By Cindy Hazen, Contributing Editor
At the height of the low-fat craze, comedian Dave Barry observed, “American consumers have no problems with carcinogens, but they will not purchase any product, including floor wax, that has fat in it."
It’s an exaggeration, but it speaks to the incongruities of consumer purchase behavior.
Today’s food buyers are just as discerning about selecting products based on ingredient statements. And one of their concerns is fat, although they are not always well-informed.
The USDA Report on the 2010 Dietary Guidelines for Americans specifically targets “solid fat (fats that are solid at room temperature, such as animal fats or fats made from vegetable oils by hydrogenations) and added sugars" with the acronym SoFAS. These contribute approximately 35% of calories to the American diet. “Reducing the intake of SoFAS can lead to a badly needed reduction in energy intake and inclusion of more healthful food into the total diet," the report says. The reasoning is that sugars and solid fats contribute excess calories “and few, if any, nutrients."
Fats contribute 9 calories per gram, which may contribute to obesity. Moreover, because intakes of dietary fatty acids and cholesterol are major determinants of cardiovascular disease, the dietary guidelines recommend limiting saturated-fatty-acid intake to less than 7% of total calories and opting for food sources of mono- and/or polyunsaturated fatty acids. Recognizing that this might not be immediately achievable, the report suggests aiming for less than 10% and gradually reducing intake over time.
Cholesterol-raising fats are described as saturated fats exclusive of stearic acid and trans fatty acids. Because trans fatty acids are believed to increase the risk of cardiovascular disease, the Guidelines recommend avoiding trans fatty acids from industrial hydrogenation as a beneficial change, “leaving small amounts (less than 0.5% of calories) from natural (ruminant) sources."
Calling for changes in dietary intake of certain fats is easy enough, but cutting the percentage of fat or dropping in a substitute is not a simple task in most products. Fat is multifunctional. Formulators must account for the many ways that it contributes to the final product.
As a flavor, fat may be neutral or it may have notes derived from its source, e.g., beef tallow. The degree of processing also can determine flavor. Equally important, fat may mask off flavors from other ingredients in a product or round-out the overall flavor perception. The choice of fat is also connected to potential development of off flavors due to oxidation and rancidity. There is a correlation between stability and the degree of saturation in a fat. Polyunsaturated fats react rapidly with oxygen, so storage conditions, processing stress, packaging protection and shelf-life expectations must be considered.
Further, mouth-coating, adhesiveness and melt impression are generally associated with solid or semisolid fats. Slipperiness is a sensory descriptor related to liquid oils. In baked goods, fat provides texture, helps with aeration and reduces moisture loss. In soups, sauces, dressings and dairy products, fat can add viscosity, creaminess and opacity. In all of these foods, it adds lubricity.
When formulating a reduced-fat product, the first step is to determine what functionality the fat is performing in the particular application, then using a gum or combination of gums to mimic the functionality. Because each gum has its own characteristics and may or may not work synergistically with other ingredients, seeking the advice of a supplier can save time and money.
For example, a reduced-fat cake application requires “something that will favor the air entrapment and help to bind just the right amount of moisture without making the product too moist," explains Janae Kuc, laboratory technician, Gum Technology Corporation, Tucson, AZ. “It should also be able to create a very nice crumb and help with suspension of any particulates in the formula. Some gums usually used in combination for this type of application are xanthan, carboxymethyl cellulose (CMC), microcrystalline cellulose, gum arabic, konjac and guar gum. Typically, a 50% fat reduction is easily achievable."