06 basic cooking principles

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Methods of heat transfer

06 basic cooking principles

  1. 1. Basic Cooking Principles Chef Mehernosh Dhanda2/8/2013 BAC 101 Culinary Foundation Level 1 1
  2. 2. Scope After this session you will be able to:  Know what is heat  How heat is transferred to foods  What is the effect of heat on different constituents of food2/8/2013 BAC 101 Culinary Foundation Level 1 2
  3. 3. What is Heat?  Heat is a type of energy.  When the food item is heated, the molecules absorb this energy they vibrate rapidly, expand & bounce off each other causing the transmission of heat.  The faster the molecules move, the higher is the temperature.2/8/2013 BAC 101 Culinary Foundation Level 1 3
  4. 4. Heat TransferTransmission of heat occurs by: Conduction Convection  Natural  Mechanical Radiation  Infrared  Microwave• Induction2/8/2013 BAC 101 Culinary Foundation Level 1 4
  5. 5. Conduction  The movement of heat from one item to another with direct contact.2/8/2013 BAC 101 Culinary Foundation Level 1 5
  6. 6. Convection The transfer of heat through a medium (liquid/ gaseous) There are two types of convection, namely  Natural  Mechanical2/8/2013 BAC 101 Culinary Foundation Level 1 6
  7. 7. Natural convection  Natural convection occurs due to the tendency of warm liquids/gasses to rise upwards while cooler ones fall2/8/2013 BAC 101 Culinary Foundation Level 1 7
  8. 8. Mechanical convection  Mechanical convection requires a fan or stirring action to circulate heat quickly & evenly.2/8/2013 BAC 101 Culinary Foundation Level 1 8
  9. 9. Radiation Radiation method does not require physical contact between the heat source & the food, instead the heat energy is transferred by waves of heat or light which strike the food There are two types of radiation heat transfer, namely  Infrared  Microwave2/8/2013 BAC 101 Culinary Foundation Level 1 9
  10. 10. Infrared radiation Infrared radiation uses high temperature electric/heat sources which transfer the energy as radiant heat to the food. Eg: The coils of an electric toaster2/8/2013 BAC 101 Culinary Foundation Level 1 10
  11. 11. Microwave radiation Microwave radiation uses high frequency waves which penetrate inside the food & agitate the water molecules , causing friction which in turn increases the temperature & results in cooking2/8/2013 BAC 101 Culinary Foundation Level 1 11
  12. 12. Induction Induction heating is the process of heating an electrically conducting object (usually a metal) by electromagnetic induction Heat is generated directly in the pot or pan (cooking vessel), as opposed to being generated in the stovetop by electrical coils or burning gas2/8/2013 BAC 101 Culinary Foundation Level 1 12
  13. 13. Effects of Heat on Foods  Carbohydrates  Fruit and vegetable fiber  Proteins  Fats  Minerals, vitamins, pigment, and flavor components  Water2/8/2013 BAC 101 Culinary Foundation Level 1 13
  14. 14.  Proteins coagulate  Starches gelatinize  Sugars caramelize  Water evaporates  Fats melt  Fiber is softened  Vitamins and pigments can be destroyed2/8/2013 BAC 101 Culinary Foundation Level 1 14
  15. 15. Cooking Times  Consider:  The cooking temperature  The different speeds of heat transfer  The size, temperature, and individual characteristics of the food2/8/2013 BAC 101 Culinary Foundation Level 1 15
  16. 16. Group assignment Prepare a word document of 500 words on any of the following topics: 1. Green fuels/Eco friendly fuels for commercial food preparation (e.g. Solar cooking) 2. Conserving energy costs in a commercial hotel kitchen2/8/2013 BAC 101 Culinary Foundation Level 1 16
  17. 17. Thank You Sir, didn’t you have a full-faced beard 3 seconds ago?2/8/2013 BAC 101 Culinary Foundation Level 1 17

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