How can you prove that congee contains carbohydrates ?

Explanation

Aim : To confirm the presence of carbohydrates in congee.
Materials : Dilute iodine solution, congee, bowl, dropper,
Procedure :
1) Take some congee water in a small bowl.
2) Add two drops of iodine to the congee water.
3) If carbohydrates are present in water, it will turn into blue-black colour.
Observation : Congee water turns into blue-black colour.
Inference : Carbohydrates are present in congee water.