Vegetables, Legumes, Starches and Grain Cookery
This domain tests pigment chemistry, blanching, legume cookery, starch gelatinisation and grain methods. Expect questions on colour retention, soaking, pilaf and risotto.
Vegetables and pigments
Chlorophyll gives green colour and is damaged by acid and long heat; cook green vegetables quickly in boiling salted water and shock in ice water. Anthocyanins are red-blue and sensitive to pH. Carotenoids are stable but fat-soluble. Avoid overcooking, which dulls colour and texture.
Legumes
Dried legumes need soaking and thorough cooking. Acid, such as tomato or vinegar, should be added after beans soften because acid strengthens the skin and slows softening. Salt is acceptable in moderation. Discard soaked water for some beans and boil kidney beans thoroughly to destroy lectins.
Starches and grains
Starch gelatinises when heated with water, thickening and softening. Pilaf coats rice in fat before adding liquid; risotto releases starch by stirring, creating creaminess. Pasta should be cooked in well-salted water and finished in sauce.
Worked example
Green beans are blanched in boiling water for 2–3 minutes, then shocked in ice water. The boiling water is not acidulated because acid dulls chlorophyll. They are drained, dried and reheated quickly in butter. If held hot for hours, they turn olive-brown.
Traps that cost marks
Adding acid early to legumes; overstirring risotto; salting cooking water too little for pasta; crowding vegetables so water stops boiling; and holding green vegetables in a hot bain-marie.
Key points
- Chlorophyll is dulled by acid and long heat; shock greens after blanching.
- Add acid to legumes after they soften.
- Starch gelatinises with heat and water.
- Pilaf coats rice in fat; risotto stirs to release starch.
- Cook pasta in well-salted water and finish in sauce.