Selenium bioactive compounds produced by beneficial microbes.

Selenium (Se) is an essential trace element present as selenocysteine (SeCys) in selenoproteins, which have an important role in thyroid metabolism and the redox system in humans. Se deficiency affects between 500 and 1000 million people worldwide. Increasing Se intake can prevent from bacterial and viral infections. Se deficiency has been associated with cancer, Alzheimer, Parkinson, decreased thyroid function, and male infertility. Se intake depends on the food consumed which is directly related to the amount of Se in the soil as well as on its availability. Se is unevenly distributed on the earth's crust, being scarce in some regions and in excess in others. The easiest way to counteract the symptoms of Se deficiency is to enhance the Se status of the human diet. Se salts are the most toxic form of Se, while Se amino acids and Se-nanoparticles (SeNPs) are the least toxic and most bio-available forms. Some bacteria transform Se salts into these Se species. Generally accepted as safe selenized microorganisms can be directly used in the manufacture of selenized fermented and/or probiotic foods. On the other hand, plant growth-promoting bacteria and/or the SeNPs produced by them can be used to promote plant growth and produce crops enriched with Se. In this chapter we discuss bacterial Se metabolism, the effect of Se on human health, the applications of SeNPs and Se-enriched bacteria, as well as their effect on food fortification. Different strategies to counteract Se deficiency by enriching foods using sustainable strategies and their possible implications for improving human health are discussed.

Effects of replacing Na selenite in laying hen feed with selenized glucose on production performance, egg quality, egg selenium content, microbial population, immunological response, antioxidant enzymes, and fatty acid composition.

This study aimed to explore the effects of selenized glucose (SeGlu) and Na selenite supplementation on various aspects of laying hens such as production performance, egg quality, egg Se concentration, microbial population, antioxidant enzymes activity, immunological response, and yolk fatty acid profile. Using a 2 × 2 factorial design, 168 laying hens at 27-wk of age were randomly divided into 4 treatment groups with 7 replications. Se source (Na selenite and SeGlu) and Se level (0.3 and 0.6 mg/kg) were used as treatments. When 0.3 mg SeGlu/kg was compared to 0.3 mg Na selenite/kg, the interaction findings revealed that 0.3 mg SeGlu/kg increased egg production percent and shell ash (P < 0.05). When compared to 0.3 mg Na selenite/kg, dietary supplementation with 0.3 and 0.6 mg SeGlu/kg resulted in an increase in albumen height, Haugh unit, and yolk color of fresh eggs (P < 0.05). SeGlu enhanced albumen height, Haugh unit, shell thickness (P < 0.01), albumen index, yolk share, specific gravity, shell ash (P < 0.05) of fresh eggs and shell thickness (P < 0.05) of stored eggs as compared to Na selenite. The interaction showed that 0.6 mg SeGlu/kg enhanced yolk Se concentration while decreasing malondialdehyde levels in fresh egg yolk (P < 0.05). SeGlu enhanced Se concentration in albumen and glutathione peroxidase activity in plasma (P < 0.05) as compared to Na selenite. 0.6 mg Se/kg increased lactic acid bacteria, antibody response to sheep red blood cells, and lowered ∑n-6 PUFA/ ∑n-3 PUFA ratio (P < 0.05). As a result, adding SeGlu to the feed of laying hens enhanced egg production, egg quality, egg Se concentration, fresh yolk lipid oxidation, and glutathione peroxidase enzyme activity.

Volatile Organic Compounds (VOCs) Produced by Levilactobacillus brevis WLP672 Fermentation in Defined Media Supplemented with Different Amino Acids.

Fermentation by lactic acid bacteria (LAB) is a promising approach to meet the increasing demand for meat or dairy plant-based analogues with realistic flavours. However, a detailed understanding of the impact of the substrate, fermentation conditions, and bacterial strains on the volatile organic compounds (VOCs) produced during fermentation is lacking. As a first step, the current study used a defined medium (DM) supplemented with the amino acids L-leucine (Leu), L-isoleucine (Ile), L-phenylalanine (Phe), L-threonine (Thr), L-methionine (Met), or L-glutamic acid (Glu) separately or combined to determine their impact on the VOCs produced by Levilactobacillus brevis WLP672 (LB672). VOCs were measured using headspace solid-phase microextraction (HS-SPME) gas chromatography-mass spectrometry (GC-MS). VOCs associated with the specific amino acids added included: benzaldehyde, phenylethyl alcohol, and benzyl alcohol with added Phe; methanethiol, methional, and dimethyl disulphide with added Met; 3-methyl butanol with added Leu; and 2-methyl butanol with added Ile. This research demonstrated that fermentation by LB672 of a DM supplemented with different amino acids separately or combined resulted in the formation of a range of dairy- and meat-related VOCs and provides information on how plant-based fermentations could be manipulated to generate desirable flavours.

Bioactive Potential of Carrot-Based Products Enriched with Lactobacillus plantarum.

The primary goal of this study was to generate different kinds of functional products based on carrots that were supplemented with lactic acid bacteria. The fact that carrots (Daucus carota sp.) rank among the most popular vegetables in our country led to the convergence of the research aim. Their abundance of bioactive compounds, primarily polyphenols, flavonoids, and carotenoids, offers numerous health benefits. Among the obtained products, the freeze-dried carrot powder (FDCP) variation presented the highest concentrations of total carotenoids (TCs) and ß-carotene (BC) of 26.977 ± 0.13 mg/g DW and 22.075 ± 0.14 mg/g DW, respectively. The amount of total carotenoids and ß-carotene significantly increased with the addition of the selected lactic acid bacteria (LAB) for most of the samples. In addition, a slight increase in the antioxidant activity compared with the control sample for the FDCP variant, with the highest value of 91.74%, was observed in these functional food products. The content of polyphenolic compounds varied from 0.044 to 0.091 mg/g DW, while the content of total flavonoids varied from 0.03 to 0.66 mg/g DW. The processing method had an impact on the population of L. plantarum that survived, as indicated by the viability of bacterial cells in all the analyzed products. The chromatographic analysis through UHPLC-MS/MS further confirmed the abundance of the bioactive compounds and their corresponding derivatives by revealing 19 different compounds. The digestibility study indicated that carotenoid compounds from carrots followed a rather controlled release. The carrot-based products enriched with Lactobacillus plantarum can be considered newly functional developed products based on their high content of biologically active compounds with beneficial effects upon the human body. Furthermore, these types of products could represent innovative products for every related industry such as the food, pharmaceutical, and cosmeceutical industries, thus converging a new strategy to improve the health of consumers or patients.

Probiotic Yogurt Supplemented with Lactococcus lactis R7 and Red Guava Extract: Bioaccessibility of Phenolic Compounds and Influence in Antioxidant Activity and Action of Alpha-amylase and Alpha-glucosidase Enzymes.

The industry has increasingly explored the development of foods with functional properties, where supplementation with probiotics and bioactive compounds has gained prominence. In this context, the study aimed to evaluate the influence of in vitro biological digestion on the content of phenolic compounds, antioxidant activity, and inhibition of α-amylase and α-glucosidase activities of probiotic yogurt supplemented with the lactic acid bacteria Lactococcus lactis R7 and red guava extract (Psidium cattleianum). A yogurt containing L. lactis R7 (0.1%) and red guava extract (4%) was characterized for the content of phenolic compounds, antioxidant activity, and potential for inhibition of digestive enzymes after a simulated in vitro digestion process. After digestion, the caffeic and hydroxybenzoic acids remained, and sinapic acid only in the last digestive phase. Antioxidant activity decreased during digestion by 28.93, 53.60, and 27.97% for DPPH, nitric oxide and hydroxyl radicals, respectively, and the inhibition of the α-amylase enzyme decreased only 4.01% after the digestion process. α-glucosidase was more efficient in intestinal digestion, demonstrating an increase of almost 50% in probiotic yogurt with red guava extract before digestion. Possibly, the phenolics change their conformation during digestion, generating new compounds, reducing antioxidant activity, and increasing the inhibitory activity of α-glucosidase digestive enzymes. It was concluded that the probiotic yogurt formulation supplemented with red guava extract could interfere with the concentration of phenolic compounds and the formation of new compounds, suggesting a positive and effective inhibition of the digestive enzymes, even after the digestive process.

Autumn grass treated with a hydrolysable tannin extract versus lactic acid bacteria inoculant: Effects on silage fermentation characteristics and nutritional value and on performance of lactating dairy cows.

Hydrolysable tannins (HT) show potential as silage additive for autumn herbage silages, high in (rumen degradable) protein, as they may reduce proteolysis. Additionally, they have abilities to form pH-reversible tannin-protein complexes, non-degradable in the rumen but degradable in the abomasum and intestines of ruminants. Therefore they can improve milk N efficiency and shift N excretions from urine to faeces, possibly mitigating the environmental impact of ruminants. In this study, two small bunker silos were filled with autumn grass. One was treated with 20 g/kg DM HT extract (TAN) (TannoSan-L), the other with 8 mg/kg DM inoculant containing lactic acid bacteria (INO) (Bonsilage Fit G). Secondly, micro-silos (2.75 L) were filled with four treatments; (1) grass without additive (CON) (n = 5); (2) TAN (n = 5); (3) INO (n = 5); and (4) TAN + INO (n = 5). The bunker silos were used in a cross-over feeding experiment with periods of 4 weeks involving 22 lactating Holstein cows (average ± SD: 183 ± 36.3 days in milk, 665 ± 71.0 kg body weight, and 33.8 ± 3.91 kg/day milk yield). The HT dose was insufficient to reduce proteolysis or alter chemical composition and nutritional value in the micro- and bunker silages. Including grass silage added with TAN (3.2 g HT/kg DM) in the diet, did not affect feed intake nor fat and protein corrected milk yield in comparison to feeding the grass silage added with INO in a similar diet. The TAN-fed cows had an increased faecal N excretion and decreased apparent total-tract N and organic matter digestibility, but no improvement in the cows' N utilization could be confirmed in milk and blood urea levels. Overall, feeding an autumn grass silage treated with 20 g/kg chestnut HT extract did not affect the performance of dairy cows in comparison to feeding an autumn grass silage treated with a lactic acid bacteria inoculant.

The therapeutic effects of fermented milk with lactic acid bacteria from traditional Daqu on hypertensive mice.

Lactic acid bacteria (LAB), a type of microorganism widely used in functional foods, has gained notable research attention in recent years. Certain strains possess the proteolytic ability to release potentially antihypertensive peptides from dairy proteins, which prompted us to explore the LAB strains from an understudied and unique ingredient, Daqu. We screened for 67 strains of LAB strains from traditional Daqu using the calcium dissolution ring method. Sixteen strains exhibiting angiotensin-converting enzyme inhibition (ACE-I) activity exceeding 50% were chosen for 16S rDNA sequencing and safety assessment. It is noteworthy that Enterococcus faecium CP640 and Lacticaseibacillus rhamnosus CP658 exhibited significant ACE-I activity, which was the result of strain fermentation in reconstituted skim milk. These 2 strains did not exhibit hemolytic activity or antibiotic resistance. They also did not produce biogenic amines and showed high survival rates in the gastrointestinal tract. Additionally, Enterococcus faecium CP640 and Lacticaseibacillus rhamnosus CP658 fermented milk exhibited a notable reduction in blood pressure levels in spontaneously hypertensive rats (SHR) compared with negative controls in SHR. Importantly, no adverse effect was observed in normal Wistar-Kyoto rats. Through the analysis of physiological, serum, and urine-related indicators, it was observed that Enterococcus faecium CP640 and Lacticaseibacillus rhamnosus CP658 have the potential to promote weight gain in SHR, alleviate excessive heart rate, improve renal function indicators, and effectively regulate blood sugar and uric acid levels in SHR. These 2 strains showed optimal properties in lowering blood pressure and have the potential to be used in functional dairy products in the future.

Synergistic effect of the coculture of Leuconostoc pseudomesenteroides and Lactococcus lactis, isolated from honeybees, on the generation of plant-based dairy alternatives based on soy, pea, oat, and potato drinks.

The production of plant-based dairy alternatives has been majorly focused on the improvement of sensorial, technological and nutritional properties, to be able to mimic and replace milk-based fermented products. The presence of off-flavours and antinutrients, the lack of production of dairy-like flavours or the metabolic inaccessibility of plant proteins are some of the challenges to overcome to generate plant-based dairy alternatives. However, in the present study, it is demonstrated how the synergistic effect of two LAB strains, when cocultured, can simultaneously solve those challenges when fermenting in four different plant-based raw materials: soy, pea, oat, and potato drinks (SPOP). The fermentation was performed through the mono- and co-culture of the two LAB strains isolated from Apis mellifera (honeybee): Leuconostoc pseudomesenteroides NFICC 2004 and Lactococcus lactis NFICC 2005. Firstly, the coculture of both strains demonstrated to increase the acidification rate of the four plant matrices. Moreover, L. pseudomesenteroides (LP) demonstrated to in situ produce high concentrations of mannitol when fructose was present as C-source. Furthermore, L. pseudomesenteroides, which encoded for PII-proteinase, demonstrated to break down SPOP proteins, releasing free amino acids that were used by L.lactis (LL) for growth and metabolism. Lastly, the analysis of their co-metabolic volatile performance showed the principal ability of removal of the main off-flavours found in SPOP, such as hexanal, 1-octen-3-ol, 2-pentylfuran, pentanal, octanal, heptanal, and nonanal, mainly led by L. pseudomesenteroides, as well as the production of dairy-like flavours, such as diacetyl and 3-methyl-1-butanol, triggered by L. lactis metabolism. Overall, these findings endorsed the use of honeybee isolated strains as starter cultures, demonstrated the potential of coupling genotypes and phenotypes of multiple strains to improve the organoleptic properties suggesting a potential of combining plant-based matrices for the generation of future high-quality plant-based dairy alternatives.

Feeding laying hens with lactobacilli improves internal egg quality and animal health.

Feeding animals with lactobacilli strains is a biotechnological strategy to improve production, food quality, and animal health. Thus, this study aimed to select new lactic acid bacteria (LAB) able to improve laying hens health and egg production. Forty Bovans White layers (two days old) were randomly divided into four experimental groups that receive an oral gavage with saline solution (control group) or with one of the three lactobacilli selected (KEG3, TBB10, and KMG127) by their antagonistic activity against the foodborne pathogen Bacillus cereus GGD_EGG01. 16 S rRNA sequencing identified KEG3 as Lentilactobacillus sp., and TBB10 and KMG127 as Lactiplantibacillus sp. The data showed that feeding birds with LAB increased weight uniformity and improved the internal quality of the eggs (high yolk index and Haugh unit) compared with the control group (p < 0.05). Beta-diversity analysis showed that LAB supplementation modifies the cecal microbiota of laying hens. The prokaryotic families Bacteroidaceae, Ruminococcaceae, Rikenellaceae, and Lactobacillaceae were most important to the total dissimilarity of the cecal microbial community (calculated by SIMPER test). At end of in vivo experiments, it was possible to conclude that the feed of laying hens with Lentilactobacillus sp. TBB10 and Lentilactobacillus sp. KEG3 can be an important biotechnological tool for improving food quality and animal health.

Improved production of lactiplantibacillus plantarum RO30 exopolysaccharide (REPS) by optimization of process parameters through statistical experimental designs.

BACKGROUND: In investigating of (exopolysaccharide) EPS from unconventional sources, lactic acid bacteria have a vital role due to their generally recognized as safe (GRAS) status. EPSs have diverse applications such as drug delivery, antimicrobial activity, surgical implants, and many more in many sectors. Despite being important, the main hindrance to the commercial application of these significant biopolymers is low productivity. Therefore, this study primarily focuses on optimizing physio-chemical conditions to maximize the previously produced EPS from probiotic Lactiplantibacillus plantarum RO30 (L. plantarum RO30) using one factor at a time (OFAT) and method Response Surface Methodology (RSM). RESULTS: The EPS obtained from L. plantarum RO30 named REPS. The medium formulation for REPS production using the OFAT method revealed that sucrose (20 g/L, beef extract (25 g/L), and ammonium sulfate at 4 g/L concentration were the optimum carbon, organic and inorganic nitrogen sources, and REPS yield was increased up to 9.11 ± 0.51 g/L. RSM experiments revealed that, a greatly significant quadratic polynomial attained from the Central Composite Design (CCD) model was fruitful for specifying the most favorable cultural conditions that have significant consequences on REPS yield. The maximal amount of REPS (10.32 g/L) was formed by: sucrose (40 g/L), beef extract (25 g/L), pH (5.5), incubation temperature (30 °C), and incubation period (72 h). A high closeness was obtained between the predicted and experimental values and it displayed the efficiency of the RSM. CONCLUSION: This study was conducted to reinforce REPS production in the probiotic LAB L. plantarum RO30 by utilizing various experimental parameters. The maximum REPS yield of 10.32 g/L was attained under the circumstances optimized in the study.

Anti-Menopausal Effect of Soybean Germ Extract and Lactobacillus gasseri in the Ovariectomized Rat Model.

Menopause is a significant phase in a woman's life. Menopausal symptoms can affect overall well-being and quality of life. Conventionally, hormone replacement therapy (HRT) is used to alleviate menopausal symptoms; however, depending on the conditions, HRT may lead to side effects, necessitating the exploration of alternative therapies with fewer side effects. In this study, we investigated the effects of a combination of soybean germ extract (S30) containing 30% (w/w) isoflavone and a probiotic, Lactobacillus gasseri (LGA1), on menopausal conditions in an ovariectomized (OVX) rat model. We evaluated the impact of S30+LGA on body weight, estrogen markers, uterine and bone health, vascular markers, and neurotransmitter levels. The results revealed that treatment with S30+LGA1 significantly improved body weight and uterine and bone health. Moreover, S30+LGA1 demonstrated promising effects on lipid profile, liver function, and vascular markers and positively impacted serotonin and norepinephrine levels, indicating potential mood-enhancing effects. In conclusion, S30+LGA1, possessing anti-menopausal effects in vitro and in vivo, can be recommended as a soy-based diet, which offers various health benefits, especially for menopausal women.

Impacts of Ultrasonic Treatment for Black Soybean Okara Culture Medium Containing Choline Chloride on the ß-Glucosidase Activity of Lactiplantibacillus plantarum BCRC 10357.

The effects of ultrasonic treatment for the culture medium of solid black soybean okara with choline chloride (ChCl) on the survival and ß-glucosidase activity of Lactiplantibacillus plantarum BCRC 10357 (Lp-BCRC10357) were investigated. A mixture of 3% dried black soybean okara in de Man-Rogosa-Sharpe (w/v) was used as the Oka medium. With ultrasonic treatment (40 kHz/300 W) of the Oka medium at 60 °C for 3 h before inoculation, the ß-glucosidase activity of Lp-BCRC10357 at 12 h and 24 h of incubation amounted to 13.35 and 15.50 U/mL, respectively, which was significantly larger than that (12.58 U/mL at 12 h and 2.86 U/mL at 24 h) without ultrasonic treatment of the medium. This indicated that ultrasonic treatment could cause the microstructure of the solid black soybean okara to be broken, facilitating the transport of ingredients and Lp-BCRC10357 into the internal structure of the okara for utilization. For the effect of ChCl (1, 3, or 5%) added to the Oka medium (w/v) with ultrasonic treatment before inoculation, using 1% ChCl in the Oka medium could stimulate the best response of Lp-BCRC10357 with the highest ß-glucosidase activity of 19.47 U/mL in 12 h of incubation, showing that Lp-BCRC10357 had a positive response when confronting the extra ChCl that acted as an osmoprotectant and nano-crowder in the extracellular environment. Furthermore, the Oka medium containing 1% ChCl with ultrasonic treatment led to higher ß-glucosidase activity of Lp-BCRC10357 than that without ultrasonic treatment, demonstrating that the ultrasonic treatment could enhance the contact of ChCl and Lp-BCRC10357 to regulate the physiological behavior for the release of enzymes. In addition, the analysis of the isoflavone content and antioxidant activity of the fermented product revealed that the addition of 1% ChCl in the Oka medium with ultrasonic treatment before inoculation allowed a higher enhancement ratio for the biotransformation of isoflavone glycosides to their aglycones, with a slight enhancement in the antioxidant activity at 24 h of fermentation. This study developed a methodology by combining ultrasonic treatment with a limited amount of ChCl to allow the culture medium to acclimate Lp-BCRC10357 and release high levels of ß-glucosidase, and this approach has the potential to be used in the fermentation of okara-related products as nutritional supplements in foods.

The Biochemical, Microbiological, Antioxidant and Sensory Characterization of Fermented Skimmed Milk Drinks Supplemented with Probiotics Lacticaseibacillus casei and Lacticaseibacillus rhamnosus.

A variety of foods fermented with lactic acid bacteria (LAB) serve as dietary staples in many countries. The incorporation of health-promoting probiotics into fermented milk products can have profound effects on human health. Considering the health benefits of Yakult, the current study was undertaken to develop an enriched Yakult-like fermented skimmed milk drink by the addition of two probiotic strains, namely Lacticaseibacillus casei (Lc) and Lacticaseibacillus rhamnosus (Lr). The prepared drinks were compared in terms of various parameters, including their physicochemical properties, proximate chemical composition, mineral estimation, microbial viable count, antioxidant activity, and sensory evaluation. Each strain was employed at five different concentrations, including 1% (T1), 1.5% (T2), 2% (T3), 2.5% (T4), and 3% (T5). The prepared Yakult samples were stored at 4 °C and analyzed on days 0, 7, 14, 21, and 28 to evaluate biochemical changes. The findings revealed that the concentration of the starter culture had a significant (p ≤ 0.05) impact on the pH value and moisture and protein contents, but had no marked impact on the fat or ash content of the developed product. With the Lc strain, Yakult's moisture content ranged from 84.25 ± 0.09 to 85.65 ± 0.13%, whereas with the Lr strain, it was from 84.24 ± 0.08 to 88.75 ± 0.13%. Protein levels reached their highest values with T5 (3% concentration). The acidity of all treatments increased significantly due to fermentation and, subsequently, pH showed a downward trend (p ≤ 0.05). The total soluble solids (TSS) content decreased during storage with Lc as compared to Lr, but the presence of carbohydrates had no appreciable impact. The drink with Lc exhibited a more uniform texture and smaller pore size than Yakult with Lr. Except for the iron values, which showed an increasing trend, the contents of other minerals decreased in increasing order of the added probiotic concentration used: 1% (T1), 1.5% (T2), 2% (T3), 2.5% (T4), and 3% (T5). The highest lactobacilli viable count of 8.69 ± 0.43 colony-forming units (CFU)/mL was observed with the T1 Lr-containing drink at the end of the storage period. Regarding the storage stability of the drink, the highest value for DPPH (88.75 ± 0.13%) was found with the T1 Lc drink on day 15, while the highest values for FRAP (4.86 ± 2.80 mmol Fe2+/L), TPC (5.97 ± 0.29 mg GAE/mL), and TFC (3.59 ± 0.17 mg GAE/mL) were found with the T5 Lr drink on day 28 of storage. However, the maximum value for ABTS (3.59 ± 0.17%) was noted with the T5 Lr drink on the first day of storage. The results of this study prove that Lc and Lr can be used in dairy-based fermented products and stored at refrigerated temperatures.

Antimicrobial activity of dietary supplements based on bacterial lysate of Lactobacillus rhamnosus DV.

Introduction: According to WHO, antibiotic resistance is increasing to hazardous levels worldwide. Candidiasis often occurs after taking antibiotics. Therefore, antibiotic resistance is a global problem and searching for antibacterial agents is necessary. Aim: To determine the antimicrobial activity of bacterial lysate of Lactobacillus (L.) rhamnosus DV separately and with plant extracts against bacterial and yeast test cultures. Material and methods: Antimicrobial activity of Del-Immune V® (cell wall and DNA fragments from a L. rhamnosus DV) separately and with cinnamon, beetroot, and blackcurrant extracts was determined by the minimum inhibitory concentration (MIC). Twofold serial dilutions determined the MIC in previously prepared meat-peptone broth (MPB) for bacteria and liquid wort for yeast. In the study, gram-negative (Escherichia coli IEM-1, Proteus vulgaris PА-12, Pseudomonas sp. MI-2, L. rhamnosus 13/2) and gram-positive (Bacillus (B.) subtilis BТ-2, Staphylococcus aureus BМС-1) bacteria, as well as yeast (Candida (C.) albicans D-6, C. tropicalis PE-2, C. utilis BVS-65) were used as test cultures. Results: The MIC for the studied bacterial test cultures after application of L. rhamnosus DV bacterial lysates was from 1.0 ± 0.05 mg/mL to 12.5 ± 0.63 mg/mL, which was significantly less than that of the thermally inactivated control (MIC from 125.0 ± 6.25 mg/mL to 250.0 ± 12.5 mg/mL). B. subtilis BT-2 culture was the least sensitive to the action of the bacterial lysate (MIC-12.5 ± 0.63 mg/mL). It showed the best antibacterial and antifungal effect bacterial lysate with the phytonutrient blackcurrant. Conclusions: It was demonstrated that bacterial lysate of lactic acid bacteria L. rhamnosus DV exhibits antibacterial and antifungal properties during direct contact with pathogenic agents.

Fermented Stevia Improves Alcohol Poisoning Symptoms Associated with Changes in Mouse Gut Microbiota.

We previously found that the continuous feeding of ethanol caused mice dysbiosis, in which the cecal microbiota were significantly altered, as compared with those in the non-feeding control group, especially in some bacterial genera involved in gut inflammation. In the present study, we have found that the fermented extract of stevia (Stevia rebaudiana) leaves with plant-derived lactic acid bacteria (LABs), Pediococcus pentosaceus LY45, improves the trimethylamine (TMA) productivity of cecal content, which can be used as an indicator of dysbiosis. The following animal experiment also shows that the LY45-fermented stevia extract represses the typical increase in serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels, which decreased from 1106 to 210 IU/L (p < 0.05) and from 591 to 100 IU/L (p < 0.05), respectively, together with the simultaneously latent TMA productivity (from 1356 to 745 µM, p < 0.05) of cecal content in the ethanol-fed mice. The microbiota analyses have shown that the observed increased alterations in pro-inflammatory genera putative SMB53 (family Clostridiaceae) and Dorea are restored by the fermented stevia extract. Our result indicates that the preliminary bioconversion of herbal medicinal precursors by fermentation with safe microorganisms like LABs is expected to be a hopeful method of producing specific metabolites that may contribute to the reconstruction of gut microbiota.

Study of the Effect of Baicalin from Scutellaria baicalensis on the Gastrointestinal Tract Normoflora and Helicobacter pylori.

The antimicrobial properties of baicalin against H. pylori and several probiotic cultures were evaluated. Baicalin was isolated from a dry plant extract obtained by extraction with water at 70 °C. For isolation, extraction was carried out with n-butanol and purification on a chromatographic column. The antimicrobial potential was assessed by evaluating changes in the optical density of the bacterial suspension during cultivation; additionally, the disk diffusion method was used. During the study, the baicalin concentrations (0.25, 0.5, and 1 mg/mL) and the pH of the medium in the range of 1.5-8.0 were tested. The test objects were: suspensions of H. pylori, Lactobacillus casei, L. brevis, Bifidobacterium longum, and B. teenis. It was found that the greater the concentration of the substance in the solution, the greater the delay in the growth of the strain zone. Thus, the highest antimicrobial activity against H. pylori was observed at pH 1.5-2.0 and a baicalin concentration of 1.00 mg/mL. In relation to probiotic strains, a stimulating effect of baicalin (1.00 mg/mL) on the growth of L. casei biomass at pH 1.5-2.0 was observed. The results open up the prospects for the use of baicalin and probiotics for the treatment of diseases caused by H. pylori.

The Occurrence of Folate Biosynthesis Genes in Lactic Acid Bacteria from Different Sources.

Research background: Lactic acid bacteria (LAB) are known to produce folate. However, this ability is highly strain-dependent. Folate synthesis in specific LAB strains is affected by the availability of folate, which can be consumed by other LAB under certain conditions. Moreover, differences in folate synthesis capabilities are related to the presence of folate biosynthesis-related genes and regulation of this pathway. Experimental approach: As basic information to better understand the regulation of folate biosynthesis among different LAB species and strains, folate biosynthetic genes were screened and identified in folate-producing and non-folate-producing LAB isolated from various local food sources in Indonesia. The extracellular folate productivity amounts of the isolates were analyzed using high-performance liquid chromatography with a diode array detector (HPLC-DAD). Results and conclusions: Eleven of the thirteen tested LAB isolates had all of the eight genes involved in folate biosynthesis (folE, folQ, folB, folK, folP, folC1, folA and folC2). Furthermore, these isolates produced extracellular folate ranging from 10.37 to 31.10 µg/mL. In contrast, two non-folate-producing isolates lacked several folate biosynthetic genes, such as folQ, folP and folA, which is possibly the reason for their inability to synthesize folate de novo. Phylogenetic tree construction revealed that the folate biosynthetic genes (excluding folK and folP) from six distinct species of folate-producing LAB isolates were monophyletic with homologous genes from other LAB species in the database. Novelty and scientific contribution: In this study, the distribution of folate biosynthetic genes in various LAB species was determined. The findings from this research support the use of folate biosynthesis marker genes in the genotypic screening for folate-producing LAB.

Inhibition of Aspergillus carbonarius growth and Ochratoxin A production using lactic acid bacteria cultivated in an optimized medium.

The Gram-positive bacteria lactic acid bacteria (LAB) are used in the food industry but are also known for inhibiting certain food spoilage microorganisms, especially fungi. Sources of nitrogen (N) for culture media are generally organic and expensive. Many attempts have been made to formulate economical culture media with alternative N sources obtained from agricultural and industrial byproducts. This study describes the design and optimization of an inexpensive culture medium for Lactiplantibacillus plantarum (formerly Lactobacillus plantarum) MZ809351 strain B31. The culture medium was optimized using statistical experimental designs to identify the factors with the most significant effects on biomass concentration to reduce the overall cost, aiming to obtain a biomass concentration similar to that obtained with the reference LAB culture medium (de Man, Rogosa and Sharpe; MRS). Sodium acetate and magnesium sulfate were the most significant factors (p < 0.005), and their contents were reduced by 22 % and 40 %, respectively, without affecting biomass concentration. Malt germ extract (MGE) was used as an alternative nitrogen source to replace meat extract (ME) and proteose peptone (PP). Through these experiments, the composition of a culture medium that is less expensive than MRS broth was defined, which produced a biomass concentration (3.8 g/L) similar to that obtained with MRS medium. The inhibitory effects of two LAB strains isolated from the Ivory Coast and Mexico on the growth and production of ochratoxin A (OTA) in an ochratoxigenic fungus was tested. The minimum cellular concentration of the LAB to prevent the development of Aspergillus carbonarius Ac 089 and the production of OTA was determined in a model assay in Petri dishes. The conditions to inhibit the germination of A. carbonarius Ac 089 and the production of OTA were found. Using the optimized medium and a ratio of 2 × 104 LAB/spore (1 × 108 CFU/mL) strain B7 (L. plantarum MZ809351) and 2 × 103 LAB/spore (1 × 107 CFU/mL) strain B31 (L. plantarum MN922335) completely inhibited the growth of the fungus. A ratio of 2 × 105 LAB/spore (1 × 109 CFU/mL) was required to inhibit OTA production with strains B7 and B31. This study indicates the potential of cultivating LAB in an optimized and inexpensive culture medium for use as a biological control agent against ochratoxigenic fungi in food.

Control of Listeria monocytogenes in a fresh cheese using aromatic and medicinal plants and enterocin: a comparative study.

The aim of this study was to investigate the effectiveness of essential oils (EOs) or crude extracts (CEs) of eight aromatic and medicinal plants (AMPs) and its association with enterocin OS1 on Listeria monocytogenes and food spoilage bacteria in Moroccan fresh cheese. The cheese batches were treated with EO of Rosmarinus officinalis, Thymus vulgaris, Syzygium aromaticum, Laurus nobilis, Allium sativum, Eucalyptus globulus, or CE of Crocus sativus and Carthamus tinctorius, and/or enterocin OS1, and stored for 15 days at 8°C. The data were subjected to correlations analysis, variance analysis, and principal components analysis. Results clearly showed a positive correlation between L. monocytogenes reduction and storage time. Moreover, reduction on Listeria counts induced by Allium-EO and Eucalyptus-EO reached 2.68 and 1.93 Log CFU/g with respect to untreated samples after 15 days, respectively. Similarly, enterocin OS1 alone has significantly reduced the L. monocytogenes population with 1.46 Log CFU/g. The most promising result was the synergy observed between many AMPs and enterocin. Indeed, treatments with Eucalyptus-EO + OS1 and Crocus-CE + OS1 decreased the Listeria population to undetectable after only 2 days and throughout the storage period. These findings suggest a promising application/use of this natural combination, which preserves the safety and long-lasting conservation of fresh cheese.

Dynamic Modelling to Describe the Effect of Plant Extracts and Customised Starter Culture on Staphylococcus aureus Survival in Goat's Raw Milk Soft Cheese.

This study characterises the effect of a customised starter culture (CSC) and plant extracts (lemon balm, sage, and spearmint) on Staphylococcus aureus (SA) and lactic acid bacteria (LAB) kinetics in goat's raw milk soft cheeses. Raw milk cheeses were produced with and without the CSC and plant extracts, and analysed for pH, SA, and LAB counts throughout ripening. The pH change over maturation was described by an empirical decay function. To assess the effect of each bio-preservative on SA, dynamic Bigelow-type models were adjusted, while their effect on LAB was evaluated by classical Huang models and dynamic Huang-Cardinal models. The models showed that the bio-preservatives decreased the time necessary for a one-log reduction but generally affected the cheese pH drop and SA decay rates (logDref = 0.621-1.190 days; controls: 0.796-0.996 days). Spearmint and sage extracts affected the LAB specific growth rate (0.503 and 1.749 ln CFU/g day-1; corresponding controls: 1.421 and 0.806 ln CFU/g day-1), while lemon balm showed no impact (p > 0.05). The Huang-Cardinal models uncovered different optimum specific growth rates of indigenous LAB (1.560-1.705 ln CFU/g day-1) and LAB of cheeses with CSC (0.979-1.198 ln CFU/g day-1). The models produced validate the potential of the tested bio-preservatives to reduce SA, while identifying the impact of such strategies on the fermentation process.