13 - 07 - 2020 Notes
Week 8
Form 2 Note
Food commodities
Egg
Definition of egg
Eggs are oval in shape with hard shells and are hatched by female birds and reptiles.
Composition of an egg
1. Shell - a hard protective cover that consists of calcium carbonate which protects the content.the shell is porous and could be white or light brown in colour.
2. Albumen - the white thick, sticky liquid thanks surrounds the yolk.
3. Yolk - the yellowish roughly spherical structure surrounds by a thin flexible membrane.
4. Chalaza or balancers - the fibrous cords that holds the yolk in position and prevent injury to the embryo by acting as a shield or shock absorber when the egg is moved.
Nutritive food value of eggs
- protein
- mineral element eg. Iron, calcium, and phosphorus.
- fat
- vitamin eg. Vitamin A,B,D .
Uses of egg in food preparation.
a.for thickening - eggs are used for thickening custards, sauces and some puddings because heat coagulates the protein.
b. As a binding agent - eggs are used to bind other ingredients as in meat leaves, croquettes and yam balls.
c. As leavening or raising agents - egg is used to lighten food. the ( white of an egg is whisked and this introduces air into the food and thus lighten it ( sponge cake and souffles).
d. For glazing: a film thin of egg brushed over rolls, bread and pastries to give a smart , glazed finish.
e. For garnishing or decoration- hard boiled eggs ,sliced thinly are used to garnish salads or others dishes.
f. In emulsifying- eggs are used to stabilize emulsions of two or more liquids which will not mix ,such as oil and vinegar in salad creams.eg. mayonnaise or salad cream.
g. For enriching food: eggs improve the nutritive value of food to which they are added eg. cake, biscuits and doughnuts.
h. For coating - eggs are used to coat foods such as fish or yam balls,meat balls, before frying.
Test for the freshness of egg.
1. A fresh egg should be heavy.
2. The egg should be clear when held towards light.
3. When a fresh egg is broken, the yolk should be floating on top of the thick white and does not matter x with it.
Test for freshness of an egg using the
brine test.
1. Fresh eggs sink in brine.
2. Partial fresh eggs suspend in brine.
3. Stale eggs float in brine .
Storage of eggs.
1. When eggs are to be kept for some time,they should be placed in a suitable tray,( egg rack) or saw dust.
2. Store in a clean,cool place with the rounded side up and the pointed end down.
3. They can be stored in refrigerator ( egg rack apartment).
4. Never wash egg or they will loose their protective shiny surfaces.
5. Eggs should not be stored near strong- scented foods: eg onion, fish.etc.
Suitable methods of cooking eggs
* Frying eg . fried egg, and scrambled egg
* Steaming: eg. steamed egg custards.
*Baking: eg.baked egg custards.
* Poaching:eg.poached egg.
*Boiling:eg boiled egg ( harder soft).