固相络合反应法提取茶叶中茶多酚

Extraction of polyphenols from tea leaves by solid phase complexation reaction

提出以CaCO3作为络合剂,采用固相络合反应法提取茶叶中茶多酚的新工艺。在固相状态中通过机械力的作用使络合剂与茶叶中多酚物质进行络合反应,并用水作为溶剂在常温下洗去反应后的可溶性部分,获得混合沉淀,利用酸液对混合沉淀转溶,最终将转溶液进行萃取提取茶多酚。通过XRD衍射图定性判定了固相络合反应的发生,探究了固相络合剂用量与反应后颗粒粒径对茶多酚提取率的交互影响,得出最佳工艺条件为络合剂CaCO3质量分数为25%,固相物料粒度D95为50~55μm,浸取过程中水与固相物料的质量比120:1,浸取时间20min,茶多酚综合提取率可达15.4~15.8%,茶多酚纯度为96.8~97.1%,产物红外光谱图证实了茶多酚结构。固相络合反应法实现了常温下提取茶多酚工艺,有效避免了茶多酚因热而氧化,是一种绿色提取工艺。

A new technique of extracting polyphenols from tea leaves by solid phase complexation reaction and using CaCO3 as a complexing agent was established. In solid state, the complexing agent reacted with the polyphenols in tea leaves by mechanical force, and water was used as a solvent to wash out the soluble part after the reaction at room temperature to obtain mixed precipitation. The mixed precipitation was transdissolved by acid solution, and then the transsolution was extracted to obtain tea polyphenols. The XRD diffraction pattern qualitatively determined the reaction of solid phase complexation reaction, and the interaction effect between the amount of solid phase complexant and the particle size after the reaction on the extraction rate of tea polyphenols was studied. The optimum technological conditions were obtained as follows : the mass fraction of CaCO3 was 25%, the particle size of solid phase was D95 50 ~ 55μm, and the mass ratio of water to solid phase was 120 : 1. The extraction time of tea polyphenols was 20 minutes, comprehensive extraction rate of tea polyphenols was 15.4 ~ 15.8% and the purity of tea polyphenols was 96.8%~ 97.1%. The structure of tea polyphenols was confirmed by IR spectrum. The solid phase complexation reaction method realizes the extraction of tea polyphenols at room temperature, and effectively avoids the oxidation of tea polyphenols due to heat transfer. It is a green extraction process.