Fluorescence study of the pro-oxidant effect of free fatty acids on marine lipids

The free fatty acid (FFA) effect on the oxidative stability of marine lipids was studied by fluorescence assessment. Under different reaction conditions, including time, temperature and FFA content and type (different chain lengths and unsaturation degrees), FFAs 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 pro‐oxidant effect of all types of FFA, which increased with time, temperature and FFA content in the reaction mixtures. At 30 °C 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 pro‐oxidant effect was also observed with increasing degree of fatty acid unsaturation (stearic < oleic < linoleic < linolenic). When a lower temperature (−10 °C) was tested, a differential pro‐oxidant effect among fatty acids (chain length and unsaturation degree) was not observed. © 2001 Society of Chemical Industry