In daily diet, many "health experts" pay great attention to vitamin C supplementation, and often eat some vegetables rich in vitamin C for three meals a day. But you know what? Vitamin C is the most delicate vitamin when cooking. If you use improper cooking methods, it is likely to lead to great losses!
One or three behaviors lead to a large loss of vitamin C.
1, washed repeatedly, chopping vegetables is too broken.
In order to ensure hygiene when cooking, many people often wash the cut vegetables repeatedly, but they don't know that vitamin C in vegetables has been lost since cutting and washing vegetables.
After cutting vegetables with a knife, some cells are destroyed, and vitamin C inside will be oxidized when it comes into contact with air. If the vegetables are cut into pieces and exposed to the air for a long time, the oxidative loss of vitamin C will be faster.
Moreover, vitamin C is a water-soluble vitamin, which will be lost from the incision as soon as it comes into contact with water. Therefore, it is not advisable to wash vegetables repeatedly or soak them for a long time after cutting, which may lead to the loss of vitamin C by more than 20%.
It is suggested that when cooking vegetables, wash them first and then cut them, drain the water as much as possible before cutting, cook them immediately after cutting, and try to keep the vegetables intact when blanching.
2, vegetable juice to eat
Many people are used to supplementing vitamin C with vegetable juice, but they don't know that this will make vitamin C lose a lot!
In the process of juicing, the cell wall of vegetables is chopped, and the vitamin C and oxidase in it get together, which is easily oxidized under the action of oxygen. Moreover, after juicing, oxidase will continue to oxidize vitamin C in vegetable juice. The longer it is stored, the more vitamin C is lost, and the loss can even reach more than 80%.
It is suggested that vitamin C is more stable under acidic conditions. If you want to juice, you can choose acidic vegetables such as tomatoes. Heating will make oxidase lose its function, so you can quickly blanch vegetables before juicing and keep vitamin C as much as possible.
Add a lot of salt when cooking.
Adding salt during cooking will form a hypertonic solution, which will make vitamin C in cells leach out and fully contact with oxidase, making it easier to oxidize. And the more salt is added, the greater the loss of vitamin C in vegetables.
It is suggested to add less salt when cooking, and add salt when cooking quickly; Onion, ginger and garlic have strong antioxidant capacity, and some can be added properly when cooking, which is helpful to delay and reduce the loss of vitamin C.
Second, which cooking method is easier to retain vitamin C?
People in China cook in a variety of ways, such as steaming, boiling, stewing, frying, frying, frying and so on, and pay attention to one color, aroma and taste. But which cooking method retains the most vitamin C and is most recommended?
1, first place: steaming
Comparatively speaking, steaming is one of the best cooking methods. It was found that steamed broccoli, spinach and lettuce only lost 9~ 15% of vitamin C, while water-soluble protein and dietary fiber lost the least.
In addition, mustard oil, carotenoids, folic acid value, sulfonated alkanes and total antioxidant capacity in vegetables were improved by cooking.
skill
Compared with steaming, the effect of microwave heating vegetables to retain vitamin C is equally excellent.
When vegetables are heated by microwave, some of the water will evaporate, but most of the water-soluble vitamin C can be retained. Moreover, the temperature of food rises rapidly but not too high under microwave, which is also beneficial to the preservation of vitamin C.
So vegetables with high water content, such as spinach, can be heated in a microwave oven.
2. second place: fry quickly.
Quick frying means adding oil to the pot. When the oil is slightly hot, add vegetables and stir fry quickly, then take out the pan. Because the heating time is short, the juice is less, and the activity of oxidase can be quickly destroyed, the preservation rate of vitamin C in vegetables after rapid frying is higher, generally more than 70%.
It is suggested that when frying quickly, pay attention to putting less oil and salt and control the oil temperature; Under the premise of ensuring ripeness, try to shorten the time of stir-frying as much as possible.
3. third place: drowning and boiling
Blanching means boiling the water first, putting the vegetables in and scalding them for a while before taking them out. Because the blanching heating time is short, the heat loss of vitamin C is not great, mainly the loss of dissolved water; Don't squeeze out juice after vegetables are quickly blanched, and the preservation rate of vitamin C can reach more than 50%.
Moreover, blanching has many other benefits, such as removing most of oxalic acid, nitrite and pesticide residues in vegetables, killing pathogenic microorganisms and parasites, and it is much safer to eat.
Blanching is equivalent to an upgraded version of scalding water, and the retention rate of vitamin C is similar to that of scalding water. Moreover, boiled vegetables are generally cooked whole and not chopped, which makes it easier to preserve nutrition.
4. Fourth place: boiled and stewed.
Boiling will lead to about 60% loss of vitamin C. The more water is added, the longer the cooking time is, and the more vitamin C is lost in vegetables. But if you make soup, you can make up for the loss by drinking soup.
Due to the long heating time, the loss of vitamin C in the stew may reach more than 90%. When stewing, it is recommended to put less seasoning and not stew for too long.
skill
Even if the cooked food remains still, vitamin C is constantly losing.
Studies have shown that a dish of stir-fried vegetables will lose about 10% of vitamin C if it is left at room temperature (generally 25℃) or in the freezer (4) for 6 hours. If the leftovers are reheated and eaten, vitamin C will lose more! Therefore, in order to ensure nutrition, it is best to cook and eat now.
Third, supplement vitamin C, which you have to understand.
Now vitamin C supplementation has become a common method to improve immunity. Even many people think that vitamin C is a "universal supplement" and start taking vitamin C as soon as they feel uncomfortable. But is the efficacy of vitamin C really so magical? Is vitamin C eaten as much as possible? How to supplement vitamin c?
1, vitamin c is a "quick-acting medicine" for reducing fever and relieving cough?
Some people have a cold and fever. After taking vitamin C, the symptoms are really relieved and the course of disease is shortened. So vitamin C can treat colds and coughs.
But experts say that vitamin C itself has no effect on preventing and treating colds. Only for people who lack vitamin C, vitamin C supplementation during a cold can help improve immunity, relieve symptoms and shorten the course of disease to some extent. For healthy people, the role of vitamin C supplementation is limited. Most common colds are self-limiting diseases, and they will heal themselves without treatment. As long as there is no shortage, there is no need to regularly supplement vitamin C preparations.
It should be noted that for people who lack vitamin C, although vitamin C has the function of "enhancing resistance", it is not a task that it can complete alone, but it also needs the comprehensive action of vitamins and trace elements such as vitamins A and B to better enhance the body's resistance.
2. The more you eat, the more you absorb vitamin C?
Vitamin C can enhance the phagocytosis of white blood cells and improve immunity, but its main function is to synthesize collagen. Once vitamin C is lacking and collagen in blood vessels is insufficient, the fragility of blood vessels will increase and it is easy to bleed, from skin bruising to gastrointestinal bleeding.
Therefore, it is necessary to ensure adequate intake of vitamin C. Healthy adults should take vitamin C 100mg every day, with a maximum intake of 2000mg.
The intake of vitamin C is mainly absorbed in the upper jejunum, but the more vitamin C you eat, the better. With the increase of vitamin C intake, not only the absorption becomes worse, but the excess vitamin C will also be converted into oxalic acid in the body, which will increase the risk of urinary calculi and damage the health of the kidneys. Therefore, vitamin C cannot be blindly supplemented.
Absorption rate of vitamin c intake
The intake is 30~60mg, and the absorption rate can reach100%;
The intake is 90mg and the absorption rate is about 80%.
Intake 1500mg, absorption rate is about 49%;
The intake is 3000mg and the absorption rate is about 36%.
3. how should vitamin c be supplemented?
Fresh fruits and vegetables are actually the main sources of vitamin C. If you choose vegetables with high vitamin C content and take enough 500g every day, you can completely ensure the demand for vitamin C. Today, Cocoa will introduce you to the "vitamin C champion" in vegetables and fruits:
① the champion of vitamin c in vegetables-colored pepper
Colored pepper is a kind of sweet pepper, including red, yellow and cyan. Each colored pepper contains vitamin C100g, which is called the "champion" of vitamin C in vegetables.
Tip: The nutrition of three-color peppers is slightly different.
Green pepper: The green appearance makes green pepper contain nutritious chlorophyll.
Red pepper: Red skin makes red pepper have antioxidant β-carotene, and dietary fiber is the highest among the three peppers, containing 2. 1 00g.
Yellow pepper: The nutrition is similar to that of red pepper. The only difference is that yellow pepper contains pyrazine, which helps to prevent vascular diseases such as hypertension, myocardial infarction or cerebral infarction.
② Fresh jujube is the champion of vitamin C in fruits.
Fresh jujube is known as "vitamin C tonic" and "king of vitamin C" in fruits. Its vitamin C content per 100 grams can reach 243 mg, which is almost 6 1 times that of apples, 0/0 times that of lemons and 4 times that of kiwifruit under the same weight!
China Nutrition Society recommends that adults take vitamin C 100mg every day. In other words, eating three fresh dates a day (about 40 grams) is enough to meet the vitamin C demand for one day.
4. How to choose vitamin C supplements?
If you can eat 500g of vegetables and 350g of fruits every day, ordinary people don't need to supplement vitamin C. If you can't eat enough, you can supplement it by supplementing vitamin C. But when buying, you should pay attention to the nutrient composition table, such as:
The vitamin C content of some vitamin C supplements is 225mg/ 100 g, and the vitamin C content of one tablet is about 9mg, which is suitable for use when the intake of fruits and vegetables reaches a certain amount.
The vitamin C content of some vitamin C compound supplements is 75mg/ 100 g, which is suitable for people with unbalanced diet to supplement daily.
Some vitamin C effervescent supplements have a high content of vitamin C, one tablet contains 1000mg of vitamin C, which is suitable for people with vitamin C deficiency, and healthy adults cannot eat it in large quantities for a long time. In addition, vitamin c is afraid of heat, and the water temperature should be controlled at 40~60 when brewing.