Food Testing Methods and Indicators

This video tutorial covers essential food tests for GCSE biology practicals, including Benedict's test for reducing sugars, iodine test for starch, Biuret test for proteins, and Sudan III and emulsion tests for lipids. It explains how to prepare food samples and conduct each test, highlighting the expected results and safety precautions.

Which test is used to identify the presence of sugars in a food sample?

• Iodine test

• Biuret test

• Benedict's test

• Sudan III test

What is the first step in preparing a food sample for testing?

• Add Benedict's solution

• Filter the solution

• Crush the food using a mortar and pestle

• Add iodine solution

At what temperature should the water bath be set for the Benedict's test?

• 100 degrees Celsius

• 75 degrees Celsius

• 50 degrees Celsius

• 60 degrees Celsius

What color change indicates the presence of reducing sugars in the Benedict's test?

• Blue to pink or purple

• Clear to cloudy white

• Blue to green, yellow, or brick red

• Brown to blue-black

Which solution is used in the iodine test for starch?

• Iodine solution

• Sudan III solution

• Benedict's solution

• Biuret solution

What color change indicates the presence of starch in the iodine test?

• Clear to cloudy white

• Blue to pink

• Brown to blue-black

• Blue to green

What is the Biuret test used to detect?

• Proteins

• Lipids

• Sugars

• Starch

What color change indicates the presence of proteins in the Biuret test?

• Blue to green

• Clear to cloudy white

• Brown to blue-black

• Blue to pink or purple

In the Sudan III test, what indicates the presence of lipids?

• A pink or purple color

• A blue-black color

• A bright red layer at the top

• A cloudy white color

What is added to the food sample in the emulsion test for lipids?

• Ethanol and distilled water

• Iodine solution

• Biuret solution

• Benedict's solution