The basic rules of healthy cooking
Healthy cooking involves preserving the nutritional content and the taste of food. Inès Birlouez, doctor in biochemistry and author shares her advice.
From boiling, steaming and frying to baking in the oven, there are many different ways of cooking food. But all methods of cooking don’t all have the same impact on your health.
Vitamins are without doubt the most fragile micronutrients. They are generally sensitive to heat (C, B1 and B9 especially), and some oxidise as soon as they come into contact with oxygen in the air (C and E especially).
Furthermore, all B vitamins and vitamin C are water soluble, which means that part of them escapes into the water used either for cooking or in recipes. As for minerals and antioxidant polyphenols, these are water-soluble too.
Inès Birlouez assures us that; “It is possible to preserve more micronutrients if you avoid cooking food in a large quantity of water, at too high a temperature or for too long.” Get into some good habits before cooking: keep food refrigerated and for as short a time as possible before cooking them; wash fruit and vegetables under running water rather than soaking them; then peel, cut or grate the vegetables just before cooking or eating them.
Steaming: it’s the best for health
“Steaming is better than boiling,” the Doctor says. Fish, vegetables, white meat and poultry can all be cooked in the steamer. As food is placed on a separate pan with holes to let the steam through and is never placed in the water, you retain all the nutrients that would otherwise be lost due to water solubility.
“Vegetables retain 70% of their vitamin C content while they only retain 40% during boiling,” she underlines. This good level of retention of nutrients is also connected to the temperature the food is cooked at, which is never higher than 100°C with steaming. You can get even more benefit from steaming by not slicing food too finely.
Another benefit of steaming is that it preserves the natural flavours of food, making them taste great. The result is almost the same if food is cooked in its own juices, covered and on a low heat, or foil baked in a bain-marie. ‘The pressure cooker is also a handy tool, as the temperature is a little higher, 110 or 120°C, but cooking time is cut by approximately half.”
Note that food can easily be cooked in water if you plan to consume the water as well, when preparing soup for example. Fish juices cooked in a broth can serve as a base for white sauce and also for pot-au-feu stews and soups.
Mastering cooking temperatures
The higher the temperature, the more the nutritional content and taste of the food can be altered through nutrients oxidising. When cooking in a pan, grilling, baking in the oven, barbecuing or frying, the temperature of the kitchen utensil or the oil can reach 250°C or even 300°C. These methods of cooking turn the food golden brown and develop its taste, making it appetising.
But this browning effect, caused by complex chemical reactions between different elements in the food (the Maillard Reaction), indicates the formation of different compounds, some of which are toxic for the body and can even be carcinogenic.
“Generally speaking,” explains Inès Birlouez, “it’s the huge increase in temperature on the surface of the food, accompanied by the drying effect caused by water evaporating, which causes these suspicious molecules.”
Among these offending compounds are heterocyclic amines (in red meat), acryl amide (in chips) and polycyclic aromatic hydrocarbons which are thought to form during inexpert barbecuing.
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