Food Tests P1

Question 1

What test can test for sugar?

Answer 1

Benedict solution

Question 2

What can be used to test for starch?

Answer 2

iodine solution

Question 3

What can be used to test for proteins?

Answer 3

Biuret Test

Question 4

What can be used to test for lipids?

Answer 4

Sudan 111

Question 5

How can you prepare a food sample?

Answer 5

1. get piece of food and break using pestle and mortar
2. transfer food to beaker and add distilled water
3. stir using glass rod to dissolve some food
4. filter solution using funnel lined with filter paper to get rid of solid bits of food

Question 6

Explain a test for sugars

Answer 6

Benedict’s test

1. prepare food sample and transfer 5cm^3 to test tube
2. prepare water bath at 75 degrees
3. add benedicts solution using a pipette 10 drops
4. leave in water bath for 5 minutes making sure tube is pointing away
5. if contains sugar it will vary between blue - green - yellow - brick-red depending on sugar content

Question 7

Explain the test for starch

Answer 7

use Iodine solution

1. make food sample and transfer 5cm^3 to test tube
2. add a few drops of iodine solution and gently shake to mix is brown-orange then non starch
   if black or blue-black then present

Question 8

How do you test for proteins?

Answer 8

Biuret test

1. prepare sample and transfer 2cm^3 to test tube
2. add 2cm^3 biuret solution to sample and gently shake
3. if contains then will change from blue to purple otherwise will stay blue

Question 9

How do you test for lipids?

Answer 9

Sudan 111 stain solution

1. prepare sample and transfer 5cm^3 to test tube
2. use pipette add 3 drop of sudan solution and gently shake
3. it will stain lipids so if contains then it will seperate into two layers the top would be red.