Eggs Flashcards
Nutritive value of Eggs
Protein: Eggs are an excellent source of HBV protein. Protein is needed for growth and repair of body cells. The main proteins present are albumin, globulin, vitellin and livetin. Eggs provide protein in an easily digested form.
Fat: almost one third of the egg yolk is made up of fat. It is saturated fat, present in a dine emulsion, becasue of the emulsifier lecithen. This makes the fat easy to digest. Fat is needed for heat and energy. Cholesterol is also present in egg yolks
Carbohydrate: Eggs do not contain carbohydrates which are needed for heat and energy, so they are usually served with a carbohydrate food, for example scrambled egg on toast
Vitamins: Fat soluble vitamins A (eyes), D E K are present in the yolk. Beta-Carotene gives the yolk its yellow colour. B group vitamins b1,b2,b12 and niacin are also present in the yolk but to a greater extent in the white. Eggs are deficient in vitamin C. B group vitamins aid metabolism and the release of energy from foods
Minerals: Eggs are important source of calcium which is needed for healthy bones and teeth, iron, phosphorus and sulphur.
Water: most of the water is present in the egg white
Dietetic Value of Eggs
C - eggs are inexpensive and they cook quickly minimising energy costs making them an economical food (6 eggs= 1.50)
A - Eggs are easily digested food, which makes them important for children, older people and convalescents
The saturated fat present in eggs may cause high cholesterol, so intake should be restricted by those on low fat and or low cholesterol diets
Eggs are a nourishing food and yet low in kilocalories (150) making them important in low kilo calorie diets
V - eggs are a versatile food, suited to many different cooking methods and culinary uses Example: main course: omelette, dessert: meringue , starter: egg mayo, baking: cakes and buns, sauces: custard, batters: binding burgers, on its own: boiled, scrambled etc
A
Selection of eggs
Buy fresh (best before date)
Eggs should be heavy for size
Ensure no cracks or breakages
Check carton for info. Size class quality and the farming method (number) which has an impact on the cost.
Farming methods of eggs
0 - organic eggs (free range eggs produced ti organic standards. There is no GM feed and restricted use of antibiotics. Birds are not treated with growth hormones and are more expensive)
1 - free range eggs (hens roam between outdoors and indoors)
2 - barn eggs (hens are kept indoors but not caged)
3 - cage/battery eggs (hens are kept in cages, large warehouse, slant floors allow eggs to roll onto conveyer belt. Artificially lit and heated)
Grading eggs
Size (XL L M S)
Class/quality (A fresh, B for use in industry)
Labelling regulations
Egg packaging
Egg packs must declare the following information in clearly visible and legible type:
The name, address and number of packer
The quality of eggs (class)
Farming method
Size (XL, L , M , S)
Best before date
Advice to consumers on storage instructions
Number of eggs
Eggs
Each egg is stamped with
Bord Bia quality mark
Number indicating farming method
Two letters (country of origin)
A code with a letter and two numbers identifying the country and the actual farm, ensuring traceability
The best before date
Quality assured eggs
Bord Bia operates the Sustainable Egg Assurance Scheme (SEAS)
The purpose of this scheme is to ensure best practice at all stages of egg production and packing, thereby minimising food safety risks
Under this plan:
All hens are certified salmonella free and are inspected regularly
The egg producing farms are monitored and must comply with the standards of the scheme
If the specific requirements are met, the producer is awarded the quality assured mark
Storage of eggs
Eggs should be stored in a fridge to prevent rapid deterioration
Store eggs with the pointed end downwards to prevent the chalazae from breaking and to keep the egg yolk intact
As shells are porous, store eggs away from strong smelling foods (Eg:) garlic, onion, fish
Eggs should be used at room temperature, so remove them from the fridge one hour prior to use to prevent the shell cracking (when boiling) or the egg curdling
Use writing recommended time
Staling of eggs
Eggs deteriorate quickly if not refrigerated and washing increases the rate of stalling
As eggs become stale, water evaporates and air space increases in size
Eggs can be preserved by freezing (de shelled) or as dried egg (used in cake mixes)
Properties of Eggs
Coagulation
Emulsification
Foam formation
Coagulation
The protein in eggs coagulates or sets during cooking.
Egg whites coagulates between 60°C and 65°C.
Yolks coagulate between 65°C and 68°C
Examples of foods using egg coagulation properties are booked fried poached and scrambled eggs, omelettes custard and dishes where egg is used for binding such as burgers and for coating such as fish coated with egg and breadcrumbs
Overcooking causes egg proteins to clump together, squeezing out the water, this is known as curdling
Emulsification
An emulsifier is a molecule that has a hydrophilic (water loving) head and a hydrophobic (water hating) tail
The hydrophilic head attaches itself to the water to the water molecule, thereby preventing the two substances from separating
Examples: lecithin is a natural emulsifier (in eggs) which binds oil and water together
This property is used in the production of mayonnaise (oil, egg yolk and vinegar)
Foam formation
Whisking eggs introduces air, which is aided by the addition of sugar
The heat produced by the friction slightly coagulates the protein around air bubbles
Cooking further coagulates the protein
The aeration property is used in the production of meringues soufflés and sponge cakes
Culinary uses of eggs
As a food
Enrich
Bind
Cost
Thicken
As an emulsifier
Aerate
Glaze
Garnish
Clarify
Effects of cooking on eggs
Protein coagulates, causing eggs to solidify
Pathogenic bacteria such as salmonella are destroyed by heat
Heat causes the loss of b group vitamins especially thiamine
The egg white changes from transparent to opaque
Over cooking or cooking at a very high temperature causes egg to cuddle
Eggs become tough and difficult to eat if overcooked
