Figure 1 Peroxyl radical (ROO·) scavenging activity of Colla Corii Asini (CCA). Peroxyl radical scavenging activity (ORAC capacity) of CCA was measured by ORAC assay as described in Materials and Methods. (A) ORAC capacity of porcine skin gelatin, bovine skin gelatin, gelatin from cold water fish skin and CCA manufactured in 2013 at 1.0 mg/mL. (B) ORAC capacity of CCA manufactured in 2017, 2013 and 2008 and digested fish gelatin (gelatin from cold water fish skin) and CCA manufactured in 2017, 2013 and 2008 at 0.5 mg/mL. Digested gelatins were all filtered through 0.22 μm filters before ORAC assay. CCAD: Enzyme- digested CCA; FGD: enzyme-digested fish gelatin; ORAC: oxygen radical absorbance capacity. Experiments were repeated 3–5 times independently. *P < 0.05, ***P < 0.001 (one-way analysis of variance followed by the least significant difference test).