Food tests Flashcards
How do you test for starch?
By adding iodine solution to a sample of food - if it is positive, it will go a blue/black colour
How are proteins tested for?
By using biuret reagent - if the mixture turns blue/purple, protein is present
What is the benedicts test?
It is used to test for carbohydrates like glucose - if the solution turns red, carbohydrates are present
What is the ethanol test?
It is used to test for lipids in a formula - if after adding ethanol it goes cloudy, lipids are present
What are lipids?
Fatty or oily compounds
What colour would the benedicts test go if carbohydrates were not present?
Blue
What happens if an ethanol test is negative?
The solution remains colourless
What would happen if the biuret test was negative?
The solution becomes light blue
What happens if the iodine test is negative?
Solution does not change colour
What does amylase do?
Breaks down starch into glucose
What does protease do?
Break down protein into amino acids
What does lipase do?
Breaks down lipids into fatty acid and glycerol
Why does bread begin to feel sugary after eating it for a while?
Our saliva contains amylase which breaks down the starch into glucose, making it taste sweet
