Study On Active Components Quality Of Kombucha Fermentation And Its Activity

Kombucha is a time-honored natural drink, nutritious and versatile. In this study, an ion exclusion chromatography method for the determination of organic acids and functional factors, and a method using co-culture assay for the determination of antibacterial activity in fermentation broth were established respectively. The main methods and results showed that:A method using ion-exclusion liquid chromatography was described for the determination of organic acids in fermentation broth. Eight organic acids(including citric acid, malic acid, succinic acid, acetic acid,propionic acid, butyric acid, lactic acid and lactic acid) were separated by a sulfonated polystyrene divinyl benzene column(Aminex HPX-87H) with a diode array detector. It is found that the optimal conditions for separation were 55℃ column temperature and 10 mmol/L sulfuric acid, which were applied to the determination of organic acid in Kombucha fermentation broth. With these conditions, six organic acids(including citric acid,malic acid, succinic acid, acetic acid, propionic acid and butyric acid) in fermentation broth could be effectively detected. The recoveries were from 97.1% to 102.9%, and the relative standard deviations were from 0.1% to6.5%.An analytical method was established for the simultaneous determination of D-Saccharic acid 1,4lactone and D-Glucuronolactone of Kombucha using reverse phase high performance liquid chromatography.The separation was performed on an Aminex HPX-87 H column(300 mm×7.8 mm, 9 μm) at 25℃ by HPLC equipped with an UV detector at the wavelength of 220 nm. The mobile phase is 5 mmol/L sulfuric acid with a flow rate of 0.6 mL/min. This method is convent, rapid, sensitive and suitable for the simultaneous determination of D-Saccharic acid 1,4 lactone and D-Glucuronolactone of Kombucha. The relative standard deviations were lower than 2.4%, and the recoveries were from 101.06% to 107.09%.The pH, soluble solids, total sugar, total acidity and polyphenols along with the culture time during Kombucha fermentation was studied. The results showed that there was a significant positive correlation between polyphenols and reducing power. The results of antioxidant activity showed that the scavenging rate of1,1-diphenyl-2-picrylhydrazyl radicals of Kombucha fermentation was very well, reached 90%, and unaffected by fermentation time. The scavenging rate of superoxide anion radicals showed a positive correlation with fermentation time, it reached 100% in 10 d. The scavenging rate of hydroxyl was lower, but still over 20%.Kombucha was drinkable when ferment 7~8 d, by this time already exhibited obvious antioxidant activity.A co-culture assay method of Kombucha for the antibacterial activities of bacteria and fungi were established. The results showed that Kombucha had evident antibacterial activities on the growth of Staphylococcus aureus, Bacillus subtilis, E. coli and Salmonella bacteria, the inhibition effects were related to the concentration of Kombucha fermentation, the concentration of selected bacteria and duration and so on.Kombucha couldn’t completely inhibit the growth of Aspergillus niger. The antibacterial activities declined after heat treatment, until uncompletely lost. The experiments showed that the antibacterial components in Kombucha partly had heat sensitive, but the others unaffected by high temperature.