Give a test for the presence of : a)starch b)fat c)protein in a food
Answers
Explanation:
a)starch
a)starch
To know the presence of starch in any given sample of food, the iodine test can be performed. In this, iodine solution is used. In this, few drops of iodine solution is added to the food sample. If starch is present in a food item, it will turn blue-black colour.
b)fat
Fat is a major source of energy and also aids your body in absorbing fat soluble vitamins. You need a minimum of 10 to 20 percent of your overall calories as fat .Test if a food item contains fat.
- Take a small quantity of the food item to be tested.
- Wrap the food item in 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.
c)protein
Proteins are needed for the growth and repair of our body. Foods containing proteins are often called ‘Body Building Foods’. Test if a food item contains protein.
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 and shake the test tube.
Using a dropper add two drops of copper sulphate solution to the test tube.
Add 10 drops of caustic soda solution and shake the test tube.
Observe the colour of the mixture.
Violet colour indicates the presence of proteins in the tested food item.