Showing 5 results for Vasi i
Volume 13, Issue 53 (5-2015)
Abstract
The aim of this work was identified lactic floraas a traditional fermented food and then evaluates antimicrobial activities of some strains. A total of 140 Gram-positive and catalase-negative isolates were subjected to grouping by physiological and biochemical tests and carbohydrates fermentation. Based on the resultsthese 140 isolateswere dividedinto 9 groups. Two or three isolated were selected from each group and 16S rRNA was amplified using universal primers. Diversity of lactic acid bacteria in horreh was as followings:Lactobacillus fermentum (30.00%),Lactobacillus plantarum (28.57%), Lactobacillus brevis (15.00%), Weissellacibaria(8.57%),Enterococcus (faecium and faecalis) (7.14 %), Leuconostoc (citreumand mesenteroides subsp.Mesenteroides) (6.42%) and Pediococcus pentosaceus (4.28%). Antagonistic activity of 20 isolates (strains) of lactic acid bacteriaobtained fromhorreh was evaluated against food- borne bacteria. Sixteen isolates in Agar spot method and 14 isolates in well diffusion assayshowed antibacterial activity against at least one of these indicators. Eight isolates including:Ent. faecium (1), Ent. faecalis (1), P. pentosaceus(1) and Lb. plantarum (2) exhibited the highest antagonistic activity toward Listeria innocoa. Antagonistic activity of cell free supernatant (CFS) from Lb. plantarum showed the highest thermal stability. Also, two isolates belonging to:Ent. faecium, Ent. Faecalis presented antibacterial activity at pH=7. Only, the supernatant of Lb. plantarum was not influenced by proteinase K.The results showed that the supernatant of some isolatestestedcan be used as a bio preservative in food products.
Volume 13, Issue 53 (5-2015)
Abstract
The purpose of this study was to evaluate the effect of time, kind of extract, extract concentration and temperature on the dynamically the population of Escherichia coli (infectious agents) in the complex food system (frankfurter sausage) and Genetic Algorithm - Artificial neural network and neuro fuzzy system (CANFIS) were used for dynamic modeling of population of E.coli. At this research laboratory, Minimum Inhibitory Concentration (MIC (and Minimum Bactericidal Concentration (MBC) of aqueous and ethanolic extracts were studied using the micro broth dilution method. GA- ANN, neuro fuzzy (CANFIS) were fed with four inputs: concentration at the five level (0, 2000, 4000, 6000, 8000 ppm), kind of extract ( watery, ethanol), temperature at the three level (5,15, 25 ̊С) and time (1-20). The results showed that the ANN with 1 hidden layer comprising 10 neurons, Tangent hyperbolic function, momentum training rule and percent of used data 30/30/40 for training/cross validation/testing respectively gives the best fitting with the experimental data, which made it possible to predict with high determination coefficient (R2 equal to 0.995). Also the correlation between CANFIS predictions and experimental data was very good (R2 equal to 0.96). It's worth to mention that in this research GA- ANN was better approach to simulation dynamically the population of E.coli.
Volume 13, Issue 54 (8-2015)
Abstract
Kimchi is a fermented herbal supplement, and appetizer that according to a raw material, process and geographical location are classified more than161 types. In this study, after kimchi production, isolation and identification of microorganisms was performed by molecular method. Lipase producing strain, Trichosporon asahii was isolated from kimchi sample (19.01 ±3 U/ml). The various medium components and culture parameters to achieve a more cost effective and economically viable bioprocess were screened and optimized using Design Expert software. PBdesignsare used to screen the most effective variables on lipase production that fermentation temperature and initial pHfor 48 hours 30 . According to the results, extract of nigella sativa, olive oil, yeast extract, magnesium chloride, respectively, were the most variable. Variable particle size and pepton ehavenegative effect. The variable selection and optimization on was performed more efficiently. Finally, lipase activity was 35 ± 0.5 U/ml in the optimal conditions using a medium containing15% sativa extract, 10 g/l yeast extract, 22.5 g/l olive oiland25 mM/l magnesium chloride in the rotation speed of 150 rpm, respectively, as well as enzyme activityafter84/1times the optimal state before optimization. The kinetic parameters V (max) and K (m) was 0.367 mM / min and 0.53 mM through Michaelis–Menten Chart, respectively. Low Km indicates high affinity between enzyme and substrate and high Vmax demonstrates high catalytic performance of the enzyme
Volume 13, Issue 54 (8-2015)
Abstract
Kimchi is a general term for fermented vegetables.The aim of this study was to isolate and identify the Lactic Acid Bacteria involved in spontaneous fermentation of this product used biochemical and molecular methods. In this study, after successive culture on specific media, in order to classify of 85 selected isolates that according to preliminary experiments seemed Lactic Acid Bacteria, physiological and biochemical tests were done and then fermentation of 10 different carbohydrates were performed. Based on these tests, 85 isolates were divided into 10 groups. Some isolates were selected from each group and 16S rRNA was amplified using universal primers. Diversity of lactic acid bacteria in Kimichi was as followings: Lactobacillus plantarum (41.17%), Lactobacillus fermentum (9.41%), Enterococcus faecalis (3.52%), Enterococcus faecium (7.06%), Leuconostoc citreum (2.35%), Leuconostoc mesenteroides (3.52%), Pediococcus pentosaceus (8.23%), Wisella cibaria (24.70%). This fermented product has a wide microbial diversity which originates from natural microbiota presented in the raw vegetable. Lactic acid bacteria can produce a variety of acids and enzymes which play an important role in development of unique flavor and tasteTherefore, this strains that isolated from Kimchi can be used in the food industry.
Volume 13, Issue 55 (9-2015)
Abstract
Infectious diseases created by strains of Antibiotic resistance Escherichia coli and Staphylococcus aureus, is increasing in many countries such as Iran. Therefore, many efforts are performing in order to find a new composition as replacement for antibiotics. In this experimental research, an antimicrobial effect of the ethanolic and aqueous extract of Hibiscus Sabdariffa was investigated on several strains of Escherichia coli and Staphylococcus aureus resistant to common clinical antibiotics.The extract of Hibiscus Sabdariffa was prepared using rotary. Twenty strains of Escherichia coli and Staphylococcus aureus were provided from Mashhad University of Medical Sciences. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined using Serial Dilution Method in six concentrations onto strains of Escherichia coli and Staphylococcus aureus in broth media.The results showed that Escherichia coli was resistant to antibiotics of penicillin (75.9%), erythromycin (58.3%), tetracycline (56.9%), and cefixime (37%), and Staphylococcus aureus showed resistant to antibiotics of penicillin (83.5%), cefixime (80%), erythromycin (55.6%), and tetracycline (26.1%), respectively. Also, the ethanolic extract of Hibiscus Sabdariffa has acceptable effect on antibiotic resistant strains of Escherichia coli and Staphylococcus aureus that MIC of the Hibiscus Sabdariffa ethanolic extract was 4 and 16 mg/mL for Escherichia coli and Staphylococcus aureus, respectively.The overall, the Hibiscus Sabdariffa extract has inhibitory ability on Antibiotic resistant Escherichia coli and Staphylococcus aureus strains. So, the ethanolic and aqueous extract of Hibiscus tea can be used in in pharmaceutical industry for medical treatments with perfect study.