Identification and Quantification of Anthocyanin and Catechin Compounds in Purple Tea Leaves and Flakes

Abstract

Tea is the first most popular beverage worldwide and 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 (Camellia sinensis). This study investigated purple tea leaves (non-oxidized) and flakes (water extractable) to thoroughly identify their composition of anthocyanins and catechins and to study the effect of a water extraction process on their compositional properties in comparison with green tea. 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. Delphinidin was the principal anthocyaninidin in purple tea, while cyanidin came in second. The major anthocyanin pigments in purple tea were delphinidin-coumaroyl-hexoside followed by delphinidin-3-galactoside and cyanidin-coumaroyl-hexoside. The water extraction process resulted in substantial reductions in anthocyanins in purple tea flakes. There were no anthocyanin compounds detected in green tea samples. Both purple and green tea types were rich in catechins, with green tea containing higher concentrations than purple tea. The main catechin in purple or green tea was epigallocatechin gallate (EGCG) followed by either epicatechin gallate (ECG) or epigallocatechin (EGC), subject to tea type. The extraction process increased the concentration of catechins in both purple and green tea flakes. The results suggest that purple tea holds promise in making healthy brews, natural colorants and antioxidants and/or functional ingredients for beverages, cosmetics and healthcare industries due to its high content of anthocyanins and catechins.

The Effect of Brewing Time on the Antioxidant Activity of Tea Infusions

“…The degradation of these anthocyanins produces gallic acid and protocatechuic acid, which is accompanied by colour change. Abdel-Aal et al [39] indicates that some anthocyanin compounds are also lost and/or oxidised in processes associated with tea manufacturing.…”

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“…Purple tea shows presence of 8 anthocyanin fractions which are pelargonidin-3,5-diglucoside, cyanidin-3-O-galactoside, cyanidin-3-O-glucoside, delphinidin, cyanidin, pelargonidin, peonidin, and malvidin, among which malvidin is the most predominantly detected anthocyanin for some plants cyanidin-3-O-galactoside for other plants. This difference is observed mainly due to difference in the genotype and the environment of plant growth 22 . Polyphenols found in purple tea consist of catechins such as epigallocatechin (EGC), catechin, epicatechin (EC), epigallocatechin gallate (EGCG) and epicatechin gallate (ECG).…”

“…Polyphenols found in purple tea consist of catechins such as epigallocatechin (EGC), catechin, epicatechin (EC), epigallocatechin gallate (EGCG) and epicatechin gallate (ECG). These catechins are responsible for the antioxidant property of tea 22 . Catechin synthesis is done using malonic acid-and shikimic acid metabolic pathways 23 .…”

Extraction and Purification of Catechins from Tea Leaves: An Overview of Methods, Advantages, and Disadvantages

“…Supercritical CO 2 possesses both gas-like and liquid-like properties, effectively penetrating tea leaves and dissolving catechins. SFE offers advantages such as higher selectivity, reduced solvent usage, and minimal environmental impact compared to traditional organic solvents [15].…”