Question

you have been supplied with a sample of food .how will you perform tests for the presence of starch and proteins in it

Answer 1

for the present of starch we add iodine to food if colour turns to blue black it means starch is present in food and vice-versa i don't know about protein so I m soory about it

Answer 2

Answer:

Test for starch

• Take the food sample. put it into a test tube containing water and boil to make a solution.
• Cool the solution and add 2-3 drops of dilute iodine solution to it.
• Blue-black colour of the solution indicates the presence of starch in the food item.

Test for proteins

• Take a small quantity of the food item to be tested. mash 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.
• violent colour indicates the presence of proteins in the tested food item.