ABSTRACT
Tea is dened as the hot aqueous infusion of the dried leaves of the plant Camellia sinensis. It is one of the most popular beverages worldwide, and its consumption is second only to water.1 The earliest records of tea date back to 5,000 years ago in China, and since then it has been utilized both as a beverage and as a medicine.2 Recently, the health-enhancing properties of tea have received much attention. Epidemiological and animal studies suggest that tea is protective against certain cancers, cardiovascular diseases, and neurodegenerative diseases.3-5 Therefore, tea extracts have gained popularity as ingredients in dietary supplements and functional foods. Depending on the degree of fermentation prior to further heating and processing, teas are categorized into three major varieties: green tea, oolong tea, and black tea. The unfermented green tea and semifermented oolong tea are popular mainly in China, Japan, and India.6 However, in the rest of the world the fully fermented black tea is the regular choice, such as in the UK, Canada, and the U.S.1
