The principle of the DPPH assay is that the antioxidants react with the stable free radical that is α,α-diphenyl-ß-picrylhydrazyl (violet) and convert it to α,α-diphenyl-ß-picrylhydrazine (yellow). The degree of discoloration indicates the scavenging potential of the antioxidant sample (Abdille et al., 2005). The result of DPPH radical scavenging activity of the gac juice was expressed as IC50 value in Figure 3. In addition, less IC50 value generally presents a high scavenging potential of sample. The result revealed that IC50 value of gac juice slowly decreased from 1.12±0.17 ml sample to 1.03±0.09 ml sample when the temperature increased from 60ºC to 70ºC. Interestingly, the lowest IC50 values, implying content and DPPH radical scavenging activity. Hence, the optimum temperature for thermal processing of gac juice that can retain the maximum phytochemical compounds and antioxidant activity was 80ºC. Further information would still need to be investigated such as microbial and sensory properties to determine if this pasteurization condition (80ºC, 2 min) would appropriate for gac juice preparation.