Generally, moist-heat cooking methods use a liquid for cooking – usually water, stock or steam. The advantage of steam is that it transfers more heat at the same temperature. As a result, the food cooks faster and fewer nutrients are lost. The cooking temperature may vary from 70° – 120° C (158° – 212° F). These methods are particularly suitable for preparing pasta, rice, pulses and vegetables. The methods referenced below, though not exhaustive, are the more common techniques.
Boiling:
Cooking in a lot of liquid at a temperature of about 100° C (212° F).
Poaching:
Cooking in liquid at a temperature under the boiling point (75°– 95° C/ 167°– 203° F)
Steaming:
Cooking at a temperature of about 100°C (212° F) in steam, with the food and cooking liquid completely separated. You can use a commercial steamer or a pot with a rack that suspends the food above a small amount of simmering liquid.
Stewing / Braising:
Meat is often browned before liquid is added. Meats and vegetables can be cooked or steamed in their own juice. A particular way of stewing is to glaze: vegetables (carrots, small onions) become covered with the stew stock, which is reduced and enriched with a little sugar.
Pressure cooking:
Cooking in an airtight pressure cooker at about 105° – 120° C (221° – 248° F).
Higher temperature equals shorter cooking time. The steamer is also suitable for blanching, poaching and reheating.
Microwave cooking:
Cooking with electromagnetic waves, either with or without a small amount of added liquid. The food can be browned or given a crust only if combined with a dry-heat method such as grilling. It is ideally suited for reheating food.
How does a microwave work?
In other cooking methods food warms up from the outside in. But with the microwave, the heat comes from inside the food, from its water molecules. The electromagnetic waves of the microwave cause these water molecules to vibrate and the resulting heat cooks the food. Deciding factors for determining the required cooking time of certain products can be water content, molecular density, the starting temperature of the food, as well as the penetration or strength of the rays (normally 2 – 4 cm). According to current findings there is no risk of radiation exposure if microwave ovens are used properly.
Blanching
Purpose:
Loss of about 20 – 30% of vitamin C, but vitamin retention improves during subsequent storage (chill-freeze process).
Osmosis: Nutrients in food leak or diffuse to liquid with lower concentration. Therefore, it is important to use this liquid for the sauce or as stock for soups because it is rich in vitamins and minerals.
Phytochemicals
The term phytochemicals refers to a class of substances (at the moment 60 000 – 100 000 are known), which exist only in plants. They are classified into several groups (e.g. carotenoids, flavonoids, phytoestrogens, glucosinolates) and rated as health-supporting substances. They have, for example, antioxidant, anti-carcinogenic and anti-inflammatory effects and may also reduce blood cholesterol. These effects can only be verified when the phytochemicals are obtained from whole foods in fruits and vegetables. Their effect when taken as supplements cannot currently be verified. Their loss during cooking varies greatly. Some are soluble and sensitive to heat and air; others are better obtained from well-done foods (lycopene in cooked tomatoes). Tip: The best way to serve a variety of phytochemicals is to create a diet that includes every colour of the rainbow (red, orange, yellow, green, blue/violet).