EFFECT OF NATURAL COPPER CHELATING COMPOUNDS ON THE PROOXIDANT ACTIVITY OF ASCORBIC-ACID IN STEAM-COOKED GROUND FISH

The antioxidative effects of several natural polyphenolic substances o n ascorbic acid-induced lipid oxidation. measured as thiobarbituric ac id-reactive substances (TBARS) was studied in steam-cooked ground fish . Those natural polyphenolic compounds that were potent antioxidants i n the presence of ascorbic acid were also effective inhibitors of copp er-induced oxidation of ascorbic acid. The order of potency of the nat ural products was: tannic acid almost-equal-to ellagic acid > myriceti n > n-Propyl gallate > fisetin > quercetin almost-equal-to luteolin > gallic acid. It is likely that the potent flavonoids inhibited lipid o xidation in ascorbic acid pre-treated cooked ground fish by reducing t he rate of copper-induced oxidation of ascorbic acid, thereby decreasi ng the production of free radicals. Flavonoids are able to exert antio xidative potential due to their free radical scavenging and metal chel ating properties.