Table 3 EC₅₀ values of ethanolic black ginger extracts

Steaming and drying step	DPPH scavenging activity, EC50 a (μg/ml)
0	25.083 ± 0.511
1	25.511 ± 0.266
2	25.726 ± 0.303
3	25.146 ± 0.200
4	25.285 ± 0.109
5	25.461 ± 0.343
6	25.776 ± 0.502
7	26.003 ± 0.228
8	26.406 ± 0.871
9	26.381 ± 0.087
Troloxb	45.186 ± 0.196

Values obtained from regression lines with a 95% confidence level. EC₅₀ is defined as the concentration sufficient to obtain 50% of a maximum effect estimate in 100%.
Trolox was used as a standard.