It is generally considered that frozen vegetables are not nutritious. Is this really the case?
Frozen vegetables can effectively retain nutrients through killing cyanide and rapid freezing technology, and their nutritional value may not be inferior to stale or commercially available frozen vegetables.
As the pace of modern life accelerates, slowly we have to choose between "nutrition and health" and "convenient and fast". Even if I can go to the market occasionally to buy, and wait until I really want to cook, these originally fresh fruits and vegetables may have turned yellow and rotten. In response to the convenience of cooking and the preservation of fruits and vegetables, "frozen vegetables" came out! However, some people may think that frozen vegetables after processing seem to be less nutritious! But is this true?
Frozen vegetables may have higher nutritional value
Generally, frozen vegetables sold on the market will undergo sorting, cleaning and other processing after the fruits and vegetables are collected in the factory. The most critical processing technology is "killing cyanide".
There are natural enzymes in fruits and vegetables, such as: polyphenol oxidase (to oxidize brown fruits and vegetables), pectinase (to soften fruits and vegetables tissues), etc. These enzymes will continue to function in the process of freezing or refrigerating fruits and vegetables, leading to fruits and vegetables Medium nutrition loss and color texture change. The principle of "killing cyanide" is to destroy the activity of enzymes by heating to achieve the effect of preservation. With the "quick freeze" after the killing of cyanide, the nutrients in fruits and vegetables can be effectively retained.
However, compared with some commercially available vegetables and fruits, they may be harvested in advance before they are fully mature due to longer storage and transportation or equivalent factors. Although the vegetables and fruits will continue to mature after picking, it is still difficult to reach the branch. Dry to full nutritional value. Not to mention stale fruits and vegetables purchased from the market and refrigerated to soft rot, may have better nutritional value than frozen frozen ripe fruits and vegetables.
Two-stage "killing" technology upgrades the taste!
The combination of cyanide killing and rapid freezing technology solves the problem of nutrient loss. However, in the traditional cyanide killing technology, "one-stage" heat treatment is often used to avoid nutrition loss of vegetables and fruits, but at the same time, it is easy to soften the tissue of fruits and vegetables and affect the taste. In order to solve the problem of retaining nutrition without sacrificing taste, the technology of "two-stage killing cyanide" was later derived. As the name suggests, it is "stage killing cyanide". It is pre-cooked at medium temperature (50 ~ 70 ℃). To activate the "pectin esterase (a kind of pectinase)" in vegetables and fruits and decompose the pectin molecules of fruits and vegetables, so that the decomposed pectin molecules and calcium ions recombine to form a stable tissue structure, so that the texture of vegetables and fruits It becomes brittle and hard, and then uses high temperature (above 90 ° C) for cooking, which destroys the enzymes in fruits and vegetables, so that the nutritional components of fruits and vegetables can be effectively retained without being destroyed. After the uniform rapid freezing, the frozen vegetables are retained. At the same time as nutrition, the taste is also upgraded!
Not all vegetables are suitable for freezing
However, currently there are not many types of frozen vegetables on the market. The most common is the three-colored vegetables (peas, corn, carrots) commonly used in thick soups or fried rice, which cannot meet all consumer tastes. The main reason is that not all Vegetables are suitable for making frozen vegetables. Generally, the main processing objects are vegetables that have a hard texture, are not easy to lose water, and need to be cooked for a long time. Therefore, you can know that if you want to preserve vegetables by killing them, choosing the right vegetables is also important!
Easily make frozen vegetables at home
With the development of processing technology, these frozen vegetables can effectively retain the proper nutritional value while maintaining the texture of the ingredients. But how can these vegetables be easily preserved at home?
In fact, the basic effect of "killing cyanide" can usually be easily achieved by boiling water or scalding, but it should be noted that the water should be drained as much as possible before sealing and freezing, because excessive water remains Ice crystals will be produced when frozen, and ice crystals will damage the tissue of vegetables, which will cause these vegetables to taste bad or become rotten when they de-ice and cook.
However, even if you learn the simple killing technology to save vegetables, you still have to remind everyone that this will not make the vegetable taste period "forever", and freezing the vegetables will not make the vegetables in your refrigerator disappear, as soon as possible Eat it while it's fresh!