From a scientific perspective, eating some vegetables raw can help the body obtain essential energy, aid in detoxification, and allow for the absorption of rich 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 not as simple as just heating them up—there's a lot to consider! This varies from person to person and from vegetable to vegetable, but one principle should always be followed: to prevent the loss or destruction of the beneficial nutrients in the vegetables.
Regarding eating vegetables raw:
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 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 anti-viral and anti-cancer properties. This is because lettuce contains interferon inducers, which can act on normal cells to produce interferon, an anti-viral substance. However, we should note that these functions of lettuce are destroyed at high temperatures of 100°C. It is not advisable to dip lettuce in a hot pot for a brief moment before eating.
Some other vegetables, such as carrots, are not suitable for eating raw. Carrots are rich in carotene, with 4.2 mg per 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 can dissolve in oil 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 stir-frying them slowly in vegetable oil.
Regarding how to stir-fry vegetables:
In traditional Chinese cooking techniques, the most important method is to use a hot wok and stir-fry quickly, with dishes made in small woks being the most fragrant. This not only keeps the vegetables colorful, tender, and tasty but also helps to reduce the loss of nutrients. Some less experienced housewives often 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 the loss of vitamin C in vegetables. 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, 21% after 8 minutes, and 35% after 12 minutes. Green peppers stir-fried for 6 minutes lose 13%, 18% after 10 minutes, and if then simmered for another 15 minutes, the loss can be as high as 44%.
The time each vegetable needs to be stir-fried in the wok is different. For example, cucumber only needs to be tossed in the wok a few times. In our specific practice, we can experience this carefully and accumulate experience.
Regarding squeezing vegetable juice:
When we eat buns, dumplings, and wontons, we often add some vegetables to make the filling. Vegetables like Chinese cabbage, bok choy, mustard greens, and chives need to be chopped into small pieces first. In this process, a large amount of vegetable juice from the vegetables also comes out. The traditional habit is to squeeze out the juice, as if the drier the better, because if the filling has too much water, it won't hold its shape. But did you know? This practice can lead to a 60%-70% loss of the rich vitamins in the vegetables, which is a real pity.
This is a dilemma, but it is not unsolvable. To avoid wasting the vegetable juice, you can refer to the following 3 methods. First, chop the vegetables together with dried tofu, mushrooms, and meat. The juice from the vegetables can then seep into the filling. Second, don't squeeze it too dry; you can also add a little starch to thicken the juice. Even the juice that has to be squeezed out can be used to make soup, such as adding it to the water when 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 also tried drinking the squeezed vegetable juice with hot water as a "tea," which is also a viable method.
In conclusion, cooking is a very important science, and processing vegetables is no exception. China has always emphasized the color, aroma, and taste of dishes, but in processing, the retention of nutrition should also be taken into account. If one only emphasizes one aspect and neglects the others, the meaning of dietary nutrition is lost.