Lab_7 - Lab 7: Milk Foams and Egg Foams Overview of Lab 7:...

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Lab 7: Milk Foams and Egg Foams Overview of Lab 7: 1. Milk Foam and Egg Foam Student Presentation 2. 3. Prepare assigned recipes 4. Evaluate the sensory properties of prepared recipes. Objectives: The student should be able to: 1. Discuss the stages of foam formation. 2. Discuss factors that affect the stability of milk foams and egg foams. 3. Prepare selected food products using foams.
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FOOD SCIENCE PRINCIPLES FOR EGGS Note: Lab 7 focuses on milk foams and egg foams. The following information on eggs is provided to deepen your general understanding of eggs. 1.Eggs are the most bioavailable source of protein. The majority of the protein in eggs is found in the white while the fat, cholesterol and most of the vitamins and minerals are found in the yolk. The majority of the fat in eggs is monounsaturated fat. One egg contains 212 mg of cholesterol, thus consumption of more than one egg in a day will result in an intake that exceeds the Dietary Guideline for cholesterol. 2.Eggs should always be eaten cooked because they can be contaminated with Salmonella enteritidis, a bacteria that can cause severe illness. The young, the elderly, pregnant women and those with compromised immune systems are most at risk of salmonella poisoning. Coagulation of egg proteins is dependent on the following factors: a. Temperature : The temperature at which egg white and egg yolk coagulate differs because of their different proteins. Undiluted egg white coagulates at temperatures from 144º-149º F (62º-65º C) and egg yolk coagulates from 149º-158º F (65º-70º C). b. Concentration : Dilution of egg proteins raises the temperature at which the proteins coagulate. c. Acid : Adding acid to egg white (which is naturally alkaline) decreases the pH to near the isolectric point of the egg proteins. At the isolectric point, proteins are least stable and most sensitive to denaturation (coagulation). Hence, small amounts of acid lower the coagulation temperature of most egg proteins. d. Sugar : Sugar elevates the temperature of coagulation and produces a tenderer coagulum. e. Salt : Salt lowers the temperature of coagulation. Hard-cooked eggs should be simmered in less than 185º F (85º C) water, never boiled. Boiling or overcooking produces a tougher, rubbery egg white. It may also produce a grayish-green film at the yolk-white interface from a reaction between the iron in the yolk and sulfur in the white. Plunging the just-cooked egg into cold water to cool quickly will minimize this reaction. Rapid cooling reduces the pressure toward the outer part of the egg and draws hydrogen sulfide away from the yolk. Egg yolks have the greatest thickening ability, followed by whole egg, with whites having the least. But two egg yolks substituted for one whole egg raise the temperature at which a gel forms. Two egg whites will lower the temperature at which a gel forms.
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FOOD SCIENCE PRINCIPLES FOR MILK FOAMS AND EGG FOAMS 1. A foam is a gas dispersed in a liquid.
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Lab_7 - Lab 7: Milk Foams and Egg Foams Overview of Lab 7:...

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