ABSTRACT
Fats and oils in foods have long been appreciated for their contribution to taste and texture, among other properties. Fats and oils are chemically triglycerides, and whether the particular triglyceride is a fat (solid at room temperature) or an oil (liquid at room temperature) depends on several factors, among them fatty acid chain length and degree of hydrogenation. These triglycerides have numerous uses in food, for example, as tenderizers in baked goods, leaveners (for plastic fats) in baked goods such as cakes, and as a component of emulsions (typically this is a function of liquid oils but it can be ful lled by solid fats). Dietary triglycerides also provide essential fatty acids and carry fat-soluble vitamins to where they are needed. Fat replacers usually do only one (or perhaps two) of the jobs that are done by conventional fats and oils. Their main function is to provide a fat-like texture to the foods in which they are found. Because fats and oils make foods taste good, there is a concern regarding the overconsumption of these ingredients in the diet. The American Heart Association (AHA) recommends a diet in which lipids provide no more than 30% of calories and in which saturated fat (typically an animal product) provides not more than 10% of the calories. Data from the NHANES III study (McDowell et al. 1994) indicate that Americans are typically consuming 34% of the calories in their diets as fat. Although this is still above AHA recommendations, it is not nearly the 40%–42%
they were consuming in the late 1970s. The main concern regarding dietary fat is in regard to its contribution to obesity, which is epidemic in the United States at present. Moreover, obesity has been identi ed as a risk factor for coronary heart disease (CHD) and some types of cancer. As unsaturated fats are synthesized in nature, their double bonds are of the cis type. However, the hydrogenation process used in making plastic fats or vegetable margarines causes the cis double bonds to be isomerized to the trans form. The trans fats are of concern because they raise levels of low-density lipoprotein (LDL), which in turn could lead to an increased risk of CHD.
