Preparation and antimicrobial activities of tea polyphenols

Using green tea powder,tea polyphenols was prepared.The antimicrobial activities of tea polyphenols and the effects of the factors including concentration,time,pH value,temperature,NaCl concentration on the antimicrobial activities were studied by plate count and filtering paper method.The results showed that tea polyphenols had strong inhibition on bacteria activities but no distinct inhibition on yeast.The minimum antimicrobial concentration of tea polyphenols was 6.25% to Staphylococcus aureus,12.5% to Bacillus subfilis,25% to Escherichia coil.The higher concentration of tea polyphenols and the longer the tea polyphenols interact with microble,the stronger was antimicrobial activity.Antimicrobial activities in low alkali environment were strongest.Antimicrobial activities of tea polyphenols would not be affected in a certain temperature scope.NaCl could strengthen the antimicrobial activity of tea polyphenols.