Antioxidant properties of ascorbic acid in bulk oils at different relative humidity

•Relative humidity (RH) and antioxidant property of ascorbic acid was tested in oils.•As concentration of ascorbic acid increased, the oxidative stability increased.•Oils with ascorbic acid had higher oxidative stability at low RH than at high RH.•RH greatly affected the oxidative stability of oils containing ascorbic acid. The effects of relative humidity (RH) on the antioxidant properties of ascorbic acid (10, 20, 42, and 84ppm) were investigated in stripped corn oils stored at 60°C. The degree of oxidation in oils was determined by analysing headspace oxygen content and conjugated dienoic acids. The oxidative stability of bulk oils without addition of ascorbic acid was significantly different depending on the RH. As the concentration of ascorbic acid increased from 10 to 84ppm, oxidative stability increased significantly irrespective of RH (p