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D. J. MCCLEMENTS, Dept. of Food Science, Univ. of Massachusetts, Amherst, 238 Chenoweth Lab., Box 31410, Amherst, MA 01003-1410 Many foods consist either partly or wholly as oil-in-water emulsions, including milk, cream, salad cream, mayonnaise, salad dressings, soups, sauces, dips, spreads, beverages, ice cream and coffee whitener. The sensory and physicochemical properties of these foods (appearance, flavor, rheology and stability) depend strongly on the characteristics of the fat droplets (concentration, size, crystallinity, interactions). When fat droplets are removed to create reduced-caloric versions of conventional products there are usually adverse effects on product quality. The successful development of fat-reduced food emulsions therefore depends on understanding the multiple-roles that fat droplets play in determining the overall properties of a fatty food. Emulsion appearance depends on the intensity of light scattered by the fat droplets. Emulsion rheology and stability depends on the concentration, size and interactions of the fat droplets. Emulsion flavor depends on the partitioning and release rate of non-polar flavor molecules from fat droplets. The partial or total removal of fat droplets from an emulsion can therefore lead to major changes in the desirable physicochemical and sensory properties of a food product. The fact that fat droplets play so many different functional roles in food emulsions has meant that the food industry has faced considerable challenges in developing reduced-fat products with quality attributes that mimic those of conventional products. In response to this challenge, food scientists have developed a variety of fat replacement technologies. This presentation provides an overview of the different roles that fat droplets play in determining emulsion properties and how these roles can be performed by other ingredients.
Session 8, Physics and chemistry of modifying food for caloric reduction
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