u CHAPTER 2
Components of Food
We know that each dish is usually made up of one or more ingredients, which we get from plants or animals. The ingredients contain some components that are needed by our body. These components are called nutrients.
Nutrients that are required in large amounts by our body are called macronutrients.
Example: Carbohydrates, Fats, Proteins etc.
Nutrients that are required in small amounts by our body are called micronutrients.
Example: Vitamins, Minerals etc.
Our food consists of seven components These are carbohydrates, fats, proteins, vitamins, minerals, roughage and water. Water is not a nutrient but it is an essential part of food.
Carbohydrates provide us energy. It digests very easily.
Example: Maize, Rice, wheat, Milk, Coconut
etc .
Carbohydrates present in food are:
Starch Example: Rice, Potato
Sugar Example: Sugar (sucrose), Juicy fruits
(fructose), Milk (lactose)
Glucose Example: Grapes, Onion
Fats also provide us energy. Fats give us twice as much energy as carbohydrates. It takes more time than carbohydrates to digest.
Example: Meat, Ghee, Atil, Butter Peanut etc.
Proteins are an important part of our food. Proteins help in growth and repair of the damaged cells in our body. It does not digest very easily. Proteins are required by children more than adults. Proteins are called body building foods.
Example: Eggs, Meat, Pulses, Milk, Beans etc.
Vitamins are substances that occur in our food which we get from plants and animals. Vitamins are necessary for health and protection of the body from diseases. Vitamins are required in small amounts.
Shortage or lack of vitamins in our food may lead to illness.
Vitamin
Sources
Uses
Vitamin A
Green yellow fruits and vegetables like carrot and papaya, Butter, Ghee, cod(fish) liver oil and corn.
For healthy skin and bright eyes . Its deficiency may lead to night-blindness (poor night vision) and dryness of the lining of the mouth.
Vitamin B complex
Yeast, wheat-germ, whole grains, brown rice, beans, porridge, turnip-top, skinned potatoes, bananas, eggs and meat.
Saves from beri-beri (nervous disease) , eyesore and anaemia (not enough blood), Relieves from nerve pain. Protects from skin disorders.
Vitamin C
Orange, lemon and other citrus fruits, aamla,guava, green vegetables. Chemically it is Ascorbic Acid.
Prevents cold, throat and chest infection. Helps in early repair of injuries.
Vitamin D
Milk fat, fish, liver, egg, cheese, butter, edible oils.
Prevents softening and deformation of bone.
Vitamin D is known as 'sunshine vitamin'. Sunrays react with oils of the skin to produce Vitamin D within the body in natural way.
Minerals are elements present in certain substances found in many kinds of food. Minerals are also present in the water we drink. Minerals are necessary for healthy bones, teeth, blood cells and for performing certain important body functions. Our body requires some minerals in large amounts (macrominerals) and some in small amounts (microminerals). For example, calcium and phosphorus are essential for the formation of strong and healthy bones and teeth. We need them in good quantity Some minerals like zinc and iodine are required in traces only.
Mineral
Sources
Uses
Iodine
Green vegetables, iodised salt, sea food, marine fish, coconut water.
For normal body growth.
Phosphorus
Milk, nuts, pulses, wholemeal cereals, fruits, fish and meat.
For utilising proteins in the body. Part of bones and teeth. For transfer of energy.
Iron
Milk, black gram, beans, sesame (til), turnip, green leafy vegetables, egg, fish, liver.
For the formation of haemoglobin in red blood cells.
Calcium
Milk, cheese, pulses, soyabean, green leafy vegetables, mineral water, cashew and dry foods.
For strong bones and teeth. Necessary for clotting of blood.
Dietary fibres are an important port of our food. Dietary fibres are also termed a 'roughage'. Beans, pulses with seed coats, whole grains, unpolished rice, raw fruits, crunchy vegetables and soft stems contribute dietary fibres. They form the bulk of the food and help the movement of food through the food canal. Dietary fibre helps to prevent constipation (indigestion).
WATER, an important part of our food. Water is not a food in itself but it is an essential part of our food. We can live without food for a few days but not without water. Bur body is nearly 70% of water. Water makes the food soft and pulpy and helps its movement through the food canal. Water helps in the removal of wastes from the body (urination, perspiration, and semi-solid wastes). Water is also lost during respiration. Water keeps our skin moist. One should take at least 3 to 4 litres of water in a day. If the loss of water from our body is more and intake is less, it may result in dehydration. Fruits and juices are a good source of water.
That diet which includes all components of food according to age, sex, nature of occupation and environmental conditions is called balanced diet.
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.
If a person does not get enough proteins in his/her food for a long time, he/she is likely to have stunted growth, swelling of face, discolouration of hair, skin diseases and diarrhoea.
If the diet is deficient in both carbohydrates and proteins for a long period of time, the growth may stop completely. Such a person becomes very lean and thin and so weak that he/she may not even be able to move.
Deficiency of different vitamins and minerals may also result in certain diseases or disorders. Some of these are mentioned here.
Vitamin / Mineral
Deficiency disease / disorder
Symptoms
Vitamin A
Loss of vision
Poor vision, loss of vision in darkness (night), sometimes complete loss of vision.
Vitamin B1
Beri-beri
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
Aim: To identify that rice contains starch.
Require materials: Boiled rice, iodine solution, test tube, dropper.
Method: First of all we will take some boiled rice. Then, we will put it into the test tube. After that we will mix a few drops of iodine solution with the help of a dropper. After sometime we will see the boiled rice colour turns into blue-black colour.
Observation: We will see the colour of boiled rice change into blue-black. It happens due to the reaction between starch and iodine solution.
Conclusion/Result: On the basis of above activity it is proved that boiled rice contains starch.
Aim: To identify that gram contains protein.
Require materials: Gram, copper sulphate solution, caustic soda solution, water, test tube, dropper.
Method: Take some gram. Grind or mash it. 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 (sodium hydroxide solution) to the test tube. After sometime we will see the colour of the powder of gram turns into violet colour.
Observation: We will see the colour of the powder of gram change into violet. A violet colour indicates the presence of protein in the food item. It happens due to the reaction between copper sulphate solution, caustic soda solution and protein.
Conclusion/Result: On the basis of above activity it is proved that gram contains protein.
Aim: To identify that groundnuts contain fats.
Require materials: Peeled groundnuts, paper.
Method: Take some groundnuts (peeled). 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. It has an oily patch.
Observation: An oily patch on paper shows that the groundnut contains fat.
Conclusion/Result: On the basis of above activity it is proved that groundnut contains fat.
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