The Research Progress of Main Chemical Constituents and Functional Activity in Purple Tea

Purple tea is made from the traditional processing of green tea, black tea and dark tea, which will maintain the purple characteristic of the tea soup during the processing. It has been widely concerned and studied due to its high anthocyanin content, unique color and biological activities such as scavenging free radicals, anti-oxidation, anti-cancer, anti-inflammatory, anti-bacterial, protecting eyesight and relieving visual fatigue. In addition, purple tea also contains active ingredients such as tea polysaccharides and tea polyphenols. At present, although purple tea is widely used in skin care, food, medicine and other fields, the research on purple tea is still in the exploratory stage, and its unique economic value has not been fully utilized. In order to improve processing technology, develop high-quality products to meet market demand, and improve the stability of anthocyanins in tea extracts, this paper is about of the varieties of purple tea, the effects of different processing methods on the quality, the analysis of color change mechanism of purple tea leaf, the chemical composition and its physiologically active substances, metabolic pathways and gene expression. And the key research directions and new product development of purple tea are prospected, which provides a further reference for related research on purple tea.