红茶菌发酵液的有机酸组成分析

Determination of organic acids in kombucha fermentation broth

首先对红茶菌发酵过程中的p H、糖度、总糖、总酸及总酚含量等随发酵时间的变化进行研究,又采用离子排斥液相色谱法对发酵液中的有机酸进行分析。以高交联度磺化苯乙烯-二乙烯基苯共聚物多孔微球作为固定相的Aminex HPX-87H离子色谱柱作为分析柱,利用二极管阵列检测器对8种有机酸（柠檬酸、苹果酸、琥珀酸、乙酸、丙酸、丁酸、草酸、乳酸）进行了较成功的分离,并应用于红茶菌发酵液的有机酸分析。通过色谱条件优化,选定了55℃为柱温和10 mmol/L的H2SO4作为流动相。利用上述方法进行测定,能够有效地对红茶菌发酵液中的6种有机酸（柠檬酸、苹果酸、琥珀酸、乙酸、丙酸和丁酸）进行提取、分离和测定,回收率为97.1%～102.9%,RSD为0.1%～6.5%。

The content change of pH, soluble solids, total sugar, total acidity and polyphenols in the fermentation of kombucha was studied first, then a method using ion-exclusion liquid chromatography was described for the simultaneous determination of organic acids in fermentation broth. Eight organic acids （including citric acid, malic acid, succinic acid, acetic acid, propionic acid, butyric acid, oxalic acid and lactic acid） were separated by a sulflnared polystyrene divinyl benzene column （Aminex HPX-87H） with a diode array detector. It is found that the optimal 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 separated and detected. The recoveries were 97.1% to 102.9%, and the relative standard deviations were 0.1% to 6.5%.