In all other cases, it will be necessary to convey fatty acids so that they are incorporated in a stable way in the food matrix, e.g. by resorting to emulsifiers or to more sophisticated systems such as their micro-or nano-encapsulation. Among the substances used for encapsulation, there are gelatins, pectins and other hydrocolloids, or proteins with the natural tendency to assemble into micelles or tubules as the ß-lactoglobulin extractable from whey. There are also versions rich in essential fatty acids even of “unusual” foods, such as meat. Fortification can be achieved directly by feeding animals (e.g. chickens or pigs) with selected fatty acids, but facing a series of problems including meat off-odors and more “oily” texture of the meat fats. Recently, these applications have been evolving, thanks to the selection of healthy plant-based feed which are naturally rich in ω3 (grains, flax seeds, etc.), with the additional advantage that animals fed in this way are healthier and require less veterinary care. Chemical instability: PUFAs are rich in double bonds, some reach up to 5; such non-saturations are sources of fragility since they can be easily attacked by oxygen, with rancidity of lipids (the reason why saturated fats, e.g. lard, are more easily preserved than oils which are rich in unsaturated fatty acids). PUFAs are also quite sensitive to heat. For these reasons, both during extraction, conservation, addition to the food to be fortified, it is necessary to treat these substances with a series of measures in order to maintain unchanged their quality as well as the beneficial effect and declared quantity on the label until the end of the product’s shelf life. It is often essential to add antioxidants, either natural or not. Encapsulation can moreover be a good strategy for addressing the problems caused by the instability of such chemical substances. Unpleasant taste: essential fatty acids, especially ω3 series, are often extracted from fish, which is one of their richest sources. Despite the purification processes to which the product is subjected, the smell and the flavor of fish are almost unavoidable, therefore the addition of fatty acids (even if in small amount) to the food matrix often causes an unacceptable organoleptic profile. To overcome this drawback, one can once again resort to encapsulation. Recently other sources for extracting such fatty acids have been available, with a significant reduction of the problems of off-odors and off-flavors, e.g. marine microalgae (which are also the source from which even fish are enriched through feeding), krill and other marine invertebrates. Possible presence of contaminants: if Pufas are extracted from fish, it is common to find a number of contaminants which typically accumulate in lipid tissues of water beings, in particular dioxins and organic derivatives of mercury. These contaminants may be present in considerable quantity, which is particularly worrying in case the food fortified with Pufas is aimed at people or sensitive age ranges, such as pregnant women or children. It is therefore important for food companies using these substances to fortify their products, to be sure of the quality and safety of raw materials they use. Like for the previous point, also in this case the use of microalgae as a source of Pufas, although more expensive, reveals being a better choice with regards to the amount of contaminants present, since these tend to accumulate along the food chain and are therefore higher in big-size fish species.
References
Nicholson T, Khademi H, Moghadasian MH. 2013. The role of marine n-3 fatty acids in improving cardiovascular health: a review. Food Funct. Epub ahead of print
Schuchardt JP, Huss M, Stauss-Grabo M, Hahn A. 2010. Significance of long-chain polyunsaturated fatty acids (PUFAs) for the development and behaviour of children. Eur J Pediatr. 169(2):149-164
Maqsood S, Benjakul S, Kamal-Eldin A. 2012. Extraction, processing, and stabilization of health-promoting fish oils. Recent Pat Food Nutr Agric. 4(2):141-147
Zimet P, Livney YD. 2009. Beta-lactoglobulin and its nanocomplexes with pectin as vehicles for ω-3 polyunsaturated fatty acids. Food Hydrocolloids, 23(4):1120-1126
