1, blanching can make vegetables brighter in color, more crisp and tender in texture, reduce astringency, bitterness and spicy taste, and can also sterilize. For example, spinach, celery and rape will become greener when scalded. Blanching bitter gourd and radish can alleviate the bitterness. Hemagglutinin in lentils can be removed by blanching.

When scalding vegetables, boiled water is usually used. Adding some salt and oil to water can make the color of vegetables brighter and keep the nutrition of vegetables. Add salt before putting the vegetables into boiling water, and put oil after putting the vegetables into boiling water. Pigment contained in vegetables will be fully displayed under the osmotic action of salt, and oil will be wrapped around vegetables, which will block the contact between water and vegetables to a certain extent, reduce the overflow of water-soluble substances, and also reduce the oxidation of vegetables by air, light and temperature, so that vegetables will not change color for a long time. Of course, boiled water can also be put into cold water immediately, which can also prevent vegetables from turning yellow.

Vegetables should be washed when they are bought home, because they are afraid of pesticide residues, so they must be washed repeatedly in water, that is, by soaking, and it is best to change the water after ten minutes. Washing vegetables with rice washing water can remove some pesticides left in vegetables. At present, most organophosphorus pesticides in China are used to kill insects, and these pesticides will lose their toxicity when they encounter acidic substances. Soaking in rice washing water for about 10 minute and washing with clear water can reduce pesticide residues in vegetables a lot.

Second, when to add salt to cooking?

Now nutritionists generally advocate putting salt after cooking, except for some dishes that must be salted first, such as baked and fried foods. Putting salt after cooking has many advantages: put salt in the early stage of cooking, and the salty taste of salt will disappear when the dishes are cooked. If the salty taste is the same, the amount of salt put after cooking is less than that put first, so putting salt after cooking can achieve the effect of putting less salt. When frying leafy vegetables, if you put salt first, the umami taste and vitamins of vegetables will be lost, and the color of vegetables will be bad. Of course, putting salt after cooking does not mean turning off the fire and putting it. It depends on the kind of vegetables you fry. You can put the leaves away before turning off the fire, and put the roots away when the dishes are cooked at 8 or 9 o'clock. For the sake of health, the later the better.

Steaming vegetables is the best way to keep food nutritious?

Cooking from the nutritional point of view, frying is the most unhealthy, so eat less. Steaming is the healthiest way to cook. You can keep the nutrition of food to the greatest extent, and the calories are not as high as those of fried or fried vegetables. You can try to cook more steamed vegetables according to the different characteristics of ingredients.

Do you use cold water or boiled water for cooking?

Steamed rice is usually boiled with cold water after washing rice, but in fact, the correct way is to boil the water first and boil it with boiling water. So, what are the benefits of doing so?

1. Cooking with boiling water can shorten cooking time and protect vitamins in rice. Rice contains a lot of starch. When cooking with boiled water, the temperature is about 100℃ (the boiling point of water). Such a temperature can make the rice cooked quickly, shorten the cooking time and prevent the vitamins in the rice from being destroyed by long-term high-temperature heating.

2. Boiling water can volatilize chlorine and avoid destroying vitamin B 1. Vitamin B 1 is the most important nutrient in rice, and the tap water we usually use is disinfected with chlorine. If we use this water to cook rice directly, the chlorine in the water will destroy the vitamin B 1 in rice. When cooking with boiling water, chlorine has evaporated with water vapor, which greatly reduces the loss of B vitamins such as vitamin B 1.

3, boiling water cooking is not easy to stick to the pot, resulting in less pot.

Five, cooking should be divided into hot and cold.

Many people add oil when the pot is a little hot, and then burn the oil until it smokes. The fried food is delicious, but you don't know that such oil is very harmful to human body. Vegetable oil contains little trans fat. But high oil temperature will produce trans fats. For example, high-temperature fried foods such as pumpkin pie and fritters contain trans fats. If the same oil is used repeatedly, it will also produce trans fats. I would like to remind everyone here that the oil temperature should not be too high when cooking, and the used oil should be resolutely dumped and not recycled, so as not to endanger health. So when cooking, it doesn't matter if the pot is very hot, even if there is a little smoke. Then you can put the food into the frying pan immediately after refueling, which does not affect the taste of the food at all. It is as effective and healthy as frying them in high-temperature oil.

Remember to have a big fire when cooking. This time is fast, the loss of vitamins in vegetables is less, and most of the nutrients contained in vegetables can't stand high temperature, especially leafy vegetables such as asparagus, Chinese cabbage, celery, beet and Chinese cabbage. If fried for a long time, the loss of nutrients will be more. Some vegetables can be well protected by adding a few drops of vinegar or thickening during this cooking process.