微波辅助水提绿茶多酚。

Microwave-assisted water extraction of green tea polyphenols.

机构信息

Université Cadi Ayyad, Faculté des Sciences Semlalia, Marrakech, Morocco.

出版信息

Phytochem Anal. 2009 Sep-Oct;20(5):408-15. doi: 10.1002/pca.1141.

DOI:10.1002/pca.1141

PMID:19609884

Abstract

INTRODUCTION

Green tea, a popular drink with beneficial health properties, is a rich source of specific flavanols (polyphenols). There is a special interest in the water extraction of green tea polyphenols since the composition of the corresponding extracts is expected to reflect the one of green tea infusions consumed worldwide.

OBJECTIVE

To develop a microwave-assisted water extraction (MWE) of green tea polyphenols.

METHODOLOGY

MWE of green tea polyphenols has been investigated as an alternative to water extraction under conventional heating (CWE). The experimental conditions were selected after consideration of both temperature and extraction time. The efficiency and selectivity of the process were determined in terms of extraction time, total phenolic content, chemical composition (HPLC-MS analysis) and antioxidant activity of the extracts.

RESULTS

By MWE (80 degrees C, 30 min), the flavanol content of the extract reached 97.46 (+/- 0.08) mg of catechin equivalent/g of green tea extract, vs. only 83.06 (+/- 0.08) by CWE (80 degrees C, 45 min). In particular, the concentration of the most bioactive flavanol EGCG was 77.14 (+/- 0.26) mg of catechin equivalent/g of green tea extract obtained by MWE, vs 64.18 (+/- 0.26) mg/g by CWE.

CONCLUSION

MWE appears more efficient than CWE at both 80 and 100 degrees C, particularly for the extraction of flavanols and hydroxycinnamic acids. Although MWE at 100 degrees C typically affords higher yields in total phenols, MWE at 80 degrees C appears more convenient for the extraction of the green tea-specific and chemically sensitive flavanols.

摘要

简介

绿茶是一种具有有益健康特性的流行饮品，是特定黄烷醇（多酚）的丰富来源。由于预期相应提取物的组成将反映全球消费的绿茶浸出物的组成，因此对绿茶多酚的水提取特别感兴趣。

目的

开发一种绿茶多酚的微波辅助水提取（MWE）方法。

方法

研究了 MWE 作为常规加热（CWE）下水提取的替代方法。在考虑温度和提取时间后选择了实验条件。根据提取时间、总酚含量、化学组成（HPLC-MS 分析）和提取物的抗氧化活性来确定该过程的效率和选择性。

结果

通过 MWE（80°C，30 分钟），提取物中的黄烷醇含量达到 97.46（+/-0.08）mg 表儿茶素当量/g 绿茶提取物，而 CWE（80°C，45 分钟）仅为 83.06（+/-0.08）mg。特别是，最具生物活性的黄烷醇 EGCG 的浓度通过 MWE 获得为 77.14（+/-0.26）mg 表儿茶素当量/g 绿茶提取物，而通过 CWE 获得为 64.18（+/-0.26）mg/g。