“I don’t believe that saturated fatty acids will be ungrouped on food labels down the road,” says Radcliffe. “There is only so much room available on a food label, and it would be very complicated, as different foods contain different amounts of particular fatty acids, but the combination of all fatty acids in a food is what is important when considering daily percentage intake.”
This topic of grouping or singling out saturated fatty acids is one the Dietary Guidelines committee is also reviewing. “This topic re-ceived much discussion during the 2005 Dietary Guidelines Advisory Committee meetings, and is again receiving some attention during the current 2010 Dietary Guideline discussions,” says Bob Wainwright, technical director, Cargill oils and shortening team, Minneapolis. “This is a difficult topic, especially with respect to how such a message might be conveyed in language that consumers understand and can make informed choices about.”
Chain length and functionality
The role of saturated fatty acids in our body is strongly linked to their chain length. Each saturated fatty acid has its own merits.
Chain length impacts fat’s functionality in a food system, too. “The fatty acid profile provides a ‘fingerprint’ that gives some useful information regarding what to expect in terms of performance and application utility from a given fat or oil,” says Wainwright. “It is also important to consider the architecture of the fat, or, more appropriately, the triglyceride, in terms of which fatty acids are esterified to specific positions on the glycerol backbone.”
Take the pleasant eating experience associated with chocolate, for example. “Cocoa butter plays a significant role in delivering that sensory delight,” continues Wainwright. “If the fatty acids associated with cocoa butter are reallocated across the glycerol backbone in a random fashion, as opposed to a very directed and symmetrical native association, the resultant fat exhibits a melting point that is well above mouth temperature and hence very undesirable for a chocolate. In fact, the melting point can be expected to increase from the native 97 to 125°F or higher.”
Further, fats and oils for long-shelf-life products should have the lowest polyunsaturated-fatty-acid content possible, as polyunsatu-rates are several times more unstable when exposed to oxygen than monounsaturated fatty acids.
“Saturated fatty acids, by far, are the most stable, which was one of the main reasons for using hydrogenation,” says McNeill. “It reduced or eliminated polyunsaturated fatty acids in a fat, rendering it more stable. When polyunsaturated fats react with air, the com-pounds that are formed have an undesirable taste and odor.”
Though the omega-3 fatty acid linolenic acid has many health benefits associated with its consumption, it is highly unstable and prone to rancidity. “It readily oxidizes at very low concentration, producing undesirable off flavors,” says McNeill. “This knowledge stimulated the development of new oils that have low levels of linolenic acid.”
Radcliffe adds: “High levels of unsaturated fatty acids in oils such as soybean oil and canola oil can reduce the shelf life of the oil, reduce fry life and give rise to undesirable flavors in fried products. Oils that have higher levels of saturated fatty acids, such as cotton-seed oil, which contains 26% saturated fatty acids, do not need to be hydrogenated and can replace hydrogenated oils in the production of fried foods such as french fries.”
Exploring options
Cottonseed oil has a 2:1 ratio of polyunsaturated to saturated fatty acids. Unlike many other naturally trans-free alternatives available to product designers, cottonseed oil is rich in tocopherol (vitamin E), with one tablespoon containing 4.8 mg, making it an excellent source of this fat-soluble vitamin. Further, the vitamin E functions as a natural antioxidant, thus providing extra resistance to oxidative rancidity, according to the National Cottonseed Products Association, Cordova, TN.
A number of partially hydrogenated fat alternatives are made from soybean oil. “The first soybean trait innovation to become com-mercially available was the low-linolenic variety. Major food companies have made the transition to low-linolenic soybean oils from partially hydrogenated oils for frying and processed food applications,” says Lisa Kelly, a representative with the United Soybean Board (USB), St. Louis, MO. “Decreasing linolenic acid increases flavor stability and supports oxidative stability. Low-linolenic soybean oil can be used as a direct replacement for lightly hydrogenated oil in many applications, including light frying, sauces, rolls and pizza dough.”