The purpose of this work was to study the modification of the commercial protease Flavourzyme 500L by choline chloride, aiming the production of protein hydrolysates from chicken viscera with antioxidant properties. The values of antioxidant activities for the hydrolysates obtained with the enzyme-IL combination (treated enzyme) in relation to the samples produced only with the enzyme was used to express the relative antioxidant activity. For the DPPH method, relative increases of 13% and 15% were detected for the hydrolysates obtained at 36°C, pH 6.4 and 120 and 60 U/mL, respectively. However, the highest value was detected at 45°C, pH 7 and 90 U/mL for the non-treated enzyme, reaching 91% of DPPH-radical scavenging, while the enzyme-IL combination reached 88% of inhibition at 54°C, pH 4.6 and 60 U/mL. Regarding to the FRAP method, relative gains of antioxidant activities ranging from 14 to 27% were observed. The major increase was evidenced at 30°C, pH 5.5 and 90 U/mL. The highest values of antioxidant activity for the non-treated enzyme and enzyme-IL combination were 22 and 26 Trolox EQ/g, which were obtained at 36°C, pH 4.6 and 120 U/mL and 60°C, pH 5.5 and 90 U/mL, respectively.