Food Tests Required Practical

Question 1

How do you prepare a sample?

Answer 1

• break up food using a pestle and mortar
• transfer to beaker and add distilled water
• stir with glass rod to dissolve
• filter solution to get rid of lumps

Question 2

What do you use to test for sugars?

Answer 2

Benedict’s Test

Question 3

What colour will the solution go if it contains sugars?

What will happen if there’s no sugars present?

Answer 3

• blue colour to green, yellow or brick-red (depending on how much is there)
• no change

Question 4

How do you test for sugars?

Answer 4

• transfer 5cm[cubed] of food sample to test tube
• put water bath at 75*C
• add about 10 drops of Benedict’s solution to the test tube
• leave in water bath for 5 minutes
• take out and observe if there’s change in colour

Question 5

What do you use to test for starch?

Answer 5

Iodine Solution

Question 6

What will happen if starch is present?

Answer 6

the colour will change from browny-orange to black or blue-black

Question 7

What do you use to test for proteins?

Answer 7

Biuret Test

Question 8

What will happen if proteins are present?

Answer 8

colour will change from blue to pink or purple

Question 9

What do you use to test for lipids?

Answer 9

Sudan III Test

Question 10

What will happen if lipids are present?

Answer 10

a layer of bright red will be on the top of the solution

Question 11

What method do you use to test for starch, proteins and lipids?

Answer 11

• put about 5cm[cubed] of the food sample in the test tube

- add a few drops of the testing solution you need to use and gently shake