Quality characterization and process design of salmon oil production for human consumption

Abstract

Salmon oil is an abundant source of polyunsaturated fatty acids, especially eicosapentaenoic acid and docosahexaenoic acid. Finding more lucrative markets for this unpurified fish oil requires well designed purification steps to reduce impurities such as free fatty acids (FFA), oxidative components, moisture, minerals, and trace metals. The temperature dependency of the rate constants for lipid oxidation and rheological properties of unpurified oil were measured and modeled using the Arrhenius equation. Performances of chitosan and/or activated earth as adsorbents were investigated to remove impurities from the oil. Activated earth was found more effective in adsorbing primary oxidation products than chitosan. Neither chitosan nor activated earth was effective in reducing FFA from the unpurified oil. Oils purified using activated earth adsorption, neutralization process, and/or combined neutralization and activated earth adsorption processes were characterized for peroxide value (PV), FFA, color, minerals, tocopherols, insoluble impurities, thermal properties, and viscosity. The neutralization process reduced FFA in the unpurified oil but PV increased. The combined method was more effective in reducing impurities than each individual process. The research findings from this study will provide a good model for purifying oil produced from salmon byproducts.