Comparison of the Antioxidant Properties of Commonly Consumed Commercial Teas

Figures & data

Table 1 Composition of studied teas

Commercial name	Composition according to the producer	Tea mass in bag, g
B1, Tropical fruits	Black tea, flavor of tropical fruits (11.7*), pineapple (2.3), grapefruit peel (2.3), sugar syrup	1.81
B2, Gold tea	Black tea from Ceylon (91.8), natural aroma (7), marigold petals (1.1)	1.78
B3, Earl Grey	Black tea (89.3), aroma (10.2), cornflower petals (0.3), jasmine petals (0.2)	1.84
B4, Puerh pineapple	Tea from Yunnan province (73), pineapple (2.8)	1.47
B5, Yellow label	Premium black tea	1.99
F1, Char Ming	Fruit tea with hibiscus (57.6), rosehip (24.7 ), aroma (14.4), blackberry (0.5), blackcurrant (0.5), raspberry (0.3), blueberry (0.3)	2.02
F2, Caribbean	Rosehip, aroma (19.7), orange leaves, citrus grass, orange peel, licorice, hibiscus (1.6), papaya (1.3)	1.77
G1, Green tea Indonesia	Green tea (98.8), natural aroma (1.2)	1.72
G2, White tea	Green tea with small addition of white tea, aroma (0.7)	1.61
*g/100 g tea.

Table 2 The antioxidant capacities of tea infusions prepared from different kinds of tea measured by Folin and CUPRAC assays

	Folin-Ciocalteu assay
Tea	mg GA/g	mM TR/g	CUPRAC assay mM TR/g
B1	278.6 ± 13.5	9.2 ± 0.5	13.1 ± 0.7
B2	329.9 ± 16.5	10.9 ± 0.4	11.4 ± 0.6
B3	381.7 ± 19.1	12.6 ± 0.6	11.7 ± 0.6
B4	345.5 ± 17.2	11.4 ± 0.6	10.1 ± 0.5
B5	419.6 ± 21.0	13.9 ± 0.7	12.6 ± 0.6
F1	138.3 ± 6.9	4.5 ± 0.2	6.0 ± 0.3
F2	122.9 ± 6.0	4.0 ± 0.2	5.0 ± 0.3
G1	513.4 ± 25.7	17.1 ± 0.9	27.1 ± 1.4
G2	448.7 ± 22.4	14.9 ± 0.8	16.9 ± 0.8

Figure 1 The correlation between the results of Folin-Ciocalteu method and CUPRAC assay for studied tea infusions.

Figure 2 Cyclic voltammograms of some flavonoids recorded in 0.1 M LiClO₄ solution at glassy carbon electrode, scan rate 100 mV/s (the background response due to the buffer solution has been subtracted from each curve).

Table 3 Reducing activity of tea infusions provided by cyclic voltammetry method

Tea	Total charge under anodic valve, μC	Reducing activity, mM TR/g
B1	39.0 ± 2.0	3.93 ± 0.19
B2	27.5 ± 1.4	2.81 ± 0.19
B3	42.3 ± 2.1	4.20 ± 0.21
B4	7.6 ± 0.4	0.94 ± 0.05
B5	24.9 ± 1.3	2.28 ± 0.12
F1	6.5 ± 0.3	0.56 ± 0.05
F2	4.1 ± 0.2	0.42 ± 0.03
G1	116.9 ± 5.9	12.4 ± 0.61
G2	73.1 ± 3.7	8.27 ± 0.46

Figure 3 Examples of cyclic voltammograms of tea infusions recorded in 0.1 M LiClO₄ solution at glassy carbon electrode, scan rate 100 mV/s (the background response due to the buffer solution has been subtracted from each curve).