Flavonoids and Other Polyphenols in Consumer Brews of Tea and Other Caffeinated Beverages
| Autor: | Svenja Lapczynski, Ulrich H. Engelhardt, Beate Maiwald, Christiane Lakenbrink |
|---|---|
| Rok vydání: | 2000 |
| Předmět: |
Flavonoids
chemistry.chemical_classification Magnetic Resonance Spectroscopy Tea Polymers Chemistry business.industry Extraction (chemistry) Flavonoid Commerce General Chemistry Flavones Beverages chemistry.chemical_compound Flavonols Phenols Polyphenol Caffeine Brewing Composition (visual arts) Food science General Agricultural and Biological Sciences business |
| Zdroj: | Journal of Agricultural and Food Chemistry. 48:2848-2852 |
| ISSN: | 1520-5118 0021-8561 |
| DOI: | 10.1021/jf9908042 |
| Popis: | The polyphenolic, flavonoid, and caffeine compositions of four commercial tea bag products (typical of those used in the UK, US, continental Europe, and the Middle East) and beverages prepared from them under a range of typical consumer use conditions have been studied. Leaf composition was determined by extraction with aqueous methanol: the absolute compositions of all four products were remarkably similar in terms of most phenolic compounds. The flavonoids comprised the major proportion (93-94%) of the total phenolics estimated by the Folin-Ciocalteu method. At brew times up to 2 min the composition of the brew solids was for each product practically independent of brew time, with flavonoids again comprising the major proportion (86-88%) of the total phenolics. The efficiency of extraction in brewing of total phenolics, total flavonoids, catechins, and theaflavins was up to 35-55% of the total available in the leaf, whereas the flavonol and flavone glycosides and caffeine were more efficiently extracted (up to 55-90%). The contribution of tea to the UK adult average total dietary intake of flavonols and flavones was calculated to be up to 80% depending on brewing conditions. |
| Databáze: | OpenAIRE |
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