Identifying nutrients in real foods
Use the four standard food tests on six real food samples. For each food, predict which nutrients are present, run all four tests, then check your prediction against the mark scheme.
You ran the practical above — now answer as if it were the exam. The namstudy tutor marks your written answers against the mark scheme.
A student tests an unknown food and it turns blue-black with iodine but stays blue with Biuret. Describe what this tells you about the food, and name the reagent and colour change for the positive test.
Explain how you would carry out the emulsion (ethanol) test for a lipid, and why a positive result looks the way it does.
A student says the Benedict's test on their food was 'positive'. Suggest two things they must control to make it a fair test, and state the safety precaution for heating.