The protective effect of Bifidobacterium bifidum G9-1 against mucus degradation by Akkermansia muciniphila following small intestine injury caused by a proton pump inhibitor and aspirin.

BACKGROUND: Proton pump inhibitors (PPIs) can alleviate upper gastrointestinal injury but paradoxically exacerbate aspirin (ASA)-induced small intestine injury. In this study, our goal was to simulate this exacerbation by developing an appropriate animal model, which may help in establishing treatments. Methods: Male mice were fed a 60% fructose diet for 9 weeks, then administered 200 mg/kg ASA 3 h before sacrifice. The PPI omeprazole was administered intraperitoneally once daily for 9 weeks. Bifidobacterium bifidum G9-1 was administered orally for the last week. In addition, Akkermansia muciniphila was administered orally for 9 weeks instead of omeprazole. Results: ASA-induced small-intestine injury was observed in high-fructose fed mice. Omeprazole exacerbated ASA-induced intestinal damage, significantly decreased Bifidobacteria levels, and significantly increased A. muciniphila counts in the jejunum. The direct administration of A. muciniphila caused thinning of the jejunum mucus layer, which was also observed in mice that received ASA and omeprazole. On the other hand, the administration of Bifidobacterium bifidum G9-1 inhibited A. muciniphila growth and reduced thinning of the mucus layer. The number of goblet cells in the jejunum was reduced by the administration of ASA and omeprazole, while Bifidobacterium bifidum G9-1 prevented the reduction. Conclusions: These results suggest that omeprazole-induced gut dysbiosis promotes Akkermansia growth and inhibits Bifidobacterium growth, leading to a thinning of the mucus layer through a reduction in goblet cells in the small intestine. Probiotics are, therefore, a promising approach for the treatment of small intestine injury.

Probiotic Bifidobacterium bifidum G9-1 ameliorates phytohemagglutinin-induced diarrhea caused by intestinal dysbiosis.

Diarrhea is largely caused by dysbiosis accompanying the hyperproliferation of Escherichia coli (E. coli). While current treatments can resolve the symptoms, they cannot suppress the proliferation of pathogenic bacteria in the intestine. Probiotics have numerous beneficial effects on host health, including restoring the balance of the intestinal microbiota. This study investigated the effect of the probiotic Bifidobacterium bifidum G9-1 (BBG9-1), which is active in intestinal dysbiosis, in the incidence of diarrhea, in the composition of the intestinal microbiota, and in the intestinal tissue of a rat model of phytohemagglutinin (PHA)-induced diarrhea. The rats were treated with PHA, with and without BBG9-1, and the microbiota composition throughout the intestine and stool was examined using high-throughput 16S rRNA sequencing. In line with previous reports, PHA administration caused diarrhea as well as dysbiosis due to E. coli hyperproliferation. Histological findings indicated that the jejunal villus length was shortened. Rats that received BBG9-1 showed clear improvements in dysbiosis, diarrhea symptoms, and jejunal villus length. Principal coordinates analysis demonstrated the microbiota profile to be more similar between the BBG9-1 and normal groups than between the PHA and normal groups. These results indicated that BBG9-1 suppresses the hyperproliferation of E. coli and restores the jejunal villus length, thereby improving dysbiosis, and in turn, alleviating the symptoms of diarrhea.

Melanins of Inonotus Obliquus: Bifidogenic and Antioxidant Properties.

Extracts and melanins from Inonotus obliquus are widely used in medicine due to their high antioxidant properties. This study is dedicated to define the influence of the physicochemical and antioxidant properties of Inonotus obliquus melanins and their bifidogenic effects on Bifidobacterium bifidum 1 and Bifidobacterium animalis subsp. lactis. For this purpose, melanins precipitated from Inonotus obliquus aqueous extracts, obtained by a few methods, and separated melanin fractions by organic solvents were used. For the melanin physicochemical properties analysis spectrophotometry, electron paramagnetic resonance (EPR) spectroscopy and dynamic light scattering methods were applied. Melanins and their fractions difference in particle size and charge, antioxidant properties, and redox potential were revealed. It was shown that the redox potential, the size of melanin particles and the z-potential had maximum influence on bifidobacteria growth. The greatest activating effect on bifidobacteria was established by using melanin isolated from aqueous microwave extracts in concentrations of 10-13, 10-10, 10-5 g/cm3. The use of this melanin with antioxidant activity 0.67 ± 0.06 mg/g (expressed as ascorbic acid equivalent), and with redox potential -5.51 ± 2.22 mV as a prebiotic allowed the growth of Bifidobacterium bifidum 1 s to increase by 1.4 times in comparison with ascorbic acid by 24 h of cultivation.

Cutibacterium avidum is phylogenetically diverse with a subpopulation being adapted to the infant gut.

The infant gut harbors a diverse microbial community consisting of several taxa whose persistence depends on adaptation to the ecosystem. In healthy breast-fed infants, the gut microbiota is dominated by Bifidobacterium spp.. Cutibacterium avidum is among the initial colonizers, however, the phylogenetic relationship of infant fecal isolates to isolates from other body sites, and C. avidum carbon utilization related to the infant gut ecosystem have been little investigated. In this study, we investigated the phylogenetic and phenotypic diversity of 28 C. avidum strains, including 16 strains isolated from feces of healthy infants. We investigated the in vitro capacity of C. avidum infant isolates to degrade and consume carbon sources present in the infant gut, and metabolic interactions of C. avidum with infant associated Bifidobacterium longum subsp. infantis and Bifidobacterium bifidum. Isolates of C. avidum showed genetic heterogeneity. C. avidum consumed d- and l-lactate, glycerol, glucose, galactose, N-acetyl-d-glucosamine and maltodextrins. Alpha-galactosidase- and ß-glucuronidase activity were a trait of a group of non-hemolytic strains, which were mostly isolated from infant feces. Beta-glucuronidase activity correlated with the ability to ferment glucuronic acid. Co-cultivation with B. infantis and B. bifidum enhanced C. avidum growth and production of propionate, confirming metabolic cross-feeding. This study highlights the phylogenetic and functional diversity of C. avidum, their role as secondary glycan degraders and propionate producers, and suggests adaptation of a subpopulation to the infant gut.

Bifidobacterium bifidum ATCC 15696 and Bifidobacterium breve 24b Metabolic Interaction Based on 2'-O-Fucosyl-Lactose Studied in Steady-State Cultures in a Freter-Style Chemostat.

Infants fed breast milk harbor a gut microbiota in which bifidobacteria are generally predominant. The metabolic interactions of bifidobacterial species need investigation because they may offer insight into the colonization of the gut in early life. Bifidobacterium bifidum ATCC 15696 hydrolyzes 2'-O-fucosyl-lactose (2FL; a major fucosylated human milk oligosaccharide) but does not use fucose released into the culture medium. However, fucose is a growth substrate for Bifidobacterium breve 24b, and both strains utilize lactose for growth. The provision of fucose and lactose by B. bifidum (the donor) allowing the growth of B. breve (the beneficiary) conforms to the concept of syntrophy, but both strains will compete for lactose to multiply. To determine the metabolic impact of this syntrophic/competitive relationship on the donor, the transcriptomes of B. bifidum were determined and compared in steady-state monoculture and coculture using transcriptome sequencing (RNA-seq) and reverse transcription-quantitative PCR (RT-qPCR). B. bifidum genes upregulated in coculture included those encoding alpha-l-fucosidase and carbohydrate transporters and those involved in energy production and conversion. B. bifidum abundance was the same in coculture as in monoculture, but B. breve dominated the coculture numerically. Cocultures during steady-state growth in 2FL medium produced mostly acetate with little lactate (acetate:lactate molar ratio, 8:1) compared to that in monobatch cultures containing lactose (2:1), which reflected the maintenance of steady-state cells in log-phase growth. Darwinian competition is an implicit feature of bacterial communities, but syntrophy is a phenomenon putatively based on cooperation. Our results suggest that the regulation of syntrophy, in addition to competition, may shape bacterial communities.IMPORTANCE This study addresses the microbiology and function of a natural ecosystem (the infant bowel) using in vitro experimentation with bacterial cultures maintained under controlled growth and environmental conditions. We studied the growth of bifidobacteria whose nutrition centered on the hydrolysis of a human milk oligosaccharide. The results revealed responses relating to metabolism occurring in a Bifidobacterium bifidum strain when it provided nutrients that allowed the growth of Bifidobacterium breve, and so discovered biochemical features of these bifidobacteria in relation to metabolic interaction in the shared environment. These kinds of experiments are essential in developing concepts of bifidobacterial ecology that relate to the development of the gut microbiota in early life.

In-vitro GIT Tolerance of Microencapsulated Bifidobacterium bifidum ATCC 35914 Using Polysaccharide-Protein Matrix.

Longevity of probiotic is the main concern for getting maximum benefits when added in food product. Bifidobacterium, a probiotic, tends to lose its viability during gastrointestinal track (GIT) transit and storage of food. Their viability can be enhanced through microencapsulation technology. In this study, Bifidobacterium bifidum (B. bifidum) ATCC 35914 was encapsulated by using two experimental plans. In the first plan, chitosan (CH) at 0.6, 0.8, and 1.0% and sodium alginate (SA) at 4, 5, and 6% were used. Based on encapsulation efficiency, 6% sodium alginate and 0.8% chitosan were selected for single coating of the bacteria, and the resulting micro beads were double coated with different concentrations (5, 7.5, and 10%) of whey protein concentrate (WPC) in the second plan. Encapsulation efficiency and GIT tolerance were determined by incubating the micro beads in simulated gastrointestinal juices (SIJ) at variable pH and exposure times, and their release (liberation of bacterial cells) profile was also observed in SIJ. The microencapsulated bacterial cells showed significantly (P < 0.01) higher viability as compared to the unencapsulated (free) cells during GIT assay. The double-coated micro beads SA 6%-WPC 5% and CH 0.8%-WPC 5% were proven to have the higher survival at pH 3.0 after 90 min of incubation time and at pH 7.0 after 3-h exposure in comparison to free cells in simulated conditions of the stomach and intestine, respectively. Moreover, double coating with whey protein concentrate played a significant role in the targeted (106-9 CFU/mL) delivery under simulated intestinal conditions.

The Use of Probiotic-Loaded Single- and Double-Layered Microcapsules in Cake Production.

To date, the probiotic product development studies have mostly focused on dairy-based foods. However, endowing bakery products with probiotic properties not only provides a variety in food selection but would also potentially improve public health when the consumption rates are taken into consideration. This study aimed to incorporate single- and double-layered microcapsules containing Saccharomyces boulardii, Lactobacillus acidophilus, and Bifidobacterium bifidum, produced by spray drying and chilling, in cake production. Microcapsules were added after baking to the three different types of cakes (cream-filled, marmalade-filled, and chocolate-coated). Additionally, the microcapsules were injected into the center of the cake mix and baked at 200 °C for 20 min, for plain cake only. After baking of plain cakes, the count of S. boulardii and L. acidophilus as determined in the double-layered microcapsules produced by spray chilling was 2.9 log cfu/g. The survivability rates of S. boulardii and L. acidophilus were also determined as 67.4 and 70.7% in this microcapsule, respectively. However, there were no viable B. bifidum detected after baking. The free forms of these probiotics did not survive in any plain cake experiments. Single-layered microcapsules produced by spray chilling provided a better protective effect on the probiotics in cream-filled and marmalade-filled cake samples during storage, particularly the cream-filled cakes. This study showed that combined spray chilling and spray drying microencapsulation techniques (double-layered microcapsules) could increase the survivability of probiotic microorganisms during the cake baking process. During storage, the cake samples had a near neutral pH value, and the textural properties deteriorated due to staling. However, cake staling had a limited effect on the sensorial attributes of the cakes and the samples could be readily consumed after storage for 90 days.

Safety Evaluations of Bifidobacterium bifidum BGN4 and Bifidobacterium longum BORI.

Over the past decade, a variety of lactic acid bacteria have been commercially available to and steadily used by consumers. However, recent studies have shown that some lactic acid bacteria produce toxic substances and display properties of virulence. To establish safety guidelines for lactic acid bacteria, the Food and Agriculture Organization of the United Nations (FAO)/World Health Organization (WHO) has suggested that lactic acid bacteria be characterized and proven safe for consumers’ health via multiple experiments (e.g., antibiotic resistance, metabolic activity, toxin production, hemolytic activity, infectivity in immune-compromised animal species, human side effects, and adverse-outcome analyses). Among the lactic acid bacteria, Bifidobacterium and Lactobacillus species are probiotic strains that are most commonly commercially produced and actively studied. Bifidobacterium bifidum BGN4 and Bifidobacterium longum BORI have been used in global functional food markets (e.g., China, Germany, Jordan, Korea, Lithuania, New Zealand, Poland, Singapore, Thailand, Turkey, and Vietnam) as nutraceutical ingredients for decades, without any adverse events. However, given that the safety of some newly screened probiotic species has recently been debated, it is crucial that the consumer safety of each commercially utilized strain be confirmed. Accordingly, this paper details a safety assessment of B. bifidum BGN4 and B. longum BORI via the assessment of ammonia production, hemolysis of blood cells, biogenic amine production, antimicrobial susceptibility pattern, antibiotic resistance gene transferability, PCR data on antibiotic resistance genes, mucin degradation, genome stability, and possession of virulence factors. These probiotic strains showed neither hemolytic activity nor mucin degradation activity, and they did not produce ammonia or biogenic amines (i.e., cadaverine, histamine or tyramine). B. bifidum BGN4 and B. longum BORI produced a small amount of putrescine, commonly found in living cells, at levels similar to or lower than that found in other foods (e.g., spinach, ketchup, green pea, sauerkraut, and sausage). B. bifidum BGN4 showed higher resistance to gentamicin than the European Food Safety Authority (EFSA) cut-off. However, this paper shows the gentamicin resistance of B. bifidum BGN4 was not transferred via conjugation with L. acidophilus ATCC 4356, the latter of which is highly susceptible to gentamicin. The entire genomic sequence of B. bifidum BGN4 has been published in GenBank (accession no.: CP001361.1), documenting the lack of retention of plasmids capable of transferring an antibiotic-resistant gene. Moreover, there was little genetic mutation between the first and 25th generations of B. bifidum BGN4. Tetracycline-resistant genes are prevalent among B. longum strains; B. longum BORI has a tet(W) gene on its chromosome DNA and has also shown resistance to tetracycline. However, this research shows that its tetracycline resistance was not transferred via conjugation with L. fermentum AGBG1, the latter of which is highly sensitive to tetracycline. These findings support the continuous use of B. bifidum BGN4 and B. longum BORI as probiotics, both of which have been reported as safe by several clinical studies, and have been used in food supplements for many years.

Probiotic Strawberry Yogurts: Microbiological, Chemical and Sensory Properties.

This study was performed to determine the viability of Lactobacillus acidophilus and Bifidobacterium bifidum in yogurt made with strawberry marmalade (SM) and to examine the quality properties of probiotic yogurt. Acidity, pH, bacterial counts and sensory analysis of the yogurt samples were investigated on days 1, 3, 5, 7, 10 and 14 during storage at 4 °C. The survival rate of L. acidophilus was greater than that of B. bifidum. The viability of L. acidophilus decreased during the storage period, but B. bifidum numbers remained stable during the storage period. The highest L. acidophilus count (7.20 log cfu/g) was found in L. acidophilus + B. bifidum SM yogurt on day 1. The highest B. bifidum count (6.13 log cfu/g) was detected in yogurt containing L. acidophilus + B. bifidum SM yogurt on day 7. Yeast and mould counts of all yogurts increased during the storage period. Coliform bacteria and Staphylococcus aureus were not detected in the yogurt samples. The highest overall acceptance sensory score was observed in yogurts containing L. acidophilus. Considering the sensory and probiotic characteristics of all yogurt samples, this study suggested that strawberry yogurt with a suitable 5-7 day storage period can be produced with single L. acidophilus addition or single B. bifidum addition.

Probiotics modulate gut microbiota and improve insulin sensitivity in DIO mice.

Obesity and type 2 diabetes are characterized by subclinical inflammatory process. Changes in composition or modulation of the gut microbiota may play an important role in the obesity-associated inflammatory process. In the current study, we evaluated the effects of probiotics (Lactobacillus rhamnosus, L. acidophilus and Bifidobacterium bifidumi) on gut microbiota, changes in permeability, and insulin sensitivity and signaling in high-fat diet and control animals. More importantly, we investigated the effects of these gut modulations on hypothalamic control of food intake, and insulin and leptin signaling. Swiss mice were submitted to a high-fat diet (HFD) with probiotics or pair-feeding for 5 weeks. Metagenome analyses were performed on DNA samples from mouse feces. Blood was drawn to determine levels of glucose, insulin, LPS, cytokines and GLP-1. Liver, muscle, ileum and hypothalamus tissue proteins were analyzed by Western blotting and real-time polymerase chain reaction. In addition, liver and adipose tissues were analyzed using histology and immunohistochemistry. The HFD induced huge alterations in gut microbiota accompanied by increased intestinal permeability, LPS translocation and systemic low-grade inflammation, resulting in decreased glucose tolerance and hyperphagic behavior. All these obesity-related features were reversed by changes in the gut microbiota profile induced by probiotics. Probiotics also induced an improvement in hypothalamic insulin and leptin resistance. Our data demonstrate that the intestinal microbiome is a key modulator of inflammatory and metabolic pathways in both peripheral and central tissues. These findings shed light on probiotics as an important tool to prevent and treat patients with obesity and insulin resistance.

[Development of Lyophilization Procedure Ensuring Survival of Bifidobacteria and Preservation of Their Probiotic Potential upon Long-Term Storage].

Survival of bifidobacteria and preservation of their morphological characteristics after 12-month storage of lyophilized cells was studied for the strains of Bifidobacterium bifidum and B. animalis isolated and maintained in the microbial collection of the Department of Microbiology, Moscow State University. A combined approach to pre-lyophilization treatment of microorganisms and subsequent storage was developed in order to improve cell survival. Compared to the standard cryoprotector concentrations, sucrose and glucose (5% and higher) in skim milk, as well as freezing at ‒70°C with subsequent storage at the same temperature resulted in improved survival of bifidobacteria. Under such conditions, the number of viable cells (CFU) after 12 months of storage was two to three orders of magnitude higher than in the case of the standard lyophilization procedure. Investigation of dynamics of resistance of reactivated clones to such gastrointestinal stress factors as gastric juice and bile acids revealed preservation of these properties at all storage modes. However, since the number of surviving cells decreased during storage according to the standard procedure, the number of stress-affected cells was correspondingly lower. Reactivated cultures exhibited high resistance to oxygen, with survival decreasing to 35% of the initial level.

Probiotic supplementation in diabetic hemodialysis patients has beneficial metabolic effects.

This study determined the effects of probiotic supplementation on glycemic control, lipid concentrations, biomarkers of inflammation and oxidative stress in 60 diabetic patients on hemodialysis in a parallel randomized double-blind placebo-controlled clinical trial. Participants were initially matched based on sex, duration of dialysis and diabetes, body mass index and age. Subsequently, they were randomly divided into two groups to take either a capsule containing the probiotics Lactobacillus acidophilus, Lactobacillus casei and Bifidobacterium bifidum or placebo for 12 weeks. Based on three-day dietary records throughout the trial, there was no significant change in dietary macro- and micro-nutrients or total dietary fiber to confound results. After the 12 weeks, analysis of patients who received probiotic supplements compared with the placebo showed they had significantly decreased fasting plasma glucose (-22.0 vs. +6.6 mg/dl), serum insulin (-6.4 vs. +2.3 µIU/ml), homeostasis model of assessment-estimated insulin resistance (-2.9 vs. +2.5), homeostasis model of assessment-estimated beta-cell function (-14.1 vs. +6.1) and HbA1c (-0.4 vs. -0.1%,), and improved quantitative insulin sensitivity check index (+0.03 vs. -0.02). Additionally, compared with the placebo, probiotic supplementation resulted in significant reductions in serum high-sensitivity C-reactive protein (-1933 vs. +252 ng/ml), plasma malondialdehyde (-0.3 vs. +1.0 µmol/l), subjective global assessment scores (-0.7 vs. +0.7) and total iron binding capacity (-230 vs. +33 µg/dl), and a significant increase in plasma total antioxidant capacity (+15 vs. -88 mmol/l). Thus, probiotic supplementation for 12 weeks among diabetic hemodialysis patients had beneficial effects on parameters of glucose homeostasis, and some biomarkers of inflammation and oxidative stress.

Quantification of microbial uptake of quercetin and its derivatives using an UHPLC-ESI-QTOF mass spectrometry assay.

A liquid chromatography-mass spectrometry-based method for the quantification of intracellular concentrations of dietary phenolics in bacteria was developed. Using this assay, the time-dependent uptake of quercetin and two of its glycosides into gut microbiota model organisms (Escherichia coli and Bifidobacterium bifidum) under aerobic and anaerobic conditions was studied. For the first time, quantitative data on the uptake of dietary phenols were obtained indicating a time-dependent differential uptake of the dietary compounds. The shape of the uptake curve and the comparative use of bacterial mutants lacking porins OmpFC or the multi-drug efflux pump AcrAB, respectively, along with the identification and quantification of selected bacterial metabolites provided a mechanistic insight into the uptake process.

The effects of synbiotic supplementation on markers of insulin metabolism and lipid profiles in gestational diabetes: a randomised, double-blind, placebo-controlled trial.

To the best of our knowledge, data on the effects of synbiotic supplementation on markers of insulin metabolism and lipid concentrations in patients with gestational diabetes mellitus (GDM) are scarce. The aim of the current study was to determine the effects of synbiotic supplementation on markers of insulin metabolism and lipid profiles in GDM patients. In total, seventy patients with GDM aged 18-40 years were assigned to two groups - the synbiotic group (n 35) and the placebo group (n 35) - in this randomised, double-blind, placebo-controlled trial. Patients in the synbiotic group received a daily capsule that contained three viable and freeze-dried strains: Lactobacillus acidophilus, Lactobacillus casei and Bifidobacterium bifidum (2×109 colony-forming units/g each) plus 800 mg inulin for 6 weeks. Fasting blood samples were collected at the beginning and week 6 to quantify related markers. After 6 weeks of intervention, compared with the placebo, synbiotic supplementation led to a significant decrease in serum insulin levels (-1·5 (sd 5·9) v. +4·8 (sd 11·5) µIU/ml, P=0·005), homoeostatic model assessment for insulin resistance (-0·4 (sd 1·3) v. +1·1 (sd 2·7), P=0·003) and homoeostatic model assessment for ß cell function (-5·1 (sd 24·2) v. +18·9 (sd 45·6), P=0·008) and a significant increase in quantitative insulin sensitivity check index (+0·01 (sd 0·01) v. -0·007 (sd 0·02), P=0·02). In addition, synbiotic intake significantly decreased serum TAG (-14·8 (sd 56·5) v. +30·4 (sd 37·8) mg/dl, P<0·001) and VLDL-cholesterol concentrations (-3·0 (sd 11·3) v. +6·1 (sd 7·6) mg/dl, P<0·001) compared with the placebo. Overall, the results of this study demonstrate that taking synbiotic supplements for 6 weeks among patients with GDM had beneficial effects on markers of insulin metabolism, TAG and VLDL-cholesterol concentrations.

Integration of genomic and proteomic data to identify candidate genes in HT-29 cells after incubation with Bifidobacterium bifidum ATCC 29521.

As the predominant group inhabiting the human gastrointestinal tract, bifidobacteria play a vital role in human nutrition, therapeutics, and health by shaping and maintaining the gut ecosystem, reducing blood cholesterol, and promoting the supply of nutrients. The interaction between bacterial cells and human intestinal epithelial cell lines has been studied for decades in an attempt to understand the mechanisms of action. These studies, however, have been limited by lack of genomic and proteomic database to aid in achieving comprehensive understanding of these mechanisms at molecular levels. Microarray data (GSE: 74119) coupled with isobaric tags for relative and absolute quantitation (iTRAQ) were performed to detect differentially expressed genes and proteins in HT-29 cells after incubation with Bifidobacterium bifidum. Real-time quantitative PCR, gene ontology, and Kyoto Encyclopedia of Genes and Genomes analyses were further conducted for mRNA validation, functional annotation, and pathway identification, respectively. According to the results of microarray, 1,717 differentially expressed genes, including 1,693 upregulated and 24 downregulated genes, were selected and classified by the gene ontology database. The iTRAQ analysis identified 43 differentially expressed proteins, where 29 proteins were upregulated and 14 proteins were downregulated. Eighty-two candidate genes showing consistent differences with microarray and iTRAQ were further validated in HT-29 and Caco-2 cells by real-time quantitative PCR. Nine of the top genes showing interesting results with high confidence were further investigated in vivo in mice intestine samples. Integration of genomic and proteomic data provides an approach to identify candidate genes that are more likely to function in ubiquitin-mediated proteolysis, positive regulation of apoptosis, membrane proteins, and transferase catalysis. These findings might contribute to our understanding of molecular mechanisms regulating the interaction between probiotics and intestinal epithelial cell lines.

Effect of bacteria proportion on the fermentation of goat yoghurt with probiotic culture.

BACKGROUND: Goat milk production in Shaanxi province is dominant in China, but the product is mainly infant formula and adult milk powder; product homogeneity is serious and has no goat yoghurt with probiotic culture. METHODS: The effect of bacteria proportion (1:3:1, 1:2:1, 1:1:1, 2:1:1, 3:1:1) on pH, acidity, and viable counts and sensory evaluation of goat milk fermented by probiotics including L. acidophilus, B. bifidum  or L. casei besides, S. thermophilus and L. bulgaricus for developing AB-goat yoghurt and BC-goat yoghurt was investigated. RESULTS: The optimum bacteria proportion of L. acidophilus : B. bifidum : S. thermophilus and L. bulgaricus for AB-goat yoghurt and B. bifidum : L. casei : S. thermophilus and L. bulgaricus for BC-goat yoghurt were both 2:1:1. The pH, acidity, the viable counts of L. acidophilus and B. bifidum, the total viable counts were respectively 4.60, 7.73 (g/L), 3.50×107 cfu/mL, 3.40×107 cfu/mL and 2.30×109 cfu/mL in AB-goat yoghurt. The pH, acidity, the viable counts of B. bifidum and L. casei, the total viable counts were respectively  4.61, 8.16 (g/L), 7.60×107 cfu/mL, 5.60×107 cfu/mL and 2.04×109 cfu/mL in BC-goat yoghurt. CONCLUSIONS: The bacteria proportion had a significant effect on fermentation of AB- and BC-goat yoghurt, the results are beneficial for developing AB-goat yoghurt and BC-goat yoghurt.