FLUORESCENCE STUDY OF THE PROOXIDANT ACTIVITY OF FREE FATTY ACIDS ON MARINE LIPIDS

The free fatty acids (FFA) effect on the oxidative stability of marine lipids was studied by fluorescence assessment. Under different reaction conditions including time, temperature, FFA content and types (different chain length and unsaturation degree), FFA were made to interact in model systems with a commercial marine oil (cod liver oil) and two different fish (hake and pout) white muscles. Fluorescence assessment showed a prooxidant effect of all kinds of FFA, that increased with time, temperature and FFA content in the reaction mixtures. At 30ºC, a higher degree of oxidation was obtained in systems including the shorter chain length fatty acids (lauric and myristic) compared to systems including the longest ones (arachidic and stearic); at the same temperature, an increasing prooxidant effect was also observed with increasing degree of the fatty acid unsaturation (stearic < oleic < linoleic < linolenic). When a lower temperature (-10ºC) was tested, a differential prooxidant effect among fatty acids (chain length and unsaturation degree) was not observed