Authenticity evaluation of tea-based products
2008
Cizkova, H.,Vysoka Skola Chemicko-technologicka, Prague (Czech Republic). Ustav Konzervace Potravin a Technologie Masa | Voldrich, M.,Vysoka Skola Chemicko-technologicka, Prague (Czech Republic). Ustav Konzervace Potravin a Technologie Masa | Mlejnecka, J.,Vysoka Skola Chemicko-technologicka, Prague (Czech Republic). Ustav Konzervace Potravin a Technologie Masa | Kvasnicka, F.,Vysoka Skola Chemicko-technologicka, Prague (Czech Republic). Ustav Konzervace Potravin a Technologie Masa
Concentrations of selected markers (theobromine, caffeine, theanine, and total polyphenols) in tea-based products (iced teas, instant teas) were determined. Then the dry tea content in these products, expressed as the equivalent amount of dry tea leaves, was calculated on the basis of two sets of mean data for these analytes as follows: average literature data and the mean experimental data obtained with our samples of leaf tea. With regards to the latter, we propose to use the following averages for caffeine, theobromine, theanine, and polyphenols: for 100 g of black tea-based products: 1.9 g, 0.13 g, 1.3 g, and 9.1 g, respectively; for 100 g of green tea-based products: 1.9 g, 0.16, 1.7 g, and 14.7 g, respectively. Using this method, we found that approximately one third of the analysed samples failed to meet the tea extract levels required by German and Austrian legislations, while about 10% did not comply with the less demanding Czech legislative requirements.
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