امیر خدنگ نیک فرجام

The aim of this study was to identify the lactic acid of the dominant bacteria in pickled garlic, using initial biochemical tests and PCR technique and to investigate their potential probiotic potential. For this purpose, to determine the probiotic potential of these isolates, some confirmatory tests including resistance to acid, resistance to simulated gastric conditions, resistance to bile salts, activity against pathogenic bacteria, susceptibility to some common antibiotics and hemolytic activity of isolates were performed. Based on BLAST results, five isolates of Lactobacillus plantarum, two isolates as Pediococcus ethanolidurans and one isolate as Lactobacillus brevis were identified. The lactic acid bacteria isolated in this study had the ability to survive at pH 2.5, grow in medium containing 0.3% bile salt, were sensitive to antibiotics and lacked hemolytic activity and therefore have probiotic properties. Supernatant of isolates of this study in high concentrations had the ability to inhibit growth of pathogenic bacteria and the lethal activity against them. Finally, the isolates of this study can be added to other products in the future as a strain with probiotic potential.

In this study, optimum conditions for extraction of the alcoholic extract of Vaccinium macrocarpon by soaking method and its antibacterial effects were determined by Response Surface Method. Extraction was carried out at a temperature of 5 to 60 ° C, 2 to 10 hours, and the sample to solvent ratio of 4 to 20%, and an ethanol / methanol solvent ratio of 0 to 100%. The antimicrobial effects of the extracts were evaluated by detection of MIC and MBC against Staphylococcus aureus, Listeria monocytogenes, Bacillus cereus and Escherichia coli bacteria. The optimum operating conditions to obtain the maximum amount of Cranberry extract were at 60 ° C, 10 hours, and the sample to solvent ratio 11.43% and the ethanol to methanol ratio 88.88%. In these conditions, the extraction yield was 4.88%. Extraction yield of cranberry extract was predicted based on the mathematical model was 5.17%. This value is close to the value predicted by the model indicates a relatively good performance model. Alcoholic extract of Vaccinium macrocarpon resulting antibacterial activity and influence on the growth of all bacteria was tested. Gram-positive bacteria were more sensitive than gram-negative bacteria. Bacillus cereus and E. coli, had the most and the least sensitivity to the alcoholic extract of Vaccinium macrocarpon. So that they had the lowest and the highest values of MIC and MBC among bacteria respectively.