Describe the Test for proteins ,starch & fats for detecting the presence in the food.......with good explanation,Also the materials required.
Dear student,
Please find below the answer:
Biuret Test: Biuret solution is used to identify the presence of protein. It is a blue solution that contains copper sulphate and sodium hydroxide, when it reacts with protein, will change colour to pink-purple or violet.
Procedure:
Violet colour indicates the presence of proteins in the tested food item.
Regards.
Please find below the answer:
Biuret Test: Biuret solution is used to identify the presence of protein. It is a blue solution that contains copper sulphate and sodium hydroxide, when it reacts with protein, will change colour to pink-purple or violet.
Procedure:
- Take a small quantity of the food items to be tested.
- Grind/mash/paste/powder the food item.
- Put the food item into a test tube.
- Add 10 drops of water to the test tube.
- Add two drops of copper sulphate solution to the test tube.
- Add 10 drops of sodium hydroxide solution and shake the test tube.
- Observe the colour of the mixture.
Violet colour indicates the presence of proteins in the tested food item.
Iodine test: Iodine solution is used to test the presence of starch in a food item.
Procedure:
- Take a paste of food sample.
- Pour iodine solution on it.
- To prepare iodine solution, take tincture iodine and mix it with a test tube half-filled with water.
- If a blue-black colour appears, it indicates the presence of starch
- Take a small quantity of the food item to be tested.
- Wrap the food item on a piece of paper and crush it.
- Straighten the paper.
- Dry the paper by keeping it in sunlight for a while.
- Observe the paper.
- An oily patch on the paper indicates the presence of fats in the tested food item.
Regards.