Oxidation can challenge acceptance of omega-3 fatty acids.

Consuming dietary omega-3 fatty acids is essential to keeping us in good shape. This is especially the case for pregnant and lactating women, and for individuals with coronary heart disease, diabetes, mental illness and immune response disorders. Oil-rich fish and supplements, such as fish oil and cod liver oil, are the richest and most readily available sources of omega-3 fatty acids.

Nevertheless, there is strong evidence that the level of omega-3 fatty acids currently consumed by the general population is inadequate. So, there is a need to develop desirable and convenient functional foods containing physiologically significant amounts of omega-3 fatty acids. However, the foods must be kept from undergoing oxidative deterioration.

These types of products could be produced from a variety of omega-3 sources, including fish oils, algal oils, linseed oil and ethyl esters of omega-3 fatty acids. These oils vary considerably in the concentration and type of omega-3 fatty acids they contain, as well as in their cost and oxidative stability.

To be able to successfully incorporate these oils into functional foods, their oxidation levels must be controlled. Several strategies have been developed to increase the oxidative stability of bulk oils high in omega-3 fatty acids. Unfortunately, many of these antioxidative strategies show limited success when utilized in heterogeneous food systems.

Scientists have found that oil-in-water emulsions may be easier to disperse into water-based foods, such as dairy, meat and emulsion-based foods, than bulk oils. In addition, they would more likely retain their antioxidant protection in processed foods, since the antioxidants effective in oil-in-water emulsions would also be effective in water-based foods.

Antioxidant technologies that may increase the oxidative stability of omega-3 fatty acids in oil-in-water emulsions include emulsion droplet interfacial engineering, chelators (binders of divalent cations) and lipid-soluble antioxidants. Experimental results suggest that both whey protein isolate-stabilized algal or menhaden oil-in-water emulsions could be used as an ingredient delivery system that incorporates omega-3 fatty acids into functional foods.

It is possible to develop a physically and oxidatively stable n-3 fatty acid delivery ingredient, in an emulsion form, that only needs to be added to foods in small quantities to provide nutritionally significant amounts of n-3 fatty acids.

Further information. Eric Decker, Department of Food Science, University of Massachusetts, Amherst, Room 236, Chenoweth Laboratory, Box 31410, Amherst, MA 01003; phone: [phone]; fax: [phone]; email: [e-mail].