Food Preparation
Core concepts
Know the reasons food is prepared: to make it safe, digestible, palatable, and attractive. Understand the main methods - moist heat (boiling, steaming, stewing, poaching), dry heat (baking, roasting, grilling), and fat-based (frying, sautéing) - and their effects on nutrients and texture. Learn the science: gelatinisation of starch, coagulation of protein (egg and meat), caramelisation of sugar, the Maillard reaction (browning of protein and sugar), emulsification, and the role of raising agents (yeast, baking powder, bicarbonate of soda). Know the functions of ingredients in baking and the principles of preserving food (heat, cold, drying, salting, sugar, acid, fermentation).
Traps to watch
- Overcooking vegetables in water leaches water-soluble vitamins; steaming preserves more.
- Baking powder is double-acting; bicarbonate of soda needs an acid to react.
- The Maillard reaction needs both protein and sugar and dry heat; caramelisation involves sugar alone.
- Emulsions can be temporary (oil and water) or stabilised by an emulsifier such as egg yolk.
Worked example
Why does a cake rise? Baking powder releases carbon dioxide when heated (and on mixing with liquid), which expands air cells in the batter; the gluten network set by heat traps the gas. State both the gas source and the structure that holds it - marks are awarded for both.
Rule of thumb
Identify the change (gas, gel, brown, set) and then name the agent or condition that causes it; that two-part answer scores reliably.