The effect of storage time on tea Polyphenols, catechin compounds, total flavones and the biological activity of Ya’an Tibetan tea ( Camellia sinensis )

Abstract

Tea (Camellia sinensis) is highly consumed and enjoyed, by virtue of its taste, aroma, health benefits, and cultural value. In China, there are six types of tea, such as green tea, yellow tea, white tea, Oolong tea, black tea and dark tea (Ke et al., 2019). Consumption of Chinese dark tea began during the Ming Dynasty. It originated from Sichuan province of China and was distributed to Tibet and Xinjiang. As the most popular drink consumed in Tibet, dark tea not only has a unique aroma but also has many bioactivities, including antioxidation capac-

A Rising Star in Dark Teas: The Processing, Microorganisms, Chemicals, Bioactivities, and Safety of Qingzhuan Tea

“…As shown in Figure 2D, the processing technology of QZT can be summarized as first processing of raw tea, pile-fermentation, second processing and blending, steam pressing, drying and aging. 22 2.1. First Processing of Raw Tea.…”

“…The composition, content and degradation products of amino acids are the main sources which will directly affect the aroma and umami of QZT. At present, the amino acids isolated and identified from QZT mainly include isoleucine (16), glutamate (17), aspartic acid (18), theanine (19), arginine (20), proline (21), phenylalanine (22), leucyl-proline (23), valine (24), leucine (25), tryptophan (26), 3-O-methyl-L-Dopa (27), γ-aminobutyric acid (28), tyrosine (29), pantothenic acid (30), and so on (Figure 4). 20,44 Thereinto, L-theanine, aspartic acid, and glutamate are the main sources of umami after tea brewing, 45 and their contents decrease significantly after the first turning, which may be the reason for the decrease of fresh taste of QZT.…”

“…Traditionally, with the mature leaves and leaves of high camellia trees at an altitude of 600–1200 m as raw materials, QZT is made by high temperature autoclaves. As shown in Figure D, the processing technology of QZT can be summarized as first processing of raw tea, pile-fermentation, second processing and blending, steam pressing, drying and aging …”

Green extraction, chemical composition, and in vitro antioxidant activity of theabrownins from Kangzhuan dark tea

“…et al, 2022 ). Among above tea, KZDT is also known as “Ya'an Tibetan tea” from China's Sichuan Province ( Zheng et al, 2020 ; Zheng et al, 2021 ; Liu Y.T. et al, 2022 ).…”

Distinguishing Different Varieties of Oolong Tea by Fluorescence Hyperspectral Technology Combined with Chemometrics

“…Tea is one of the most popular nonalcoholic beverages in the world and is widely loved by people [ 1 ]. Oolong tea belongs to semi-fermented tea, which is one of the most popular beverages in China [ 2 ]. According to a report on China’s tea consumption market in 2021, the output of five of six traditional Chinese tea categories, except yellow tea, increased by varying degrees.…”