Comment on the freshness of canned food

Chinese people in the age of lack of food and clothing have taken hard food and clothing as their goal. Nowadays, the well-to-do people who have solved their food and clothing problems naturally shift their goals from being “eaten” to “eat well” under the influence of “the people regard food as the heaven”. In the tide of “eating well”, the pursuit of “freshness” has become the mainstream of the tide. Some food companies and catering hotels are eager to follow the trend and strive to take advantage of business opportunities, even under the surface of the water. “Let chasing fresh people” is like a wave, and their understanding of food science determines their “water-based” quality. Among them, there are many consumers who are “underwater” and are guilty of misunderstandings. Among the many misunderstandings, the biggest misconception is that “canned food is not fresh”.

Most consumers believe that freshly slaughtered animal foods and freshly picked plant foods are fresh, and processed foods are not “fresh”. This understanding is not wrong in defining the concept of “freshness”. However, the “freshness” in the real sense must be whether the food itself is delicious at the time of consumption, and whether it should maintain the flavor and nutrition that the food should have. Therefore, it is necessary to consider the following questions: Is the animal food just slaughtered and the freshly picked plant food all suitable for immediate consumption; for the part of the “fresh” food suitable for immediate consumption, can the average consumer use the economy? The price is purchased and immediately consumed; in addition to direct consumption of fruits and some vegetables, whether the consumer's cooking skills can guarantee the freshness of the cooked food; greenhouse vegetables (seasonal vegetables) even if just picked As the taste and nutrition are more or less inferior to normal season production, the "fresh" connotation has changed and must be treated differently.

People who compare fresh pineapple and canned pineapple, fresh yellow peaches and canned peaches can easily recognize that not all fresh fruit that has just been picked has a more “taste” than processed ones. Fresh pineapple contains bromelain. The protease has a strong decomposition effect on animal proteins, and has a destructive effect on the mucous surface of the tongue and gastric mucosa. This is why eating fresh pineapple produces astringent and individual stomach discomfort. a feeling of. In the course of heat sterilization of canned pineapple, the bromelain in the pineapple is inactivated, and at the same time, a large amount of plant fibers in the pineapple is softened and the taste becomes better. The same is true for animal-based foods. Freshly slaughtered meat contains active lytic enzymes. After nearly 24 hours of cooling, the pH of the steroids is reduced by the decomposition of lytic enzymes, thereby tenderizing muscle fibers and degrading proteins. Produce amino acids that contribute to flavor. This process is called "after-ripening," which is what is called "sour meat." It can be concluded that not all animal and plant foods are more "fresh" the better.

The degree of maintenance of the original nutrients in food is one of the important indicators to judge the freshness of food. It is well-known that the corruption of fish after death is extremely fast and that rapid processing after fishing is the best way to preserve freshness. The largest fish can on the Chinese market today is canned mackerel. In order to ensure the freshness of the products, the regular processing factories moved the pre-treatment process to the edge of the fish pond. They were slaughtered and quickly fried after harvesting. Some processing plants were built on the riverside. The docks are included in the pre-treatment workshops. These efforts are aimed at maximally maintaining the freshness and nutrition of the fish. Therefore, China's canned mackerel can enjoy a high reputation in the international market. Corruption of plant foods appears to be slower than animal food on the surface. In fact, any vegetable or fruit continues to “breathe” after picking. Since normal biochemical synthesis is not possible, chemical reactions are often reversed. of. Research by foreign scientists shows that some nutrients begin to decrease after picking. Vitamins are very sensitive to oxidation, light and high temperatures. For example, asparagus loses 40% of vitamin C during 24 hours of storage and transportation, and spinach loses 30%. Green beans will Lose 20%. It can be said that the vegetables that consumers purchase from farmers' markets or supermarkets cannot be called fresh no matter how perfect their appearance is. From a nutritional point of view, "fresh", it is only the freshest picking and eating at the field. In contrast, canned foods for fruits and vegetables are unique in the preservation of nutrition. In many occasions, compared with the vegetables sold in supermarkets, the time for the raw materials of canned foods to be picked up, transported and processed is very short, generally not exceeding 2 hours. At the same time, short-term high-temperature heat treatment stops the fruits and vegetables products. Any chemical reaction, anaerobic and dark, keeps the freshness and nutrient content of the product for at least two years before being sterilized. Many consumers believe that canned foods will destroy heat-sensitive vitamin C during processing, but studies have shown that the amount of vitamin C lost during processing of canned foods is less than that caused by cooking in normal households. At present, China's regular canned fruit and vegetable processing companies have added vitamin C to preserve the primary colors of fruits and vegetables. Obviously, canned food not only maximizes the nutritional value of foods, but even some canned foods improve the nutritional value of foods.

In 2002, the study led by Mönchenglabach, organizing committee of the Institute of Ecological Nutrition at the Willich Institute for Food Quality in Germany and Niederrbein Technical School, compared the loss of the main vitamins in fresh foods and canned foods during the test period. Comparing the nutritive value and vitamin content of the canned monomer food and its equivalent fresh food under normal conditions, the results show that the canned food contains vitamins A1, B1, B2, B6, E and folic acid and fresh vegetables. The content of the dishes made is roughly the same. As for carbohydrates, protein, and fat, there is no obvious difference. Thus, Dr. Reiwbard Hambitzer, professor of ecological nutrition at the Niederrbein Technical School, came to the conclusion that eating canned food is beneficial to the human body, and the consumer absorbs nutrients and important vitamins. Canned food is not only suitable for people who want to save time, but also highly recommended for people with fresh food awareness.

Today's canning technology is also constantly innovating, creating its own characteristics in a world increasingly sensitive to food safety, hygiene and nutrition, and preservation. The exquisite processing technology and effective heat conduction ensure the sterilization temperature, so that the heating time is as short as possible, thereby ensuring the nutrition and quality of food, to meet the near-fussy needs of contemporary consumers. Although traditional Chinese cooking is attractive in terms of color, aroma, taste, and shape, it is necessary to ensure that foods after cooking have the best freshness and nutritional value. In addition to superb craftsmanship, chefs must also conduct food science. Research. It is a pity that the graduates of the food specialties are hardly engaged in the work of the chefs, and the housewives or “master men” may not understand both the cooking arts and the food science. In other words, even if the family dishes use the freshest ingredients, it is difficult to guarantee the freshness of the dishes and the maintenance of nutrition. Therefore, the pursuit of “freshness” has no practical significance, and it is at best a kind of imaginary psychological enjoyment.

With the development and promotion of greenhouse cultivation technology and storage and preservation technology after harvesting, the listing of fruits and vegetables ensures that “fresh” fruits and vegetables can be eaten throughout the year. This creates an external condition for “recovering fresh families”. However, more and more “reviewers” ​​have begun to complain about the "tastelessness" of anti-season fruits and vegetables. As for the "fresh fruits and vegetables" that use waxing and preservation, it can be said that it is the most cost-effective choice from a nutritional point of view. The raw materials used for canning are the products of the normal season. The raw materials contain various nutrients and flavor substances that they should have. Although many products are difficult to achieve “original”, they can not deny its advantage in preservation.

Of course, the unique flavor of canned food is sometimes difficult to achieve with other processed foods. Canned experts in China understand that using non-painted tin cans to hold canned yellow peaches, tinplate trace elements can not only play a role in color protection, but also can improve product flavor, beneficial to human health.

Since the invention of canned food, it has experienced a history of nearly 200 years since its inception. Canned food processing technology has advanced by leaps and bounds. Canned food consumption in developed countries, such as Europe, USA and Japan, is on the rise. The consumption of canned food in China has also changed in recent years. More and more consumers have gone out of their misunderstandings. The transition from a correct understanding of canned food to canned canned foods indicates an optimistic outlook for the canned domestic market.