Characterization of Lactobacillus plantarum as a potential probiotic in vitro and use of a dairy product (yogurt) as food carrier

Background and Objective: The current study was undertaken to check in vitro different characteristics of Lactobacillus plantarum as potential probiotic. These characteristics include viability of probiotic and pH during cold storage, tolerance to acid and bile, and antibiotic resistance

Material and Methods: Samples of yogurt were stored at 4[degree sign]C and analyzed in time 0, 1, 3, 7, 10 and 14 days of storage. In these periods, probiotic and starter cultures were enumerated and the pH parameter was analyzed

Results and Conclusion: A gradual decline in pH was noticed throughout the storage. Counting of starter cultures decreased by 0.42 log cycle, and the probiotic's viability decreased by 0.68 log cycle at the end of storage, whereas the probiotic's viability in the samples subjected to re-pasteurization decreased by 0.30, 0.22 log cycles in the selective and reference media, respectively. The average viable cell counts of Lactobacillus plantarum decreased by 0.76, and 0.28 log cycles after incubation period [3 h] at 37[degree sign]C in the simulated gastric juice [pH 2.0 and 3.0], respectively. Generally, probiotic can maintain its viability by 76.672% in [1.0% w v [-1]] bile. Lactobacillus plantarum was resistant to gentamicin, streptomycin, and vancomycin but susceptible to chloramphenicol, and tetracycline. Depended on these characteristics, Lactobacillus plantarum showed probiotic potential

Autophagy gene activity may act as a key factor for sensitivity of tumor cells to oncolytic vesicular stomatitis virus

Background: Beclin1 is an important, primary molecule for autophagy

Objectives: It is suggested that the control of the autophagy path increases the sensitivity of tumor cells to VSV

Materials and Methods: In this study, the degree of Beclin1 gene expression in two cell lines, HeLa and A549, has been examined and the percentage of living cells subsequent infection with virus has been evaluated by MTT assay method

Results: The results showed that the degree of Beclin1 gene expression in HeLa cells in comparison with A549 cells has reduced, and the sensitivity of these cells to vesicular stomatits virus [VSV] oncolysis is more than A549

Conclusions: It seems that by using some methods for reducing autophagy, it is possible to make tumor cells more sensitive to virotherapy and even other treatments

effect of Saccharomyces strain and fermentation conditions on quality prameters of non-alcoholic beer

In this study, the effect of several species of fermenting yeast and fermentation conditions [periodic aeration and temperature] on quality parameters of non-alcoholic beer is assessed. Yeast starters with different inoculation percent were added separately into wort with determined gravity. Wort was fermented for 48 h in different temperatures under aerobic condition or periodic aeration [every 12 h]. Growth rate, wort gravity and ethanol content were analyzed for 48 hours [12-h interval]. Also, 6 trained panelists were asked for sensory evaluation of final product. The highest growth rate and the highest ethanol content were found in treatments with 4×10[7] cfu/ml inoculation fermented at 24[degree sign]C under periodic aeration and in those fermented under anaerobic conditions, respectively. The highest gravity was observed for treatments with 10[7] cfu/ml inoculation, periodic aeration and fermentation at 4[degree sign]C. The lowest growth rate and ethanol content were observed in treatments with 10[7] cfu/ml, fermented at 4[degree sign]C under anaerobic condition and those fermented under periodic aeration, respectively. In treatments with 4×10[7] cfu/ml inoculation, anaerobic condition and fermentation at 4[degree sign]C, the lowest gravity was observed. In addition, among yeasts, Saccharomyces cerevisiae and Saccharomyces rouxii showed the highest and the lowest growth rate, ethanol content and wort gravity, respectively. Additionally, treatments containing Saccharomyces cerevisiae resulted in non-alcoholic beer with more satisfactory flavor attributes

effect of Saccharomyces strain and fermentation conditions on quality prameters of non-alcoholic beer

In this study, the effect of several species of fermenting yeast and fermentation conditions [periodic aeration and temperature] on quality parameters of non-alcoholic beer is assessed. Yeast starters with different inoculation percent were added separately into wort with determined gravity. Wort was fermented for 48 h in different temperatures under aerobic condition or periodic aeration [every 12 h]. Growth rate, wort gravity and ethanol content were analyzed for 48 hours [12-h interval]. Also, 6 trained panelists were asked for sensory evaluation of final product. The highest growth rate and the highest ethanol content were found in treatments with 4×10[7] cfu/ml inoculation fermented at 24[degree sign] under periodic aeration and in those fermented under anaerobic conditions, respectively. The highest gravity was observed for treatments with 10[7] cfu/ml inoculation, periodic aeration and fermentation at 4[degree sign]. The lowest growth rate and ethanol content were observed in treatments with 10[7] cfu/ml, fermented at 4[degree sign] under anaerobic condition and those fermented under periodic aeration, respectively. In treatments with 4×10[7] cfu/ml inoculation, anaerobic condition and fermentation at 4[degree sign], the lowest gravity was observed. In addition, among yeasts, Saccharomyces cerevisiae and Saccharomyces rouxii showed the highest and the lowest growth rate, ethanol content and wort gravity, respectively. Additionally, treatments containing Saccharomyces cerevisiae resulted in non-alcoholic beer with more satisfactory flavor attributes

Evaluation of Ca-independent alpha-amylase production by Bacillus sp. KR-8104 in submerged and solid state fermentation systems

This study investigates the production of crude Caindependent and low pH active alpha-amylase by Bacillus sp. KR-8104 in submerged fermentation [SmF] and solid-state fermentation [SSF] systems. Different parameters were evaluated in each system using "one factor at a time" approach to improve the production of enzyme. The results showed that in the SmF the maximum enzyme production was achieved in culture medium that contained dextrin as a carbon source, as well as yeast extract and meat extract as nitrogen sources incubated at 37§C and 180 rpm for 48 h. While SSF of Bacillus sp. KR-8104 using wheat bran [WB] as a substrate showed that using tap water or distilled water as a moisturizing agent, a substrate-water ratio of 1:1.5 [w/v] and incubation at 37§C for 48 h gave the maximum alpha-amylase production. From different extraction medium examined in this study 0.1% [v/v] aqueous mixture of Tween 20 and distilled water illustrated maximum results [100 U/g]

Principles and methods of microencapsulation of probiotic microorganisms

Worldwide popularity of probiotic- microorganisms and their products on the one hand, and their general weak viability in food products [especially fermented types] as well as gastrointestinal conditions on the other hand, has encouraged researchers to innovate different methods of probiotics viability improvement. Microencapsulation of the probiotic cells is one of the newest and highly efficient methods, which is now under the especial attention and is being developed by various researchers. This article reviews the principles and methods of probiotic cell microencapsulation