Cause and Control of Spurious Thiobarbituric Acid Values from Fish Muscle in the Presence of Inorganic Iron Salts

Abstract

The distillation method for determining the thiobarbituric acid value gave spurious results when applied to cod muscle containing trace amounts of Fe⁺⁺⁺ or Fe⁺⁺. This was the result of metal-catalyzed oxidation that took place in the acidified tissue during distillation. It was prevented by replacing the oxygen in the distillation flask with nitrogen or by immobilizing the iron catalyst by addition of the disodium salt of ethylenediaminetetraacetic acid or propyl gallate.Complex organic iron compounds, copper salts, cysteine, or sodium chloride did not interfere with the TBA test.