Abstract: Flavanol compounds are the most abundant phenolic subclass of plant phytochemicals known as flavonoids,which are commonly found in the stems,leaves and fruits of plants.Both epidemiological and biological evidences suggest a health protective role for dietary flavanols,leading to increasing interest in the composition and bioavailability of these compounds from foods.The purpose of this paper is to provide an overview of variation in flavanol composition from tea,which are common types of tea products (green tea,oolong tea,black tea etc).Key researches describing the effect of processing on flavanol composition were summarized,including its chemical change,stability,enzymatic oxidation and bioactivity.In addition,some suggestions for the future study of flavanols were put forward in order to provide reference for the development and application of flavanols.

Key words: flavanols, processing stability, enzymatic oxidation, theaflavins, thearubigins