0.1 mm dpph solution

The antioxidant capacity of extracts was assessed based on the reduction of the synthetic and stable 2,2-diphenyl-1-picrylhydrazyl (DPPH^●) free radical. The colorimetric method allows for the measurement of changes in the absorbance of a DPPH solution at a wavelength of 517 nm as the result of the antioxidant activity of the sample [47 (link)]. A volume of 2.8 mL of 0.1 mM DPPH solution (Sigma-Aldrich, St. Louis, MO, USA) in 96% ethanol was mixed with 0.2 mL of the pumpkin extract. Absorbance was measured after 30 min of incubation using a spectrophotometer (UV-2600i, Shimadzu, Japan). The results were expressed as μmol Trolox (Sigma-Aldrich, St. Louis, MO, USA) per 100 g fresh weight (TEAC μ mol∙^L−1 Trolox FW).

Free radical scavenging activity was determined using the DPPH based on the method described by Brand-Williams et al. [83 (link)], with slight modifications. A mixture comprising 100 μL of kiwiberry extract and 900 μL of 0.1 mM DPPH solution (Sigma-Aldrich) was incubated in the dark at room temperature for 15 min. The absorbance of the solution was measured at 515 nm using a multi-mode microplate reader. Gallic acid was used as a standard. The DPPH scavenging activity was calculated using the following equation: