Thermal and rheological properties and the effects of temperature on the viscosity and oxidation rate of unpurified salmon oil

The effects of temperature on the magnitude of viscosity and lipid oxidation rates of unpurified salmon oil were measured and modeled using the Arrhenius equation. The melting point of salmon oil ranged from -61.3 to 31.2 oC. The flow behavior index of the oil samples was less than one, which indicated that the salmon oil exhibited non-Newtonian fluid behavior. The apparent viscosity at 5 oC was significantly higher (P < 0.05) than those at 10, 15, 20, 25, 30, and 35 oC. The average magnitude of activation energy for apparent viscosity of the oil was 21.8 kJ/mol. The estimated viscosity obtained by the Arrhenius equation agreed with the experimental viscosity. The rate of lipid oxidation for unpurified salmon oil was temperature dependent (R2 = 0.99). The apparent activation energy for lipid oxidation of the oil was 51.3 kJ/mol. © 2008 Elsevier Ltd. All rights reserved.