In traditional Chinese cooking, the most important technique is stir-frying over high heat quickly, with dishes cooked in small woks being the most flavorful. This not only keeps vegetables fresh in color, tender in texture, and delicious to eat, but also helps to reduce the loss of nutrients.
"One can go a month without meat or fish, but not a day without vegetables." In today's modern lifestyle, vegetables have become increasingly indispensable to us. We rely on vegetables in our daily lives, and cooking them is far more than simply heating them up—there's a great deal of technique involved! This technique varies from person to person and from dish to dish, but it should always follow one principle: to prevent the loss or destruction of the beneficial nutrients in vegetables.
Regarding eating raw vegetables:
In Western countries, eating raw vegetables is very common. They have a saying that cooking vegetables destroys the natural gift bestowed upon humanity by nature. From a scientific perspective, eating some vegetables raw can help the body obtain essential energy, aid in detoxification and cleansing, and allow for the absorption of rich nutrients.
In the vegetable family, lettuce is the top choice for Chinese people to eat raw. Lettuce has a slightly bitter taste, which can stimulate the appetite, has analgesic effects, and can also lower blood sugar. Recently, scientists have discovered that eating lettuce also has antiviral and anti-cancer properties. This is because lettuce contains an interferon inducer, which can act on normal cells to produce interferon, an antiviral substance. However, we should note that these functions of lettuce are destroyed at high temperatures of 100°C. Therefore, it is not advisable to dip lettuce in a boiling pot for a moment before eating it.
Some other vegetables, such as carrots, are not suitable for eating raw. Carrots are rich in carotene, with 4.2 mg in every 100g. Carotene can be converted into vitamin A in the human body, so it is also known as provitamin A. Because carotene is a fat-soluble vitamin, it dissolves in fats but not in water. It is only absorbed by the body after dissolving in oil during stir-frying. Many of us have the habit of eating carrots raw, which is a waste. It is best to eat them after gently stir-frying them in vegetable oil.
Regarding how to stir-fry vegetables:
In traditional Chinese cooking, the most important technique is stir-frying over high heat quickly, with dishes cooked in small woks being the most flavorful. This not only keeps vegetables fresh in color, tender in texture, and delicious to eat, but also helps to reduce the loss of nutrients. Some less experienced housewives often tend to extend the stir-frying time, believing this will make the dish taste better. This is a misconception.
Nutritionists have conducted special experiments for us to determine the relationship between stir-frying time and vitamin C loss. The final conclusion was: the longer vegetables are stir-fried, the more vitamin C is lost.
Specifically, celery stir-fried for 5 minutes loses 12% of its vitamin C, 8 minutes loses 21%, and 12 minutes loses 35%. Green peppers stir-fried for 6 minutes lose 13%, 10 minutes lose 18%, and if steamed for another 15 minutes, the loss can be as high as 44%. Each vegetable needs a different amount of time in the wok; for example, cucumber only needs to be tossed a few times. We can experience this in our specific practices and accumulate experience.
Regarding squeezing vegetable juice:
When we eat dumplings, wontons, and potstickers, we often add some vegetables to the filling. Vegetables like Napa cabbage, bok choy, mustard greens, and chives must first be chopped into fine pieces. In this process, a large amount of vegetable juice is also squeezed out. The traditional habit is to squeeze out the juice, as if the drier the better, because too much moisture in the filling will prevent it from holding its shape. But did you know? This practice can cause a 60%-70% loss of the rich vitamins in the vegetables, which is a real shame.
This is a dilemma, but it is not unsolvable. To avoid wasting the vegetable juice, you can refer to the following three methods. First, chop the vegetables together with dried tofu, mushrooms, and meat. The juice from the vegetables can then seep into the filling. Second, do not squeeze it too dry; you can also add a little starch to help absorb the juice. Even the juice that has been squeezed out can be used to make soup, such as adding it to the water for boiling dumplings or using it as the broth for wontons. Third, use the squeezed vegetable juice instead of water to knead the dough. Although the dough will have a green color from the vegetables, this does not affect the taste and prevents the loss of nutrients. Some people have even tried drinking the squeezed vegetable juice with hot water as "tea," which is also a viable method.
In conclusion, cooking is a very important science, and the preparation of vegetables is no exception. China has always emphasized the color, aroma, and flavor of dishes, but in the process of preparation, the retention of nutrients should also be taken into account. If only one aspect is emphasized while the others are ignored, the meaning of nutritional eating is lost.