Components of Food PDF

1 Components of Food I n lower classes, we made lists of the curd, butter milk and pickles. Some food items that we eat. We also examples of meals from different regions identified food items eaten in are given in Table 1.1. Select foo...

1 Components of Food I n lower classes, we made lists of the curd, butter milk and pickles. Some food items that we eat. We also examples of meals from different regions identified food items eaten in are given in Table 1.1. Select food items different parts of India and marked and enter these in Table 1.1. these on its map. Sometimes, we may not really have A meal could consist of chapati, dal all this variety in our meals. If we are and brinjal curry. Another may be rice, travelling, we may eat whatever is sambar and a vegetable preparation of available on the way. It may not be lady’s finger (bhindi). Yet another meal possible for some of us, to eat such a could be appam, fish curry and variety of items, most of the time. vegetables. There must be some reason though, why meals usually consist of such a distribution. Do you think that our body needs different kinds of food for some special purpose? 1.1 WHAT DO DIFFERENT FOOD ITEMS CONTAIN? Activity 1 We know that each dish is usually made Our meals usually have at least one item up of one or more ingredients, which made of some kind of grain. Other items we get from plants or animals. These could be a dal or a dish of meat and ingredients contain some components vegetables. It may also include items like that are needed by our body. These Table 1.1 Some common meals of different regions/states Region/ Item of grain Item of Vegetables Others State dal/meat Rajma Sarson saag Curd, ghee Punjab Makki (cor n) roti (Kidney beans) (Mustard leaf curry) Andhra Tuar dal and Butter milk, ghee, Pradesh Rice rasam (charu) Kunduru (dondakai) pickle (aavakai) COMPONENTS OF FOOD 1 Rationalised 2023-24 components are called nutrients. The A dilute solution of iodine can be major nutrients in our food are named prepared by adding a few drops of carbohydrates, proteins, fats, vitamins and minerals. In addition, food contains tincture iodine to a test tube half filled dietary fibres and water which are also with water. needed by our body. Copper sulphate solution can be Do all foods contain all these pr epar ed by dissolving 2 gram (g) of nutrients? With some simple methods copper sulphate in 100 millilitre (mL) we can test whether cooked food or a raw ingredient contains one or more of of water. these nutrients. The tests for presence 10 g of caustic soda dissolved in of carbohydrates, proteins and fats 100 mL of water makes the required are simpler to do as compared to the solution of caustic soda. tests for other nutrients. Let us do these tests and record all our observations Activity 2 in Table 1.2. For carrying out these tests, you will Test for Starch need solutions of iodine, copper Take a small quantity of a food item or sulphate and caustic soda. You will also a raw ingredient. Put 2-3 drops of dilute need a few test tubes and a dropper. iodine solution on it (Fig. 1.1). Observe Try these tests on cooked food items if there is any change in the colour of as well as raw materials. Table 1.2 shows the food item. Did it turn blue-black? you a way to record the observations A blue-black colour indicates that it from these tests. Some food items are contains starch. given in this table. You can conduct the tests either with these or any other available food items. Do these tests carefully and do not try to eat or taste any chemicals. If the required solutions are not available in readymade form, your teacher can prepare them as given in the box. Let us begin by testing different food items to see if they contain carbohydrates. 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. Fig. 1.1 Testing for starch 2 SCIENCE Rationalised 2023-24  Repeat this test with other food items and let the test tube stand for a few to find out which of these contain starch. minutes. What do you see? Did the Enter all your observations in Table 1.2. contents of the test tube turn violet? A violet colour indicates presence of Test for Protein proteins in the food item. Take a small quantity of a food item for Now, you can repeat this test on other testing. If the food you want to test is a food items. solid, you first need to make a paste of it or powder it. Grind or mash a Table 1.2 Nutrients present in some small quantity of the food item. food items Put some of this in a clean test tube, add 10 drops of water to it Food item Starch Protein Fat (present) (present) (present) and shake the test tube. Now, using a dropper, add Raw potato Yes two drops of solution of copper Milk Yes sulphate and ten drops of solution of caustic soda to the Groundnut Yes test tube (Fig. 1.2). Shake well Uncooked powdered rice Cooked rice Dry coconut Uncooked tuar dal (powdered) Cooked dal A slice of any vegetable A slice of any fruit Boiled egg (white portion) Fig. 1.2 Testing for protein COMPONENTS OF FOOD 3 Rationalised 2023-24 Test for Fats and carbohydrates are also called Take a small quantity of a food item. ‘energy giving foods’ (Fig. 1.3 and Wrap it in a piece of paper and crush it. Fig. 1.4). Take care that the paper does not tear. Proteins are needed for the growth Now, straighten the paper and observe and repair of our body. Foods proteins it carefully. Does it have an oily patch? Sweet potato Potato Sugarcane Hold the paper against light. Are you able to see the light faintly, through Papaya this patch? An oily patch on paper shows that Wheat the food item contains fat. The food Melon items may sometimes contain a little Mango water. Therefore, after you have rubbed Rice an item on paper, let the paper dry for a while. If there were any water that may Bajra Maize have come from food, it would dry up Fig. 1.3 Some sources of carbohydrates after some time. If no oily patch shows up after this, the food item does not contain any fat. What do these tests show? Are fats, proteins and starch present in all the food items that you tested? Does a food item contain more than one nutrient? Nuts Do you find any food item that does not contain any of these nutrients? We tested food items for three Groundnuts Til nutrients — carbohydrates, proteins (a) and fats. There are also other nutrients like vitamins and minerals that are present in different food items. Why do Meat we need all these nutrients? 1.2 WHAT DO VARIOUS NUTRIENTS DO FOR OUR BODY? Carbohydrates mainly provide energy Eggs to our body. Fats also give us energy. Fish In fact, fats give much more energy (b) as compared to the same amount of Fig. 1.4 Some sources of fats: (a) plant sources carbohydrates. Foods containing fats and (b) animal sources 4 SCIENCE Rationalised 2023-24 Gram Moong Tuar dal small quantities. Vitamin A keeps our skin and eyes healthy. Vitamin C helps Beans body to fight against many diseases. Vitamin D helps our body to use calcium for bones and teeth. Foods that are rich in different vitamins are shown in Fig. 1.6 to Fig. 1.9. Minerals are needed by our body in small amounts. Each one is essential Papaya Peas Soyabeans (a) Carrot Meat Mango Fig. 1.6 Some sources of Vitamin A Wheat Rice Fish Liver Fig. 1.7 Some sources of Vitamin B Paneer Eggs Orange Guava (b) Fig. 1.5 Some sources of proteins: (a) plant Tomato sources and (b) animal sources Green Chilli are often called ‘body building foods’ (Fig 1.5). Lemon Vitamins help in protecting our body Amla against diseases. Vitamins also help in Fig. 1.8 Some sources of Vitamin C keeping our eyes, bones, teeth and gums healthy. Fish 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. Liver Egg Our body needs all types of vitamins in Fig. 1.9 Some sources of Vitamin D COMPONENTS OF FOOD 5 Rationalised 2023-24  Our body also Some sources of iodine prepares Vitamin D in the presence of sunlight. Nowadays, insufficient exposure to sunlight is causing Vitamin D deficiency in many people. Ginger Some sources of phosphorous for proper growth of body and to maintain good health. Some sources of different minerals are shown in Fig. 1.10. Most food items, usually, have more than one nutrient. You may have noticed this, while recording your observations Some sources in Table 1.2. However, in a given raw of iron material, one particular nutrient may be present in much larger quantity than in others. For example, rice has more carbohydrates than other nutrients. Thus, we say that rice is a “carbohydrate rich” source of food. Besides these nutrients, our body Some sources needs dietary fibres and water. Dietary of calcium 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. Fig. 1.10 Sources of some minerals 6 SCIENCE Rationalised 2023-24  Water helps our body to absorb think that, what we need for a balanced nutrients from food. It also helps in diet would depend on the amount of throwing out some wastes from body as physical work that we do? urine and sweat. Normally, we get most Prepare a chart of whatever you eat of the water that our body needs from over a period of a week. Check whether the liquids we drink — such as water, all the nutrients mentioned are present milk and tea. In addition, we add water in one or the other food items being to most cooked foods. Let’s see if there eaten within a day or so. is any other source which provides water Pulses, groundnut, soyabean, to our body. sprouted seeds (moong and Bengal gram), fermented foods (South Indian Activity 3 foods such as idlis), a combination of Take a tomato or a fruit like lemon. Cut flours (missi roti, thepla made from it into small pieces. Do your hands get cereals and pulses), banana, spinach, wet while doing so? sattu, jaggery, available vegetables and Carefully observe whenever other such foods provide many vegetables and fruits are being cut, nutrients. Therefore, one can eat a peeled, grated or mashed at your balanced diet without expensive food home. Do you find any fresh vegetables materials. or fruits that do not contain some Eating the right kind of food is not amount of water? enough. It should also be cooked We see that many food materials themselves contain water. To some extent, our body needs are met by this Paheli wonders whether animal water. Apart from this, we also add water food also consists of these while cooking many food items. different components and do 1.3 BALANCED DIET they also need a balanced diet? The food we normally eat in a day is our 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 properly so that its nutrients are not should also contain a good amount of lost. Are you aware that some nutrients roughage and water. Such a diet is called get lost in the process of cooking and a balanced diet. preparations? Do you think that people of all ages If the vegetables and fruits are need the same type of diet? Do you also washed after cutting or peeling them, it COMPONENTS OF FOOD 7 Rationalised 2023-24 may result in the loss of some vitamins. in fats — fried food like samosa and poori The skins of many vegetables and fruits (snacks), malai, rabdi and peda (sweets). contain vitamins and minerals. Do you think he was right? No, of Similarly, repeated washing of rice and course not! It can be very harmful for pulses may remove some vitamins and us to eat too much of fat rich foods and minerals present in them. we may end up suffering from a We all know that cooking improves condition called obesity. the taste of food and makes it easier to 1.4 DEFICIENCY DISEASES digest. At the same time, cooking also A person may be getting enough food to results in the loss of certain nutrients. eat, but sometimes the food may not Many useful proteins and considerable contain a particular nutrient. If this amounts of minerals are lost if excess continues over a long period of time, the water is used during cooking and is person may suffer from its deficiency. then thrown away. Deficiency of one or more nutrients can Vitamin C gets easily destroyed by cause diseases or disorders in our body. heat during cooking. Would it not be Diseases that occur due to lack of sensible to include some fruits and raw nutrients over a long period are called vegetables in our diet? deficiency diseases. Boojho thought that fats would be If a person does not get enough the best foods to eat, all the time. A katori proteins in his/her food for a long time, (bowl) of fat will give much more energy he/she is likely to have stunted growth, than a katori of carbohydrate rich food, swelling of face, discolouration of hair, isn’t it? So, he ate nothing but food rich 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 in Table 1.3. All deficiency diseases can be prevented by taking a balanced diet. In this chapter, we asked ourselves the reason why widely varying food from different regions had a common 8 SCIENCE Rationalised 2023-24 Table 1.3 – Some diseases/disorders caused by deficiency of vitamins and minerals Vitamin/ Deficiency Symptoms Mineral disease/disorder Poor vision, loss of This is a logo for fortified vision in darkness foods as per standards by Vitamin A Loss of vision FSSAI. Fortification of (night), sometimes complete loss of vision food is the addition of key vitamins and minerals to Vitamin Weak muscles and staple foods such as rice, B1 Beriberi very little energy to wheat, oil, milk and salt to work improve their nutritional content. Bleeding gums, Vitamin C Scurvy wounds take longer time to heal Balanced diet Vitamin D Rickets Bones become soft and bent Beriberi Calcium Bone and tooth Weak bones, tooth Carbohydrates decay decay Energy Glands in the neck Iodine Goiter appear swollen, Fats mental disability in children Minerals Iron Anaemia Weakness Nutrients distribution. This distribution, we find, ensures that Proteins our meals have a balance of the different nutrients needed by the body. Roughage Scurvy The major nutrients in our food are carbohydrates, pro- Starch teins, fats, vitamins and minerals. In addition, food also contains dietary fibres and water. Vitamins Carbohydrates and fats mainly provide energy to our body. Proteins and minerals are needed for the growth and the maintenance of our body. Vitamins help in protecting our body against diseases. Balanced diet provides all the nutrients that our body needs, in right quantities, along with adequate amount of roughage and water. Deficiency of one or more nutrients in our food for a long time may cause certain diseases or disorders. COMPONENTS OF FOOD 9 Rationalised 2023-24  1. Name the major nutrients in our food. 2. Name the following: (a) The nutrients which mainly give energy to our body. (b) The nutrients that are needed for the growth and maintenance of our body. (c) A vitamin required for maintaining good eyesight. (d) A mineral that is required for keeping our bones healthy. 3. Name two foods each rich in: (a) Fats (b) Starch (c) Dietary fibre (d) Protein 4. Tick () the statements that are correct. (a) By eating rice alone, we can fulfill nutritional requirement of our body. ( ) (b) Deficiency diseases can be prevented by eating a balanced diet. ( ) (c) Balanced diet for the body should contain a variety of food items. ( ) (d) Meat alone is sufficient to provide all nutrients to the body. ( ) 5. Fill in the blanks. (a) ______________ is caused by deficiency of Vitamin D. (b) Deficiency of ______________ causes a disease known as beri-beri. (c) Deficiency of Vitamin C causes a disease known as ______________. (d) Night blindness is caused due to deficiency of ____________ in our food. SUGGESTED PROJECTS AND ACTIVITIES 1. Prepare a diet chart to provide balance diet to a twelve year old child. The diet chart should include food items which are not expensive and are com- monly available in your area. 2. We have learnt that excess intake of fats is harmful for the body. What about other nutrients? Would it be harmful for the body to take too much of proteins or vitamins in the diet? Read about diet related problems to find answers to these questions and have a class discussion on this topic. 3. Test the food usually eaten by cattle or a pet to find out which nutrients are present in animal food. Compare results obtained from the whole class to conclude about balanced diet requirements for different animals. 10 SCIENCE Rationalised 2023-24