“The food matrix can be conducive or detrimental to omega-3 oxidation,” says Srini Vasan, a principle scientist at Martek Biosciences Boulder Corp. (Boulder, Colo.). For example, yogurt is less susceptible to oxidation than extruded cereal. “The omega-3 in the yogurt matrix is protected by a protein film, and the physical gel-like structure further helps in stabilizing an emulsion that minimizes oxygen uptake,” says Vasan. Omega-3s are less vulnerable to oxidation since yogurt requires refrigerated storage, which means a lower temperature and shorter shelflife (45 days).

In contrast, extruded cereals require high-temperature processing and are kept in ambient storage for a longer shelflife. Auto-oxidation increases by two to three times for each 10°C incremental increase of heat. Processing issues are compounded by a cereal grain's abundance of minerals and large, porous surface area, which also encourages oxidative deterioration. Stability may be reduced by 50% for every 0.1ppm of copper and every 1.0ppm of iron in a product