Food Science Flashcards
What are the main reasons food is cooked
Make it safe to eat, change raw to cooked, make it palatable, improve texture, help keep quality, make it easier to digest, give variety to diet
What are the three cooking methods
Wet, dry, fat based
Examples of wet methods
Boiling, steaming, braising, stewing, poaching
Examples of dry methods
Baking, roasting, grilling
Examples of fat based methods
Frying, stirfrying
How to reduce hot spots
Stir food thoroughly ans left to stand to allow the heat to be evenly distributed through the food
What is conduction
Food molecules vibrate to transfer heat via conduction, heat is transferred by contact of heat source of pan to food
What is Convection
Convention takes place in air(in ovens) or liquids, currents occur as heated air or water rises and cooler air or water falls e.g boiling water
What is radiation
Heat energy passing in direct lines to good, energy from microwaves penetrate food to transfer energy
What can denature proteins
Heat, pH, ,mechanical agitation, enzymes
What two proteins does wheat flour contain
Glutenin and gliadin
What does gluten do in bread
Makes it stretchy and elastic
What is shortening
Rubbing fat into flour coats the flour particles in a waterproof layer of fat, when cold water is added to the mix to bind together, the waterproof layers of fat prevent the formation of long gluten molecules only short ones, short gluten molecules allow the product to be crumbly
How can enzymic browning be inhibited
Blanching cut fruit or veg in hot water, dipping fruit or veg in acid, removal of air by submerging in water, blanching veg before freezing
What does oxidation cause
Discolouration, vitamins to be lost, enables enzyme activity,
How can vitamin loss be reduced
Cooking veg in small amounts of water, using a quicker shorter method of cooking, serving veg straight after cooking, keeping lid on when boiling veg
What is plasticity
The ability of fat to change properties over a range of temperatures. Temperature is an important factor
High plasticity-unsaturated fat,very soft ; low plasticity-saturated,very hard
Examples of unsaturated fat
Margarine, veg spread
Example of saturated fat
Lard, butter
What is an emulsion
Emulsions are mixtures of liquids that do not usually mix e.g. oil and water
What does the hydrophilic end of an emulsification
Water-loving
What is the water hating end of an emulsion
Hydrophobic
What is aeration
Fats can trap air bubbles when they are beaten, the trapped air bubbles expand when baking products such as cakes giving a light fluffy texture
What is a biological raising agent
Yeast
What are the physical raising agents
Air, water vapour, steam
Chemical raising agents
Bicarb of soda, baking powder, self raising flour
