components of food 6th class science

 I n Chapter 1, we made lists of the food items that we eat. We also identified food items eaten in different parts of India and marked these on its map. A meal could consist of chapati, dal and brinjal curry. Another may be rice, sambar and a vegetable preparation of lady’s finger (bhindi). Yet another meal could be appam, fish curry and vegetables.

Activity 1 Our meals usually have at least one item made of some kind of grain. Other items could be a dal or a dish of meat and vegetables. It may also include items likecurd, butter milk and pickles. Some examples of meals from different regions are given in Table 2.1. Select food items you depicted on the map in Chapter 1. Add some more meals to this list and enter these in Table 2.1. Sometimes, we may not really have all this variety in our meals. If we are travelling, we may eat whatever is available on the way. It may not be possible for some of us, to eat such a variety of items, most of the time. 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?

2.1 WHAT DO DIFFERENT FOOD ITEMS CONTAIN? We know that each dish is usually made up of one or more ingredients, which we get from plants or animals. Theseingredients 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. Let us do these tests and record all our observations in Table 2.2. For carrying out these tests, you will need solutions of iodine, copper sulphate and caustic soda. You will also need a few test tubes and a dropper. Try these tests on cooked food items as well as raw materials. Table 2.2 shows you a way to record the observations from these tests. Some food items are 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 inthe form of starch and sugars. We can easily test if a food item contains starch. Activity 2 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?