Determination of the tannins content in Ziziphus jujuba roots and its extraction technology.

[Objective] To optimize the extraction technology of tannins from Ziziphus jujuba roots,and to establish stable determination method of tannins content in Z.jujuba roots.[Method] Content of total tannins was detected by casein method.With tannins content as the evaluation index,the extraction time,solid-liquid ratio,extraction times,and acetone concentration were taken as the investigation factors.Extraction technology conditions were optimized by orthogonal design.[Result] Results showed that extraction times was the major influencing factor.The optimal extraction condition was as follows: 70% acetone concentration,1∶20(W/V,g/ml)solid-liquid ratio,30 min extraction time and 3 extraction times.Under this condition,the tannins content in Z.jujuba roots reached 6.82%.[Conclusion] The optimized extraction technology was reasonable,simple and feasible.