Nowadays, canned food is not favored by Chinese people. Canned food on supermarket shelves is seldom seen. Family meals seldom see them. Even canned food is regarded as the representative of unhealthy food by some people. But canned foods are clearly misunderstood, and in fact they are not only delicious, nutritious, but also hygienic and safe. Please see -

 

Misunderstanding: canned food does not deteriorate because of preservative fact: canned food is not necessary and preservatives are not allowed.

 

The most fundamental feature of canned food is the use of sealed and high-temperature sterilization technology, eliminating pathogenic bacteria and spoilage bacteria, is the food industry on food storage and long-term supply of a thorough revolution. From the beginning of canned food, it means safe food. Canned products eliminate food spoilage and are therefore a class of foods that do not require or allow the addition of any preservatives. No matter how to improve the canned food processing technology, safety is the primary feature and basic element of canned food. According to the FDA, none of the more than 4,000 cases of foodborne diseases reported in the United States between 2007 and 2012 were related to canned food.

 

Canning generally adopts the following processes: food is processed and packed into a can, and the heat of the food is as high as 80 degrees Celsius after the exhaust step; then, the cans are sealed by electric welding to make the cans vacuum; then, the cans are put into the furnace and heated to 135 degrees Celsius for up to an hour and a half to ensure that the bacteria in the cans are completely exposed to high temperature. The cans are stored in the warehouse until they are cooled; the warehouse is kept at 25 degrees C for 7 to 14 days (which is the temperature most likely to cause bacteria to grow), during which time the broken cans are thrown away to avoid entering the market.

 

Mistake 2: Canned food is junk food, no nutritional facts: Canned food nutrient loss will not exceed the normal cooking level

 

Researchers at the University of California in the United States compared the nutrients of canned fruits and vegetables with fresh and frozen fruits and vegetables. They found that most fresh fruits and vegetables only provide vitamins and minerals when they are just picked, but the oxidation during storage can lead to the loss of nutrients. Therefore, the loss of nutrients caused by cooking and storage is higher than expected. Commercialized canning and freezing storage can maintain the main nutrients.

 

Water-soluble and oxygen-unstable nutrients such as vitamin C and vitamin B may be lost during the initial heat treatment stage of canning, but these substances are relatively stable due to lack of oxygen during the later storage of canned products. Meanwhile, the retention of vitamin K, E, A and D in canned products was relatively stable. At the same time, the phenolic substances which are also water-soluble and oxygen-unstable were also studied. It was found that the situation is more complicated. Storage and cooking would lead to the loss of phenolic substances. However, heating the pretreatment of canned tomatoes would help to increase the polyphenol content and antioxidant activity. Comparing minerals with cellulose, minerals and cellulose generally remain stable during processing, storage and cooking, but lose more in peeling and other links. The carotene content of fresh corn and canned corn also showed that lutein, zeaxanthin and total carotenoids were not significantly different, indicating that canned processing did not reduce the carotene content of corn. The reason is that canned vegetable production in factories takes shorter and less time to produce products of stable quality from picking to processing. Home cooking has a longer time to enter the family because of the logistics after picking than the time from factory production to pre-processing, so the loss of nutrition after picking is greater. At the same time, home cooking The processing loss of the court is greater than that of the factory.

 

Misunderstanding three: raw materials can only be made into canned facts: canned food is more fresh.

 

First of all, the raw materials used for canned food are fresh. Canning, in pursuit of lower cost and better taste, will be the most appropriate season to choose the freshest ingredients. Moreover, the cannery has its own raw material base, in the chemical fertilizer, pesticides and other aspects of strict control, can fully guarantee the quality of raw materials.

 

Secondly, the processing of canned food is "fresh keeping" for food. If meat and fish can not be processed in time, they will quickly rot. If vegetables and fruits are not processed in time after harvest, they will also cause nutrient loss. Studies have shown that plants can not be picked for normal biochemical synthesis, many chemical reactions are carried out in reverse, vitamins and other nutrients will be constantly depleted. Therefore, too long transportation and sales will make the food that we thought was fresh become stale. Canned food from the field to the factory, from fresh raw materials to finished products, as long as less than an hour, sterilization process can stop the chemical reaction of food in time, so that the nutrients of food are fully preserved in a fresh state.