Determination of Carbohydrates in Jujube Extract and Optimization of Extraction Technology

Abstract

A method for simultaneously determining nine water-soluble carbohydrates(rhamnose, xylitol, arabitol, fructose, mannose, glucose, inositol, sucrose and maltose) in jujube extract based on high performance liquid chromatography-evaporative light scattering detector(HPLC-ELSD) was developed, the analytes were subjected to purification by Poly-Sery HLB solid phase extraction cartridges and gradient elution with acetonitrile-water then separated by a Prevail Carbohydrate ES column. The effects of extraction solvent, temperature, time and sample/solvent ratio on the content of carbohydrates in jujube extract were investigated with single factor test and L9(34) orthogonal test. The results showed that: 1) The calibration curves of the analytes exhibited good linearity(R20.998) within the range of 0.1-1.0 mg/mL, the recoveries ranged from 90% to 107%, and the relative standard deviation(RSD) was lower than 5.1%. This method is simple, stable and suitable for the routine analysis of carbohydrates in jujube extract. 2) All of the testing factors affected the content of carbohydrates in jujube extract, the influence degree was in the order of alcohol concentration ﹥ sample/solvent ratioextraction timeextraction temperature. The optimal extraction condition was: alcohol concentration 95%, extraction temperature 80 Ⅰ, extraction time two hours and sample/solvent ratio 1∶7. Under this condition, the total carbohydrates in jujube extract reached 345.63 mg/g, and fructose, glucose, inositol, sucrose and maltose were all detectable.