Revision Notes of Ch 2 Components of Food Class 6th Science

Topics in the chapter

  • What are nutrients?
  • Carbohydrates
  • Proteins
  • Vitamins
  • Minerals
  • Fats
  • Roughage
  • Fibres
  • Balance Diet
  • Diseases caused due to the deficiency of various nutrients

What are Nutrients?

→ The food that we eat consists of different nutrients or components.

→ The components of food which are needed by our body is known as nutrient.

→ There are six main components present in food:
Carbohydrates, fats, proteins, vitamins, minerals and fibers.

→ These components fulfill the different needs of the body.


→ Carbohydrates are the compound which is made up of three elements:-
Carbon, Hydrogen and Oxygen

→ Carbohydrate provides energy to our body, which keeps it going throughout the day.

→ The main carbohydrates found in our food are in the form of sugars and starch. If food contains starch we can easily test it.

→ The sources of carbohydrates include cereals such as wheat, maize, rice, jawar, bajra, potatoes, bread etc.

→ We can test the presence of carbohydrates by iodine test.

Test for carbohydrates:

Step 1: Take the food item in the test tube and add 2-3 drops of dilute iodine solution to it.

Step 2: After some time if the colour changes to blue-black, it indicates the presence of starch in the food item.


→ Proteins are the complex compounds made up of carbon, hydrogen, oxygen, nitrogen and sulphur.

→ The sources of proteins are: cheese, egg, soya bean, pulses, meat etc.

→ Protein is known as body-building food.

Test for proteins:

Step 1: Take food item in the test tube and Add 10 drops of water to it and mix well.

Step 2: Now add 2 drops of copper sulphate and ten drops of caustic soda (sodium hydroxide) solution.

Step 3: Mix it well and keep it undisturbed for some time.

Step 3: After some time you observe the development of violet color in the test tube, it indicates the presence or the proteins.


→ Fat also provides energy to our body. Fat gives more energy as compared to carbohydrates.

→ Some sources of fat are oil, ghee, egg yolk, milk, butter etc.

Test for fats:

Step 1: Take some food item in a paper and wrap it.

Step 2: Then try to crush it taking care that the paper is not torn.

Step 3: After that take out the food item and allow the paper to be dried for some time.

Step 4: If you can find the oil spots on the paper it indicates the presence of fats in the food item.


→ Vitamins are a group of organic compound which is essential in small amounts for maintaining normal health and development.

→ Vitamins help in protecting our body against diseases. It helps in keeping our eyes, bones, teeth and gums healthy.

→ There are two types of vitamins some are fat soluble and some are water soluble.

→ Vitamins are of different types: - vitamin A, vitamin C, vitamin D, vitamin E, and vitamin K.
→ There are some other vitamins known as vitamin B complex which contain vitamin B1, vitamin B2, vitamin B3, vitamin B5, vitamin B6, vitamin B7, vitamin B9 and vitamin B12.


→ Minerals perform important functions such as formation of bones, teeth and blood cell and also maintain the normal heartbeat.


→ Roughage is also called dietary fibers.

→ It consist of indigestible plant carbohydrates called cellulose.

→ The source of Roughage is fresh fruits, whole grains and pulses.

Balance diet

→ Our diet should have all the required nutrients in right proportions this should also contain some water and dietary fibers this kind of diet is called as Balanced diet.

→ Balance diet is important for growth and maintenance of good health,

→ It can be very harmful for us to eat too much of fat rich foods and we may end up suffering from a condition called obesity.

Deficiency Diseases

→ Diseases that occur due to lack of nutrients over a long period are called as deficiency diseases.

→ If we do not take a particular nutrient over a long period of time, we suffer from its deficiency.

• Lack of iodine quantity in our body causes Goiter.
• Lack of calcium cause the deficiency bone and tooth decay
• Vitamin A deficiency cause loss of vision
• Vitamin D deficiency cause Rickets
• Lack of iron causes Anemia. 
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