Fats and oils - changing properties Flashcards
(19 cards)
What is creaming ?
When fats such as butter are beaten with sugar
How is aeration incorporated when beating butter and sugar together ?
Air becomes trapped in the mixture (aeration)
How does aeration incorporated fats and oils help food production?
The air makes the mcintyre fluffier and lighter in colour.
It gives cake a spongy and light texture when they’re cooked
What is shortening ?
When you rub fat into flour, so that you cover flour particles with fat (giving them a waterproof coating)
What does the water proof coating for the flour particles in shortening ?
It prevents long gluten molecules forming when water is added to the flour
What does shortening to do the dough ?
It means that the dough cannot become stretchy and baked goods like shortbread keep and shirt and crumbly texture
How do fats have plasticity ?
were able to spread and manipulate them
How is it possible to spread and manipulate fats ?
Because they contain a mixture of different triglycerides. These different triglycerides all melt at different temperatures - so fats gradually soften over a range of temperatures rather than melting at just one
What is plasticity useful for ?
-Decorating cakes with butter cream
- Rubbing fat into flour
How are vegetable fat spread ‘easy to spread’ ?
because they contain a mix of triglycerides with low melting points - you can spread it as soon as you get it out of the fridge
How are emulsions formed in oil and water ?
Emulsions are formed when oily and watery liquids are shaken together
What are examples emulsions ?
Milk, margarine and mayonnaise
What stops emulsions separating out again ?
- Keep string and shaking them
- Use an emulsifier
What are the two different end of the molecules in an emulsifier ?
one is hydrophilic side (attracted to water)
One is hydrophobic (repulsed by water)
What happens when you add an emulsifier to emulsions ?
The water molecules bone to the hydrophilic side and the oil molecules bone to the hydrophobic side. Holding the oil and water together in a stable emulsion
What natural emulsifier do egg yolks contain and what is it used for ?
It is called lecithin - used as a emulsifier in margine and mayonnaise
What do you have to ensure you to in a stable emulsion like mayonnaise?
Gradually add the water or oil and mix the ingredients for long enough
how do you make hollandaise sauce?
- Melt the butter in a pan
- Mix the egg yolk and lemon juice in a bowl
- Gently warm this mixture by placing the bowl over a pan of simmering water
- Slowly add the melted butter to the mix, constantly whisking as you do
- Keep whisking the sauce until it’s all mixed together smoothly
what do you have to make sure that you do in a oil in water emulsification?
To add the liquid or emulsifier first before very slowly adding the oil/fat whilst mixing vigourously
