Comparative evaluation of the remineralizing potential of Salvadora persica and probiotic yogurt on incipient enamel lesions: An ex-vivo study.

BACKGROUND: Salvadora persica (miswak) is known to exert antibacterial, antifungal, antioxidant, and anticariogenic effects by elevating the pH of plaque after the consumption of sucrose. OBJECTIVES: The study aimed to compare the effectiveness of S. persica and probiotic yogurt in the remineralization of tooth enamel on artificially produced enamel lesions. MATERIAL AND METHODS: A total of 40 intact human premolars were collected and each tooth was sectioned longitudinally into 2 identical halves in a buccolingual direction. The buccal halves were selected for inclusion in this study, and standardized windows (5 mm × 3 mm) were isolated on the buccal surface of the enamel. The samples were incubated in a demineralizing solution at 37°C for 96 h. Subsequently, they were randomly selected for treatment with one of the experimental remineralizing solutions (S. persica or probiotic yogurt). After treatment, the samples were examined using scanning electron microscopy (SEM), energy dispersive X-ray (EDX) and polarized light microscopy at baseline, after demineralization and after remineralization. RESULTS: The remineralizing effect of S. persica was found to be greater than that of probiotic yogurt. With regard to mineral content, S. persica exhibited the highest calcium and phosphorus levels among all groups. No significant differences were observed between the samples treated with S. persica and normal enamel. CONCLUSIONS: Salvadora persica extract has been demonstrated to effectively reduce the demineralization of enamel in experimental conditions. Furthermore, it has the potential to restore the mineral content to its original level.

Functional genomic analysis of the isolated potential probiotic Lactobacillus delbrueckii subsp. indicus TY-11 and its comparison with other Lactobacillus delbrueckii strains.

Probiotics refer to living microorganisms that exert a variety of beneficial effects on human health. On the contrary, they also can cause infection, produce toxins within the body, and transfer antibiotic-resistant genes to the other microorganisms in the digestive tract necessitating a comprehensive safety assessment. This study aimed to conduct functional genomic analysis and some relevant biochemical tests to uncover the probiotic potentials of Lactobacillus delbrueckii subsp. indicus TY-11 isolated from native yogurt in Bangladesh. We also performed transmission electron microscopic (TEM) analysis, comparative genomic study as well as phylogenetic tree construction with 332 core genes from 262 genomes. The strain TY-11 was identified as Lactobacillus delbrueckii subsp. indicus, whose genome (1,916,674 bp) contained 1911 CDS, and no gene was identified for either antibiotic resistance or toxic metabolites. It carried genes for the degradation of toxic metabolites, treatment of lactose intolerance, toll-like receptor 2-dependent innate immune response, heat and cold shock, bile salts tolerance, and acidic pH tolerance. Genes were annotated for inhibiting pathogenic bacteria by inhibitory substances [bacteriocin: Helveticin-J (331 bp) and Enterolysin-A (275 bp), hydrogen peroxide, and acid]; blockage of adhesion sites; and competition for nutrients. The genes involved in its metabolic pathway were detected as suitable for digesting indigestible nutrients in the human gut. The TY-11 genome possessed an additional 37 core genes of subspecies indicus which were deficient in the core genome of the most popular subsp. bulgaricus. During the phenotypic testing, the isolate TY-11 demonstrated high antagonistic activity (inhibition zone of 21.33 ± 1.53 mm) against Escherichia coli ATCC 8739 and was not sensitive to any of the 10 tested antibiotics. This study was the first study to explore the molecular insights into probiotic roles, including antimicrobial activities and antibiotic sensitivity, of a representative strain (TY-11) of Lactobacillus delbrueckii subsp. indicus. IMPORTANCE: This study aimed to conduct functional genomic analysis to uncover the probiotic potential of Lactobacillus delbrueckii subsp. indicus TY-11 isolated from native yogurt in Bangladesh. We also performed transmission electron microscopic (TEM) analysis, comparative genomic study as well as phylogenetic tree construction with 332 core genes from 262 genomes. In our current investigation, we revealed a number of common and unique excellences of the probiotic Lactobacillus delbrueckii subsp. indicus TY-11 that are likely to be important to illustrate its intestinal residence and probiotic roles. This is the first study to explore the molecular insights into intestinal residence and probiotic roles, including antimicrobial activities and antibiotic sensitivity, of a representative strain (TY-11) of Lactobacillus delbrueckii subsp. indicus.

Natural approach of using nisin and its nanoform as food bio-preservatives against methicillin resistant Staphylococcus aureus and E.coli O157:H7 in yoghurt.

BACKGROUND: Natural antimicrobial agents such as nisin were used to control the growth of foodborne pathogens in dairy products. The current study aimed to examine the inhibitory effect of pure nisin and nisin nanoparticles (nisin NPs) against methicillin resistant Staphylococcus aureus (MRSA) and E.coli O157:H7 during the manufacturing and storage of yoghurt. Nisin NPs were prepared using new, natural, and safe nano-precipitation method by acetic acid. The prepared NPs were characterized using zeta-sizer and transmission electron microscopy (TEM). In addition, the cytotoxicity of nisin NPs on vero cells was assessed using the 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The minimum inhibitory concentrations (MICs) of nisin and its nanoparticles were determined using agar well-diffusion method. Further, fresh buffalo's milk was inoculated with MRSA or E.coli O157:H7 (1 × 106 CFU/ml) with the addition of either nisin or nisin NPs, and then the inoculated milk was used for yoghurt making. The organoleptic properties, pH and bacterial load of the obtained yoghurt were evaluated during storage in comparison to control group. RESULTS: The obtained results showed a strong antibacterial activity of nisin NPs (0.125 mg/mL) against MRSA and E.coli O157:H7 in comparison with control and pure nisin groups. Notably, complete eradication of MRSA and E.coli O157:H7 was observed in yoghurt formulated with nisin NPs after 24 h and 5th day of storage, respectively. The shelf life of yoghurt inoculated with nisin nanoparticles was extended than those manufactured without addition of such nanoparticles. CONCLUSIONS: Overall, the present study indicated that the addition of nisin NPs during processing of yoghurt could be a useful tool for food preservation against MRSA and E.coli O157:H7 in dairy industry.

Production and Evaluation of Set-Type Yoghurt Fortified with Chlorella vulgaris and Moringa oleifera Powder.

Considering the growing popularity of functional foods, fortifying yoghurt with natural ingredients with various flavours and appearances could improve its nutritional and health potential. The current study aimed to evaluate the effect of Chlorella vulgaris (0.3 and 0.5%) and Moringa oleifera (0.3 and 0.5%) on the fermentation kinetics, apparent viscosity, antioxidant activity, microbiological, sensorial, and FTIR properties of yoghurt during storage. The results demonstrated that the incorporation of Chlorella vulgaris and Moringa oleifera into yoghurt increased acidification rate and decreased fermentation time (p < 0.05). Moringa oleifera (0.5%) improved the growth and survival of lactic acid bacteria as well as the phenolic and antioxidant properties of yoghurt. However, Chlorella vulgaris, at a concentration of 0.5% reduced the viability of lactic acid bacteria, viscosity, total phenolic, and antioxidant properties of yoghurt. In conclusion, it was found that Chlorella vulgaris, at 0.3%, and Moringa oleifera improved the phenolic, antioxidant properties, and acidification rate of yoghurt.

Microbial risk assessment of dairy products from retail marketplaces in Basrah province, Iraq.

Background: Milk-borne bacteria cause degradation of milk products and constitute a significant risk to public health. Aim: The objectives of the present study are to determine the microbiological quality of dairy products and to investigate pathogenic microorganisms. Methods: A total of 60 samples of raw milk, homemade cheese, and yogurt were randomly selected from different retail marketplaces in Basrah. The bacteriological and biochemical tests were utilized to identify the pathogens in dairy samples, as well as the molecular technique was used as an accurate diagnostic test. Results: The prevalence of contamination of milk products with various isolates was estimated as 50% (95% Cl: 36.8-63.2). The mean of total bacteria count for cheese was 7.29 ± 2.70, raw milk 4.62 ± 2.86, and yogurt 2.87 ± 1.05, with a significant p-value (p = 0.001). The mean count of aerobic spore-forming (ASF) contaminated raw milk was analyzed as 3.77 ± 1.18 and less contamination detected in the yogurt samples with mean of ASF was estimated as 2.52 ± 1.47 SD log 10 CFU/ml. A range of important microorganisms to human health were identified by employing the VITEK_2 system and sequencing 16S rDNA gene, including Staphylococcus aureus, Escherichia coli, Pseudomonas aerogenosa, and Bacillus cereus. Conclusion: The study indicates that there is a high level of bacterial contamination in dairy products with different bacteria species, which is medically important. Therefore, food safety management must be implemented to reduce biological risks carried by dairy products and ensure healthy food for consumers.

Lacticaseibacillus rhamnosus HF01 fermented yogurt alleviated high-fat diet-induced obesity and hepatic steatosis via the gut microbiota-butyric acid-hepatic lipid metabolism axis.

The objective of this study was to investigate the anti-obesity effects and underlying mechanism of Lacticaseibacillus rhamnosus HF01 fermented yogurt (HF01-Y). Herein, obesity was induced in mice through a high-fat diet and the changes in the gut microbiota were evaluated using 16S rRNA gene sequencing, combined with the expression levels of the liver AMPK signaling pathway to analyze the potential relationship between HF01-Y-mediated gut microbiota and obesity. The results showed that supplementation with HF01-Y improved obesity-related phenotypes in mice, including reduced body weight, improved serum lipid profiles, and decreased hepatic lipid droplet formation. In addition, HF01-Y altered the composition of the gut microbiota in obese mice, significantly upregulated norank_f__Muribaculaceae, unclassified_c__Clostridia, Blautia, unclassified_o__Bacteroidales, and Rikenellaceae_RC9_gut_group, while downregulating unclassified_f__Desulfovibrionaceae, Colidextribacter, and unclassified_f__Oscillospiraceae. These alterations led to an increase of the cecum butyric acid content, which in turn indirectly promoted the activation of the AMPK signaling pathway, subsequently, inhibited fat synthesis, and promoted fatty acid oxidation related gene expression. Therefore, HF01-Y was likely to alleviate hepatic fat and relieve obesity by modulating the gut microbiota-butyric acid-hepatic lipid metabolism axis, ultimately promoting host health.

High performance poly(L-lactic acid)-based film by one-step synthesis of poly (L-lactic acid-co-butylene itaconate-co-glycolic acid) for efficient preservation of yogurt storage.

Biodegradable poly(L-lactic acid) (PLLA) has seldom used for dairy packaging due to medium permeability and brittleness. Novel PLLA copolymers, poly (L-lactic acid-co-butylene itaconate-co-glycolic acid) (PLBIGA), were developed by integrating glycolic acid (GA) and poly(butylene itaconate) (PBI) into PLLA's structure using low molecular weight PLLA as a key initiator. Then, packaging materials with better barrier and mechanical properties were obtained by blended PLBIGA with PLLA. Both PLLA/PLBIGA films and polyethylene nylon composite film (PE/NY) were used for stirred yogurt packaging and storage at 4 °C for 25 days. Results revealed that yogurt packed by PLLA/PLBIGA films maintained stabler water-holding capacity, color, and viscosity over the storage period. Moreover, the integrity of the gel structure and the total viable count of lactic acid bacteria in yogurt packaged in PLLA/40-PLBIGA8 were also found to be superior to those in PE/NY packages, highlighting its eco-friendly advantages in dairy packaging.

Effects of 2'-fucosyllactose on the viability of starter cultures and Bifidobacterium strains of human origin in yogurt during refrigerated storage.

2'-Fucosyllactose (2'-FL) is postulated to provide health benefits and promote the growth of probiotics. This work was undertaken to study the effects of 2'-FL on the viability of starter cultures and Bifidobacterium strains of human origin in yogurt during refrigerated storage. Yogurts were produced containing 2'-FL (0 or 2 g/L) and Bifidobacterium strains of human origin (Bifidobacterium longum subsp. longum BB536 or Bifidobacterium longum subsp. infantis ATCC 15697) at a concentration of at least 109 CFU/mL. All yogurts were stored at 4°C for 5 weeks. Results showed that 2'-FL was stable in yogurts for at least 5 weeks of cold storage, and the addition of 2'-FL did not significantly alter yogurt fermentation parameters, associated metabolites, and the viability of mixed yogurt starter cultures and Bifidobacterium strains (p > 0.05). The addition of bifidobacteria had a negative impact (p < 0.05) on the survival rate of starter cultures, Streptococcus thermophilus and Lactobacillus delbureckii subsp. bulgaricus. Meanwhile, it is difficult to maintain a high survival rate of bifidobacteria in final yogurt products, and the addition of 2'-FL could not enhance the viability of bifidobacteria. B. longum BB536 survived at a level higher than 106 CFU/g for 28 days, while B. infantis ATCC15697 maintained this level for only 7 days. In summary, this study has shown the impact of 2'-FL and bifidobacterial species on yogurt properties, and results suggest that it is promising to use 2'-FL in yogurt products as a prebiotic. PRACTICAL APPLICATION: Yogurt is known for its beneficial effects on human health and nutrition. This study reported the production of symbiotic yogurt containing bifidobacteria and 2'-fucosyllactose (2'-FL) as a functional food for specified health uses. The viability of yogurt starter cultures and probiotic bifidobacterial strains was analyzed in this study. Moreover, this research demonstrated that 2'-FL could be added to yogurt without affecting the characteristics of yogurt significantly.

Does Yogurt Enriched with Platelet-Activating Factor Inhibitors from Olive Oil By-Products Affect Gut Microbiota and Faecal Metabolites in Healthy Overweight Subjects? (A randomized, parallel, three arm trial.).

OBJECTIVE: The effect of the daily consumption of a low-fat yogurt (150 g) enriched with Platelet-Activating Factor receptor (PAF-R) antagonists, or the plain one, on gut microbiota and faecal metabolites was investigated in healthy overweight subjects. METHODS: A randomized, three-arm, double-blind, placebo-controlled, parallel-group study was performed that lasted 8 weeks. Blood and stools were collected and analyzed before and after the intervention. RESULTS: Our findings revealed that the intake of the enriched yogurt resulted in a significant increase in the levels of Bifidobacterium spp., Clostridium perfringens group and Firmicutes-to-Bacteroidetes (F/B) ratio. On the other hand, a significant increase in the levels of Lactobacillus and C. perfringens group was detected after the intake of the plain yogurt. The increase in the levels of C. perfringens group was inversely associated with the plasma catabolic enzyme of PAF, namely LpPLA2 (lipoprotein-associated phospholipase A2), a cardiovascular risk marker that has been linked with inflammation and atherosclerosis. Moreover, in the enriched with PAF-R antagonists yogurt group, the increased levels of C. perfringens group were also associated with lower PAF action assessed as ex vivo human platelet-rich plasma (PRP) aggregation. Additionally, a higher % increase in molar ratio of Branched Short Chain Fatty Acids (BSCFAs) was detected for both yogurt groups after the 8 week-intervention compared to control. The consumption of the enriched yogurt also resulted in a significant drop in faecal caproic levels and a trend for lower ratio of butyrate to total volatile fatty acids (VFAs) compared to baseline levels. CONCLUSION: Yogurt consumption seems to favorably affect gut microbiota while its enrichment with PAF-R antagonists from olive oil by-products, may provide further benefits in healthy overweight subjects. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov (NCT02259205).

Combining thermosonication microstress and pineapple peel extract addition to achieve quality and post-acidification control in yogurt fermentation.

This work investigated the effects of the combined use of thermosonication-preconditioned lactic acid bacteria (LAB) with the addition of ultrasound-assisted pineapple peel extracts (UU group) on the post-acidification potential, physicochemical and functional qualities of yogurt products, aimed at achieving prolonged preservation and enhancing functional attributes. Accordingly, the physical-chemical features, adhesion properties, and sensory profiles, acidification kinetics, the contents of major organic acids, and antioxidant activities of the differentially processed yogurts during refrigeration were characterized. Following a 14-day chilled storage process, UU group exhibited acidity levels of 0.5-2 oT lower than the control group and a higher lactose content of 0.07 mg/ml as well as unmodified adhesion potential, indicating that the proposed combination method efficiently inhibited post-acidification and delayed lactose metabolism without leading to significant impairment of the probiotic properties. The results of physicochemical analysis showed no significant changes in viscosity, hardness, and color of yogurt. Furthermore, the total phenolic content of UU-treated samples was 98 µg/mL, 1.78 times higher than that of the control, corresponding with the significantly lower IC50 values of DPPH and ABTS radical scavenging activities of the UU group than those of the control group. Observations by fluorescence inverted microscopy demonstrated the obvious adhesion phenomenon with no significant difference found among differentially prepared yogurts. The results of targeted metabolomics indicated the proposed combination strategy significantly modified the microbial metabolism, leading to the delayed utilization of lactose and the inhibited conversion into glucose during post-fermentation, as well as the decreased lactic acid production and a notable shift towards the formation of relatively weak acids such as succinic acid and citric acid. This study confirmed the feasibility of thermosonication-preconditioned LAB inocula, in combination with the use of natural active components from fruit processing byproducts, to alleviate post-acidification in yogurt and to enhance its antioxidant activities as well as simultaneously maintaining sensory features.

Deciphering the metabolism of Lactobacillus delbrueckii subsp. delbrueckii during soy juice fermentation using phenotypic and transcriptional analysis.

In the context of sustainable diet, the development of soy-based yogurt fermented with lactic acid bacteria is an attractive alternative to dairy yogurts. To decipher the metabolism of Lactobacillus delbrueckii subsp. delbrueckii during soy juice (SJ) fermentation, the whole genome of the strain CIRM-BIA865 (Ld865) was sequenced and annotated. Then Ld865 was used to ferment SJ. Samples were analyzed throughout fermentation for their cell number, carbohydrate, organic acid, free amino acid, and volatile compound contents. Despite acidification, the number of Ld865 cells did not rise, and microscopic observations revealed the elongation of cells from 3.6 µm (inoculation) to 36.9 µm (end of fermentation). This elongation was observed in SJ but not in laboratory-rich medium MRS. Using transcriptomic analysis, we showed that the biosynthesis genes of peptidoglycan and membrane lipids were stably expressed, in line with the cell elongation observed, whereas no genes implicated in cell division were upregulated. Among the main sugars available in SJ (sucrose, raffinose, and stachyose), Ld865 only used sucrose. The transcriptomic analysis showed that Ld865 implemented the two transport systems that it contains to import sucrose: a PTS system and an ABC transporter. To fulfill its nitrogen needs, Ld865 probably first consumed the free amino acids of the SJ and then implemented different oligopeptide transporters and proteolytic/peptidase enzymes. In conclusion, this study showed that Ld865 enables fast acidification of SJ, despite the absence of cell division, leads to a product rich in free amino acids, and also leads to the production of aromatic compounds of interest. IMPORTANCE: To reduce the environmental and health concerns related to food, an alternative diet is recommended, containing 50% of plant-based proteins. Soy juice, which is protein rich, is a relevant alternative to animal milk, for the production of yogurt-like products. However, soy "beany" and "green" off-flavors limit the consumption of such products. The lactic acid bacteria (LAB) used for fermentation can help to improve the organoleptic properties of soy products. But metabolic data concerning LAB adapted to soy juice are lacking. The aim of this study was, thus, to decipher the metabolism of Lactobacillus delbrueckii subsp. delbrueckii during fermentation of a soy juice, based on a multidisciplinary approach. This result will contribute to give tracks for a relevant selection of starter. Indeed, the improvement of the organoleptic properties of these types of products could help to promote plant-based proteins in our diet.

Effect of Lactobacillus helveticus exopolysaccharides molecular weight on yogurt gel properties and its internal mechanism.

The processing characteristics of yogurt are closely related to the composition and arrangement of exopolysaccharides (EPS) in lactic acid bacteria (LAB). To fully understand and develop the functional properties of EPS and to study the effect of EPS molecular weight on yogurt and its mechanism, the physicochemical properties of high molecular weight EPS-LH43, medium molecular weight EPS-LH13, and low molecular weight EPS-LH23, as well as the gel properties and protein conformation of yogurt, were determined and analyzed in this experiment. The results indicate that EPS-LH43 and EPS-LH13 are both composed of mannose, rhamnose, galacturonic acid, glucose, and galactose. EPS-LH23 is composed of mannose, galacturonic acid, glucose, and galactose. Their Number-average Molecular Weight is 5.21 × 106 Da, 2.39 × 106 Da and 3.76 × 105 Da, respectively. In addition, all three types of EPS have good thermal stability and can improve the stability of casein. In addition, the analysis of the texture, particle size, potential, water holding capacity, rheology, low field nuclear magnetic resonance, microstructure, and flavor characteristics of yogurt confirmed the relationship between the molecular weight of LAB EPS and the gel properties of yogurt. Fluorescence spectrophotometer and circular dichroism analysis indicate that the different molecular weights of LAB EPS have different effects on protein structure, which is an intrinsic factor leading to significant differences in the gel properties of the three types of fermented milk. These findings provide new references for enhancing the understanding of the structure-activity relationship of EPS and indicate that EPS-LH43 can be used to improve the gel properties of dairy products.

Physicochemical, microbiological and metabolomics changes in yogurt supplemented with lactosucrose.

Lactosucrose (LS) is a known prebiotic that has gained recognition for its low caloric content and various health benefits. However, its potential in food applications remains largely unexplored. In this study the effects of adding LS to milk at concentrations (0 %, 2 %, 5 % and 8 % w/v) for yogurt production, and the relevant changes in yogurt texture, microbial composition and metabolomics were investigated. Our findings revealed that LS played a role in promoting the formation of a structured gel during fermentation, resulting in increased elasticity and viscosity while reducing fluidity. Additionally incorporating high doses of LS into yogurt led to reduced post-acidification, enhanced survival of starter bacteria, improved water retention capacity and overall texture throughout a refrigerated storage period of 21 days. Notably higher concentrations of LS (8 % w/v) exhibited effects on enhancing yogurt quality. Furthermore, untargeted metabolomics analysis using UPLC Q TOF MS/MS revealed 45 differentially expressed metabolites, including up-regulated L-arginine, L-proline and L-glutamic acid along with the down-regulated glutathione, L-tyrosine, L-phenylalanyl and L-proline. These differential metabolites were primarily associated with amino acid metabolism such as thiamine metabolism, nicotinic acid salt and nicotinamide metabolism, and pyrimidine metabolism. As a result, the inclusion of LS in yogurt had an impact on the production of various beneficial metabolites in yogurt, highlighting the importance of combining prebiotic LS with probiotics to obtain desired physiological benefits of yogurt.

The enhancement effect of mungbean on the physical, functional, and sensory characteristics of soy yoghurt.

Vegetable drinks offer a convenient way to increase the daily intake of vegetables containing vitamins, antioxidants, and fiber. In this study, we discovered that mungbean milk serves as a carbohydrate source during fermentation using lactic acid bacteria (LAB) and enhances the nutritional value of vegetable yoghurt. Mungbean milk reduces pH while titratable acidity increases faster than soybean milk during fermentation. M0S, Soybean milk 100% with added sucrose exhibited the highest titratable acidity after 16 h of fermentation. The acetic acid content of all samples did not show significant changes during fermentation, but the lactic acid content increased. Proximate analysis showed no significant change during fermentation, regardless of the fermentation time and mixing ratio of mungbean to soybean milk. The sucrose content of samples except M0S decreased after 16 h of fermentation. Mungbean milk exhibited high antioxidant activity both before and after fermentation, while M0S showed the lowest antioxidant activity. The results of this study demonstrated the potential application of mungbean milk to improve fermented vegetable drinks using LAB functionally. Fermented mungbean milk yoghurt can be a valuable addition to a healthy and balanced diet for those who consume plant-based diets.

Effect of exopolysaccharides yield and addition concentration of Lactobacillus helveticus on the processing characteristics of fermented milk and its mechanism.

Exopolysaccharides (EPS) yield and added concentration of lactic acid bacteria can greatly affect the processing characteristics of fermented milk. In order to investigate the effects and mechanisms of EPS yield and added concentration on fermented milk, researchers extracted EPS from 50 strains of Lactobacillus helvedicus (L. helvedicus) and selected the two strains with the largest difference in EPS yield (L. helvedicus LH18 and L. helvetigus LH33) for subsequent experiments. The physicochemical properties of EPS-LH18 and EPS-LH33 were analyzed. The gel characteristics and protein conformation of fermented milk were studied by means of texture analyzer, rheometer, scanning electron microscopy, nuclear magnetic resonance machine, fluorescence spectrophotometer and circular dichroism. The results indicate that the monosaccharide compositions of EPS-LH18 and EPS-LH33 are the same and have good thermal stability. The texture and rheological properties of L. helveticus LH18 fermented milk are significantly superior to other fermented milk. The reason is that L. helveticus LH18 EPS has the highest yield, which leads to a denser gel structure, lower surface hydrophobicity and free sulfhydryl content of its fermented milk. According to circular dichroism analysis, ß- sheet and random coil are the internal factors leading to the difference in fermented milk gel. In addition, the fermented milk improved even more favorably as the concentration of the two EPS additions increased. As described above, L. helveticus LH18 has the potential to be an excellent yogurt starter, and both of the above EPS can be used as probiotic stabilizer alternatives for fermented dairy products.

Efficacy and Safety of BB-12 Supplemented Strawberry Yogurt For Healthy Children on Antibiotics (PLAY ON).

Context: Probiotics are live microorganisms that, when administered in adequate amounts, confer a health benefit on the host. One of the most common indications for probiotic treatment is the prevention of antibiotic-associated diarrhea (AAD). Unfortunately, many probiotic products used for AAD are not supported by rigorous independent research, and often results in non-evidence-based usage. The overarching objective is to move research forward for the most well-studied Bifidobacterium strain. Objectives: The primary aim is to test the efficacy of high dose, BB-12-supplemented yogurt in preventing AAD, compared to yogurt without BB-12, in children receiving antibiotics. Other aims are to further assess the safety of yogurt supplemented with BB-12, and to carry out longitudinal community structure and gene expression analysis of fecal microbiota to evaluate the impact of high dose BB-12 in a pediatric population receiving antibiotics. The microbiota includes hundreds of species, and its disruption is hypothesized to be an important factor in the development of AAD. AIM 1: To test the efficacy of high dose, BB-12-supplemented yogurt in preventing AAD, compared to yogurt without BB-12, in children receiving antibiotics. Hypothesis: Children receiving antibiotics who receive the yogurt with BB-12 will demonstrate less diarrhea than those receiving a control yogurt without BB-12. This is a Phase II trial that requires additional safety evaluation of high dose BB-12. Hypotheses 3: Administration of antibiotics will alter the composition and gene expression profile of the gut microbiota in pediatric patients, and concomitant ingestion of BB-12 in yogurt will mitigate the antibiotic-induced disturbance in the gut microbiota, as identified using 16S rRNA and metatranscriptomic profiling. Study Design and Analysis: We will finish in the June 2023 a Phase II, randomized, doubleblinded controlled trial with allocation concealment. Setting: Capital Areal Primary Care Practice Based Research Network. Population Studied: 270 patients, ages 3-12 years, clinically diagnosed with a respiratory infection requiring 7-10 days of antibiotics. Interventions: The two arms are, BB-12-supplemented yogurt and non-supplemented control yogurt, in a 1:1 randomized allocation. Participants of all ages will be asked to consume the same dose, 100 ml, of product per day. The 100 ml serving of probiotic yogurt will deliver ≥1010 CFU of BB-12. The BB-12 probiotic was not be added.

Honey Varietals Differentially Impact Bifidobacterium animalis ssp. lactis Survivability in Yogurt through Simulated In Vitro Digestion.

BACKGROUND: Bifidobacterium animalis ssp. lactis DN-173 010/CNCM I-2494 (B. animalis) is a probiotic strain commonly added to yogurt. Yogurt and honey are a popular culinary pairing. Honey improves bifidobacteria survival in vitro. However, probiotic survival in yogurt with honey during in vitro digestion has not been investigated. OBJECTIVES: The study aimed to evaluate the effects of different honey varietals and concentrations on B. animalis survivability in yogurt through in vitro digestion. METHODS: Yogurt with honey or control-treated samples underwent in vitro simulated oral, gastric, and intestinal digestion. B. animalis cells were enumerated on de Man Rogosa and Sharpe (MRS) medium followed by an overlay with a modified selective MRS medium; all underwent anaerobic incubation. B. animalis were enumerated predigestion and after oral, gastric, and intestinal digestion. There were 2 study phases: Phase 1 tested 4 honey varietals at 20% wt/wt per 170 g yogurt, and Phase 2 tested 7 dosages of clover honey (20, 14, 10, 9, 8, 6, and 4% wt/wt) per 170 g yogurt. RESULTS: Similar B. animalis counts were observed between all treatments after oral and gastric digestion (<1 Log colony forming units (CFU)/g probiotic reduction). Higher B. animalis survivability was observed in yogurt with clover honey after exposure to simulated intestinal fluids (∼3.5 Log CFU/g reduction; P < 0.05) compared to all control treatments (∼5.5 Log CFU/g reduction; P < 0.05). Yogurt with 10-20% wt/wt clover honey increased B. animalis survivability after simulated in vitro digestion (≤ ∼4.7 Log CFU/g survival; P < 0.05). CONCLUSIONS: Yogurt with added honey improves probiotic survivability during in vitro digestion. The effective dose of clover honey in yogurt was 10-20% wt/wt per serving (1-2 tablespoons per 170 g yogurt) for increased probiotic survivability during in vitro digestion.

Metagenomics reveals differences in the composition of bacterial antimicrobial resistance and antibiotic resistance genes in pasteurized yogurt and probiotic bacteria yogurt from China.

Antimicrobial resistance has become a global public health concern, and antibiotic resistance genes (ARG) in food are a research focus. In China, probiotics and pasteurized yogurts are the 2 main types of commercially available yogurt, but the distribution and differences of antibiotic-resistant bacteria and gene types in these products are not well known. This study used a shotgun metagenomic approach to analyze 22 different types of yogurt collected from 9 main yogurt-producing areas in China; each type of yogurt included 8 different batches of samples. The abundance and diversity of bacteria identified in probiotic yogurt were significantly higher than those in pasteurized yogurt, with Acetobacter, Raoultella, and Burkholderia identified as unique and highly abundant genera in probiotic yogurt. Similarly, the abundance of Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter spp. was higher than that in pasteurized yogurt. A total of 1,149 ARG subtypes belonging to 16 ARG types were identified, with the highest abundance of rifampicin, multidrug efflux pumps, and quinolone resistance genes detected. Network analysis revealed significant nonrandom co-occurrence relationships between different types and subtypes of ARG in yogurt samples. A total of 44 ARG subtypes in pasteurized yogurt were potentially hosted by 36 bacterial genera, and in probiotic yogurt, 63 ARG were expected to be hosted by 86 bacterial species from 37 genera. These findings indicate potential safety issues in fermented dairy products and emphasize the need for a more hygienic environment when processing probiotic yogurt.

Role of fumarate reductase on the fermentation properties of Lactobacillus delbrueckii ssp. bulgaricus.

Lactobacillus delbrueckii ssp. bulgaricus and Streptococcus thermophilus are symbiotic starters widely used in yogurt fermentation. They exchange metabolites to meet their nutritional demands during fermentation, promoting mutual growth. Although S. thermophilus produces fumaric acid, and the addition of fumaric acid has been shown to promote the growth of L. bulgaricus monoculture, whether fumaric acid produced by S. thermophilus is used by L. bulgaricus during coculture remains unclear. Furthermore, the importance of fumaric acid metabolism in the growth of L. bulgaricus is yet to be elucidated. Therefore, in this study, we investigated the importance of fumaric acid metabolism in L. bulgaricus monocultures and coculture with S. thermophilus. We deleted the fumarate reductase gene (frd), which is responsible for the metabolism of fumaric acid to succinic acid, in L. bulgaricus strains 2038 and NCIMB 701373. Both Δfrd strains exhibited longer fermentation times than their parent strains, and fumaric acid was metabolized to malic acid rather than succinic acid. Coculture of Δfrd strains with S. thermophilus 1131 also resulted in a longer fermentation time, and the accumulation of malic acid was observed. These results indicated that fumaric acid produced by S. thermophilus is used by L. bulgaricus as a symbiotic substance during yogurt fermentation and that the metabolism of fumaric acid to succinic acid by fumarate reductase is a key factor determining the fermentation ability of L. bulgaricus.

Yogurt starter strains ameliorate intestinal barrier dysfunction via activating AMPK in Caco-2 cells.

Lactic acid bacteria (LAB) are commonly used probiotics that improve human health in various aspects. We previously reported that yogurt starter strains, Lactobacillus delbrueckii subsp. bulgaricus 2038 and Streptococcus thermophilus 1131, potentially enhance the intestinal epithelial barrier function by inducing the expression of antimicrobial peptides in the small intestine. However, their effects on physical barrier functions remain unknown. In this study, we found that both strains ameliorated the decreased trans-epithelial resistance and the increased permeability of fluorescein isothiocyanate-dextran induced by tumor necrosis factor (TNF)-α and interferon (IFN)-γ in Caco-2 cells. We also demonstrated that LAB prevented a decrease in the expression and disassembly of tight junctions (TJs) induced by TNF-α and IFN-γ. To assess the repair activity of TJs, a calcium switch assay was performed. Both strains were found to promote the reassembly of TJs, and their activity was canceled by the inhibitor of AMP-activated protein kinase (AMPK). Moreover, these strains showed increased AMPK phosphorylation. These observations suggest that the strains ameliorated physical barrier dysfunction via the activation of AMPK. The activities preventing barrier destruction induced by TNF-α and IFN-γ were strain-dependent. Several strains containing L. bulgaricus 2038 and S. thermophilus 1131 significantly suppressed the barrier impairment, and L. bulgaricus 2038 showed the strongest activity among them. Our findings suggest that the intake of L. bulgaricus 2038 and S. thermophilus 1131 is a potential strategy for the prevention and repair of leaky gut.