food tests

Question 1

What is the test for starch?

Answer 1

Iodine solution

Iodine solution is used to identify the presence of starch in food samples.

Question 2

What is the positive result of the starch test?

Answer 2

Blue-black colour

A blue-black color indicates the presence of starch.

Question 3

What does a negative result for the starch test look like?

Answer 3

Orange-brown (no change)

No change indicates that starch is not present.

Question 4

What is the test for reducing sugars?

Answer 4

Benedict’s solution

Benedict’s solution is used to test for reducing sugars, such as glucose.

Question 5

What is the method for the sugar test?

Answer 5

Add Benedict’s solution and heat in a water bath for 5 minutes

Heating is essential for the reaction to occur.

Question 6

What is a positive result for the sugar test?

Answer 6

Colour change from blue → green → yellow → orange → brick red

The specific color change depends on the amount of sugar present.

Question 7

What does a negative result for the sugar test indicate?

Answer 7

Stays blue

A blue color indicates that no reducing sugars are present.

Question 8

What is the test for protein?

Answer 8

Biuret solution

Biuret solution is used to detect the presence of proteins in food samples.

Question 9

What is the positive result for the protein test?

Answer 9

Purple/lilac colour

A purple or lilac color indicates that protein is present.

Question 10

What does a negative result for the protein test look like?

Answer 10

Stays blue

A blue color indicates that no proteins are present.

Question 11

What is the test for lipids?

Answer 11

Ethanol emulsion test

This test is used to identify the presence of fats and oils.

Question 12

What is the method for the fat test?

Answer 12

Add ethanol, shake, then add water

The shaking helps to dissolve the lipids in ethanol.

Question 13

What is a positive result for the fat test?

Answer 13

Cloudy white emulsion

A milky layer indicates the presence of lipids.

Question 14

What does a negative result for the fat test indicate?

Answer 14

Solution stays clear

A clear solution indicates that no lipids are present.

Question 15

What are some tips for conducting food tests?

Answer 15

Use small food samples, test each nutrient separately, heat Benedict’s test gently, compare results with a control

These tips help ensure accurate and reliable test results.