The types of fats and oils used in formulations have specific impacts on sensory, nutritional and functional aspects of finished products. Fats and oils, collectively called “lipids,” impart lubricity, which improves food texture. The way cocoa butter melts on the tongue gives chocolate its unique sensual properties. Lipids are solvents for flavors; cream and butter are regaled not only for their textural qualities, but also for their ability to carry flavors people crave. The species-specific flavors of meats are carried in their lipids; the flavors of beef, lamb and pork are indistinguishable, if the lipids are stripped from the meats. The structure of lipids affects their nutritional and functional properties. Partially-hydrogenated trans fats, now considered the bad boys of the nutrition world, were for many years extremely popular for their functionality in dough products. Trans fats largely have been replaced by combinations of saturated and unsaturated fats, which are modified to provide similar functional attributes with improved nutritional profiles. Lipid components, such as mono- and diglycerides and lecithin, are routinely used as emulsifiers in many food products. Lipids, such as omega-3 fatty acids and conjugated linoleic acid, also impart positive nutritional benefits. (See sidebar “Healthy Fats.”) All in all, lipids are the components that can move food from mundane to memorable.
Function Follows Form
Lipids are produced in all living things as the components that make up the structure of cell membranes, as biochemical messenger compounds and as energy storage. The structure of the lipid determines its function in the cell. Most of the lipids that have value for food products are in the triglyceride, energy-storage form. Food fats and oils are extracted as triglycerides from plant and animal sources. Triglycerides (see illustration “A Triglyceride Structure”) are composed of three fatty acids attached by an ester linkage to a glycerol backbone. Glycerol is water-soluble, while the fatty acids generally are oil-soluble. The order in which the fatty acids are attached to the glycerol backbone is highly structured in nature.