Face an ingredient
A thousand people have a thousand different cooking methods in their hearts.
China people have the most diverse research on food cooking.
There are twenty or thirty cooking methods alone.
But have you ever wondered what difference these cooking methods will make besides changing the color and fragrance? In fact, in the process of food cooking, the nutritional composition is also changing.
Then why is there such a change?
Why is there nutrient loss? (the situation of various vitamins)
In fact, it is not difficult to understand that the same chicken leg has completely different nutritional components after frying and frying. One can be eaten as a healthy meal, and the other is the source of obesity. In addition, in addition to changing the nutritional composition of food by adding edible oil, some subtle changes are taking place inside the food.
Many cooking methods will greatly affect the nutritional content of food, especially those we often think are very healthy. This is due to the special properties of some trace elements, such as:
1) Vitamin C and B vitamins, both of which are water-soluble vitamins, will lose a lot when heated or heated in water;
2) Vitamins A, D, E and K, different from the two vitamins mentioned above, are fat-soluble vitamins, which, as the name implies, are more easily lost in high-temperature oil;
3) Minerals magnesium, potassium, sodium and calcium. Although these minerals will not be lost due to water or oil, they may be lost if the vinegar content in food is high.
So which cooking method causes the highest nutritional loss? Let's analyze various common cooking methods one by one.
Among the common cooking methods, cooking loses the most nutrients! (Comparison of common cooking methods and nutrient loss)
water cooking
First of all, let's take a look at the cooking method that everyone usually thinks is the healthiest-cooking. Undoubtedly, there is no need to add any extra oil, seasoning and other things that may increase the calorie of food, but in fact, the proportion of nutrient loss of boiled vegetables is amazing.
In 2009, a study published by Zhejiang University in China showed that the way of boiling water would make the loss of vitamin C in vegetables the most serious. Among them, broccoli, cabbage and lettuce lost more than 50% vitamin C after boiling.
Another study published in the United States also pointed out that in the process of stewing meat, vitamin B in meat will also be lost to soup, and the loss of B vitamins is as high as 60%.
This is because water-soluble vitamins are soluble in water, which further increases the loss rate under high temperature heating, and this loss rate will increase with the increase of water temperature.
Cooking and frying
Cooking is also one of the most common cooking methods in our daily life, but because of our misunderstanding of oil, it is included in the list of unhealthy cooking methods. But the opposite is true. Cooking and frying are far superior to boiling in preserving food nutrition.
This is because in the process of cooking and frying for a short time, it can not only prevent the loss of water-soluble vitamins into the soup, but also increase the absorption rate of some nutrients and antioxidants by adding oil. This makes the originally nutritious food easier to be used by the body.
In 20 12, a study published in the British Journal of Nutrition showed that the absorption rate of β -carotene in carrots with the same quality after cooking was 5.5 times that of raw carrots.
A study published in the Asia-Pacific Journal of Clinical Nutrition in 2005 also showed that when people eat fried tomatoes, compared with raw tomatoes, the content of lycopene in blood increased by more than 80%.
So it seems that the cooking is not worse than the cooking, but it can be said that the nutrition of the cooked food has been enhanced.
evaporate
In fact, in life, people often mix cooking with cooking, thinking that since cooking will cause serious nutrient loss, steaming will naturally do the same. But in fact, steaming can be said to be a very good way to retain nutrition.
Although there is steam and high temperature heating during steaming, in fact, vegetables do not directly contact hot water, which makes water-soluble vitamins remain.
After steaming, the content of vitamin C in broccoli, spinach and lettuce only decreased by 9~ 15%. In this way, more than 30% vitamins are retained compared with cooking method, and the intake of extra calories is also avoided. Just add some seasoning after steaming, which is convenient and nutritious.
deep-fry
There is no denying that frying can make food fresh and tender. The food treated in this way will make people have an appetite and have a unique aroma. However, this practice can be said to be the worst of all cooking methods. It will not only produce a lot of carcinogens, but also cause a lot of loss of beneficial fatty acids.
As we all know, when the oil temperature is overheated, a toxic substance called aldehyde will be produced, and its content will increase after secondary heating. This substance is defined as a first-class carcinogen by the World Health Organization, which will cause various diseases with high mortality, such as cancer.
In addition, the form of frying will make the beneficial fatty acids (omega-3) almost exhausted. 20 13 A study published in International Food Science and Technology showed that the omega-3 fatty acid content in fried tuna decreased by nearly 85%.
So frying is really a cooking method that harms others and yourself, just as we think. In addition, we don't think the healthiest boiled water is the most ideal cooking form, so I will give you a brief ranking of the advantages and disadvantages of cooking methods here.
Cooking > steaming > boiling > frying
But having said that, I believe many people still have a question like me: Since cooking will cause nutrient loss, why not eat it raw?
Why not eat and drink like primitive people?
Indeed, some foods, such as cucumbers, tomatoes, lettuce and various salads, can retain the nutrients in the food to the maximum extent when eaten raw.
This will make all vitamin C, minerals and other phytochemicals in food absorbed by the body. But there are also some problems, such as food hygiene and food digestibility. Health problems are not difficult to understand, so I won't say much here.
We may not consider the digestibility of food. Many raw foods, although they look more nutritious, are actually greatly reduced in digestion and absorption.
Taking eggs as an example, the digestibility of uncooked eggs is only 5 1.3%, while the digestibility of cooked eggs is greatly improved, reaching 9 1%, which is nearly 1 times higher than that of raw eggs.
Zero lab has something to say.
Finally, Zero Lab wants to tell you that the choice of food is very important on the way to lose weight. But don't ignore the choice of cooking methods. Sometimes the choice of cooking method is even more important than the ingredients. Finally, I want to share with you some suggestions to reduce nutrient loss:
1) Reduce the water consumption when cooking.
2) Make vegetable soup with boiled water.
3) Try to shorten the cooking time.
4) Prefer low-temperature cooking.
5) Try not to peel when cooking.