枣子提取物中糖类含量的测定及提取工艺研究

Determination of Carbohydrates in Jujube Extract and Optimization of Extraction Technology

建立了Poly—SeryHLB固相萃取小柱净化、乙腈一水梯度洗脱、Prevai lCarbohydrate ES糖柱-高效液相色谱-蒸发光散射检测器（HPLC—ELSD）法同时测定枣子提取物中9种水溶性糖（鼠李糖、木糖醇、阿拉伯糖醇、果糖、甘露糖、葡萄糖、肌糖、蔗糖和麦芽糖）的分析方法，通过单因素实验和L9（3^4）正交实验考察了提取工艺条件（提取溶剂、提取温度、提取时间和料液比）对糖类物质提取量的影响。结果表明：①各目标物在0．1～1．0mg／mL范围内线性良好（R。〉0．998），精密度（RSD）〈5．1％，回收率90％～107％。该方法操作简单、稳定性好，适用于枣子提取物中糖类物质的常规检测。②4种因素均影响枣子提取物中糖类物质的含量，其重要性依次为：乙醇浓度〉料液比〉提取时间〉提取温度；优化确定的最佳提取工艺条件为：乙醇浓度95％、提取温度80℃、提取时间2h、料液比1：7，在此条件下，从枣子提取物中鉴定出5种糖（果糖、葡萄糖、肌糖、蔗糖和麦芽糖），糖总量达到345．63mg／g。

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（3^4） orthogonal test. The results showed that： 1） The calibration curves of the analytes exhibited good linearity （R2〉0.998） 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 ratio〉extraction time〉extraction temperature. The optimal extraction condition was： alcohol concentration 95%, extraction temperature 80 ℃, extraction time two hours and sample/solvent ratio 1：7. Underthis condition, the total carbohydrates in jujube extract reached 345.63 mg/g, and fructose, glucose, inositol, sucrose and maltose were all detectable.