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[10] [11] Tea has one of the highest contents of flavonoids among common food and beverage products. [7] Catechins are the largest type of flavonoids in growing tea leaves. [6] According to a report released by USDA, in a 200-ml cup of tea, the mean total content of flavonoids is 266.68 mg for green tea, and 233.12 mg for black tea. [7]
Tea tree oil, also known as melaleuca oil, is an essential oil with a fresh, camphoraceous odour and a colour that ranges from pale yellow to nearly colourless and clear. [ 1 ] [ 2 ] It is derived from the leaves of the tea tree, Melaleuca alternifolia , native to southeast Queensland and the northeast coast of New South Wales , Australia.
Particularly abundant flavanoids in foods are catechin (tea, fruits), hesperetin (citrus fruits), cyanidin (red fruits and berries), daidzein , proanthocyanidins (apple, grape, cocoa), and quercetin (onion, tea, apples). [2] Phenolic acids include caffeic acid; Lignans are polyphenols derived from phenylalanine found in flax seed and other cereals.
It is found in high content in the dried leaves of green tea (7380 mg per 100 g), white tea (4245 mg per 100 g), and in smaller quantities, black tea (936 mg per 100 g). [2] During black tea production, the catechins are mostly converted to theaflavins and thearubigins via polyphenol oxidases .
The phenolic unit can be found dimerized or further polymerized, creating a new class of polyphenol. For example, ellagic acid is a dimer of gallic acid and forms the class of ellagitannins, or a catechin and a gallocatechin can combine to form the red compound theaflavin, a process that also results in the large class of brown thearubigins in tea.
Other more detailed chemical research has elucidated the difficulty of isolating individual phenolics. Because significant variation in phenolic content occurs among various brands of tea, there are possible [9] inconsistencies among epidemiological studies implying beneficial health effects of phenolic antioxidants of green tea blends.
Wild Camellia oleifera contains ~47% oil, whilst cultivated varieties have shown oil content from 42 to 53%. [3] Oil analysis of cultivated varieties showed : ~76-82% oleic acid; 5-11% linoleic acid; 7.5-10% palmitic acid; 1.5-3% stearic acid - the ratios are similar to that found in wild oleifera. [3] The composition is similar to that of ...
Theaflavin (TF) and its derivatives, known collectively as theaflavins, are antioxidant polyphenols that are formed from the condensation of flavan-3-ols in tea leaves during the enzymatic oxidation (sometimes erroneously referred to as fermentation) of black tea.