The effectiveness of a white grape dietary fiber concentrate (WGDF) against hemoglobin-mediated oxidation of washed cod mince, with and without 10% added herring oil, was evaluated during ice storage. WGDF was added at two different levels: 2 and 4% based on final weight. An ethanol extract with the ethanol extractable polyphenols (EPP) and the ethanol-extracted grape dietary fiber residue were also tested as antioxidants in the washed cod mince. The addition of WGDF to the model system completely and significantly (p <or= 0.05) inhibited the hemoglobin-mediated development of rancid odor during the entire ice storage (10 days). Thiobarbituric acid reactive substances (TBARS) development and red color (a*) losses supported the sensory data. Controls fortified with 10% herring oil oxidized at the same rate as oil-free controls and were also significantly stabilized by 2% WGDF. The EEP of the WGDF had the same high antioxidant capacity as whole WGDF. The ethanol-extracted fiber residue significantly (p <or= 0.05) reduced maximum oxidation values obtained for controls by approximately 50% and extended the oxidation lag phase by 1 day (p <or= 0.05). Thus, this study showed great potential of WGDF to prevent rancidity in fish, mainly due to EPP but also due to the ethanol-extracted dietary fiber residue itself.