Nutrition And Food Tests Flashcards
What is protein used for?
Growth and repair of cells
What is fat used for and what can it be broken down into?
Fat is used for eneegy and insulation and can be broken down into fatty acids and glycerol
What do carbohydrates, protein and fats all contain?
Carbon, hydrogen and oxygen
What do proteins also contain?
Nitrogen
How do you test for starch?
- Put some starch solution in a test tube and add a few drops of iodine solution
- The solution will turn from yellow/brown to blue/black
How do you test for glucose?
- Put some glucose solution in a boiling tube and add some benedicts solution.
- Put the boiling tube in a beaker of boiling water
- The solution will turn from blue to brick red
How do you test for protein?
- Put some protein solution into a test tube and add a few drops of copper sulphate solution.
- Add a few drops of sodium hydroxide solution
- The solution will turn purple
How do you test for fat?
- Add some ethanol to some cooking oil then shake the test tube
- Add the same amount of water as ethanol and shake again
- The solution will turn white
How can you investigate the amount of energy in food?
By placing burning food held on a pointed needle underneath a test tube with water in it and measuring how much the temperature increases.
What equation is used to calculate how much energy is in a food sample?
Energy released in joules (J) = mass of water (g) X rise in temperature (degrees C) X 4.2
How can you make it a fair test when comparing the amount of energy in different foods?
- Keeping the same amount of water in the test tube
- Keeping the same amount of each food
- Keeping the flame at the same distance from each test tube
How is some energy lost during the food test?
- Some energy heats up the air
- Some heats up the water
- Some heats up the glass
