Food Commodities and Food Science
What you must understand
Group foods by commodity: cereals and starchy staples (rice, corn, wheat, cassava, sweet potato, plantain), pulses and legumes, vegetables and fruit, milk and dairy, eggs, meat, poultry and fish, fats and oils, sugars, and water. For each know main nutrients, selection signs of freshness, storage needs and simple uses.
Food science explains why foods behave as they do. Learn the processes: gelatinisation (starch granules absorb water and thicken on heating), dextrinisation (dry heat browns starch), caramelisation (sugar melts and browns), Maillard reaction (protein and sugar brown together), coagulation (protein sets, as in egg or fish), emulsification (lecithin in egg yolk holds oil and water together), aeration and fermentation (yeast produces carbon dioxide).
Traps in questions
- Calling caramelisation and the Maillard reaction the same thing - caramelisation involves sugar only; Maillard needs protein plus sugar.
- Saying starch "dissolves" in water; it swells and gelatinises.
- Forgetting that overcooked protein becomes tough because coagulation continues and water is squeezed out.
- Confusing raising agents: yeast (biological), baking powder and bicarbonate of soda (chemical), whisked egg or steam (physical).
Worked rule of thumb
"Why did the sauce thicken?" Answer in three linked steps: heat + water → starch granules swell → granules burst and release starch → mixture thickens (gelatinisation). Three steps usually earn three marks.