STABILITY OF N-3 FATTY-ACIDS OF FISH-PROTEIN CONCENTRATE DURING DRYING AND STORAGE

The susceptibility of n-3 fatty acids of fish protein concentrate to o xidation during drying and storage under different conditions was dete rmined by gas chromatographic analyses of methylesters of fatty acids on a capillary column. Results indicate that an increase in water cont ent of fish protein concentrate has a marked inhibitory effect on oxid ative reactions. The inhibitory effect of water is most pronounced at higher water activity and the kinetics of oxidation can be represented in the initial stage by the decomposition of unsaturated fatty acids The kinetic constants were evaluated as a function of moisture and tem perature and are comparable to values reported in the literature in an other oil systems. The rate of n-3 fatty acids oxidation during drying was influenced by the rate of diffusion of oxygen through the materia l. The use of ethoxyquin as an antioxidant prior to drying of fish pro tein concentrate provides a good protection against oxidation of n-3 f atty acids.