The protective effects of omega-3 have been well documented, with its protective effects against heart disease and cancers well established. However, in fortifying foods with this oil poses it own set of problems, as the fatty acid is highly susceptible to oxidation, which can affect the taste of the finished product.
The researchers, from Lyngby, Denmark, discovered that combinations of altered rapeseed oil and specific anti-oxidants inhibited oxidation of a fish-oil enriched milk emulsion. Anti-oxidants used in the study included alpha-tocopherol, gamma-tocopherol, ascorbyl palmitate and ethylenediaminetetraacetic acid.
While emulsions of fish oil combined with alpha-tocopherol and gamma-tocopherol were found to be less stable than antioxidant-free emulsions of milk and fish oil, gamma-tocopherol appeared to inhibit oxidation of fish oil and milk emulsions more efficiently than alpha-tocopherol.
Ascorbyl palmitate was more effective at preventing oxidation in fish-oil-enriched milk emulsions than tocopherols, as determined by methods including assessment of volatile oxidation products, as well as sensory evaluation.
AP was also found to prevent the pro-oxidant effect of tocopherols added to fish oil prior to emulsification. No interactions between ascorbyl palmitate, tocopherols, and ethylenediaminetetraacetic acid were noted. The latter, when added alone to fish oil, did not have an antioxidant effect in the milk emulsions.
The discovery could provide answers to protecting the fish oil from oxidation during production processes in which high temperatures, the presence of oxidative agents, and the matrix of the food provide triggers for the initiation of the oxidative process.
Omega-3 has become a buzzword within the nutraceutical and supplement industry, due to the health benefits attributed to this fatty acid. This has not been lost on the food industry, and many food manufacturers are now developing products with added omega-3.
UK bakers Warburtons last year introduced its 'Good Health Loaf for Women' fortified with various vitamins and omega-3 DHA, while GlaxoSmithKline has added DHA to a variant of its Horlicks brand in the Indian market.
The results of the study are published in the Journal of Agricultural and Food Chemistry (53, 13:5429-37, 2005).