International dietary guidelines advocate replacement of saturated and trans fat in food with unsaturated oils. Also, there is growing interest in incorporating highly unsaturated omega-3 oils in to food products due to beneficial health effects. A major obstacle to incorporating highly unsaturated oils in to food products is the extreme susceptibility to oxidative deterioration. Oil bodies were prepared from tuna oil, oleosin, and phospholipid mimicking natural oil bodies within oilseed. Oleosin was extracted from canola (Brassica napus) meal by solubilization in aqueous sodium hydroxide (pH 12) and subsequent precipitation at its isoelectric point of pH 6.5. The tuna oil artificial oil bodies (AOBs) readily dispersed in water to produce oil-in-water (o/w) emulsions, which did not coalesce on storage and were amenable to pasteurization using standard conditions. Accelerated oxidation studies showed that these AOB emulsions were substantially more resistant to lipid oxidation than o/w emulsions prepared from tuna oil using Tween40, sodium caseinate, and commercial canola protein isolate, respectively. There is potential to use commercial canola meal, which is cheap and abundant, as a natural source of oleosin for the preparation of physically and oxidatively stable food emulsions containing highly unsaturated oils.
Artificial oil bodies offer the prospect of stabilizing highly unsaturated oils within food emulsions without or with minimal use of synthetic antioxidants and emulsifiers. The highly unsaturated oil could be any healthful oil obtained from diverse sources. In particular, this new technology is suitable for preventing rancidity in fish oil emulsions containing high levels of EPA and DHA.