茶绿色素的提取及体外清除自由基活性研究

目的研究几种不同提取方法提取的茶绿色素的得率、化学组成、色相及体外清除自由基活性。方法分别用95%乙醇经常温浸泡、热水提取、超声波提取及微波提取茶绿色素,采用常规方法分析该色素化学组成及色相,试剂盒检查其清除自由基活性。结果与其他几种提取方法相比,微波提取茶绿色素的得率、色素中叶绿素含量均最高,分别为37.02%、8.92%;该色素所含茶多酚、总黄酮、氨基酸含量也相对较高;微波提取色素的绿度最高,为-27.63,亮度(40.21)仅略低于常温提取色素的亮度(40.29);该色素清除羟自由基(·OH)、超氧阴离子自由基(O_2~-·)的活性也较高,分别仅略低于热水提取色素的清除活性,但没有显著性差异。结论微波提取茶绿色素不仅得率高、色相好,且该色素清除自由基活性高,是茶绿色素提取的最佳方法。

Study on the extraction and in vitro free radical scavenging activity of tea green pigment

Objective To evaluate the yield, chemical components, color appearance and in vitro free radical scavenging activity of tea green pigment extracted with different methods. Methods Tea green pigment was extracted with 95% ethanol through the methods of room-temperature immersion, hot water extraction, ultrasonic extraction and microwave extraction, respectively. Its chemical components and color appear-ance were studied with conventional methods, and the free radical scavenging activity was measured with commercially assay kits. Results Compared to other extraction methods, the yield of the pigment extracted with microwave and the chlorophyll content in the pigment were the highest, 37.02% and 8.92%, respectively. The content of tea polyphenols, total flavonoids and amino acids in the pigment was also relatively high. The greenness of the pigment was the highest, -27.63, and the brightness (40.21) was only lower than that of tea green pigment extracted with room-temperature immersion (40.29). The scavenging activities against hydroxylradical and superoxide anion radical were high, and slightly lower than that of tea green pigment extracted with room-temperature immersion. Conclusion The yield and color appearance of the tea green pigment extracted with microwave is excellent, and the free radical scavenging activity is high. The microwave extraction method is the best method for the extraction of tea green pigment.