FACTORS TO BE CONSIDERED WHEN 
     FACTORS TO BE CONSIDERED WHEN 
                      PLANNING A MEAL
                      PLANNING A MEAL
    Nutrition- balanced meal.             Time available.
      Nutrition- balanced meal.              Time available.
    Follow healthy eating guidelines.     Knowledge & skill.
      Follow healthy eating guidelines.      Knowledge & skill.
    Requirements of age-group being       Budget.
      Requirements of age-group being        Budget.
      served.                             
      served.                                Availability of ingredients.
                                             Availability of ingredients.
    Special diets e.g. coeliac.          
      Special diets e.g. coeliac.            Availability of equipment.
                                             Availability of equipment.
    Variety- tastes, colour, texture, 
      Variety- tastes, colour, texture, 
      cooking methods.
      cooking methods.
  CHANGES THAT HAPPEN DURING FOOD 
  CHANGES THAT HAPPEN DURING FOOD 
                       PREPARATION 
                       PREPARATION 
                                             Chemical changes
           Physical Changes                  Chemical changes
            Physical Changes
                                    Colour change e.g. 
     Increase in size e.g. soaking     Colour change e.g. 
     Increase in size e.g. soaking 
                                       enzymatic browning.
     dried food.                       enzymatic browning.
     dried food.
                                    Nutrient loss e.g. enzyme 
     Thickening e.g. whipping          Nutrient loss e.g. enzyme 
     Thickening e.g. whipping 
                                       oxidase destroys vitamin C.
     cream.                            oxidase destroys vitamin C.
     cream.
                                    Tenderising e.g. proteolytic 
     Loss of nutritive value e.g.      Tenderising e.g. proteolytic 
     Loss of nutritive value e.g. 
                                       enzymes tenderise meat 
     water - soluble vitamins          enzymes tenderise meat 
     water - soluble vitamins 
                                       fibres.
     dissolve into water.              fibres.
     dissolve into water.
                                    Increase in size e.g. yeast 
     Tenderising e.g. meat is          Increase in size e.g. yeast 
     Tenderising e.g. meat is 
                                       dough expands as 
     tenderised by beating,            dough expands as 
     tenderised by beating, 
                                       enzymes make CO  .
     mincing.                          enzymes make CO  .
     mincing.                                             2
                                                          2
         CHANGES THAT HAPPEN DURING 
         CHANGES THAT HAPPEN DURING 
                         COOKING OF FOOD 
                         COOKING OF FOOD 
               Physical Changes                             Chemical Changes
               Physical Changes                             Chemical Changes
    Texture changes e.g. cell walls soften      Maillard reaction – when amino acids 
       Texture changes e.g. cell walls soften      Maillard reaction – when amino acids 
       in vegetables.                              & carbohydrates are heated together, 
       in vegetables.                              & carbohydrates are heated together, 
                                                  the food turns brown.
       Bacteria killed.                            the food turns brown.
       Bacteria killed.
                                                Caramelisation - sugar heated above 
       Nutrient loss e.g. vitamins &               Caramelisation - sugar heated above 
       Nutrient loss e.g. vitamins &               dissolving point turns brown e.g. 
       minerals dissolve into cooking liquid.      dissolving point turns brown e.g. 
       minerals dissolve into cooking liquid.      toffee.
    Food solidifies e.g. egg protein              toffee.
       Food solidifies e.g. egg protein 
                                                 Dextrinisation - long starch chains 
       coagulates.                                 Dextrinisation - long starch chains 
       coagulates.                                 break into shorter chains called 
    Food thickens e.g. gelatinisation of          break into shorter chains called 
       Food thickens e.g. gelatinisation of        dextrins & a  brown colour develops 
       starch.                                     dextrins & a  brown colour develops 
       starch.                                     e.g. toasting bread.
                                                   e.g. toasting bread.
    Shrinkage - protein coagulates & 
       Shrinkage - protein coagulates & 
       shrinks e.g. meat.
       shrinks e.g. meat.
      REASONS FOR COOKING FOOD
      REASONS FOR COOKING FOOD
   To destroy pathogenic bacteria making food safer.
    To destroy pathogenic bacteria making food safer.
   To destroy enzymes and prevent food spoilage.
    To destroy enzymes and prevent food spoilage.
   To make food palatable & digestible e.g. starchy foods like potatoes.
    To make food palatable & digestible e.g. starchy foods like potatoes.
   To improve appearance e.g. meat.
    To improve appearance e.g. meat.
   To develop flavour e.g. meat extractives released.
    To develop flavour e.g. meat extractives released.
   To stimulate digestive juices - sight & smells of cooked food.
    To stimulate digestive juices - sight & smells of cooked food.
   To destroy natural toxins e.g. red kidney beans.
    To destroy natural toxins e.g. red kidney beans.
   To combine ingredients and create new flavours.
    To combine ingredients and create new flavours.
      UNDERLYING PRINCIPLES OF 
      UNDERLYING PRINCIPLES OF 
             COOKING FOOD
             COOKING FOOD
   Conduction - Transfer of heat from one molecule to another by vibration of 
   Conduction - Transfer of heat from one molecule to another by vibration of 
   molecules. E.g. heat passing from the cooker hob through the base of the 
   molecules. E.g. heat passing from the cooker hob through the base of the 
   saucepan.
   saucepan.
   Convection - Molecules near heat source become hot, less dense and rise up. 
   Convection - Molecules near heat source become hot, less dense and rise up. 
   This allows cold molecules to take their place.  This sets up convection 
   This allows cold molecules to take their place.  This sets up convection 
   currents and heat is spread e.g. simmering stews.
   currents and heat is spread e.g. simmering stews.
   Radiation - Heat passes in straight rays, from the source, to the first solid 
   Radiation - Heat passes in straight rays, from the source, to the first solid 
   object they reach, without heating air in between e.g. grilling burgers.
   object they reach, without heating air in between e.g. grilling burgers.
          Most cooking methods involve one or more of these principles.
          Most cooking methods involve one or more of these principles.