Tests for the Presence of Starch, Glucose, Protein

Food substances often contain starch, glucose, and protein. Testing for these compounds will help understand the digestive processes.
To test for Starch:
- A common method involves using iodine solution, which changes colour in the presence of starch.
- In a positive test, the iodine solution turns from its original yellowish-brown colour to a blue-black colour.
To test for Glucose:
- A common method is the Benedict’s test.
- For this test, mix the food with Benedict’s solution and heat the mixture.
- In case of a positive reaction, the solution will change from its original blue colour to green, yellow, orange or red based on the glucose concentration.
To test for Protein:
- Commonly, Biuret test is used to detect the presence of protein.
- In this test, a solution of food is mixed with biuret reagent.
- If protein is present, the mixture will change colour from blue to pink or purple.
These colour-based tests are simple and effective to understand if a certain compound is present in the food.
Understanding these tests is vital for understanding the role and presence of these compounds in our daily diet and how our body processes them during digestion.
These tests also provide a practical context for understanding food chemistry principles taught in biology.