Biology Topic Practice

Food Tests Practical

Quick test: are you exam ready? Knowing your chemical reagents and their positive colour changes is essential for practical questions.

Do you know which test requires a heat bath?

What is Food Tests Practical?

"Food tests are chemical procedures used to identify the presence of starch, reducing sugars, proteins, and lipids in food samples."

Question 1

What colour change shows starch is present when iodine solution is added?

Question 2

Which result would show protein is present?

Question 3

A food sample gives a brick-red precipitate with Benedict’s solution after heating. What does this show?

Question 4

Which observation is a positive result for the emulsion test for lipids?

Reagent Colours

Starch: Iodine (Orange -> Blue-Black). Sugars: Benedict's (Blue -> Brick-Red after heating).

Proteins: Biuret (Blue -> Purple). Lipids: Ethanol (Cloudy emulsion).

Exam Tip

Always wear safety goggles when handling hazardous reagents like Biuret or Ethanol.

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