Food Tests: Multiple Choice Questions

What is the correct reagent to use when testing a food sample for starch?

• Benedict's Solution

• Biuret Solution

• Iodine Solution

• Ethanol

A student adds Benedict's solution to a food sample and places it in a hot water bath. The solution turns from blue to brick-red. What does this result indicate?

• The presence of starch.

• The presence of protein.

• The presence of fat.

• The presence of a reducing sugar.

What is the starting colour of Biuret solution before it is added to a food sample?

• Blue

• Purple

• Colourless

• Brown/Yellow

When testing for protein, a positive result is a colour change from blue to...

• Blue-black

• Brick-red

• Cloudy white

• Purple/Lilac

The ethanol emulsion test is used to identify the presence of which biological molecule?

• Starch

• Reducing Sugar

• Protein

• Fats and Oils

What is the key observation for a positive ethanol emulsion test?

• The solution turns blue-black.

• The solution turns purple.

• A cloudy white emulsion forms.

• The solution stays blue.

A student tests an unknown food sample with iodine solution. The solution stays a brown/yellow colour. What can the student conclude?

• Starch is present.

• Starch is not present.

• Protein is present.

• A reducing sugar is present.

Which food test requires the use of a hot water bath?

• The test for starch.

• The test for reducing sugars.

• The test for protein.

• The test for fats.

Why is it important to wear eye protection during this practical?

• To see the colour changes more clearly.

• To protect your eyes from chemical splashes and the hot water bath.

• To prevent the food samples from being contaminated.

• To keep the ethanol from evaporating.

A student tests a sample of milk. The Biuret test is positive (purple), and the ethanol emulsion test is positive (cloudy). What can be concluded about the milk?

• It contains starch and protein.

• It contains reducing sugar and fat.

• It contains protein and fat.

• It contains only protein.