Test food for Starch Protein Fat & Sugar- Science Animation - Class 6th

Before we start our experiment to test the presence of starch in food, let us first understand what starch is?

Starch is a complex carbohydrate present in the food we eat.

Starch is odourless, tasteless and white in colour.

What are the major sources of starch ?

Major sources of starch: Rice, Corn, Wheat and Potatoes.

Let us start our experiment to test the presence of starch in food.

(1) Take a small quantity of rice in a Petri dish.

(2) Make a fine paste of the rice using water.

(3) Put the paste in a test tube.

(4) Add few drops of iodine solution with the help of a dropper.

What do you observe?

The sample turns blue-black which confirms the presence of starch in rice.

Note: Whenever starch reacts with iodine solution, it turns blue-black.



Test food for protein

Before we start our experiment to test food for protein, let us first understand what is protein.

Proteins are large molecules consisting of amino acids which our body and the cells in our body require to function properly. Our body structure, functions, regulation of the body's cells, tissues and organs cannot exist without proteins.

The muscles, the skin, the bones and many other parts in the human body contain significant amount of protein. In fact, protein accounts for 20% of the total body weight.

What are the major sources of protein?

Major sources of vegetable protein: Soyabean, Cereals, Beans and Groundnuts

Major sources of animal protein: Egg, Fish, Meat and Milk

Let us start our experiment to test the presence of protein in our food.

(1) Take a small quantity of mashed beans in a Petri dish.

(2) Put it in a test tube and add some water.

(3) Add a few drops of copper sulphate solution to it with the help of a dropper.

(4) Then add a few drops of sodium hydroxide solution.

What do you observe?

The sample turns purple which confirms the presence of protein in the food sample.

Note: Whenever protein reacts with copper sulphate and sodium hydroxide solution, it turns purple.

Test food for fat

Before we start our experiment to test food for fat, let us first understand what is fat.

Fat is a nutrient essential for normal function of the body and living is not possible without it. Not only does fat supply us with energy, it also makes it possible for other nutrients to do their jobs.



What are the major sources of fat?



Major sources of Fat obtained from plants: Mustard oil, Coconut oil and Dry Fruits.

Major sources of Fat obtained from animals: Butter, Ghee and Cheese

Let us start our experiment to test the presence of fat in food.

(1) Take a small quantity of dry fruits (Cashew, Almonds) in a Petri dish.

(2) Rub it on a clean white paper.

(3) You will observe oily patches on the paper.

(4) Hold the paper against the light to see the oily and translucent patch clearly.

The fat present in the food sample is what makes the paper oily and translucent.



Test food for sugar

Before we start our experiment to test food for sugar, let us first understand what is Sugar.

Sugar is the generalised name for sweet carbohydrates which are soluble in water. They are composed of carbon, hydrogen, and oxygen.

What are the major sources of sugar?

Major sources of sugar: Fruits, Milk, Honey and Jaggery.

Let us start our experiment to test the presence of sugar in food.

(1) Take a small quantity of glucose in a test tube.

(2) Add few drops of Benedict’s solution.

(3) Heat the test tube in water bath.

What do you observe?

The sample turns orange which confirms the presence of sugar in the food sample.

Note: Whenever sugar reacts with Benedict’s solution, it turns orange.

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