Optimization of the microwave-assisted extraction conditions of tea polyphenols from green tea

Abstract

Green tea, a popular drink with beneficial health properties, is a rich source of polyphenols that have a wealth of physiological activities. The purpose of the present study was to develop a microwave-assisted extraction (MAE) of green tea polyphenols. MAE of tea phenols from green tea was investigated through orthogonal array design. The content of total phenols in tea infusions was determined using UV/vis spectrophotometric methods. Four factors (microwave intensity, microwave irradiate time, microwave irradiate number of times and tea/water ratio) have a substantial impact on the extraction. The extraction conditions of tea polyphenols are optimized, and the order of importance that influenced the extraction rate was found to be: microwave radiate time>microwave intensity>tea/water ratio>radiate number of times, and the optimal performance of extraction was obtained under microwave intensity 600 W, microwave radiate time 3 min and microwave radiate number of times once with tea/water ratio 1:20.MAE offers important advantages over conventional methods, such as shorter extraction times, substantial savings of energy and a reduced environmental burden.

Keywords::

• Tea polyphenols
• microwave-assisted extraction
• orthogonal array design
• extraction

Declaration of interest: The present project was supported by National Key Technology R&D Program 2006BAD27B04. The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.