Food Tests Flashcards
What solution do you add to startch to test the food?
Iodine
What colour is iodine
Yellow/brown
What happens to iodine in the presence of starch?
It turns blue/black
What solution do you use to test for sugar in the food
Benedicts
Why do you have to be careful when using benedicts?
It’s poisonous
What do you have to do to the benedicts and food to activate it
Heat gently
What will the sugar do to benedicts
Turn it orange eventually brick red
What solution do you use to test for protein In the food
Biuret solution
What is in biuret solution
A few drops of copper sulfate and sodium hydroxide
What happens to biuret when protein is present
It turns purple
What solution do you use to test for lipid
Ethanol
How much ethanol do you add
5cm3
How much substance should there be
2cm3
What do you have to do to activate it
Shake the tube
What does shaking it do
Dissolves any lipid
How much water do you add?
5cm3
What do you have to do again
Shake it
What will happen to the lipid
It will turn a cloudy white emulsion
Examples of food with startch
Potato crisps
Examples of food with sugar
Chocolate,biscuits and fruit
Examples of food with protein
Eggs,chicken and fish
Examples of food with fat
Ice cream,meat,butter,chips and dairy
