| Popis: |
Introduction: Potent antimicrobial activity is important biological property of wine. Besides organic acids, ethanol and low pH, wine phenolics have been proposed to play a major role in this biological effect of wine. In order to evaluate the role of wine phenolics content on its antimicrobial activity, we compared standard and polyphenols-rich white wine (PRWW ) obtained by Georgian traditional wine-making in which white grape juice is fermented and left in long contact with the hard parts of grape. Materials and methods: The organisms studied included standard Escherichia coli (ATCC 25922) and Salmonella enterica (ATCC 13076). Aliquots of 200 μL of the bacterial suspension were added to 3.8 mL of standard or PRWW (Grasevina, Krauthaker winery, 2015, 13.0 vol% alcohol, total phenolic content 210 and 2699 mg GAE/L, respectively) yielding an initial concentration of 105 to 106 colony forming units/ml. 0.01 mL of that suspension was then at fixed times inoculated on blood agar. Plates were incubated for 24 hours at 35ºC at ambient atmosphere. Bacterial growth was determined as the number of colonies seen with the naked eye. Results: The minimal incubation time of the bacterial suspension with the standard white wine necessary for prevention of bacterial growth, was 6 and 5 minutes for E. coli and Salmonella, respectively. The incubation time needed for prevention of the bacterial growth with the PRWW prolonged to 23 and 22 minutes for E. coli and Salmonella, respectively. Conclusion: Increase in total phenolic content does not improve antibacterial activity of white wine. |
