蒽酮法测定红枣可溶性糖含量条件的优化

Sample Preparation Optimization for Determination of Soluble Sugar in Red Jujube Fruits by Anthrone Method

以红枣为试材,通过单因素试验研究反应温度、蒽酮质量浓度、蒽酮用量、显色反应时间、冷却时间对红枣可溶性糖含量测定的影响,并采用正交试验优化测定红枣可溶性糖含量的最佳反应条件。结果表明,红枣可溶性糖含量测定的最佳条件为:蒽酮质量浓度25 mg/m L、蒽酮试剂用量3 m L、室温反应时间1 min、冷却时间25 min。该方法操作简便、快速、灵敏度高。验证实验结果表明,蔗糖标准液含量在20~240μg/m L范围内有较好的线性关系(A=0.004 5C-0.013 4,相关系数为R2=0.999 2,式中,A为吸光度;C为糖含量)。实验重现性好,相对标准偏差(relative standard deviation,RSD)为0.20%(n=3);平均回收率达102.87%,RSD为0.84%(n=3)。最佳优化条件下测得的红枣可溶性糖含量为68.43%(以干质量计)。

This paper reports the optimization of sample preparation conditions including reaction temperature, anthrone concentration and amount, color development time and cooling time for the determination of soluble sugar in red jujube fruits using a combination of single factor and orthogonal array designs. The results showed that 1 min reaction at room temperature in the presence of 3 m L of 25 mg/m L anthrone reagent followed by 25 min of cooling was found to be optimal. The established analytical method was characteristics of simple operation, rapidity and high sensitivity. Verification experiments showed that the standard curve of sucrose standard solution in the range of 20–240 mg/m L had good linearity(A = 0.004 5C- 0.013 4, R2 = 0.999 2), with a good reproducibility. The accuracy, expressed as RSD, was 0.20%(n = 3) and the average recovery was 102.87%(n = 3) with a RSD of 0.84%. Dried red jujubes contained 68.43% soluble sugar as determined by this method.