Chapter - II (VI) (S)

Components of Food

We know that each dish is usually made up of one or more ingredients, which we get from plants or animals. These ingredients contain some components that are needed by our body. These components are called nutrients.

The major nutrients in our food are named carbohydrates, proteins, fats, vitamins and minerals. In addition, food contains dietary fibres and water which are also needed by our body.

Do all foods contain all these nutrients? With some simple methods we can test whether cooked food or a raw ingredient contains one or more of these nutrients. The tests for presence of carbohydrates, proteins and fats are simpler to do as compared to the tests for other nutrients.

There are many types of carbohydrates. The main carbohydrates found in our food are in the form of starch and sugars. We can easily test if a food item contains starch.

Requisites for conducting tests A dilute solution of iodine can be prepared by adding a few drops of tincture iodine to a test tube half filled with water. Copper sulphate solution can be prepared by dissolving 2 gram (g) of copper sulphate in 100 millilitre (mL)of water. 10 g of caustic soda dissolved in 100 mL of water makes the required solution of caustic soda.

Test for Starch

Take a small quantity of a food item or a raw ingredient. Put 2-3 drops of dilute iodine solution on it (Fig. 2.1). Observe if there is any change in the colour of the food item. Did it turn blue-black? A blue-black colour indicates that it contains starch.

Test for Protein

Take a small quantity of a food item fortesting. If the food you want to test is a solid, you first need to make a paste of it or powder it. Grind or mash a small quantity of the food item. Put some of this in a clean test tube, add 10 drops of water to it and shake the test tube.

Now, using a dropper, add two drops of solution of copper sulphate and ten drops of solution of caustic soda to the test tube (Fig. 2.2). Shake well and let the test tube stand for a few minutes.

What do you see? Did the contents of the test tube turn violet? A violet colour indicates presence of proteins in the food item.

Test for Fats

Take a small quantity of a food item. Wrap it in a piece of paper and crush it. Take care that the paper does not tear. Now, straighten the paper and observe it carefully. An oily patch on paper shows that the food item contains fat.

Food items can contain more than one ingredient.

We tested food items for three nutrients — carbohydrates, proteins and fats. There are also other nutrients like vitamins and minerals that are present in different food items.

Role of Nutrients in our body

Carbohydrates mainly provide energy to our body.

Fats also give us energy. In fact, fats give much more energy as compared to the same amount of

carbohydrates. Foods containing fats and carbohydrates are also called ‘energy giving foods’.

Proteins are needed for the growth and repair of our body. Foods containing proteins are often called ‘body building foods’.

Vitamins help in protecting our body against diseases. Vitamins also help in keeping our eyes, bones, teeth and gums healthy. Vitamins are of different kinds known by different names. Some of these are Vitamin A, Vitamin C, Vitamin D, Vitamin E and K. There is also a group of vitamins called Vitamin B-complex. Our body needs all types of vitamins in small quantities. Vitamin A keeps our skin and eyes healthy.

Vitamin C helps body to fight against many diseases.

Vitamin D helps our body to use calcium for bones and teeth.

Minerals are needed by our body in small amounts. Each one is essential for proper growth of body and to maintain good health.

Besides these nutrients, our body needs dietary fibres and water. Dietary fibres are also known as roughage. Roughage is mainly provided by plant products in our foods. Whole grains and

pulses, potatoes, fresh fruits and vegetables are main sources of roughage. Roughage does not provide any nutrient to our body, but is an essential component of our food and adds to its bulk. This helps our body get rid of undigested food.

Water helps our body to absorb nutrients from food. It also helps in throwing out some wastes from body as urine and sweat. Normally, we get most of the water that our body needs from the liquids we drink — such as water, milk and tea.

BALANCED DIET

For growth and maintenance of good health, our diet should have all the nutrients that our body needs, in right quantities. Not too much of one and not too little of the other. The diet should also contain a good amount of roughage and water. Such a diet is called a balanced diet.

Are you aware that some nutrients get lost in the process of cooking and preparations?

If the vegetables and fruits are washed after cutting or peeling them, it may result in the loss of some vitamins. The skins of many vegetables and fruits contain vitamins and minerals. Similarly, repeated washing of rice and pulses may remove some vitamins and minerals present in them.

We all know that cooking improves the taste of food and makes it easier to digest. At the same time, cooking also results in the loss of certain nutrients. Many useful proteins and considerable

amounts of minerals are lost if excess water is used during cooking and is then thrown away. Vitamin C gets easily destroyed by heat during cooking.

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

A person may be getting enough food to eat, but sometimes the food may not contain a particular nutrient. If this continues over a long period of time, the person may suffer from its deficiency.

Deficiency of one or more nutrients can cause diseases or disorders in our body. Diseases that occur due to lack of nutrients over a long period are called deficiency diseases.

All deficiency diseases can be prevented by taking a balanced diet.

Some diseases/disorders caused by deficiency of vitamins and minerals

Vitamin/Mineral	Deficiencydisease/disorder	Symptoms
Vitamin A	Loss of vision	Poor vision, loss of vision in darkness(night), sometimes complete loss of vision
VitaminB1	Beriberi	Weak muscles and very little energy to work
Vitamin C	Scurvy	Bleeding gums, wounds take longer time to heal
Vitamin D	Rickets	Bones become soft and bent
Calcium	Bone and tooth decay	Weak bones, tooth decay
Iodine	Goiter	Glands in the neck appear swollen, mental disability in children
Iron	Anaemia	Weakness

Words to be remembered

Balanced diet

Beriberi

Carbohydrates

Energy

Fats

Minerals

Nutrients

Proteins

Roughage

Scurvy

Starch

Vitamins