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Methods of cooking

methods of cooking,advantages,disadvantages,effects of cooking......

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Methods of cooking

  2. 2. Methods of cooking.  Dry, moist, frying and microwave cooking.  Advantages and disadvantages and effect of various methods on food. Made by- SRISHTI
  3. 3. cooking Food preparations help in combining food ingredients in various ways with delicate flavour. Textures and colour with appeal to eyes. Food has to be pleasing in appearance and tastes so that it can be consumed. Understanding the behaviour in specific term helps in choosing best method of cooking. The preparation is an important step in meeting the nutritional need of family. Foods like fruits vegetable and nuts are eaten raw but most of the food are cooked to bring about desirable changes. The process of subjecting food to action of heat is termed “COOKING”
  4. 4. Objectives of cooking 1) Improve the taste and food quality- Cooking improves natural flavours and textures of food Ex- roasting groundnut, cooking rice and roasting coffee seeds improves flavour. Too much cooking lowers the flavour as flavouring compounds are volatile. Over cooked pullav, does not tastes good as well as cooked pullav.
  5. 5. 2)Destruction of microorganism- They are present everywhere and some are useful in making curd, cheese and bread. Some are harmful and causes infection or produce toxins. Ex- clostridium botulins and salmollena. Some moulds produces toxins. Aspergillus flavour produces aflatoxin in groundnut, cereals and spices. One of the most important method of preparation of food against harmful microorganism is by application of heat.
  6. 6. 3) Improves digestibility Cooking soften the connective tissues of meat and the coarse of cereals, pulses and vegetables so that digestive period is shortened and gastrointestinal tracks is less subjected to irritation. Cooking improves the texture and hence it become more chewable. Cooking also contributes the starch granules of pulse and the cereals so that starch digestion is more easy, rapid and complete.
  7. 7. 4) Improves variety By cooking same food can be made into various dishes. Ex- rice can be made into plain, pullav, lemon rice, briyani or combination with pulse or idli. 5) Increases consumption of food- Cooking improves the textures and make food more chewable. Improvement in texture and flavours by cooking increases the consumption of food to meet our nutritional requirement.
  8. 8. 6) Increases availability of nutrients- Raw eggs contain avadin which binds biotin making biotin unavailable to the body. By cooking avadin gets denatured and biotin is available to body. Trypsin inhibitor present in soya beans and deck egg get denatured on cooking availability of protein is improved. Toxin substance from khesari dhal can also be removed by boiling it and throwing away the water. Cooking increases the quality of protein by making some amino acid available to body.
  9. 9. 7) Concentrates nutrients This mat be due to removal of moisture or using combination of food due to cooking procedures. Ex- sweets. 8) Increase antioxidants value- Cooked tomatoes are associated wit greater health benefits, compared to uncooked because the heating processes makes lycopene more easily absorbed by body. Lycopene is the pigment present in tomatoes reduces some kinds of cancers.
  10. 10. Limitation of cooking  Thiamin, which is heat sensible, may be lost during cooking. Water soluble nutrients are leached into water during cooking. Vitamin A and contents may be reduced due to oxidation and heat.  Quality of protein may be reduced due to destruction of certain amino acid during cooking. Ex- bread crust has less quality of proteins compared to inside portion
  11. 11. Preliminary preparation 1) Cleaning-the term cleaning is applicable ta vegetables, fruits and many other food products. It include the discarded portion which is not acceptable and also it include washing. 2) Peeling and stringing- Both these methods involves the removal of non edible or fibrous portion of fruits and vegetable. Ex- peeling of banana and potato; stringing of beans.
  12. 12. . cleaning peeling
  13. 13. .3) Cutting and grating- This is dividing food into smaller pieces, thus helping in easy cooking apart from knife, various other machines are used to cut like food slicer, chopper, grinder and vertical cutter. 4) Sieving- It is done to remove coarse fibre and insects. It is also done in preparing cakes for blending of flour with baking powder. 5) Soaking- Done in water, either plane or salted with sodium chloride or sodium carbonate.
  14. 14. cutting sieving soaking
  15. 15. Cooking methods Heat may be transferred to food during cooking by conduction, radiation or by the energy of microwaves. Water or stream and air or fat or combination of these are used as cooking media. Moist heat involves water and steam. Air or fat used in dry heat. Food can be cooked my microwaves also.
  16. 16. Moist methods (A) BOILING It is cooking method by just immersing them in water at 100 degree C and maintaining the water at the temperature till the food is tender. Water is said to be boiling when large bubbles are seen raising constantly on the surface of liquid and then breaking rapidly. When food are cooked by boiling, the food should be brought to a vigorous boil first and the heat is then turned down, as a violent boiling throughout tends to break the food. The food may be boiled in any liquid which is bubbling at the surface such as stock, milk, juices or syrups. Foods, that are cooked by boiling are rice, eggs, dhals, potatoes, meat and vegetales. Boiling can be done with excess amount of water(egg, potato) or with sufficient water(dhal, upma).
  17. 17. . boiling
  18. 18. . ADVANTAGES 1. It is the most simple method. 2. It does not requires special skill and equipment. 3. Protein soluble starch can be removed and grain are separated. 4. Protein get denatured, starch gets gelatinized and collagens get hydrolysed. 5. Uniform cooking can be done.
  19. 19. . DISADVANTAGE 1. Loss of nutrients- if excess water is used in cooking and water Is discarded, 30-70% of nutrients like vitamin C may be lost. 2. Loss of colour- water soluble pigments like betanins from beetroot my be lost. 3. Loss of flavours and texture- boiled food are can not considered tasty because flavour compound are leaches into water. 4. Time consuming- boiling may take time and fuel may get wasted.
  20. 20. .(B) SIMMERING When food are cooked in a well fitting lid at temperature just below the boiling point. The temperature of liquid is 82-90 degree C in which they are immersed the process is known as simmering. It is useful method when foods have to cooked for a long time.
  21. 21. . ADVANTAGE 1. Food gets cooked thoroughly. 2. Scorching or burning is prevented. 3. Losses due to leaching is minimum. DISADVANTAGE 1. There is loss of heat sensitive nutrients due to long period of cooking. 2. Takes more time and more fuel is required.
  22. 22. (C) Poaching This requires cooking in minimum amount of liquid at temperature of 80-85 degree C that is below the boiling point. Foods generally poached are egg, fish and fruits. For poaching eggs, the addition of little salt or vinegar to cooking liquid lowers the temperature of coagulation. Eggs get cooked quickly by the process.
  23. 23. . Perfectly poached eggs
  24. 24. . ADVANTAGES 1. Very quick method of cooking. 2. Easily digestible since no fat no used. DISADVANTAGES 1. It is bland in taste 2. Water soluble nutrients may be leached into water.
  25. 25. (D) Stewing This is gentle method of cooking in a pan with a tight fitting lid, using small quantities of liquid to cover only half of food. The food above the liquid is cooked by steam generated within the pan. The liquid is brought to a boiling point and then the heat applied is reduced maintain the cooking at simmering temp i.e. 98 degree C. Stewing is slow method of cooking taking from 2-4 hrs depending upon the nature and volume of food being stewed. This method is generally used for cooking cheaper cuts of meat along with some root vegetable and legumes all put in the same cooking pot and cooked in stock or water. The larger cooking time and lower temperature enables tougher meat fibre to become soft. The cooking of meat and vegetables together to make the dish attractive and nutritious since no liquid is discarded.
  26. 26. . Vegetable stew
  27. 27. . ADVANTAGE 1. Loss of nutrients by leaching does not takes place. 2. Flavour is retained. Ex- In making oondhya vegetables are stewed by which flavour is retained.
  28. 28. (E) Steaming This method requires the food to be cooked in steam. This is generated from vigorously boiling water or liquid in a pan so that the food is completely surrounded by steam and not in contact with water or liquid. The water should be boiled before the food is placed in steamer. Here the food gets cooked at 100 degree C. Types of steaming are: 1.WET STEAMING- Here the food is in direct contact with the steams.
  29. 29. . 2. DRY STEAMING- Here double broiler is used for cooking the food in a container over hot or boiling water. This process is used for such preparation as sauces and custards. 3.WATERLESS COOKING- In steaming the food is cooked by steam from added water while in waterless cooking the steam originates from food itself. There is advantages in this case of preventing the transmission of flavor from or to the sealed food.
  30. 30. . Steamed momos
  31. 31. .
  32. 32. . DISADVANTAGES 1. Special equipment are required. 2. Many food cannot be prepared by this method. Ex- cooking whole grains.
  33. 33. (F) Pressure cooking A relative small increase in temperature can drastically reduced cooking time and this fact is utilized in pressure cookers. In this the escaping steam is trapped and kept under pressure so that the temperature of boiling water and steam can be raised above 100 degree C and reduced cooking time.
  34. 34. . Pressure cooking
  35. 35. . ADVANTAGES 1. It takes less time to cook. 2. Different items may be cooked at same time. 3. Fuel is saved. 4. Requires less attention. 5. Nutrients or flavor losses may be less. 6. Food is cooked thoroughly by this method. 7. There is an indication for completion of cooking. 8. There is less chances of scorching or burning.
  36. 36. . DISADVANTAGES 1. Though knowledge of using the equipment is required, other wise accidents can happen. 2. There may be mixing of flavors. 3. Food may be undesirably soft. Ex- of food cooked in pressure cookers are rice, dhal, vegetables, meats, etc.
  37. 37. (G) Blanching This is plunging food into boiling liquid and immersing in cold water. This destroys enzymes presents in food hence used as preparation for preservation. Food products normally blanched are tomatoes, potatoes, almonds, carrots and beans.
  38. 38. .ADVANTAGES 1. Peels can be removed easily. 2. It is preliminary method for canning and freezing. 3. Microorganism present on surface are partially removed. 4. Enzymes bringing spoilage can be inactivated. 5. Blanching causes better exposures of pigments hence improves the color of food products. DISADVANTAGES 1. Part of water soluble nutrients may be lost. 2. Long time blanching undesirably softens the food.
  39. 39. Dry heat methods (A) Grilling or broiling Grilling consists of placing the food below or above or in between a red hot surface. When under the heater, the food is heated by radiation only. Food cooked by grilling are corn, papads, brinjals, phulkas, sweet potatoes. Barbeques are also may be this methods.
  40. 40. . grilling different foods
  41. 41. . ADVANTAGES 1. Quick method of cooking. 2. Less or no fat required. 3. Flavors are improved. DISADVANTAGES 1. Constant attention is required to prevent charring.
  42. 42. (B) Pan boiling or roasting When food is cooked uncovered on heating metal or a frying pan method is known as pan broiling. Ex- groundnuts and chapattis. ADVANTAGES 1. Improves the color, flavor and texture of the foods. 2. Reduces moisture contents of food and increases and improves keeping quality such a in Rava. 3. It become easy to powder. Ex- coriander seeds and cumin seeds after roasting. 4. It is one of the quick method of cooking. DISADVANTAGES 1. Constant attention is required. 2. Losses of nutrients like amino acids occurs when the food becomes brown.
  43. 43. . Roasting of rava
  44. 44. (C) Baking Here food gets cooked by hot air basically it is a dry heat methods of cooking but the action of dry heat is combined with that of steam which is generated while the food is being cooked. Foods baked are generally brown and crisp on the top, soft and porous in the center as in cakes, pudding and breads. The principle involved in baking is the air inside the oven is heated by a source of heat either electricity or gas or wood in case of tandoori. The oven is insulated to prevent the outside temperatures from causing fluctuation in internal temperatures of the equipment.
  45. 45. . Baking
  46. 46. . The temperature that is normally maintained in the oven are 120-260 degree C. The oven has to be heated slightly more than required temperature before placing the food in it. Food prepared by baking are custards, pies, biscuits, pizzas, buns, breads, cakes, tandoori items. ADVANTAGES 1. Flavor and textures are improved. 2. Variety of dishes can be made. 3. Uniform and bulk cooking can be achieved. Ex- bun and bread. DISADVANTAGES 1. Special equipment and skills are required.
  47. 47. Fats as a medium of cooking (A) Sautéing This method involves cooking in just enough of oil to cover the base of pan. The food is tossed occasionally or turned over with a spatula to enable all pieces to come in contact with the oil and get cooked evenly. Sometimes the pan is covered with lid, reducing the flame and allowing the food to be cooked till tender in its own steam. The product obtained in cooking by this method is slightly moist, tender but without any liquid or gravy. Foods cooked by sautéing are generally vegetables used as side dishes in a menu. The heat is transferred to the food mainly by conduction.
  48. 48. . Sautéing vegetables
  49. 49. . (B) Shallow fat frying Here the food is cooked in fat or oil but not enough to cover it. Heat is transferred to the food partially by conduction by contact with the heated pan and partially by convection currents of foods. This prevents local burning of the food by keeping away the intense heat of frying pan. Ex- paranths, chapattis, fish, cutlets and tikkas. The finished dish will be crispy brown outside, soft and tender inside. The iron content of food increase when iron tavas are used. Non stick coating frying pan can be used.
  50. 50. . Shallow frying
  51. 51. .(C)Deep fat frying Food is totally immersed in hot oil and cooked by vigorous convection currents and cooking is uniform on all sides of the foods. Cooking can be rapidly completed in deep fat frying because the temperature used is 180- 220 degree C. In most foods, this high temperature results in rapid drying out of surface and the production of a hard crisp surface, brown in color. The absorption of fat by the food increase the calorific value of food. Generally some 10% of oil is absorbed but larger amount of fat is absorbed when oils are used repeatedly. Samosa, papads, chips, pakodas, etc are made by deep fat frying.
  52. 52. . Deep frying of samosas
  53. 53. .ADVANTAGES 1. Tastes is improved, along with the textures. 2. Increase the calorific value. 3. Fastened method of cooking. 4. In shallow frying, the amount of oil consumption can be controlled. DISADVANTAGES 1. Sometimes the food may become oily and soggy with too much absorption of oil. 2. More attention is required while cooking. 3. The food becomes very expensive. 4. Fried food takes long time to digests. 5. Repeated use of heated oils may produce harmful substances and reduce the smoking point.
  54. 54. Microwave heating Electromagnetic waves from a power source magnetron are absorbed by the food and food becomes hot at once. Does, microwaves do not requires any medium of transfer of heat in cooking? The microwaves can be absorbed, transmitted or reflected. They are reflected by metal and by food. When food is kept in the cavity of the microwave oven for cooking, the microwaves generated by the magnetron strike the food and the metal walls of the oven. Microwaves that strike the metal walls are reflected and bounced back so they dispersed throughout the oven and accomplish uniform heating of the food. Cooking with microwaves differs from conventional cooking methods because the heat is generated inside the food rather than transferred to the exterior of the food by conduction, convection or radiation.
  55. 55. .The energy of these electro magnetic radiation excite the water molecule in food which bear a positive electrical charge in one position and negative charge in other position of the molecule. When the electric field of the micro waves interact with the water dipole, the water molecules get to vibrate very rapidly in food. This vibration produce friction that creates heat within in the food as the microwaves are able to penetrate. The efficiency of microwaves cookery depends heavily upon the constitution of the food being cooked. Different components of the food will interact with the microwave radiation at various rates. The most important material in any food is water. Microwave cooking enhances the flavor of food because it cooks quickly with little or no water and thus preserves the natural color and flavor of foods.
  56. 56. . Microwave cooking
  57. 57. Practical hints in using microwave oven.Do not use the oven for home canning or the heating of any closed jars. Pressure will build up and jars may explode. Small quantities of food with low moisture content can dry out, burn or catch on fire.  Do not dry metal, herbs, fruits and vegetables in the oven. Do not attempt to deep fry in microwave ovens. Cooking oils may burst into flames.
  58. 58. . Do not heat eggs in their shells in microwave oven pressure will build up and the eggs will expload. Do not use paper bags or recycled paper product in the microwave oven. if the food is wrapped, the wrapper should be perforated or otherwise allow for steam to escape to prevent it from bursting Always cook food for the minimum cooking time. Once over cooked, nothing can be done
  59. 59. Advantages  Microwave oven cooks many food in about 1/4th of the time necessary on gas burner. There is no wastage of energy.  It saves time in heating frozen foods. Thawing can be done in minutes or seconds.  Only the food is heated during cooking the oven or utensil does not get heated except under prolonged heating period.  Flavour and texture do not change when reheated in microwave oven.
  60. 60. .  Loss of nutrients is minimised. Beta-carotene and vitamin C are better retain.  After cooking in this washing dishes is much easier as food does not stick to sides of the vessels.  Food gets cooked uniformly.  Preserves the natural color and flavour of vegetables and fruits.  No fat or low fat cooking can be done.
  61. 61. Disadvantage  Due to short period of cooking, food does not become brown unless the microwave has a browning unit.  it is not possible to make chapattis or tandoori roti in it. It can not cook soft or hard boiled eggs. Deep frying necessary for puris, jalebis, pakodas, vadas can not be done in it.  Sometimes unwanted chemicals migrate to food from plastic cookware or food packages. Only “microwave safe” should be used.  The short cooking time may not give a chance of blending of flavours as in conventional methods.  The operator should be careful in operating the microwaves ovens since any exposure to microwaves oven causes physiological abnormalities.
  62. 62. Effects of cooking on Food  If vegetables are cooked in water containing salt & the cooking water discarded . This results in loss of minerals like sodium, potassium and calcium.  Cutting vegetables into small pieces and exposing them to air may result in loss of Vitamin C.  Water soluble vitamins are lost during excessive washing as in repeated washing of legumes, rice, etc. Washing may remove as much as 40 % thiamine & nicotinic acid.  Cooking for long periods results in vitamin loss. If fat is repeatedly used in frying, it may contain toxins due to peroxidation and rancidity.  Excessive heating of milk with lactose & other foods with Jaggery may affect protein quality as it may lead to browning.
  63. 63. . Thank You..