test for components in food

Question 1

what is the test for protein?

Answer 1

• put 1cm of solution in test tube
• add same volume of Biuret’s reagent
• if protein is present, the colour will change from blue to lilac

Question 2

what is the test for glucose?

Answer 2

• put 1cm of solution into test tube
• add same amount of benedict’s agent
• place in 80 degree water bath for 5 mins
• if glucose is present colour will change from blue to brick red

Question 3

what is the test for starch?

Answer 3

• put a couple drops of solution onto a dropper tile
• add one or two drops of iodine solution
• if there is starch present it will change from yellow to dark blue

Question 4

what is the test for fats?

Answer 4

• put 1cm of solution into a test tube
• add the same volume of ethanol
• add similar amount of water
• if fat is present the colour will change from clear to milky white