蓝莓叶中可萃取多酚和不可萃取多酚提取的研究

Analysis on extractable and non-extractable polyphenols in blueberry leaves

【目的】探讨萃取溶剂种类、体积比及溶剂pH对蓝莓叶中可萃取多酚和不可萃取多酚含量的影响,为工业化提取蓝莓叶中的多酚奠定基础。【方法】以蓝莓叶为材料,采用两步萃取法提取可萃取多酚,采用甲醇—硫酸加热水解法分离不可萃取多酚,并用Folin-Ciocalteu法测定可萃取多酚和不可萃取多酚含量。【结果】无论是以甲醇还是乙醇为萃取溶剂,蓝莓叶中总可萃取多酚含量(TEPP)均以萃取剂/H2O的体积比为50∶50、pH2的处理最高;不可萃取多酚含量(NEPP)变化趋势与总可萃取多酚相反,以萃取剂/H2O的体积比为50∶50、pH2处理的含量最低。各处理的总多酚含量相差不大,均在82.00mg/g以上。提取因素显著性分析结果显示,第一步萃取获得的可萃取多酚含量(EPP1)主要受pH影响;各单因素和复合因素均能显著影响可萃取多酚的第二步萃取,但对蓝莓叶中总多酚的提取无显著影响;复合因素对不可萃取多酚的提取亦无显著影响。【结论】萃取溶剂pH值对蓝莓叶中多酚的提取率具有明显的影响作用;蓝莓叶中可萃取多酚和不可萃取多酚的含量基本相同,其总多酚的平均含量为85.49mg/g。

[Objective]The present experiment was conducted to study the effects of solvent type,volume and pH on the content of extractable polyphenols and non-extractable polyphenols in blueberry leaves to provide basis for commercial extraction of polyphenols from blueberry leaves.[Method]The leaf of blueberry was used to extract the extractable polyphenol using two-step extraction method.The non-extractable polyphenols in leaves of blueberry were isolated by sulfuric acid hydrolysis,and both polyphenol contents were determined by Folin-Ciocalteu colorimetric method.[Results]The results showed that the content of total extractable polyphenol（TEPP）was the highest under condition of 50∶50 extractant to H2O ratio and pH 2 irrespective of the extractant used（carbinol or ethanol）,while the non-extractable polyphenol（NEPP）,on the contrary,showed lowest content.Therefore,low pH value and 50∶50 extractant to H2O ratio and pH 2 were beneficial for extraction of TEPP,and not for NEPP.The content of total polyphenols in different treatments differed little and was over 82.00 mg/g.The analysis showed that the content of extractable polyphenol on the 1s t step was mainly affected by pH value,while that content on 2 n d step was affected significantly by single factor and complex factors,and these factors had no significant effects on the extraction of total polyphenol.The complex factors also have no significant effects on non-extractable polyphenol.[Conclusion]The pH value of extractant has significant effect on extraction of polyphenols,and the content of extractable polyphenol was similar to that of non-extractable polyphenols in the leaf of blueberry.The average total polyphenol content was recorded as 85.49 mg/g.