Vegetables are an important part of the diet and must be included in every meal. But how well do you know your vegetables and how to cook them? Based on the edible part, vegetables are classified as:
Flower vegetables: Artichoke, broccoli and cauliflower.
Tuber vegetables: Cassava, potato, sweet potato and yams.
Stem vegetables: Asparagus, celery, fennel and bamboo shoot.
Fruit vegetables: Bell peppers, chayote, cucumber, okra, olive, squash, eggplant and tomato.
Leaf vegetables: Cabbage, spinach, sukuma wiki and lettuce.
Root vegetables: Beet root, carrot, radish and turnip.
Bulb vegetables: Onion, garlic and shallot.
Vegetables should be cooked as briefly as possible since they become bland if overcooked and lose vitamins and minerals.
Cut them into smaller pieces so that they cook evenly. Reduce the cooking time if vegetables are to be reheated or served cold because the cooking process will continue when they are hot.
The cooking process can be stopped by running vegetables under cold water but this will lead to the loss of vitamins and minerals. Keep peeled or sliced vegetables covered while cooking to prevent them from drying.
Spices and herbs, on the other hand, lose their flavour or can become overly intense when added earlier in the cooking.
The cooking methods
Quick-braising: This involves cooking vegetables in their own juices after sautéing in a small amount of cooking oil.
The vegetables are covered and cooked over low heat to blend flavours well and make them tender. This method is good for squash, tomatoes, onions and shallots.
Braising: This involves cooking vegetables slowly, covered over low heat after sautéing in cooking oil. The vegetables are cooked whole or in pieces.
Braising can be done with vegetables on their own or with pieces of meat to create tasty combinations. This method is good for hard vegetables like artichokes, cabbage, celery and fennel.
Boiling: They should be placed in a covered cooking pot large enough for them to cook evenly. Add the vegetables when the water has come to a full boil and keep the heat high so that the water returns to boil quickly.
Then lower the heat so that the vegetables can simmer. However, green vegetables should be cooked uncovered to prevent the acids they contain from becoming concentrated and destroying their chrophyll, making them lose their colour.
Adding an acidic ingredient like vinegar or citrus juice preserves the colour and firmness of red vegetables like beets, red cabbage, tomatoes, red bell pepper, radish, red chilli pepper, radicchio and red leaf lettuce as well as white vegetables like potatoes, cauliflowers, turnips, parsnips, kohlrabi, and mushrooms.
Vegetables that discolour easily like artichokes, once peeled and cut, should be cooked in four cups of boiling salted water containing three tablespoons of lemon juice. Salt draws water from vegetables and makes them tender.
However, when added at the beginning of cooking, it makes the vegetable juices run out, leading to loss of nutrients.
The salt also becomes concentrated as cooking continues. It should not be used with vegetables that have high water content like tomatoes and cucumbers and it is also not recommended for other vegetables like cabbage and bell peppers since it leads to loss of firmness and flavour.
Boiling reduces nutritional value of vegetables significantly. Therefore, it is recommended that only a small amount of water is used in boiling and the remaining reserved for soups and sauces instead of discarding it.
Steaming: This involves the use of heat released by a small amount of boiling water. The vegetables are only added to the steamer when the water starts to boil.
When the lid vibrates or releases steam, the heat should be lowered to keep the water at simmering point. Steaming vegetables takes slightly longer than boiling but has less losses of flavour and nutrients.
It is an easy and relatively quick way to prepare vegetables such as carrots, cabbage, asparagus, beets, cauliflower, celery and radishes.
Pressure cooking: This involves cooking in an airtight container – pressure cooker. The temperatures within the cooker rise above boiling point so that the vegetables cook very fast. Examples of vegetables that can be pressure-cooked include potatoes, squashes and artichokes.
Dry-heat cooking: This involves the use of an oven. The vegetables are cooked whole in their skin or cut into pieces.
Cooking in dry heat makes vegetables tender, juicy and tasty. This method is good for eggplant, squash and potatoes.
Microwaving: Cooking vegetables in the microwave preserves the flavour and colour better. Microwave safe containers should be used for cooking.
Place vegetables that require longer cooking time at edge of the cooking dish and those that cook more quickly at the centre.
Stir-frying: The vegetables are fried quickly in oil over high heat. Cooking is done very briefly to avoid nutrient loss and preserve flavour, texture as well as colour.
Ginger, garlic and or other spices can be added if desired. Stir-frying is good for firm vegetables like cauliflower, carrots and broccoli.
Deep-frying: This involves cooking at high temperatures by immersing food in cooking oil. Vegetables should be well-dried or coated by dipping in flour or beaten eggs and bread crumbs.
When cooked, the vegetables are drained on paper towel. Potatoes, artichokes, cauliflower and eggplant.
The writer is based at Egerton University.
