Fig. 1.

Response surface graphs showing effect of extraction variables on antioxidant properties [(A) total flavonoid content (TFC), (B) total phenol content (TPC), (C) 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging activity, and (D) 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity] during aqueous extraction of ginger powder. TEM, temperature; CON, concentration; TIM, time; CE, catechin equivalent; GAE, gallic acid equivalent; TE, Trolox equivalent.