Abstract
Tea (Camellia sinensis, Theaceae) is one of the most widely consumed beverages in the world. The three major types of tea, green tea, oolong tea, and black tea, differ in terms of the manufacture and chemical composition. Catechins, theaflavins, and thearubigins have been identified as the major components in tea. Other minor oligomers have also been found in tea. Different kinds of ring fission and formation elucidate the major transformed pathways of tea catechins to their dimers and polymers. The present review summarizes the data concerning the enzymatic oxidation of catechins, their dimers, and thearubigins in tea.
Highlights
Tea is one of the most widely consumed beverages in the world and is second only to water in popularity
Catechins contained in the tea leaves undergo enzymatic transformation consisting in oxidation and polymerization to yield a complex mixture of secondary polyphenols including theaflavins and thearubigins [9,10,11,12], theasinensins [13,14], theacitrins [15,16,17], and oolongtheanins [18] that contribute to the characteristic color and flavor of black tea
Using ESI/HPLC tandem mass spectrometry in the SII fraction of black tea thearubigins, two novel homologous series of polyhydroxylated theasinensins and theanaphthoquinones were revealed which corresponded to the prolonged experiment treating a mixture of EC and EGC with tea leaf extract
Summary
Tea is one of the most widely consumed beverages in the world and is second only to water in popularity. More than 300 different kinds of tea are produced by different manufacturing processes They are divided generally into three types: green tea (non-fermented), oolong tea (semi-fermented), and black tea (fermented). The main pigments in black tea are theaflavins and thearubigins, which are formed by the oxidation and polymerization of catechins during fermentation in the manufacturing process of tea. We will discuss the current knowledge on the chemistry of catechins, their oxidation production derivates, and the major transformation pathways of them in tea. Known as catechins, usually account for 30–42% of the dry weight of the solids in brewed green tea [1,2].
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