Optimization of microwave-assisted extraction of bioactive compounds from a tea blend

Abstract

Although tea is the second most consumed beverage in the world, its benefits is not fully achieved because its bioactive compounds are not efficiently extracted from the plant. In this work the extraction of bioactive compounds from a tea blend, composed of 40% green tea, 40% white tea, 10% mint and 10% peppermint, was investigated using a microwave-assisted technique. The effects of ethanol concentration, extraction time, and liquid/solid ratio on the total phenolic content, total flavonoid content and antioxidant potential were quantified. An optimization study was also performed to identify the conditions that enable the maximum extraction of phenolic and flavonoids contents, with a maximum antioxidant capacity. The predicted optimal conditions included a 38.8% ethanol concentration, 3 min of extraction, and a 184.1 mL/g liquid/solid ratio. HPLC analyses were also performed to identify the major antioxidant compounds and the results confirmed the high antioxidant potential of the studied tea blend.