Eggs.pdf

Understanding Food Amy Brown Chapter 13: Eggs Slide Development: Lonnie M. Lowery, Ph.D. Copyright 2003 Thomson Learning Composition of Eggs Just a few examples of how eggs are used in food preparation: Giving a foam structure to cakes and meringues Thickening custards and puddings Adding color to l...

Understanding Food Amy Brown Chapter 13: Eggs Slide Development: Lonnie M. Lowery, Ph.D. Copyright 2003 Thomson Learning Composition of Eggs Just a few examples of how eggs are used in food preparation: Giving a foam structure to cakes and meringues Thickening custards and puddings Adding color to lemon meringue pie and eggnog Emulsifying mayonnaise and hollandaise sauce Slide Development: Lonnie M. Lowery, Ph.D. Leavening soufflés and popovers Binding ingredients in meatloafs and casseroles Coating foods prior to breading Glazing pastries and breads Clarifying liquids for soups Copyright 2003 Thomson Learning Composition of Eggs The egg has five major components: – Yolk – Albumen (egg white) – Shell membranes – Air cell – Shell Each of these plays an important role in the egg’s unique attributes that make it invaluable in food preparation. Slide Development: Lonnie M. Lowery, Ph.D. Copyright 2003 Thomson Learning Slide Development: Lonnie M. Lowery, Ph.D. Copyright 2003 Thomson Learning Composition of Eggs Chalaza (pl. chalazae): The ropy, twisted strands of albumen that anchor the yolk to the center of the thick egg white. Vitelline membrane: The membrane surrounding the egg yolk and attached to the chalazae. Cuticle (bloom): A waxy coating on an eggshell that seals the pores from bacterial contamination and moisture loss. Slide Development: Lonnie M. Lowery, Ph.D. Copyright 2003 Thomson Learning Composition of Eggs Slide Development: Lonnie M. Lowery, Ph.D. Copyright 2003 Thomson Learning Purchasing Eggs Inspection The Egg Products Inspection Act of 1970 requires that egg processing plants be inspected and that their eggs and egg products be: – Wholesome – Unadulterated – Truthfully labeled This law is enforced by the USDA Poultry Division and applies to all eggs, whether imported or shipped intra- or interstate. Slide Development: Lonnie M. Lowery, Ph.D. Copyright 2003 Thomson Learning Purchasing Eggs Grading The best-quality eggs are graded USDA Grade AA, followed by USDA Grade A. – The grades sold at supermarkets. USDA Grade B, the lowest grade. – Available to food service establishments and not sold directly to consumers. Slide Development: Lonnie M. Lowery, Ph.D. Copyright 2003 Thomson Learning Slide Development: Lonnie M. Lowery, Ph.D. Copyright 2003 Thomson Learning Purchasing Eggs Candling: A method of determining egg quality based on observing eggs against a light. Slide Development: Lonnie M. Lowery, Ph.D. Copyright 2003 Thomson Learning Purchasing Eggs Haugh Units The freshness of an egg can be detected by cracking it open onto a flat surface and looking at the height of its thick albumen. Fresh egg whites sit up tall and firm, while older ones tend to spread out. Slide Development: Lonnie M. Lowery, Ph.D. Copyright 2003 Thomson Learning Purchasing Eggs Sizing is not related to grading in any way. Eggs are sold in cartons by various sizes determined by a minimum weight for a dozen eggs in their shell. Slide Development: Lonnie M. Lowery, Ph.D. Copyright 2003 Thomson Learning Purchasing Eggs Slide Development: Lonnie M. Lowery, Ph.D. Copyright 2003 Thomson Learning Slide Development: Lonnie M. Lowery, Ph.D. Copyright 2003 Thomson Learning Functions of Eggs in Foods Eggs are often combined with other ingredients. Their unique ability to: – Flavor – Color – Emulsify – Thicken – Bind – Foam – Interfere – Clarify …makes them nearly indispensable in cooking. Slide Development: Lonnie M. Lowery, Ph.D. Copyright 2003 Thomson Learning Slide Development: Lonnie M. Lowery, Ph.D. Copyright 2003 Thomson Learning Functions of Eggs in Foods Clarify: To make or become clear or pure. Slide Development: Lonnie M. Lowery, Ph.D. Copyright 2003 Thomson Learning Preparation of Eggs Eggs are extremely versatile and can be prepared alone or in combination with other foods. Countless recipes that include eggs can be cooked by either dry- or moistheat methods. Slide Development: Lonnie M. Lowery, Ph.D. Copyright 2003 Thomson Learning Preparation of Eggs Changes in Prepared Eggs The key to cooking eggs is to keep the temperature low and/or the cooking time short. Egg whites and yolks coagulate at different temperatures. Slide Development: Lonnie M. Lowery, Ph.D. Adding other ingredients to eggs changes their coagulation temperature. Undesirable color changes may occur during egg preparation. Copyright 2003 Thomson Learning Preparation of Eggs Dry-heat preparation of eggs primarily involves frying and baking. Egg dishes that are commonly fried are fried eggs, scrambled eggs, and omelets. – Prime (season): To seal the pores of a pan’s metal surface with a layer of heated-on oil. Slide Development: Lonnie M. Lowery, Ph.D. Baked egg dishes include shirred eggs, meringues (both soft and hard), and soufflés. – Weeping (syneresis): The escape of liquid to the bottom of a meringue or the formation of pores filled with liquid. – Beading :The formation of tiny syrup droplets on the surface of a baked meringue. Copyright 2003 Thomson Learning Preparation of Eggs F I G U R E 1 3 - 9 Omelet preparation. (a) With wire whisk, beat eggs with salt and water just until well mixed, but not too frothy. (b) Slowly heat a 9-inch heavy skillet or omelet pan to medium heat. Temperature is correct when drops of cold water sizzle and roll off the pan’s surface. Add butter and heat until it sizzles but is not yet brown. Gently pour the egg mixture into the heated pan. Slide Development: Lonnie M. Lowery, Ph.D. Copyright 2003 Thomson Learning Preparation of Eggs F I G U R E 1 3 - 9 Omelet preparation continued. (c) As egg mixture begins to set, use a spatula to push mixture back and allow unset egg to run onto pan’s surface. (d) Continue loosening and tilting until omelet is almost dry on top and golden-brown underneath. Slide Development: Lonnie M. Lowery, Ph.D. Copyright 2003 Thomson Learning Preparation of Eggs F I G U R E 1 3 - 9 Omelet preparation continued. (e) Add filling ingredients. (f) Using spatula, fold omelet over itself. Tilt the pan and use the spatula to slide the omelet onto a plate. Slide Development: Lonnie M. Lowery, Ph.D. Copyright 2003 Thomson Learning Preparation of Eggs A soufflé is actually a modified omelet. The main ingredients of a soufflé are a thick base generally made from a white sauce or pastry cream, an egg white foam, and flavoring ingredients – White sauce: A mixture of flour, milk, and usually fat. Stiffly beaten egg whites are folded into the thick egg yolk mixture. Slide Development: Lonnie M. Lowery, Ph.D. Figure 13-10 Copyright 2003 Thomson Learning Preparation of Eggs Moist-Heat Preparation Eggs can be prepared by moist heat using a variety of methods. Most common among these are: – “Boiled” eggs – Coddled eggs prepared in a cup – Poached eggs – A variety of custards – Eggs that are prepared using the microwave In all cases, eggs are cooked at simmering temperatures. Slide Development: Lonnie M. Lowery, Ph.D. Copyright 2003 Thomson Learning Preparation of Eggs Hard or Soft “Boiled” Hot-Start Method: – Soft: 3 to 4 minutes – Medium: 5 to 7 minutes – Hard: 12 to 15 minutes Slide Development: Lonnie M. Lowery, Ph.D. Cold-Start Method: – Soft: 1 minute – Medium: 3 to 5 minutes – Hard: 10 minutes Copyright 2003 Thomson Learning Slide Development: Lonnie M. Lowery, Ph.D. Copyright 2003 Thomson Learning Preparation of Eggs Custards are mixtures of milk and/or cream, sweeteners (sugar, honey), flavorings (vanilla, nutmeg, etc.), and eggs or egg yolks. Custards are distinguished by whether they are sweet or savory, and by their preparation method: stirred or baked. – Sweet custards are served as desserts in the form of puddings or as fillings. Slide Development: Lonnie M. Lowery, Ph.D. – Savory (nonsweet) custards are used for dishes such as quiches. – Stirred Custard (Soft Custard or Custard Sauce) ingredients are stirred while being heated. – Baked custard mixes are poured into ungreased custard cups that are placed in the oven. Copyright 2003 Thomson Learning Preparation of Eggs Microwaving Eggs cook extremely rapidly in a microwave oven. Special caution should be taken to avoid overcooking. Manufacturer’s instructions should be followed for microwave egg cooking. Slide Development: Lonnie M. Lowery, Ph.D. Whole eggs with intact shells should never be microwaved. – Steam expanding within the shell can cause them to burst. The same principle applies to whole eggs out of the shell. – Egg yolks will burst if not punctured with a toothpick or the tip of a knife prior to going into the microwave. Copyright 2003 Thomson Learning Storage of Eggs Eggs begin to deteriorate as soon as they are laid and lose quality very rapidly at room temperature. An egg will age more in one day at room temperature than in one week in the refrigerator. Slide Development: Lonnie M. Lowery, Ph.D. To ensure the freshness of whole or liquid eggs, they may be: – Refrigerated – Frozen – Dried Copyright 2003 Thomson Learning Storage of Eggs The size of an egg’s air cell provides another indication of its age. Slide Development: Lonnie M. Lowery, Ph.D. Copyright 2003 Thomson Learning Storage of Eggs Restaurants, food service institutions, and other food manufacturers must be especially careful about storing eggs, because they purchase such large quantities. Storage eggs, used by commercial food service establishments, are usually used within a month, but can be stored for up to six months – Storage eggs: Eggs that are treated with a light coat of oil or plastic and stored in high humidity at low refrigerator temperatures very close to the egg’s freezing point (29° to 32°F/ –1.5° to 0°C). Slide Development: Lonnie M. Lowery, Ph.D. Copyright 2003 Thomson Learning Storage of Eggs Frozen Freezing a whole egg is not possible because it will crack under the expanding liquids. Food manufacturers solve this dilemma by breaking the eggs open at the processing plants where the contents are frozen – Whole (whites and yolk mixed together) – Separated as whites or yolks Slide Development: Lonnie M. Lowery, Ph.D. Copyright 2003 Thomson Learning Slide Development: Lonnie M. Lowery, Ph.D. Copyright 2003 Thomson Learning Storage of Eggs Dried Drying eggs is a simple process. Whole eggs or separated yolks are spray-dried to create a fine powder, which is mixed with anti-caking substances to prevent clumping. Slide Development: Lonnie M. Lowery, Ph.D. Egg whites are dried in different ways to form granule, flake, or milled textures. Once dried, eggs can be stored in the refrigerator for up to a year, but they must be kept in tightly closed containers to prevent the clumping that can result from moisture accumulation. Copyright 2003 Thomson Learning Slide Development: Lonnie M. Lowery, Ph.D. Copyright 2003 Thomson Learning Storage of Eggs Safety Tips The chances of an egg being internally contaminated are relatively low, less than one in 10,000 commercial eggs. It is more common for contamination to occur during handling and preparation after the egg has been removed from its shell. Slide Development: Lonnie M. Lowery, Ph.D. Copyright 2003 Thomson Learning