Many housewives put oil, salt, soy sauce and vinegar on hand when stir-frying. In fact, as long as a little study of the order in which they put them, not only can maximize the preservation of food color and flavor, but also will make more nutrients to be retained.

Oil: frying oil temperature should not be too high, once more than 180 ℃, the oil will decompose or polymerization reaction, resulting in a strong irritation of propylene glycol and other harmful substances, harmful to human health. Therefore, "hot pot cool oil" is a trick of frying. First, the pan is hot, do not wait for the oil smoke before putting vegetables, eight mature when the vegetables into the pan stir-fry. In addition, sometimes you can not burn the hot pan, direct cold oil and food at the same time frying, such as deep-fried peanuts, so that the fried peanuts are more crunchy, crispy, to avoid the outside of the burnt inside raw. When you use sesame oil or fried vegetable oil in cold dishes, you can add oil after the cold dishes are mixed, more fragrant and delicious.

Salt: Salt is an electrolyte with a strong dehydrating effect, so the salt time should be based on the characteristics and flavor of the dishes. Stewed meat and fried vegetables containing more water, should be cooked to eighty percent of the dish when the salt, too early to put will lead to too much soup in the dish, or so that the protein in the meat coagulation, not easy to stew. The use of different oil fried vegetables, salt time also makes a difference: with soybean oil and vegetable oil fried vegetables, in order to reduce the loss of vitamins in the vegetables, should be in the vegetables almost cooked when the salt; with peanut oil fried vegetables is the best first salt, can increase the temperature of the oil, and reduce the aflatoxin in the oil.

Soy sauce: When cooking, high temperature and long cooking will destroy the nutrients of soy sauce, and lose the fresh flavor. Therefore, the soy sauce should be put before the pan is about to be released. In order to make the meat tender when frying, you can also mix the meat with starch and soy sauce before frying, so that not only no loss of protein, frying out of the meat is also more tender.

Vinegar: vinegar can not only get rid of the stink, fishy, greasy, increase the aroma, but also save vitamins, promote calcium, phosphorus, iron and other dissolved, improve the nutritional value of the dishes. The best time to put vinegar in cooking is at the two ends, that is, adding vinegar immediately after the raw materials into the pot or adding vinegar before the dishes come out of the pot. The best time to add vinegar to dishes such as "fried shredded potatoes" is after the raw materials are put into the pot, which can protect the vitamins in the potatoes and soften the vegetables at the same time; and the best time to add vinegar to dishes such as "sweet and sour pork" and "onion-exploded lamb" is twice: after the raw materials are put into the pot, the vinegar can be added immediately or before the dishes are put out of the pot. Two times: after the raw materials into the pot plus can remove the stink, in addition to fishy, before leaving the pot and then add a time, you can increase the aroma, seasoning.