Probiotic Lactobacillus Acidophilus La5 Research Articles

Examining the Effect of Freezing Temperatures on the Survival Rate of Micro-Encapsulated Probiotic Lactobacillus acidophilus LA5 Using the Flash Freeze-Drying (FFD) Strategy.

This work proposes a novel drying method suitable for probiotic bacteria, called flash freeze-drying (FFD), which consists of a cyclic variation in pressure (up-down) in a very short time and is applied during primary drying. The effects of three FFD temperatures (-25 °C, -15 °C, and -3 °C) on the bacterial survival and water activity of Lactobacillus acidophilus LA5 (LA), previously microencapsulated with calcium alginate and chitosan, were evaluated. The total process time was 900 min, which is 68.75% less than the usual freeze-drying (FD) time of 2880 min. After FFD, LA treated at -25 °C reached a cell viability of 89.94%, which is 2.74% higher than that obtained by FD, as well as a water activity of 0.0522, which is 55% significantly lower than that observed using FD. Likewise, this freezing temperature showed 64.72% cell viability at the end of storage (28 days/20 °C/34% relative humidity). With the experimental data, a useful mathematical model was developed to obtain the optimal FFD operating parameters to achieve the target water content in the final drying.

Production of Traditional Grape Pickle Using Lactobacillus acidophilus and Investigation of the Inhibitory Effect of the Product on Bacillus cereus and Escherichia coli

Grape pickle is a traditional food that is made with grapes (Vitis vinifera), horseradish (Armoracia rusticana) and grape syrup. In this study, the survival of Bacillus cereus and Escherichia coli in grape pickles produced with or without using probiotic Lactobacillus acidophilus La-5 as well as microbiological, chemical and sensory properties of each group were examined during 35 days of ripening at 25°C and 5 months at refrigerated storage period. Molds and lactic acid bacteria (LAB) counts remained below the limit of detection (6 log in samples to be considered a probiotic product. E. coli counts rapidly declined to undetectable level within 7 days, while B. cereus numbers was found 1.56-1.72 log cfu/g at the end of the storage period. As a result, it was established that traditional grape pickle is not suitable food matrix for probiotication. High total soluble solid content (63 °Brix) and presence of horseradish in grape pickles ensure the microbiological stability as well as the safety of product.

Survival of Lactobacillus acidophilus LA-5 and Escherichia coli O157:H7 in Minas Frescal cheese made with oregano and rosemary essential oils

The effects of the incorporation of the essential oils from Origanum vulgare L. (OVEO; 0.07 μL/g) and Rosmarinus officinalis L. (ROEO; 2.65 μL/g) in combination in Minas Frescal cheese on the counts of the probiotic Lactobacillus acidophilus LA-5 and Escherichia coli O157:H7 were evaluated during refrigerated storage (7 ± 0.5 °C). The terpenes of OVEO and ROEO, survival of the probiotic strain during in vitro digestion, as well as the physicochemical and sensory aspects were also monitored in Minas Frescal cheese. All terpenes decreased in cheese when the storage time increased. The incorporation of OVEO and ROEO delayed the increase in L. acidophilus LA-5 counts in cheese, but did not affect its ability to survive in cheese under simulated gastrointestinal conditions. The decreases in counts of E. coli O157:H7 observed in the first 15 days of refrigerated storage were strongly correlated (r ≥ 0.82) with the terpenes detected in cheese. Scores attributed for aroma, flavor, overall impression and purchase intention of cheese with OVEO and ROEO increased with the increase of the storage time. The incorporation of OVEO and ROEO in combination could be a strategy to control E. coli O157:H7 in probiotic Minas cheese during storage; however, the amounts of these substances should be cautiously selected considering possible negative sensory impacts in this product.

Xylooligosaccharides production from wheat middlings bioprocessed with Bacillus subtilis.

Prebiotic compounds are substrates selectively metabolized by beneficial gut microbiota causing a health-promoting effect. Despite some prebiotic carbohydrates have been largely studied, xylooligosaccharides (XOS) are important prebiotics derived from arabinoxylans, which are polysaccharides found in cereals. This study aimed to investigate the production of xylanolytic enzymes and XOS during bioprocessing of wheat middlings, a product derived from wheat flour production, using a probiotic Bacillus subtilis. The composition of XOS and the enzymatic and prebiotic activities of resulting B. subtilis cultures were evaluated. The activity of xylanolytic enzymes continuously enhanced during the 72 h bacterial growth, where β-xylosidase presented the highest value (70.31 U/mL). XOS profile and concentration varied considerably between control and bioprocessed samples and among these at different times. Maximum prebiotic activity score was found for the 24 h and 72 h bioprocessed samples (1.73 and 1.61, respectively) using the commercial probiotic Lactobacillus acidophilus LA-5. Wheat middlings showed to be a promising substrate for production of prebiotics like XOS and B. subtilis FTC01 appears to be a good source of xylanolytic enzymes.

Development of Yoghurt with Juçara Pulp (Euterpe edulis M.) and the Probiotic Lactobacillus acidophilus La5.

Yoghurts are dairy products consumed worldwide and can be supplemented with substances that provide extra health benefits as well as probiotic strains. In this context, the present study aimed to prepare a yoghurt added of juçara (Euterpe edulis M.) pulp and the commercial probiotic strain Lactobacillus acidophilus La5. Moreover, the probiotic survival during storage and after in vitro exposure to simulated gastric and enteric conditions was evaluated. Four formulations of yoghurt were prepared: (a) natural yoghurt, (b) yoghurt added of probiotic, (c) yoghurt added of juçara pulp, and (d) yoghurt added of probiotic culture and juçara pulp. The preparations were evaluated for survival of probiotic strain during storage and its tolerance to gastric and enteric conditions in vitro. The probiotic population in yoghurt remained unchanged during 28days of storage. In addition, juçara pulp increased the probiotic resistance to simulated gastric and enteric conditions in the first day of storage. These data indicate that juçara pulp is a potential ingredient for the production of probiotic yoghurts.

Enterococcus faecium and Enterococcus durans isolated from cheese: Survival in the presence of medications under simulated gastrointestinal conditions and adhesion properties

In this study, we evaluated the survival of Enterococcus faecium and Enterococcus durans, isolated from cheese, in the presence of medications and under simulated in vitro gastrointestinal conditions. The presence of genes encoding virulence factors, the susceptibility to antimicrobial agents, and adhesion properties were also assessed. Enterococcus faecium and E. durans both exhibited resistance to most of the tested medications but showed a large sensitivity to analgesics and antihypertensives; they also showed wide susceptibility to antimicrobial agents. Enterococcus durans SJRP29 had greater resistance to the presence of medications in comparison with the probiotic Lactobacillus acidophilus La-5. The strains, except for E. durans SJRP05, did not harbor virulence genes. Enterococcus durans SJRP14, SJRP17, and SJRP26 were sensitive to all tested antimicrobial agents. Enterococcus faecium was more stable during the simulation of gastrointestinal tract and showed greater viability. At the end of the assay, except for E. durans SJRP17, all strains showed high viability (>7 log cfu/mL). Enterococcus durans SJRP29 stood out from the other strains and was selected for further evaluation; it tolerated up to 3.0% NaCl at 30 and 37°C, besides having good adhesion properties (high values of auto-aggregation, co-aggregation, and hydrophobicity). Additionally, the microorganism did not show bile salt hydrolase activity or mucin degradation. These results encourage carrying out additional tests to evaluate the probiotic features by using in vitro dynamic models and in vivo tests before applying these strains to a food system.

Antimicrobial effect of probiotics on bacterial species from dental plaque.

The antimicrobial role of probiotic Lactobacillus casei subspecies casei DG (L. casei DG) and of the mix culture of probiotic Lactobacillus acidophilus LA-5 and Bifidobacterium BB-12 was tested on species of Staphylococcus, Streptococcus, Pasteurella, and Neisseria genera from supragingival sites from dogs with dental disease of different breed, age, sex, weight, and diet. The research was conducted on these four genera because of their importance in zoonotic infections after dog bites. Species from Staphylococcus, Streptococcus, Pasteurella, and Neisseria genera were isolated and identified. To test the antimicrobial efficacy of L. casei DG and the mixed culture of probiotic L. acidophilus LA-5 and Bifidobacterium bifidum BB-12 on the pathogenic species, the agar overlay method was used. L. casei DG had a bactericidal effect on all analyzed species isolated from Staphylococcus, Streptococcus, Pasteurella, and Neisseria genera after 24 hours of incubation. The mixed probiotic culture made up of L. acidophilus LA-5 and Bifidobacterium BB-12 species had no bactericidal effect on the species of Staphylococcus and Streptococcus genera, which were resistant. However, it had a bacteriostatic effect on several species of Pasteurella and Neisseria genera. This work highlights the antimicrobial potential of probiotics in vitro, demonstrating that the probiotic L. casei DG has a bactericidal effect on all analyzed species isolated from dental plaque and that the mix culture of probiotic L. acidophilus LA-5 and Bifidobacterium BB-12 has only a bacteriostatic effect.

Modulation of the Lactobacillus acidophilus La-5 lipidome by different growth conditions.

Probiotics are bacteria used in the food industry due to their potential health benefits. In this study, the plasma membrane of the probiotic Lactobacillus acidophilus La-5 was investigated using state-of-the-art high-resolution shotgun lipidomics. Comparisons of the lipidome of the plasma membrane were done after altering the fatty acid composition by supplementing L. acidophilus La-5 with saturated, mono-, di- and tri-unsaturated fatty acids during fermentation. The plasma membrane with the highest degree of saturation resulted in a lipid composition with the highest proportion of cardiolipin (CL) and lowest proportion of monolysocardiolipin (MLCL). No significant changes were found for other lipid classes. The bacteria grown with di- and tri-unsaturated fatty acids were expected to have more unsaturated plasma membranes than bacteria grown with mono-unsaturated fatty acids. This was also the case for MLCL, but the numbers of double bonds for CL were quite similar for these three samples. The results indicate that L. acidophilus La-5 possesses a molecular mechanism for remodelling and optimizing the fatty acid composition of CL and MLCL species and the molar ratio of CL and MLCL. This study contributes new knowledge on the previously uninvestigated lipidome of L. acidophilus La-5.

Innovative açaí (Euterpe oleracea, Mart., Arecaceae) functional frozen dessert exhibits high probiotic viability throughout shelf-life and supplementation with inulin improves sensory acceptance

Acceptance and the probiotic viability of an innovative non-dairy frozen acai (Euterpe oleracea, Mart.) dessert supplemented and not supplemented with inulin during a shelf-life of 84 days at �18 o C were investigated. Desserts containing and not containing probiotic Lactobacillus acidophilus La-5 and Bifidobacterium animalis Bb-12 and inulin were produced, resulting in 4 mixes of frozen acai: control (M1), pro (M2), pre (M3), and synbiotic (M4). Sensory acceptability scores and probiotic counts were obtained during 84 days of storage. Inulin, a key factor for product approval, significantly (p<0.05) increased overall product acceptance of both M3 and M4, compared with M1. La-5 viability was above 7 log CFU/g for both pro and synbiotic desserts. Bb-12 counts were above 6 log CFU/g only for M4. All frozen acai desserts were suitable for probiotic delivery and were accepted by consumers. Addition of inulin is recommended both for increasing acceptance and for the synbiotic potential.

Microencapsulation of Lactobacillus acidophilus LA-5, Bifidobacterium animalis subsp. lactis BB-12 and Propionibacterium jensenii 702 by spray drying in goat's milk

A mixture of probiotic Lactobacillus acidophilus LA-5, Bifidobacterium animalis subsp. lactis BB-12 and novel potential probiotic Propionibacterium jensenii 702 was resuspended in reconstituted (20% w/v) goat's milk, spray dried in a mini spray dryer (inlet temperature=195°C and outlet temperature=85°C) and the spray dried powder was stored in air tight glass jars at 4°C and 30°C for 24 weeks. Powder quality and probiotic viability after spray drying and subsequent storage were measured. Spray drying probiotics in reconstituted goat's milk resulted in a significant reduction in the viability of all three probiotics. However, all three probiotics were able to maintain satisfactory viability levels (106–108cfu/g) after spray drying. While storage temperature did not appear to have a significant effect on moisture content, the viability of all three strains declined dramatically when stored at 30°C but lactobacilli and propionibacteria remained virtually unaffected under storage at 4°C, satisfying recommendations regarding the level of viable cells in probiotic foods.

The Effect of Fermentation Temperature on the Microstructure, Physicochemical and Rheological Properties of Probiotic Buffalo Yoghurt

The properties of buffalo and bovine milk differ and the procedures developed to make bovine yoghurt may require optimisation for the production of buffalo yoghurt. This study aimed to apply cryo-scanning electron microscopy and confocal laser scanning microscopy to determine the optimal temperature for processing buffalo yoghurt. Milk was fermented at three different temperatures (37, 40 and 43 °C), stored for 28 days and the yoghurt microstructure, physicochemical and rheological properties assessed. Yoghurt fermented at 37 °C had a compact microstructure and the probiotic Lactobacillus acidophilus La-5 was more viable on storage. In contrast, yoghurt produced from a faster fermentation at 43 °C was firmer with a more porous microstructure that exhibited a higher degree of syneresis. The rheological properties during storage including the thixotropy, consistency coefficient and flow behaviour index were not significantly affected by temperature nor were the concentration of lactose, ionic calcium or titratable acidity. This study shows how changes to processing can be used to alter the microstructure of buffalo products and suggests that a decrease in fermentation temperature could be used to improve the quality of buffalo yoghurt.

When and How to Evaluate the Natural Killer Cell Function

Aims: To optimize the process variables including: Lactobacillus acidophilus La-5, total starter (a mixture of mesophilic cheese starters (MCS) and thermophilic yoghurt starters (TYS), mesophilic cheese starter: thermophilic yoghurt starter (MCS: TYS) ratio and salt content in probiotic Iranian ultrafiltered soft cheese (IUSC). Methodology: In order to choose the best probiotic cheese formula with the highest Lactobacillus acidophilus La-5 count, a total of eight samples with 20 % total solids were produced using a small scale ultrafiltration system. Probiotic bacteria of Lactobacillus Original Research Article Annual Research & Review in Biology, 4(24): 4091-4103, 2014 4092 acidophilus La-5 (0.1 and 0.3 %), total starters (1 and 2 %), MCS: TYS ratio (8:2 and 7:3) and salt (NaCl) concentration (1 and 2 %) by the help of Taguchi design were inoculated into cheeses and the viable cell counts of Lactobacillus acidophilus La-5 enumerated within 45 d of shelf life at 5 oC, as well the multiple effects of process variables on probiotic count and colony morphologies of probiotic and starters evaluated. Results: The most suitable conditions for the highest Lactobacillus acidophilus La-5 stability were addition of 0.1 % w/w Lactobacillus acidophilus La-5, 1 % v/w total starter, MCS: TYS ratio of 8:2 and 1 % w/w salt content. The lowest and highest viable cell count of probiotic Lactobacillus acidophilus La-5 in IUSC ranged from 6.41 to 7.92 CFU.g, respectively. The acidified (pH 5.2) MRS agar medium used for the differentiation of the colony morphology of Lactobacillus bulgaricus and Lactobacillus acidophilus La-5, anaerobically. In all of the cheeses except for cheese 3 and 6 which the La-5 survived to 6.95 and 6.41 log orders, respectively, Lactobacillus acidophilus La-5 cell count survived to over10 CFU.g, when all the cheeses had the small amount of acetic acid taste with a creamy and soft texture. The MCS:TYS ratio of 8:2 and 0.1 % initial dosage of Lactobacillus acidophilus La-5 (P ˂ 0.05) affected the probiotic stability of Lactobacillus acidophilus La-5 in IUSC during shelf life, however the salt content (1 and 2 %) and total starter (1 and 2 %) did not significantly influence the Lactobacillus acidophilus La-5 viability. Conclusion: This study showed that Iranian ultrafiltered soft cheese has a probiotic potential to have 10 CFU.g viable cell count of Lactobacillus acidophilus La-5 strain, when process variables optimized and this progress will contribute to develop a healthier foods.

In vitro analysis of gastrointestinal tolerance and intestinal cell adhesion of probiotics in goat's milk ice cream and yogurt

Effect of carrier food type on in vitro gastrointestinal survival and adhesion ability of probiotic Lactobacillus acidophilus LA-5, Bifidobacterium animalis subsp. lactis BB-12 and Propionibacterium jensenii 702 were evaluated using goat's milk ice cream, plain and fruit yogurts. Carrier food matrix had a significant influence on the in vitro gastrointestinal tolerance of all three probiotics when exposed to both highly acidic conditions (pH 2.0) and 0.3% bile. Exposure to conditions of lower pH (pH 2.0) resulted in a significant reduction in probiotic viability during simulated gastric transit tolerance compared to pH levels of 3.0 and 4.0. However, ice cream was generally found to improve the acid and bile tolerance of the probiotics compared to plain and stirred fruit yogurts. In a similar manner, the in vitro adhesion ability of probiotics was found to be influenced by the carrier food matrix, with fruit yogurt providing the most favorable outcomes, although in all cases a substantial number of viable bacteria (105–106cfu/g) were able to attach to the Caco-2 cells.

Effect of stress pretreatment on survival of probiotic bacteria in gastrointestinal tract simulator

The effect of stress pretreatment on survival of probiotic Lactobacillus acidophilus La-5, Lactobacillus rhamnosus GG, and Lactobacillus fermentum ME-3 cultures was investigated in the single bioreactor gastrointestinal tract simulator (GITS). The cultures were pregrown in pH-auxostat, subjected to temperature, acid, or bile stress treatment, fast frozen in liquid nitrogen (LN(2)), and tested for survival in GITS. After LN(2) freezing the colony forming ability of L. rhamnosus GG and L. fermentum ME-3 nonstressed and stressed cells was well retained (average survival of 75.4 +/- 18.3% and 88.0 +/- 7.2%, respectively). L. acidophilus La-5 strain showed good survival of auxostat nonstressed cells after fast freezing (94.2 +/- 15.0), however the survival of stress pretreated cells was considerably lower (30.8 +/- 8.5%). All LN(2) frozen auxostat cultures survived well in the acid phase of the GIT simulation (survival 81 +/- 21%); however, after the bile phase, the colony formation ability of L. acidophilus La-5, L. rhamnosus GG, and L. fermentum ME-3 decreased by approximately 1.4 +/- 0.2, 3.8 +/- 0.3, and 3.5 +/- 1.2 logarithmic units, respectively. No statistically relevant positive effect of stress pretreatments on survival of LN(2) frozen L. acidophilus La-5, L. rhamnosus GG, and L. fermentum ME-3 in GITS was observed.