Food Commodities and Their Uses
This section covers the main food commodities, their classification, selection, storage and use in the kitchen. The exam tests whether you can match a commodity to its food group, state its function in a dish and choose suitable storage.
Commodity groups and uses
- Cereals: rice, maize, wheat, millet and sorghum; they supply starch and form the base of many meals. Wheat flour develops gluten in bread.
- Pulses and legumes: beans, cowpeas, groundnuts and soybeans; they supply plant protein and fibre and need thorough cooking.
- Vegetables and fruits: they supply vitamins, minerals, fibre and colour; handle gently and store according to type.
- Meat, poultry and fish: they supply protein, iron and fat; keep chilled and separate from ready-to-eat foods.
- Dairy, fats and oils, sugar, spices and condiments: they add nutrients, flavour, richness and texture.
Selection and storage rules
Choose fresh, sound commodities with correct labels and dates. Dry goods need cool, dry, ventilated storage; perishables need refrigeration; frozen foods must stay solidly frozen. Use first-in, first-out (FIFO) and protect foods from pests and moisture.
Worked example
A baker needs flour for bread and for sponge cake. Which flour suits each, and why? Bread needs strong flour with high protein, usually about 12–14%, so kneading develops gluten and traps gas. Cake needs soft, weak flour with low protein so the crumb stays tender. Using strong flour for cake gives a tough, chewy product; using weak flour for bread gives poor volume. The choice depends on the function of gluten, not on price alone.
Traps that cost marks
Do not call cassava, yam or potato a cereal; they are roots or tubers. Do not confuse pulses with vegetables. Do not store onions and potatoes together in damp conditions. Do not say all fruits should be refrigerated; bananas and some tropical fruits spoil in cold storage.