Lee et al [9] reported that the antioxidant activities of heated onion juices showed high DPPH radical scavenging activities of 36% at 120°C, 45% at 130°C, and 58% at 140°C. Heated onion has been found to have higher DPPH radical scavenging activities than raw onion, and that activity increases with increasing temperature. Kim et al [23] also reported that the antioxidant activity of heated ginseng extract increased with increasing temperature.

Furthermore, Woo et al [24] reported that the antioxidant activity of heated Rehmannia radix Libosch increased significantly with increasing heating temperature (from 110°C to 150°C) and heating time (from 1 hour to 5 hours). Moreover, Hwang et al [7], Kown et al selleck products [10], and Kim et al [11] reported that DPPH radical scavenging activity increased significantly with thermal processes. The ABTS cation radical scavenging activities of heated HGR and HGL under various heating conditions, expressed in terms of the AEAC (mg AA eq/g), are shown in Fig. 4. The ABTS radical scavenging activity was affected by the heating temperature in a manner similar to the DPPH radical scavenging activity. The antioxidant activities of both HGR and HGL at 150°C were higher than those of raw material. The ABTS radical scavenging activities of HGR and HGL raw materials were 0.037 mg AA eq/g and 0.162 mg AA eq/g, respectively. After heating, the AEAC values at 90°C, 110°C, 130°C, and 150°C were expressed

as 0.36 mg AA eq/g, 0.53 mg AA eq/g, 1.88 mg AA eq/g, and 4.25 mg AA eq/g for HGR, and 0.57 mg AA eq/g, 0.79 mg AA eq/g, 1.37 mg AA eq/g, and 2.86 mg AA eq/g for HGL, respectively. Our results show that by Trichostatin A nmr Ribose-5-phosphate isomerase increasing processing temperature the overall antioxidant activities of both HGR and HGL enhanced significantly. Kim et al [23] reported that the ABTS radical content (% of control) of heated ginseng extract increased with increasing heating temperature. Woo et al [25] reported that the ABTS radical scavenging activities of heated garlics and its aroma extracts increased with increasing heating temperature and time. Kim

et al [11] reported that the antioxidant activities of tomato, melon, and watermelon were 0.61 mg AA eq/100 g, 0.51 mg AA eq/100 g, and 0.64 mg AA eq/100 g in raw materials, which increased, respectively, to 4.59 mg AA eq/100 g, 13.13 mg AA eq/100 g, and 8.81 mg AA eq/100 g after heating at 140°C. As shown in Fig. 5, the reducing powers of heated HGR and HGL illustrate similar patterns of change in total polyphenol contents and ABTS radical scavenging activity. In the methods used, the ferric–ferricyanide complex was reduced to the ferrous form, depending on the presence of antioxidants [15]. The reducing powers of HGR and HGL were highest at 150°C, with values of 0.49 and 0.52, whereas the reducing powers were only 0.25 and 0.33 in raw materials, respectively. The reducing power increased significantly with increasing temperature. In addition, HGL had a relatively higher reducing power than HGR.