Class XI Practical: Physiology - Food Tests

Objective

To identify the presence of starch, glucose, sucrose, proteins, and fats in given food samples using specific chemical tests and record positive and negative results.

Guidelines

1. Preparation: Prepare dilute solutions or suspensions of known samples (e.g., starch solution, glucose solution, egg albumin, oil) and unknown food samples.
2. Test Procedures: Follow standard protocols for each test:
   • Starch: Iodine test.
   • Glucose (Reducing Sugar): Benedict's test (heating required).
   • Sucrose (Non-reducing Sugar): Hydrolysis followed by Benedict's test.
   • Proteins: Biuret test.
   • Fats: Emulsion test (alcohol and water).
3. Observation: Carefully observe color changes, precipitate formation, or other indicators.
4. Recording: Create a table to record observations for both positive and negative controls, and for the unknown samples. Clearly state the inference for each test.

Expected Outcome

A clear understanding of the chemical basis of food tests and the ability to accurately identify major food components.