Bile salt deconjugation and BSH activity of five bifidobacterial strains and their cholesterol co-precipitating properties

Five strains of bifidobacteria were screened for their bile salt deconjugation ability, bile salt hydrolase (BSH) activity and co-precipitation of cholesterol with deconjugated bile. Bile salt deconjugation was determined by the release of cholic acid. All strains exhibited deconjugation of both sodium glycocholate and sodium taurocholate. More cholic acid was liberated from the deconjugation of sodium glycocholate than sodium taurocholate. BSH activity was quantified by determining the amount of glycine or taurine liberated from conjugated bile salts by bifidobacteria strains. There was higher substrate specificity for glycine-conjugated bile compared to taurine-conjugated bile. Co-precipitation of cholesterol with cholic acid was observed from deconjugation of both sodium glycocholate and sodium taurocholate, and by all bifidobacteria strains studied. More cholesterol was precipitated with cholic acid when sodium glycocholate was used compared to sodium taurocholate. Increased cholesterol co-precipitation with deconjugated bile was observed with decreasing pH levels. Bifidobacterium infantis 17930 showed highest deconjugation ability and BSH activity towards bile mixtures that resemble the human bile, and may be a promising candidate to exert beneficial bile deconjugation activity in vivo.     

Bile salt deconjugation ability,bile salt hydrolase activity and cholesterol co-precipitation ability of lactobacilli strains

Eleven strains of lactobacilli were screened for their bile salt deconjugation ability, bile salt hydrolase activity (BSH) and co-precipitation of cholesterol with deconjugated bile. Bile salt deconjugation as determined by the release of cholic acid showed that more cholic acid was liberated from the deconjugation of sodium glycocholate than sodium taurocholate, and Lactobacillus acidophilus strains had higher deconjugation ability than L. casei strains. BSH activity, as quantified by the amount of taurine or glycine liberated from conjugated bile salts, indicated that substrate specificity was more towards glycine-conjugated bile compared to taurine-conjugated bile. Co-precipitation of cholesterol with cholic acid was observed from deconjugation of both conjugated bile, with more cholesterol being precipitated upon deconjugation of sodium glycocholate than upon that of sodium taurocholate. Cholesterol co-precipitation with deconjugated bile increased with decreasing pH. L. acidophilus ATCC 33200, 4356 and 4962 and L. casei ASCC 1521 showed highest deconjugation ability and BSH activity towards bile mixtures that resemble the human bile, and may be promising candidates to exert beneficial bile deconjugation activity in vivo.     

Bile salt deconjugation and cholesterol removal from media by Lactobacillus strains used as probiotics in chickens

BACKGROUND: Bile salt deconjugation by Lactobacillus strains is often closely linked to bile tolerance and survival of the strains in the gut and lowering of cholesterol in the host. The present study investigated the deconjugation of bile salts and removal of cholesterol by 12 Lactobacillus strains in vitro. The 12 strains were previously isolated from the gastrointestinal tract of chickens. RESULTS: The 12 Lactobacillus strains could deconjugate sodium glycocholate (GCA, 16.87–100%) and sodium taurocholate (TCA, 1.69–57.43%) bile salts to varying degrees, with all strains except L. salivarius I 24 having a higher affinity for GCA. The 12 Lactobacillus strains also showed significant (P < 0.05) differences in their ability to remove cholesterol from the growth medium (26.74–85.41%). Significant (P < 0.05) correlations were observed between cholesterol removal and deconjugation of TCA (r = 0.83) among the L. reuteri strains (C1, C10 and C16) and between cholesterol removal and deconjugation of TCA (r = 0.38) and GCA (r = 0.70) among the L. brevis strains (I 12, I 23, I 25, I 211 and I 218). In contrast, although L. gallinarum I 16 and I 26 and L. panis C 17 showed high deconjugating activity, there was no correlation between cholesterol removal and deconjugation of bile salts in these strains. CONCLUSION: The results showed that the 12 Lactobacillus strains were able to deconjugate bile salts and remove cholesterol in vitro, but not all strains with high deconjugating activity removed cholesterol effectively. Copyright © 2009 Society of Chemical Industry     

Development of vacuum‐dried probiotic milk powder with Bacillus coagulans

The present study explored the possibilities of using Bacillus coagulans as a probiotic culture in vacuum‐dried milk powder. The operational drying temperature at 63 ± 2 °C under 0.7 kg/cm² pressure emerged as the best temperature at which to prepare dried milk powder within 4.5 h with a mean (±SEM) Bacillus coagulans B37 spore count of 8.78 ± 0.03 log cfu/g and moisture content of 4.82 ± 0.12%. The total spore counts in vacuum‐dried milk powder did not change (P > 0.10) at storage temperatures of 7 °C, 37 °C or 45 °C over a three‐month period.     

Evaluation of physico‐chemical properties,trace metal content and antioxidant activity of Indian honeys

In this study, effect of plant sources viz. Gossypium hirsutum, Coriander sativum, Murraya koenigii and Dalbergia sisso on twelve physico‐chemical properties, phenolic content, flavonoids content as well as on trace mineral (Fe, Cu, Ni, Mn, Cd and Pb) contents of honey were investigated and compared. All the physico‐chemical values were in the range of approved limits of European Commission Regulation and the source of honey had a significant (P < 0.05) effect on physico‐chemical properties, phenol content, flavonoid content and trace mineral content. The results of positive correlations between physico‐chemical properties (colour and antioxidant properties) and compositional components (phenols and flavonoids content) established that antioxidant properties were dependent on source of honey rather than on colour of honey. Pattern recognition methods such as principal component analysis and linear discriminate analysis were performed to classify honey on the basis of physico‐chemical properties, phenolic content, flavonoids content and trace metal content. The variables proline and lead exhibited higher discrimination power.     

Anti‐obesity effect of feeding probiotic dahi containing Lactobacillus casei NCDC 19 in high fat diet‐induced obese mice

Nowadays, studies about the anti‐obesity potential of probiotics are of growing interest. Lactobacilli are one of the well‐studied probiotics owing to their preventing effect on metabolic disorders. This study was undertaken to access the anti‐obesity effect of probiotic dahi containing Lactobacillus casei NCDC 19 on C57BL/6 mice. Feeding of probiotic dahi showed reduce body weight gain and epididymal fat weights. Moreover, blood glucose, plasma lipids and expression level of leptin were reduced and caecal bifidobacteria counts and adiponectin expression levels were significantly increased. It can be concluded that feeding of probiotic dahi containing L. casei NCDC 19 showed potential anti‐obesity effects.     

Chemical composition,antioxidant activity and anti‐lipase activity of Origanum vulgare and Lippia turbinata essential oils

This study reported the chemical composition, phenolic content, antioxidant and anti‐lipase activity of oregano and Lippia essential oils. The major compounds found in oregano essential oil were γ‐terpinene (32.10%), α‐terpinene (15.10%), p‐cymene (8.00%) and thymol (8.00%). In Lippia essential oil, α‐limonene (76.80%) and 1,8‐cineole (4.95%) represented the major compounds. Oregano essential oil had higher phenolic content (12.47 mg gallic acid mL^?1) and DPPH scavenging activity (IC₅₀ 0.357 μg mL^?1) than Lippia essential oil (7.94 mg gallic acid mL^?1 and IC₅₀ 0.400 μg mL^?1, respectively). Both essential oils had similar antioxidant indexes (about 1.2) determined by Rancimat. Moreover, oregano essential oil had also higher anti‐lipase activity (IC₅₀ 5.09 and 7.26 μg mL^?1). Higher phenolic content in the essential oils was related with higher scavenging and anti‐lipase activities. Oregano and Lippia essential oils could be used as natural antioxidants on food products.     

Microbial,physico‐chemical and sensory characteristics of mango juice‐enriched probiotic dairy drinks

This study aimed to determine whether mango juice can improve the viability of probiotics in a fermented dairy‐based beverage whilst maintaining its quality characteristics. Formulations containing Lactobacillus acidophilus La‐5 culture, whole cow's milk and varying concentrations of mango juice (0%, 10%, 20%, 30% and 40% (w/w)) were produced and stored for five weeks at 4 °C. Results showed that probiotic viability was enhanced with the addition of 10% mango juice. Additionally, this formulation improved probiotics tolerance when exposed to in vitro gastrointestinal digestion. According to the sensory analysis, beverage sensory scores improved as levels of mango juice increased from 20% to 40%.     

Milk‐clotting enzymes produced by Aspergillus flavo furcatis strains on Amazonic fruit waste

Six strains of Aspergillus flavo furcatis were screened to investigate milk‐clotting enzyme production by fermentation in natural liquid medium. The growth media comprised extracts of cupuaçu exocarp+rice bran [10% or 20% (v/v) CE+RB] and açai waste+rice bran [10% or 20% (v/v) AW+RB] with or without supplementation of 0.1% (w/v) yeast extract and 0.5% (w/v) gelatin. Significant values of milk‐clotting activity were determined by A. flavo furcatis DPUA 1461 and DPUA 1608, in the standard and natural media, respectively. According to criteria of clot and whey formations, 8.3% of the samples tested were classified as strong coagulation, 41.70% showed weak coagulation and in 50% was not observed milk coagulation. The enzyme optimal action of DPUA 1608, the selected strain, was at 40 °C and pH 7.0. Milk‐clotting proteases were inhibited by pepstatin (94.72%) and moderately inhibited by the others metal ions tested.     

Characterisation of Lactobacillus helveticus strains isolated from home‐made dairy products in Iran

The aims of this study were the isolation and characterisation of a number of lactobacilli strains from traditional dairy products. Fifteen home‐made samples were pour‐plated onto MRS and predominant colonies were randomly picked up. Nine isolated lactobacilli were grouped using rep‐PCR fingerprinting, and partial sequencing of 16S‐rRNA of group's representatives confirmed them as Lactobacillus helveticus. Detection of two CEP (prtH and prtH2) genes and examination of acidification and growth in milk revealed intradiversity among isolates. The findings indicate the possibility of isolating novel wild strains of L. helveticus from home‐made products and emphasises on the necessity of both genetic and technological characterisation for deeper differentiation of strains.     

Detection of Salmonella spp., Yersinia enterocolitica,Listeria monocytogenes and Campylobacter spp. by real‐time multiplex PCR using amplicon DNA melting analysis and probe‐based assay

Syto9 and probe‐based multiplex real‐time PCR assays for simultaneous detection of a group of foodborne pathogens (named SYLC group), targeting Salmonella spp. (invA gene), Yersinia enterocolitica (ystA gene), Listeria monocytogenes (hly gene) and Campylobacter spp. (rrna gene), have been developed. The Syto9 assay generates amplicon DNA melting curve with four peaks of 86.5 ± 0.5, 84 ± 0.5, 81.5 ± 0.5 and 90.5 ± 0.5 °C corresponding Salmonella spp., Y. enterocolitica, L. monocytogenes and Campylobacter spp. targets, respectively. The sensitivities of the Syto9 and TaqMan assays in artificially inoculated chicken wing rinses were in a range of 3.2 × 10² to 3.1 × 10⁴ and 9.8 × 10² to 1.9 × 10⁴ colony‐forming units per millilitre, respectively, depending on the pathogen. All tested target strains (n = 100) were correctly detected by the both assays, whereas nontarget strains (n = 100) demonstrated no cross‐reactivity representing 100% specificity. The assays are suitable for application in qualitative and quantitative detection of SYLC group pathogens in food matrices.     

Production of a whey‐based functional beverage supplemented with soy isoflavones and phytosterols

Reconstituted whey beverages were prepared from whey powder by adding either soy isoflavones or phytosterols as functional compounds (at levels of 0%, 0.25%, 0.50% or 1.0% w/v) and probiotic bacteria (Lactobacillus acidophilus LA‐5 or Lactobacillus casei LBC‐81). The addition of nutraceuticals did not change the basic composition of the products. However, a time‐dependent increase in sedimentation/phase separation and acidity of fermented functional beverages was observed. Samples supplemented with phytosterols were more preferred by the panel group than the samples supplemented with isoflavones, and no considerable differences were noted between the control and phytosterol‐added samples in terms of overall perception.     

Antioxidant and tyrosinase inhibitory activity of Rosa roxburghii fruit and identification of main bioactive phytochemicals by UPLC‐Triple‐TOF/MS

The content of bioactive phytochemicals, antioxidant activity and tyrosinase inhibitory activity of the hydroalcoholic extracts of Rosa roxburghii were determined. Yellow fruits of cultivated R. roxburghii showed the highest phenolic content (154.81 mg gallic acid g^?1), and the green fruits of wild R. roxburghii showed higher content of flavonoid and triterpenoid. Rosa roxburghii fruits from different cultivars and maturity stages all demonstrated as good antioxidant agents and tyrosinase inhibitors, with IC50 value about twice of the positive standard in the DPPH assay and triple of the standard in the tyrosinase inhibitory activity assay. Nineteen compounds, mainly ellagic acids and its derivatives, flavonoids and their glycosides were identified by UPLC‐Triple‐TOF/MS analysis. As the first study of bioactive phytochemicals of R. roxburghii by UPLC‐MS, the present research may provide valuable information for fulfilling the potential of R. roxburghii in the functional food area.     

Thermo‐rheological and functional properties of gamma‐irradiated wholewheat flour

The effects of different doses (0, 0.5, 1, 2.5, 5 and 10 kGy) of gamma irradiation on the thermal, rheological and functional properties of the wholewheat flour were evaluated. Water and oil absorption capacity of the flour increased from 85.92% to 91.44% and 1.10 to 1.91 g g^?1 of flour, respectively, with increase in irradiation dose. The dough development time decreased with dose from 4.0 to 3.0 min. The transition temperatures (T_o, T_p and T_c) decreased as the dose increased; enthalpy of gelatinisation (?H) decreased from 5.18 to 4.27 J g^?1 with dose. The flow behaviour showed a shear‐thinning behaviour, and the hysteresis area decreased with dose. The structural recovery decreased with dose. FTIR did not show formation of any new chemical groups.     

Anti‐inflammatory properties of high pressure‐assisted extracts of Grifola frondosa in lipopolysaccharide‐activated RAW 264.7 macrophages

The aim of this study was to determine the in vitro anti‐inflammatory properties of the shake extract (SE) and the high pressure‐assisted extract (PE) of the mycelia of Grifola frondosa in a lipopolysaccharide‐stimulated RAW 264.7 macrophage model. The content of total polysaccharides and β‐glucans of PE at 600 MPa (PE‐600) was 41.2 and 6.2 mg g^?1 dry weight, respectively, which were significantly higher than SE extracts. The results showed that treatment with 500 μg mL^?1 of PE by 600 MPa (PE‐600) did not reduce RAW 264.7 cell viability but did significantly inhibit the production of LPS‐induced NO, PGE₂ and intracellular ROS. The PE‐600 inhibited the activation of NF‐kB and then reduced the production of LPS‐induced TNF‐α, IL‐6 and IL‐1β in a dose‐dependent manner. Thus, the PE could be used as an alternative extraction method for improving the extraction efficacy of G. frondosa and serve as an alternative source of anti‐inflammatory agents.