For DPPH assay, as reaction time is a critical point of control of antioxidant activity assessment, the percentage of inhibition was
monitored against time until not significant changes were observed. The steady stage of the inhibition reaction was obtained
at 220 min, thus, a final time of 4 h was selected for further analyses. Subsequently, the antioxidant activity of three apple pomaces were determined five times within 1 day for repeatability, while reproducibility was examined in triplicate for three different days.