Antioxidants and antioxidant capacity of food have become important especially in connection with civilization illnesses [7]. Many authors therefore focus on the determination of antioxidant capacity [8–11].
The PCL method was first described by Popov and Lewin [12]. Benzie et al. [8] and Langley-Evans [13], and Robinson et al. [14] studied the antioxidant capacity of dark and green tea according to the flavonoids content. Vertuani et al. [6] obtained values ranging from 4.27 to 30.2 mmol/L (ascorbic acid equivalent) in the studied tea extracts. The lowest value was measured in Oolong, Chinese brown tea, and the highest in Bancha, Japanese green tea.
Manufacturers of our analyzed samples stated that samples must be refrigerated and consumed within 3 days. Therefore we conducted the measurement immediately after opening of original packages and consequently on the fourth and for the control seventh day of the experiment. Results of the antioxidant capacity are expressed in the ascorbic acid equivalents (mmol/L) and stated in Table 1. Decrease in the antioxidant capacity is expressed in percentage and shown in Figures 1 and 2.