FS HN 101 Study Guide - Quiz Guide: Cream, Whipped Cream, Yolk

• School: Iowa State University
• Department: Food Science and Human Nutrition
• Course: FS HN 101
• Professor: Terri Boylston

Document Summary

Summary: emulsions and foams are colloidal systems in which one immiscible phase is dispersed in another. The droplets or dispersed phase is dispersed in a continuous phase. In emulsions, the immiscible phases are oil and water. Oil-in-water emulsions are most common and include mayonnaise, salad dressings, and milk. Butter and margarine are water-in-oil emulsions: because water and oil do not normally mix, an emulsifier is necessary to stabilize an emulsion. An emulsifier has a hydrophobic and hydrophilic portion and is able to associate with both the water and oil phases of the food: egg yolks contain lecithin which is an effective emulsifier. Other natural and synthetic emulsifiers are also used in foods to stabilize emulsions: foams contribute to the light airy texture of foods. A foam contains gas bubbles dispersed in a liquid continuous phase: protein ingredients, such as egg whites and gelatin, and high fat ingredients, such as heavy whipping cream, will form foams when beaten.