Cream formation in a semifermented tea

The formation of cream in Paochung tea, a popular semifermented tea, which undergoes a lesser degree of enzymic oxidation during manufacture, was inve stigated at various extraction temperatures, extraction times, pHs and leaf /water ratios. The primary components of Paochung tea cream were catechins (30%), caffeine (20%) and protein (16%). (-)-Epigallocatechin gallate and ( -)-epicatechin gallate were the major catechins precipitated during creamin g, constituting 19% and 5% of the tea cream respectively. The amount of tea cream produced and its composition were influenced by extraction temperatu re and pH. The tea leaf/water ratio determined the amount of tea cream form ed but did not affect the cream composition. Catechins were considered to b e the key component in tea cream. They interacted with caffeine and protein to induce tea cream formation. (C) 1999 Society of Chemical Industry.