Oxidation of Fish Oil Oleogels Formed by Natural Waxes in Comparison with Bulk Oil

Abstract

The aim of this study was to evaluate the oleogel (or organogel) technology as a new method to prevent oxidation of fish oil by immobilizing oil and to provide useful information on oxidation of oleogels for their application in actual food products. Four different natural waxes, rice bran wax, sunflower wax, candelilla wax, and beeswax were used to prepare fish oil oleogels. Peroxide value, conjugated diene value, eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA) were measured after storing oleogels at 35 °C and 50 °C, respectively. All 3% wax-fish oil oleogels showed slower oxidation than the bulk fish oil at 35 °C. Beeswax was not as effective as other waxes during storage at 50 °C due to its lower melting point. The color penetration measurement method was developed as a convenient method to predict the oxidation rate of oleogel. Cooling oleogel at a faster rate could significantly reduce the oxidation rate of the oleogel. A larger amount of wax is not recommended to increase the protective effect, which can give a negative effect due to the prooxidant activity of wax. The oleogel technology may be applied to reduce oxidation of food products and nutritional supplements containing omega-3 oil.

Practical applications: This study clearly showed that the oleogel technology can be used to prevent oil oxidation by immobilizing oil in food products. This technology can be used for commercial products such as fish oil supplements to prevent oil oxidation during production, transportation, and storage. The information presented in this study can also be used for new omega-3 oil fortified food products such as margarine, spreads, shortening, cookies, and other related products. The oleogel technology can be easily applied as a drop-in method. Natural waxes used as oleogelator are inexpensive and widely available, and most of them are already used in many food products.

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