Abstract:

The extraction conditions of geniposide in gardenia yellow waste liquid by aqueous two-phase extraction were studied. According to partition coefficient and volume ratio, ethanol-K2HPO4 system was chosen to separate geniposide. The optimum extraction conditions are as follows volume ratio of ethanol to gardenia yellow waste liquid 6:4, and addition amount of K2HPO4 log in 1.0ml of ethanol-gardenia yellow waste liquid. Under these conditions the partition coefficient is 4.56, the volume ratio is 6.38. The pH value of waste liquid and extraction temperature have little influence on partition coefficient and volume ratio. The enlarged experiment showed that the purity of geniposide reaches 62.12%, and the yield of geniposide reaches 96.32% by this system. The color value E1% (590 nm)of gardenia blue which is produced by the reaction between genipin from hydrolyz geniposide and arginine reaches 65.92.

Key words: aqueous two-phase extraction, geniposide, partition coefficient, gardenia blue