To take full advantage of the nutritional qualities of food, you have to take care of it, from preparation to cooking. Focus on good practices.
Preparation and cooking methods influence the nutritional intake of foods, and some are healthier than others.
Cooking fruits and vegetables well
Their vitamins C and B9 are very sensitive to heat and oxidation. They can escape in the soaking or cooking water, just like minerals (potassium, magnesium …) and polyphenols.
Preparation: should they be peeled?
Pro: in conventional production, the skin may contain pesticide residues. It also contains more fiber than flesh or pulp – a problem in cases of intestinal fragility.
Con: some anti-oxidant polyphenols lodge in the skin, for example the quercetin of apples or the tannins of grapes.
Large vegetables are peeled, but finely because the vitamins are more concentrated on the periphery. No need if you buy them bio and you do not fear the fibers.
The best cooking methods
Steam: It preserves water-soluble nutrients and aromatic compounds, and vegetables taste without the need for too much salt. We do not hesitate to add a little raw fat, butter or walnut oil, because the beta-carotene (pro-vitamin A) vegetables is much better assimilated in the presence of fats.
Braising: It has the same advantages as steam, if you do not throw the juice made by the vegetables.
The wok: The vitamins are not too degraded, since cooking lasts only a few minutes. We choose a heat stable oil: olive, sesame or peanut.
Cooking with water: it is not advisable, but if we have no choice, we make large pieces to limit the exchanges between water and food. Exception to the rule: the soups, because we consume the cooking water and all the minerals and vitamins that have dissolved there.
Steaming vegetables on average preserves 70% of vitamin C, compared to 40% for cooking with water.
Cook the fish well
Their B vitamins and their trace elements (iodine, fluorine, selenium) pass into the water and the cooking juices. Their omega 3s oxidize at high temperatures.
If you plan to grill, bake or fry, a marinade is required. It allows less salt and protects from drying out. Studies show that it reduces the risk of ingesting “heterocyclic amines” (AH) or acrylamide (if flour), compounds most likely carcinogenic that form when the temperature exceeds 200 ° C.
The ideal recipe: olive oil, lemon juice and spices, whose anti-oxidants limit the production of HA, as well as garlic, onion or shallot, whose components Sulfur neutralize the deleterious effects of HA. And above all, it is not dirty for the fish to retain its water of constitution.
The best cooking methods
The papillote: placed in a steamed or baked dish containing water, it prevents drying out, keeps the vitamins and minerals water soluble and cook with little fat. To avoid a long cooking that would alter the heat-sensitive vitamins, several small portions are prepared. And if the recipe includes acidic ingredients (tomato, lemon juice …), we prefer the paper baking. Aluminum is to be avoided because this metal is likely to migrate into food.
Steam: has the same nutritional benefits as the foil and is suitable for larger pieces of fish.
The court-bouillon: it is less advisable … unless one consumes the broth, filtered and cooked in white sauce.
Grilling: it is not great for health, but once a week we do not run a risk! One invests in an electric grill equipped with a thermostat not to exceed 180 ° C. Barbecue side, we place the grill at least 10 cm embers, we cook just the time needed and we avoid the blackened pieces.
Cooking meat and poultry
Their vitamins A and B1 are altered by heat. At high temperatures, their fats oxidize and make them indigestible.
Preparation: should you degrease (or remove the skin)?
Pro : less fat, it’s less calories (up to 100 for a steak or a chicken leg) and less cholesterol. In case of barbecuing, this limits the risk of fat burning on embers, which can ignite and give rise to carcinogenic compounds, “polycyclic aromatic hydrocarbons” (PAHs).
Con: fat is a good heat vector. If allowed, the core temperature increases faster and cooking is faster. Hence a better retention of vitamins.
The best cooking methods
Low temperature cooking: it avoids the formation of any toxic compound. Meat or poultry is caught in a pan or casserole: the crust formed holds the juice together with the water-soluble vitamins and minerals. The cooking is completed in a conventional oven or omnicuiseur, in which the temperature is below 100 ° C. To avoid any risk of food poisoning, a heat probe is used to ensure that the core temperature is not lower than 70 ° C.
The pan: it is more suitable for small rooms, steaks, cutlets … We set the fire reasonably so that the temperature does not exceed 180 ° C, we use an oil well supporting heating, olive or peanut, and we monitor not to overdo it.
How to avoid oxidation?
This chemical phenomenon, due to the contact with the oxygen of the air and amplified by the heat and the light, degrades vitamins A, C and B9, omega 3 and 6. It results in the blackening of the plants or the rancidity of the bodies fat. To limit it, we peel fruits and vegetables at the last moment, we divide them as little as possible and we lemon them. Butter and walnut or flaxseed oils are reserved for raw use, rapeseed or sunflower oils for quick cooking.
Cooking utensils: which materials to choose?
Some utensils may contain endocrine disruptors, which may migrate into food.
- If you opt for a plastic electric steamer, make sure it is not polycarbonate (so we avoid the number 7 in the triangle shaped logo).
- If a non-stick pan or casserole is used, “PTFE” or polytetrafluoroethylene (known as Teflon®) is not a problem as long as the cookware is not scratched or heated beyond 180 ° C, according to the National Agency for Food Safety, Environment and Labor (ANSES) and consumer association Que Choisir who conducted tests. Alternatives without PTFE or coated with ceramic are not recommended, as manufacturers do not clearly indicate which are the components.
- Cooked steam or stove, the ideal is stainless steel (stainless steel), a material certainly more expensive, but very solid. We choose the “10/18”, which leads the heat better and allows to limit the duration of cooking.