Antioxidant activity of tokaj essence

Anotace: The aim of the presented experiment was to measure the content of total polyphenols and antioxidant potential of Tokaj essence from the years 1999, 2006, 2007, 2009, 2013, 2015. Tokaj essence is produced by fermentation of concentrated must from botrytised grape berries. The highest content of polyphenols was determined in the essence of 1999 (275.8 ±18.17 mg.L-1) and the lowest in the sample of 2015 (118.8 ±12.28 mg.L-1). Antioxidant activity was determined by two methods DPPH and PRAC (permanganate reducing antioxidant capacity). Antioxidant DPPH method showed that the essence of year 1999 had significantly the highest activity (63.4 ±0.81 µmol.L-1 Trolox) while essence of year 2015 (47.5 ±1.58 µmol.L-1 Trolox) featured the lowest activity. The results of method PRAC, which determine the total reducing capacity of the essence, do not correlate with the results of DPPH and total phenolic content, because of higher content of saccharides, which gave false positive test results. The method PRAC is not suitable for measuring antioxidant activity of tokaj esence. The results showed that aging of wine increased the content of polyphenols and also its antioxidant activity. High content of polyphenols and the great antioxidant activity of Tokaj wine receive their beneficial effect to human health.