Optimization of ultrasound assisted extraction of cold brewed black tea

Abstract

The tea is a general term used for a beverage that originate from the tea plant, Camellia sinensis. Among different types of teas, black tea is always considered as a rich source of antioxidants, phenolic compounds, essential oils, dietary fiber and other natural bio-actives, which have been shown to exhibit health-promoting effects. Generally, a hot brew is the mechanism of using hot water for brewing the tea leaves. However, application of this technique leads to degradation of flavor and heat sensitive bioactive compounds after being released from the cell membranes. Cold brewing is an alternative method, which can be used to preserve the flavors and other components in the tea. However, application of this method is limited due to the low extraction efficiency and long extraction time. The aim of this project is to evaluate the feasibility of using emerging processing technologies like ultrasonication for improving the extraction of bio-active compounds from black tea and to optimize the processing conditions. This work provides insight on understanding the comparative analysis of OVAT (One variable at a time) vs RSM (Response surface methodology) modeling for cold brewed black tea. This research would make efforts of utilizing alternative process technologies like ultrasound to improve the extraction yield of cold brewed black tea.