Authors
Title
Abstract
The aim of the study was the comparison of antioxidative compounds composition and their activity as well as the accomplishment of aroma constituents of high biologically active popular beverages: ground and soluble coffees and other infusions: green tea, mate, rooibos and fongru. Polyphenols content, their composition and caffeine content by HPLC, antioxidant activity of the infusions towards ABTS•+ cation radicals and volatile compounds composition in the headspace by SPME-GC-MS were determined. It was stated, that considerable differences in antioxidative compounds content and resulting differences in the activity of the infusions obtained are to a large extent an effect of the differences in the infusions preparation way, because they are not such meaningful in case of the scientific material. The antiradical activity was much higher in green tea leaves (250 mg Trolox/g d.w.) and mate (130 mg/g) than in ground coffees (opprox. 50-70 mg/g), whereas coffees definitely predominated taking into consideration the activity of infusions (500-700 mg Trolox/100 ml in coffees, 260 mg/100 ml in tea and 120 mg/100 ml in mate). In the study it was also proved that the coffees investigated are characterised by bigger diversity of volatile aroma compounds, particularly in the relationship to green tea and rooibos (18-19 volatiles towards 2-3 in the infusions of tea and rooibos).
Keywords
coffee, green tea, mate, rooibos, fongru, polyphenols, ABTS•+, aroma