Abstract
The n-3 polyunsaturated fatty acids (PUFAs) are commonly known of their beneficial effects on the health. Nevertheless, their chemically reactive properties are a major cause of quality deterioration in many types of natural and processed foods. Therefore, a wide utilization in the food industry is not available. In this study, we examined the influence of emulsifiers on the oxidative stability of docosahexaenoic acid oil and esters from viewpoint of the emulsion droplet size. Docosahexaenoic acid oil (DHA oil) and its methyl ester (DHAME) were emulsified by using two types of emulsifiers; polyglycerol and gum arabic. The emulsion size was measured by laser-scattering particle analyzer. The emulsion was put in a reaction vessel, and a fluorescent oxygen sensor was set up to monitor the changes of the oxygen concentration in the headspace of the vessel. The emulsions prepared in this study were stable in size during the incubation for three days. It has been shown that autoxidation could be dependent on the type of emulsifier and the emulsion size. For DHA oil, larger size could protect more efficiently against oxidation independent on the types of emulsifiers used. On the other hand, for DHAME, the size of emulsion was less effective on the oxidation rate constant. The oxidation processes were successfully simulated by a mathematical model suggested.
