egg Flashcards
what are the type of eggs
-free-range eggs
-barn eggs
-cage eggs
-organic eggs
-omega-3 fatty eggs
what is the nutritional value of eggs
proteins: an excellent source of HBV protein
-the main proteins present are ovalbumin, globulin, vitellin and livetin
fat: saturated fat is present in the yolk
-the yolk contains LDL cholesterol
-the white is fat-free
carbohydrates: lacks carbohydrates: for this reason eggs are usually served with a carbohydrate-rich food, e.g. bread
vitamins: a source of B-group vitamins, particularly B1, B2, B3 and B12
-yolks are a good source of vitamins A, D, E and K
-eggs lack vitamin C
minerals: a good source of calcium, phosphorus, zinc and sulfur
-non-haem iron is present in the yolk
water: high water content with the majority found in the white
what is the dietetic value of eggs
-eggs are an excellent source of HBV protein which assists with growth and repair. this makes them an excellent meat alternative in the diets of vegetarians and a valuable food in the diets of children, teenagers and pregnant women
-eggs are a versatile food suited to many different cooking methods and culinary uses, e.g. baking and sauces
-eggs are inexpensive and they cook very quickly, minimising energy costs, making them an economical food
-egg yolks are high in saturated fat and cholesterol so they should be restricted in the diets of people with high cholesterol and at risk of coronary heart disease
-egg lack carbohydrates and vitamin C, so they should be combined with foods and rich in these to balance the diet
what are the guidelines for buying eggs
-buy eggs from a retailer with a strict food hygiene and safety policy to ensure any eggs being sold are safe and fit for consumption
-check the best before date
-avoid buying eggs with cracked shells as this will quicken the rate of spoilage
-buy eggs in small amounts. buying too many can lead to food waste as they have a short shelf life
what are the guidelines for storing eggs
-store eggs in a cool, clean and dark environment or in the fridge to slow down the rate of spoilage
-store eggs away from strong-smelling foods
-minimise the amount of time eggs are in storage. use within the best before date
-ensure eggs are stored with the pointed end downwards to prevent the chalazae from breaking and the egg yolk becoming damaged
what are the labels required to be on an egg box
-name and address of packer or seller
-egg packaging centre code
-number of eggs in the pack
-class/quality of the eggs
-date of minimum durability
-production/rearing method
-weight
-storage instructions advising to keep eggs chilled after purchase
what are the guidelines for preparing eggs
if eggs are stored in the fridge, remove them for one hour before using in order to reduce the risk of the shell cracking during boiling and curdling during cooking. this will also help the eggs to trap more air when being whisked for meringues and sponge cakes
name the culinary uses of eggs and give an example of each
-coat: eggs enable a coating to stick to foods, e.g. breadcrumbs on fish or poultry
-glaze: eggs form a shiny coating on food, giving an attractive finish when baked, e.g. scones and pastry
-bind: eggs hold ingredients together to prevent them falling apart, e.g. burgers and fish cakes
-aerate: eggs trap air when whisked, assisting aeration, e.g. sponge cake and meringue
what are the effects of cooking on eggs
-protein coagulates, white coagulates at 60C and yolks coagulate at 80C
-bacteria are destroyed
-egg whites change colour, from translucent to opaque
-some B-group vitamins, particularly B1 are lost as they are not heat stable
-eggs become tough and difficult to digest if overcooked. the egg yolk becomes dry and crumbly and the egg white becomes rubbery
what are the properties of eggs
-aeration
-coagulation
-emulsification
explain aeration as a property of eggs
when eggs are whisked, protein chains unfold and air bubbles form. the protein chains entrap air creating a foam. also creates an amount of heat that begins to set the egg albumin. this forms a temporary foam it will collapse after a while unless it is heated to coagulate and set as a permanent foam, e.g. sponges
explain coagulation as a property of eggs
when eggs are heated, protein chains unfold, straighten and bond together around small pockets of water, causing coagulation. eggs whites coagulate and change from translucent to opaque at 60C and egg yolks coagulate at 68C. overcooking causes proteins to clump together and squeeze out water and a watery liquid this is known as curdling, e.g. beef burgers
explain emulsification as a property of eggs
lecithin is a natural emulsifier present in egg yolk. it can join two immiscible liquids, e.g. oil and water as it has a hydrophilic head and a hydrophobic tail. the hydrophilic head attaches to the water and the hydrophobic tail attaches to oil, preventing them from separating. this creates a permanent emulsion, e.g. cakes (fat and sugar)
