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Flashcards in C1a Deck (9)
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1
Q

What are additives and what are some?

A
  • substances added to foods improve flavour, colour or prolong expiry
  • food colours make food look more appetising
  • flavour enhancers bring out the taste and smell of food without adding their own taste
  • antioxidants help to preserve food
  • emulsifiers help oil and water blend together in foods
2
Q

What is the structure of an emulsifier?

A
  • hydrophobic (likes oil) tail

- hydrophilic (likes water) head

3
Q

What is an emulsion?

A
  • a mixture of oil and water

- made up of lots of droplets of one liquid suspended in another liquid

4
Q

How do emulsifiers work?

A
  • stops oils and water separating
  • when you shake a oil and water together the oil with an emulsifier the oil forms droplets, bonded to a coating of emulsifier
  • the hydrophobic end is bonded to the oil, and the hydrophilic end is facing onward
  • other oil droplets are repelled by the hydrophylic head, while water latches on
  • the emulsion won’t separate
5
Q

Why are many foods cooked?

A
  • better texture and taste
  • easier to digest cooked
  • high temperature kills microbes that cause diseases
  • some foods are poisonous raw, e.g. kidney beans
6
Q

How are eggs and meat changed in cooking?

A
  • egg and meat are proteins
  • energy from cooking breaks some chemical bonds in the protein and allows its molecules to change shape
  • this is denaturing
  • a chemical change and irreversible
  • giving food a more edible texture
7
Q

How are potatoes changes during cooking?

A
  • potato cells have rigid cell walls made of cellulose
  • human’s cannot digest cellulose
  • cooking potatoes ruptures the cell walls and the starch grains inside the cell swell up and spread out
  • making the potato softer, more flexible and easier to digest
8
Q

What happens when baking powder is is heated?

A
  • thermal decomposition

- sodium hydrogencarbonate—>sodium carbonate+carbon dioxide+water

9
Q

What is thermal decomposition?

A
  • a substance breaking down into a simpler substance when heated
  • many thermal decomposition need catalyst