Tea is the first most popular beverage worldwide. Tea (<i>Camellia sinensis</i>) is available in several selections such as black (fully oxidized), Oolong (partially oxidized) and green (non-oxidized) in addition to purple tea, an emerging variety derived from the same tea plant. Purple tea could have great potential as a value-added ingredient for food and non-food industries. In the current study, three lots, each of purple tea leaves and flakes, were characterized based on their composition of anthocyanins and catechins and compared with two lots of green tea leaves and flakes. Purple or green tea leaves are unfermented dried products, while tea flakes are water extractable dried products. Anthocyanin and catechin compounds were separated and quantified using UPLC and their identity was confirmed using LC-MS/MS in positive and negative ionization modes. Tea flakes were rich in minerals and protein at levels of 8.6-9.2% and 20.2-17.5%, respectively. Anthocanin pigments were present in purple tea leaves at higher concentrations compared to their corresponding flakes. The water extraction process resulted in substantial reductions in anthocyanins in purple tea flakes. Delphinidin was the principal anthocyaninidin (aglycone) in purple tea, while cyanidin came second. The major anthocyanin pigments in purple tea were delphinidin-coumaroyl-hexoside followed by delphinidin-3-galactoside and cyanidin-coumaroyl-hexoside. There were no anthocyanin compounds detected in green tea samples. Both purple and green tea types were rich in catechins with green tea contained higher concentrations than purple tea. The main catechin in purple or green tea was epigallocatenin gallate (EGCG) followed by either epicatechin gallate (ECG) or epigallocatechin (EGC) subject to tea type. Interestingly, the extraction process increased the concentration of catechin compounds in both purple and green tea flakes. The results suggest that purple tea holds a promise to make healthy brews, natural colorants and antioxidants and/or functional ingredients for the beverage, cosmetics and healthcare industries due to its high contents of anthocyanins and catechins.

Identification and quantification of anthocyanin and catechin compounds in purple tea leaves and minimally processed flakes

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