food & its digestion.pdf

Our Food arid Its CHAPTER Digestion Warm-Up Abhinav pasted the pictures of some food items on a chart paper. He placed some pictures wrongly.Put a cross (X) on those pictures which are...

Our Food arid Its CHAPTER Digestion Warm-Up Abhinav pasted the pictures of some food items on a chart paper. He placed some pictures wrongly.Put a cross (X) on those pictures which are placed incorrectly. Protective Food  requirement of all living Food is the basic Do You Glucose is the simplest for our growth, beings. We need food provides Know? and survival. Food development perform energy which we require to us with our body and it also various functions of against diseases. protects the body Activity 1 NUTRIENTS IN FOOD To test for the presence contains substances that Aim: in a food. The food we eat These substances starch (carbohydrate) keep our body healthy. give Procedure nutrients Some nutrients are called us to grow and piece of food and some help Crush a small quantity of water. us energy, add a small from diseases. others protect us and cool. by our body are Boilit for a minute The nutrients needed and vitamins carbohydrates,proteins, fats, Add a drop of iodine and water minerals. Though roughage they are do not provide any nutrient but proper required in small quantities for the functioning of our body. Carbohydrates Carbohydrates are the main source of energy for our body. They provide energy that helps to keep our body warm. Small piece Water Sugar and starch are common carbohydrates. of food Sugar is present in all fruits, while starch is Conclusion present in rice wheat, potato, etc. Some If blue colour appears in the solution, examplesof food rich in carbohydrates are then the food contains starch. If blue colour does not appear in the solution, then the food does not contain starch. Proteins Potato Proteinsare found in body-building foods which help in growth, so they are very important for the growing children like Honey you. Proteins also help in repairing of Sweet Potato Sugar damaged cells in our body. Foods rich in carbohydrates Some examples of food rich in proteins are given below Activity 2 Aim:To test for the presenceof fat in a food. Procedure Eggs Fish Crush a piece of food sample on a piece of white paper, Rub it cm a paper. Conclusion If the white paper turns oily/ Cheese translucent; then the food material Dai containsfat or oil. Milk Chicken Foods rich in proteins Fats Vitamins Fats give us more energy than Vitamins are essential for the growth carbohydrates.They also help to keep our and maintenanceof our body We need skin smooth. Oil, ghee, butter and nuts are vitamins A, C, D, E, K and B-complex in some examples of foods rich in fats. small quantities. Table 1: Vitamins, Effects and Sources. Ghee Itamins Effects Sources Butter Vitamin A Promotes Green leafy growth, helps vegetables, Ghee night vision pumpkin, etc. oil Vitamin C For healthy Lemon, or- teeth and ange, amla, gums etc Nuts Vitamin D For normal Milk, eggs, foods rich in fats growth of exposure to Extrafat can be stored in our body and bones and sunlight, etc. insulates it from cold weather. However, teeth mostof our energy needs are met by the Vitamin E For normal Tomatoes, carbohydrates we eat. reproduction germinated gram, butter, etc 51  Fot Cabbage, fresh fruits. It helps to remove caul'f'o aet. materials from our body eaa s yolk, imory etc Soya bean t.atth vegetables ete Foods rich (n roughage are oeded for normal functioning Water boey they are required by our body Water is not a very s:natl quantities nutrient but is 2: Mu'erais Effects and Sources needed by our body for proper M*æraG Eff«ts Sources functioning of Yon For formation ; Spinach, our body It helps Of blood jaggery, eggs, us to digest our groundnut, food and remove etc. Water—ElLrir to life waste from the iodine For formation Iodised salt, body. Upto 75% of our body weight is of protein fish water. It is lost from our body every day C.aicij-gn For formation Milk, fish, so we need to drink 8-10 glasses of water of bones and meat, green vegetables and green DIFFERENT FOOD REQUIREMENTS leafy, Different people have different foot v etables requirementsdepending on their age anc F wds containing vitamins and minerals nature of their work. are cafåed protect Infants are fed mostly on milk or semi- us from many diseases. solid food. Roughage Growing children need a lot of energy to play and study. They need food rich Roughage is the fibre which cannot be in carbohydrates and fats. They also digested by our body. We get roughage need lots of proteins in their food as from leafy vegetables, salads, cereals and they are growing. SEAROi MIRROR fibre: part of a plant that we eat which is good for us  Adults need less proteins as they do Body„building foods (proteins) not grow further in size. They need Oily foods (fats) energy rich food as they have to work. Protectivefoods (vitamins and minerals) Old people need less energy as their physical activities are less. Their DIGESTION OF FOOD diet should include fresh fruits and We eat a variety of foods every day The vegetables, light protein diet like food we eat is broken down into simpler porridge or pulses. substances.The process of breaking down peoplewho do a lot of physicalwork of food into simpler substances is called such as sportspersons and labourers digestion. Many organs work together need a lot of carbohydratesas their to digest and absorb the food and form requirementof energy is more. digestive system. Quick Check Choose the correct answers. Mouth 1. Most of r energy needs are met by Food pipe the (fa carbohydrates)we eat. 2. Foods of rich in proteins called (energy- giving/ body- I ding) foods. Liver 3. Roughage is the (fi re/fit) in our food. 4. Foods rich in (vitamins/proteins) Gall Il Stomach bladder protect us from—eyediseases. 5. (Iodine/ Iron) helps in the formation Pancreas of blood. Large intestine BALANCED DIET Small The food we eat daily is called our diet. intestine A diet that contains the required amount Human digestive system of all the nutrients in correct proportion is called balanced diet. Do You No food contains all the nutrients in the The juices that help in fast digestion Know? are knownas enzymes. necessary amounts. Therefore, we should eat a variety of foods every day. A balanced diet should contain food items from each Mouth: The taking of food in the mouth of these groups. is called ingestion. Our mouth has teeth, Energy-giving foods (carbohydrates tongue and salivary glands. and fats)  Teeth help in biting, chewing and 50 grinding the food. Do You Liver is the largest gland present Tongue helps in swallowing the human body Salivary glands secrete saliva which breaks carbohydrates into sugars. Quick Check This is the reasonyou feel rice or Fill in the blanks with the correct words. bread sweet when you chew it for 1. The taking of food in the mouth a long time. called (egestion/ inge'tion) Food pipe: Food passes from the mouth 2, Saliva br through a thin long tube called the food carbohydrates) into sugars, pipe and reaches the stomach. 3. Useful nutrients are sorbed in the (small in estine/large Stomach: The stomach is a hollow and intestine). u'/ muscular bag where food stays for three 4. (Liver/ Pancreas) is the hours. It produces juices which break largest gland presentin our body. down food further. The proteins present 5. Waterfrom the undigestedfood is absorbed in the (small in the food break down into simpler forms. intestine/ larg ntestine). From the stomach, the food is pushed into a long tube called small intestine. HEALTHY EATING HABITS Small Intestine: The juices produced in the We must follow some healthy eating habits small intestine are called intestinal juices. Eat enough fruits and green vegetables The juice from glands liver and pancreas every day. are also poured into small intestine. These juices breakdown the food completely. Drink plenty of water every day. Then all the useful nutrients are absorbed Do not overeat. by the blood and taken to all the parts of Do not eat junk food. the body. Have food at fixed times. Large Intestine: Food that cannot be Rinse the mouth thoroughly after eating. digested in the small intestine comes into COOKING OF FOOD the large intestine where water is absorbed Most of our food items are cooked and by it from the undigestedfood and makes eaten. Some food items are eaten raw like the food semi-solid. fruits, nuts and some vegetables. Whenever Anus: The semi-solid waste is passed out we eat raw vegetables or fruits, we should of the body through the anus and this is wash them before eating. These raw fruits called egestion. and vegetables provide more minerals and vitamins. 54  foods are cooked before eating. some Washingfruits and vegetables Cookingoffood Half-cooked food is hard to chew and Thereare different ways to cook food. digest The food should be cooked Boilinge.g. rice and potato. properly for sufficient time, so that it Steaminge.g. idlis and dhoklas is soft enough to eat and digest. Fryinge.g. puris and bhature The water in which pulses are soaked can be used for cooking as it is rich in Bakinge.g. cakes and bread. vitamins and minerals. Roastinge.g. potatoes and meat. Takejust enough water to boil the food Importanceof Cooking Food items otherwise we have to throw the Cooking makes food tasty and chewable. water with the absorbed nutrients. It makesfood more appetising. Over cooking should not be done as it It makes food soft and helps in easy destroys the nutrients. digestion. FOOD PRESERVATION It improvesthe quality of food. Food if kept for a long time gets spoilt It helps in killing many germs that cause Microorganisms act on this food and make diseases the food unfit for eating. To prevent food from getting spoilt we need to preserve Precautions Before or While Cooking it. The method used to preserve the Uncoveredcooked food and cut nutritionalvalue of food for a long time fruits and vegetablesgather germs and dust is called food preservation. on their so we should always keep our Advantages of Food Preservation food covered. It decreasesthe food wastage. We should always wash the fruits and It increases the shelf life of food materials. vegetables before cutting. If we Preserved food is available out of wash them after cutting, water season also. soluble vitamins and mineralswill be washed away. SEARCH MIRROR appetising: Food that looks or smells attractive, makes you feel hungry I 55 shelf life: The length of time for which a product or food can be kept  Foodstuffs like milk, bread, vegetabl% Activity 3 eggs, fruits and cooked food can b preservedby keeping them in refrigerator To show tJ e spoilage of food. Canning: Some foodstuffs can be storeo Procedure in air-tight containers. Bacteria and 0th Take two slices germs cannot grow in them as they dc of bread. not get air and moisture. Fruit juices and keep one slice outside for 2-3 sweets are canned for preservation. days ard keep Boiling: Boiling it moist- at very high Other SpotTt Bread slice temperature kills slice in the refrigerator. germs. It helps after 2—3days. in preserving A brownish green layer is seen on liquid foods like B..ebread slice which was kept outside. It means it is spoilt and milk. cannot be eater'. Drying: Some Boiling The bread slice kept in the vegetables like refrigerator does not get spoilt and can be eater.E carrot, peas and cauliflower are dried and Conclusion preserved and are used in off season. Air and moisturecan spoil the food When the foodstuff is dried, bacteria and if kept for a lorg time. other germs cannot grow, as there is no moisture.In this way, foodstuff can be Methods of Preservation of Food saved from spoilage. Cookå or uncooked food an be preserved byt Pickling: Food can be stored by adding Refrigeration: Germsdo not grow at low certain chemicals known as preservatives. temperatures. A commonly used preservative is salt. Salt and oil are used for making pickles from vegetables like cauliflower, raw mango, chilly and lemon. Vinegar is also used to preserve some pickles. Making jams: Most of the fruits can be made into jams by adding sugar. Excess sugar is also a good preservativelike salt. Microbes cannot grow in jams because of excess sugar. Refngeration  Flowchart Food Nutrients in Different Food Balanced Digestion of Healthy Eating FOOd_ Requirements Diet Food Habits Carbohydrates Mouth Proteins Food pipe Fats Stomach Vitamins Small Intestine Minerals Large Intestine Roughage and Anus Water.04 Cooking of Food Food Preservation Methods of Preservation Importance of cooking food of Food Precautionsbefore or while cooking Refrigeration Canning Boiling Drying Pickling Making Jams Quick Scroll V Foodis the basic requirement for all living things. V The food we eat contains nutrients such as carbohydrates, proteins, fats, vitamins and minerals. V Waterand roughage are also important for our body to do many functions. V Differentpeople have different food requirements depending on their age and work. V Balanceddiet contains the required amount of all the nutrients in correct proportion. anus V Differentorgans such as mouth, food pipe, stomach, small intestine, large intestine and togethermake a digestive system, V Cooking makes food tasty, soft and appetising and also helps in proper digestion. V Boiling steaming, frying, baking and roasting are some ways of cooking food, drying or making jams. V We can preserve the food by refrigeration, boiling, canning, pickling, 57