4.1 SCIENCE OF COOKING FOOD Flashcards
Reasons why we cook food:
- to kill pathogenic bacteria and toxins making the food safe to eat (meat, fish, kidney beans)
- to soften food making it easier to chew and to swallow (tenderised meat, softened vegetables)
- the make the food more digestible
- to improve and intensify the flavour of the food
dry heat methods of cooking:
- BAKING- dry heat from the oven
- ROASTING- dry, hot air from the oven but food is basted with fat to prevent it from drying out
- TOASTING- dry, radiant heat is applied to food
- GRILLING- small pieces are cooed using the radiant heat produced by a hot grill
frying methods of cooking:
- SHALLOW FRYING- small pieces of food are cooked in a shallow amount of very hot oil
- DEEP FRYING- foods are submerged into very hot fat/oil
- STIR FRYING- very small pieces of meat and vegetables are cooked quickly in a minimal amount of hot oil
what is boiling?
- moist heat cooking method
- starchy foods are cooked in vigorously boiling water
what is simmering?
- moist heat cooking method
- food is submerged into boiling water which is gently bubbling
what is poaching?
- moist heat cooking method
- food is cooked in a small amount of gently boiling liquid
what is stewing?
- moist heat cooking method
- food is submerged into liquid and cooked slowly to develop flavours
what is braising?
- moist heat cooking method
- the vegetables are surrounded. by a liquid with the seared meat cooking in the steam on top o the vegetables
what is pressure cooking?
- moist heat cooking method
- food is cooked in a pressure cooker where the temperature can be increased very quickly so food cooks very quickly
what is steaming?
- moist heat cooking method
- food is cooked in the steam of boiling water
what is blanching?
- moist heat cooking method
- food is plunged briefly into boiling water or steamed, then. removed and placed into chilled water
what happens to proteins during cooking?
- they DENATURE and COAGULATE
- the structure of each protein is irreversibly changed
what temperature do most proteins coagulate at?
between 71 and 85 degrees celsius
what reaction occurs when proteins and carbohydrates are heated with a dry heat?
- Maillard reaction
what happens to fats when cooking?
- because they contain a small amount of water, they often liquefy
- they cannot evaporate- they have a property called plasticity
- adds colour and flavour to food
what happens to carbohydrates when cooking?
- gelatinisation
- when starch and liquid are heated together, physical changes occur
- occurs at 66 degrees celsius and above
what happens when sugar is cooked?
- caramelisation
what happens to water when cooking?
- it turns to steam
what are foams?
- Chocolate mousse and meringues are examples of foams.
- We make them by trapping gas inside liquids.
- When we agitate liquids storing protein (e.g. by whisking or beating), we cause the liquids’ proteins to denature. The denatured proteins expand, trapping air in the liquid.
- Then, when coagulation happens the air gets trapped and a foam is formed.
- Over-beating or over-whisking will break coagulation bonds, causing the air to escape and the foam to fall apart.
When some foams are cooked, they become solid (e.g. egg white foams turning into meringues).
what is conduction?
- heat energy is transferred through vibrating particles
- particles are tightly packed in solids
- when food is added to the hot pan, the particles in the pan transfer heat energy to those in the food
what is convection?
heat energy is transferred through liquids and/ or gases
what is radiation?
heat energy is transferred through radiation waves
what is the role of gluten?
- form of protein
- wheat flours contain protein
- gluten molecules can bend and stretch
what is shortening?
- flour particles gain a waterproof layer when covered in d=fat
