Superoxide anion is involved in the formation of free radicals (Apel and Hirt, 2004) while superoxide dismutase as a major antioxidant enzyme in cells plays a protective role against superoxide anion generation (Mittler, 2002). The enzyme can break superoxide anion into molecular oxygen and hydrogen peroxide (Lushchak, 2011). Thus, the antioxidant capability includes SOD activity and radical scavenging activity. Fig. 4 and Fig. 5 present SOD activity and radical scavenging activities in banana fruit during storage. Generally, the SOD activity and scavenging activities of superoxide anion and hydroxyl radicals in peel tissue of the oxalic acid-treated banana fruit at the later storage stage was at a higher level than in the control fruit.