promising alternatives to existing antibiotic methods to prevent pathogenic bacteria infection in Nile tilapia farming.

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

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

A review on enzyme-producing lactobacilli associated with the human digestive process: From metabolism to application

Complex carbohydrates, proteins, and other food components require a longer digestion process to be absorbed by the lining of the alimentary canal. In addition to the enzymes of the gastrointestinal tract, gut microbiota, comprising a large range of bacteria and fungi, has complementary action on the production of digestive enzymes. Within this universe of "hidden soldiers", lactobacilli are extensively studied because of their ability to produce lactase, proteases, peptidases, fructanases, amylases, bile salt hydrolases, phytases, and esterases. The administration of living lactobacilli cells has been shown to increase nutrient digestibility. However, it is still little known how these microbial-derived enzymes act in the human body. Enzyme secretion may be affected by variations in temperature, pH, and other extreme conditions faced by the bacterial cells in the human body. Besides, lactobacilli administration cannot itself be considered the only factor interfering with enzyme secretion, human diet (microbial substrate) being determinant in their metabolism. This review highlights the potential of lactobacilli to release functional enzymes associated with the digestive process and how this complex metabolism can be explored to contribute to the human diet. Enzymatic activity of lactobacilli is exerted in a strain-dependent manner, i.e., within the same lactobacilli species, there are different enzyme contents, leading to a large variety of enzymatic activities. Thus, we report current methods to select the most promising lactobacilli strains as sources of bioactive enzymes. Finally, a patent landscape and commercial products are described to provide the state of art of the transfer of knowledge from the scientific sphere to the industrial application.

Enhancing Micronutrients Bioavailability through Fermentation of Plant-Based Foods: A Concise Review

Plant-based foods are rich sources of vitamins and essential micronutrients. For the proper functioning of the human body and their crucial role, trace minerals (iron, zinc, magnesium, manganese, etc.) are required in appropriate amounts. Cereals and pulses are the chief sources of these trace minerals. Despite these minerals, adequate consumption of plant foods cannot fulfill the human body’s total nutrient requirement. Plant foods also contain ample amounts of anti-nutritional factors such as phytate, tannins, phenols, oxalates, etc. These factors can compromise the bioavailability of several essential micronutrients in plant foods. However, literature reports show that fermentation and related processing methods can improve nutrient and mineral bioavailability of plant foods. In this review, studies related to fermentation methods that can be used to improve micronutrient bioavailability in plant foods are discussed.

Biodiversity of meatborne Listeria spp. in Himachal Pradesh and their interaction with indigenous probiotics

This study determined the anti-listerial activity of indigenous probiotics from traditional fermented foods of Western Himalaya against meat borne Listera monocytogens isolates from Himachal Pradesh. One hundred samples of meat and meat products like chicken (n = 25), chevon (goat meat, n = 20), fish (n = 20) and pork (n = 30) were collected and were analyzed for the presence of Listeria spp. by recommended culture and biochemical methods. L. monocytogens isolates were confirmed by PCR targeting the virulence gene hlyA (haemolysin A) and by16S rRNA sequencing. Anti-listerial activity of probiotic bacteria isolated from indigenous fermented foods of Himachal Pradesh was determined by well diffusion method using Lactobacillus rhamnosus GG (ATCC 53103) as the reference strain. Five percent of tested samples were found positive for L. monocytogens with incidence of 8.0% in chicken (2/25), 10.0% in fish (2/20) and 4.0% in chevon meat (1/25). None of the tested pork samples were found contaminated with L. monocytogenes. Among 11 indigenous probiotics used in this study, highest antagonistic activity was exhibited by Lactobacillus plantarum (ADF 10) and Enterococcus faecium (ADF1) which was equivalent to the reference strain.

Effects of fat content on the textural and in vivo buccal breakdown properties of soy yogurt

This study aimed to evaluate the effects of fat content on the textural and in vivo buccal breakdown properties of soy yogurt (SY) at different pH (5.4, 5.0, and 4.6). The microbial analysis, textural and rheological properties, and interfacial protein composition of all the samples were monitored. Microbial results suggested that the increased fat content in SY-5.0 and SY-4.6 resulted in significantly high viable cell counts of lactic acid bacteria (LAB). Textural studies demonstrated that the presence of a low fat content (1-3%) significantly reduced the hardness, springiness, and gumminess of the sample, but this effect was negligible with the addition of fat content (4-5%). The apparent viscosity and thixotropy of the SY-4.6 sample increased as the fat content increased. in vivo buccal digestion showed that a high fat content (2-4%) reduced the number of chews and chewing durations, which might be correlated with high oil droplet release (%) after mastication.

Bioactivity of soy-based fermented foods: A review

For centuries, fermented soy foods have been dietary staples in Asia and, now, in response to consumer demand, they are available throughout the world. Fermentation bestows unique flavors, boosts nutritional values and increases or adds new functional properties. In this review, we describe the functional properties and underlying action mechanisms of soy-based fermented foods such as Natto, fermented soy milk, Tempeh and soy sauce. When possible, the contribution of specific bioactive components is highlighted. While numerous studies with in vitro and animal models have hinted at the functionality of fermented soy foods, ascribing health benefits requires well-designed, often complex human studies with analysis of diet, lifestyle, family and medical history combined with long-term follow-ups for each subject. In addition, the contribution of the microbiome to the bioactivities of fermented soy foods, possibly mediated through direct action or bioactive metabolites, needs to be studied. Potential synergy or other interactions among the microorganisms carrying out the fermentation and the host's microbial community may also contribute to food functionality, but the details still require elucidation. Finally, safety evaluation of fermented soy foods has been limited, but is essential in order to provide guidelines for consumption and confirm lack of toxicity.

Characterization of probiotic potential of Bacillus species isolated from a traditional brine pickle

Fermented foods are known for their potential as main source of probiotics. The present study aimed at investigating the probiotic properties of bacteria isolated from fermented mango pickle. Non-hemolytic fermenting microbiota isolated from mango pickle was screened in vitro for their basic probiotic properties such as acid tolerance, bile salt, lysozyme and salt tolerance. They were also tested for their beneficial characters like cholesterol removal, bacterial adhesion to hydrocarbons, auto-aggregation, antimicrobial activity, β-galactosidase activity, exopolysaccharide production and adhesion to HT-29 cell line. Outputs of these parameters were subjected to principal component analysis (PCA) and these results were interpreted to select prospective bacterial isolates that can be used as potential probiotics. Out of eight isolates, PUFSTP35 (Bacillus licheniformis), PUFSTP38 (Bacillus amyloliquefaciens) and PUFSTP39 (Bacillus subtilis) showed similar trend to Weissella cibaria (MTCC 9814) that was used as a reference strain for profiling probiotic properties. B. licheniformis PUFSTP35 from fermented mango pickle appear to be the most potential candidate for use as a beneficial probiotic.