新疆红枣果实不同部位总酚的含量测定

Determination of Total Polyphenols in Different Parts of Jujubae Fruetus Growing in Xinjiang

系统地研究新疆红枣果实不同部位总酚含量的最佳提取和测定方法,为进一步开发利用红枣资源提供有效的测试手段。以没食子酸为标准对照品,研究Folin-Ciocalteu比色法测定新疆红枣果肉和果核的中总酚含量的最适宜条件;以总酚含量为指标,通过L_9(3~4)正交试验考察甲醇浓度、料液比、提取时间和提取次数对总酚提取工艺的影响,确定红枣总酚供试品溶液的提取方法。红枣提取液在Folin-Ciocalteu试剂1.5 mL、25%Na_2CO_3溶液2 mL、反应温度30℃、反应时间60 min的条件下,测定其760 nm处的吸光值,没食子酸浓度在0~100μg/mL范围内与吸光度呈良好线性关系(R^2=0.998 8);红枣总酚的最佳提取工艺为50%的甲醇,料液比1∶10(g/mL),提取时间30 min,提取次数2次。加样回收率为98.79%,RSD为1.71%。该提取和测定方法适合于红枣果实总酚含量的测定,利用该方法提取和测定同一产地12个不同品种红枣果核中的总酚含量均明显低于果肉,果肉总酚含量约为果核总酚含量的6倍。

The study was to investigate an optimal Folin-Ciocalteu colorimetric method to determine polyphenols in Dried Jujubes systematically, and to provide an effective way to estimate the polyphenols for the value of Dried Jujubes. Gallic acid was used as a standard substance to determine total polyphenol contents in different parts of Dried Jujubes growing in Xinjiang by Folin-Ciocaheu Colorimetry. With the content of total phenols as index,effects of solvent concentration,solid-liquid ratio extraction time and times on extraction technology of total phenols were investigated by L9（3^4） orthogonal test,in order to define preparation method of the test solution for determination. The results showed that when the concentration of Folin- Ciocalteu reagent was 1.5 mL and the concentration of 25 %Na2CO3 was 2 mL, reaction 60 min in 30 ℃, there was a good linearity relationship between absorption value with the concentration from 0-100 μg/mL in 760 nm（R^2= 0.998 8））. The total phenol in Dried Jujubes in 1 ∶ 10（g/mL） to 50 % methanol for 30 min would with two times be preferably extracted. The average spiked recovery was 98.79 %,with a RSD of 1.71 %.The extraction and determination methods were suitable for the determination of total phenol in Jujubae Fruetus samples.The same total phenol contents differences between the pulp and core is larger, pulp total phenol content is about 6 times of core of the fruit.