Paper 1 food tech

• danger zone


  5-63 c
• fridge temp


  0-15 c
• freezer temp


  -18 c
• Why does food go off?

  1._____

  2.o_____

  3._eat or humidity

  4.te________

  5.________ bacteria

  1.light 2.oxygen 3.heat 4.temperature 5.spoilage
• signs of food spoilage

  discoloration,texture,odour,visible mould
• food spoilage can be prevented by removing ______ ,changing the __, using food quickly,or removing m_______.

  oxygen,Ph,moisture
• what are pathogens


  organisms that cause illness
• Lecithin


  a mixture of fats that are essential to cells in the human body
• whats an emulsifier?


  a food additive used to help mix 2 substances that are typically separated when combined
• How does emulsification work?

  The yolk contains lecithin which acts as an emulsifier allowing oil and vinegar to mix.For example when making mayonnaise.
• How is emulsification used to make mayonnaise?


  The emulsifier(lecithin)has a hydrophobic side and a hydrophyllic side. The hydrophobic side latches onto the oil particles and the hydrophyllic side latches onto the vinegar and lemon juice which brings both substances together.
• Effect of having too much protein?

  1.There will be too many surplus amino acids going to waste

  2.weight gain

  3.can cause kidney damage to those with pre-existing kidney disease
• one circumstance when protein may be required above the recommended dietary need?


  Pregnancy,muscle gain,breastfeeding
• cholesterol


  a vital component of cell membranes
• cholesterol is formed by?


  fat
• why do we need fats?

  Fats contain vitamins A, D, E and K (in fat-soluble form)
• why do we need fats?

  they provide energy and insulation as it creates a layer beneath our skin protecting our organs
• what makes up fat?

  triglyceride (chemical name for fat)
• what happens if you eat too much saturated fat?

  it can raise cholesterol levels leading to a greater risk of heart disease, obesity
• examples of saturated fat?

  from animal sources such as red meat or dairy products
• unsaturated fats are...

  mainly plant source such as pecans and avocados
• types of unsaturated fats?

  monounsaturated (avocados )or polyunsaturated (walnuts)
• monounsaturated fats have a

  one C=C double bond
• polyunsaturated fats have

  more than one C=C double bond
• consequences of too little fat?

  weight loss, vitamin deficiency, less insulation as there isn't enough fat protecting the organs = results in easily bruised bones
• why do we cook food?

  to enhance flavours (using roasting, as when foods are cooked together their flavours will combine)
• What happens during roasting?

  When we roast meats and vegetables, they brown and become crispier (because of added fat). This happens because the water within the foods evaporates.
• why do we cook food?

  Cooking food at high temperatures helps to kill any bacteria and mould present, it enhances flavour and texture, and to vary the diet
• methods of heat transfer

  radiation , convection , conduction
• Radiation

  Heat energy is transferred through radiation waves.The heat source and food don't come into direct contact.Microwaves warm up the water molecules, fat and sugar in food via radiation.
• radiation

  Toasters and grills also heat up food using radiation.They send out radiation waves. Food absorbs these waves and heats up.
• Conduction

  Heat energy is transferred through vibrating particles. Particles are tightly packed in solids, so vibrations pass quickly from one particle to another when they collide.
• Conduction

  For example when stir frying, the pan will go hotter as the atoms in the metal vibrate faster and generate thermal energy which is transferred to neighbouring molecules. THIS transfers to contents of the pan.
• Convection

  Heat energy is transferred through liquids and/or gases
• convection,when a pot of water is heated

  when a boiling pot of water is heated, the liquid closest to the heat source will heat up first. This will cause the warmer liquid to rise and the cooler liquid will flow beneath it.

  The cooler liquid then starts to heat up as it is closer to the heat source. It rises and even cooler liquid falls beneath it.

  This creates a convection current and eventually all liquid is heated.

  This can also happen is ovens where the hot air rises and cooler air takes its place
• advantages of steaming

  1.fat not used

  2.healthiest cooking method

  3.more flavour and texture
• disadvantages of steaming

  1.foods may not be as flavoursome as frying

  2.gentle cooking method, not good for tough foods like meat
• advantages of boiling

  1.fat not used

  2.healthy cooking method

  3.low energy
• disadvantages of boiling

  1.harsh cooking method

  2.veg looses vitams and flavour

  3.less flavoursome
• what is blanching?

  boiling food for a short time to part-cook it,before placing it in cold water