Recently, the topic of prefabricated dishes is very hot. "Prefabricated dishes are occupying takeout and restaurant food" and "more than 80% of chain restaurants in Guangzhou use prefabricated dishes" and other news hit the hot search... For "kitchen Xiaobai" who does not usually cook, prefabricated dishes can really help a lot. After buying them home, you can enjoy a big meal simply by processing them. Prefabricated dishes are convenient, but many people are worried that the nutrition of the prepared dishes will be seriously lost, and they suspect that the prefabricated dishes will add too many preservatives... In view of the above problems, the reporter of science and technology daily interviewed relevant experts to answer your questions. There is no need to add additional preservatives in the production process. "Prefabricated vegetables refer to finished products or semi-finished products made from agricultural, livestock, poultry and aquatic products as raw materials, with various auxiliary materials, and through pre-processing (such as cutting, mixing, pickling, rolling, shaping and seasoning) Ruan Guangfeng, director of the science and Technology Communication Department of Kexin food and health information exchange center, said in an interview with the reporter of science and Technology Daily that generally speaking, when making prefabricated vegetable products, the formal prefabricated vegetable production enterprises will use modern standardized flow process to complete the preliminary preparation and processing of the raw materials of the dishes, and then seal them and put them into the market. After buying the prefabricated vegetables home, consumers can directly enjoy the dishes by simply heating or steaming and frying. Usually, people eat canned food and other foods, which belong to the category of prefabricated vegetables. Convenience is available, but is the prefabricated food safe? Will there be excessive addition of preservatives? "In essence, prefabricated dishes are cooked in advance by merchants, and high-temperature cooking is a sterilization process, and then the merchants use liquid nitrogen and other quick freezing technologies to freeze them. This can greatly inhibit the propagation of microorganisms, so there is no need to add additional preservatives in the whole process." Ruan Guangfeng said that as long as the national standards are met, the rational use of additives will not cause harm to the human body. There is a certain degree of nutrition loss. First, high-temperature cooking, then low-temperature quick freezing. After the test of "ice and fire", how much nutrition can be left in the prefabricated vegetables? "Objectively speaking, compared with homemade dishes, there must be a certain degree of nutrient loss in prefabricated dishes." Ruan Guangfeng said that the nutrient loss of prefabricated vegetables mainly comes from the normal loss in the production and processing process and the secondary heating of the dishes after the consumers buy the prefabricated vegetables. For the former, in order to reduce the loss of nutrition, the production enterprises of prefabricated vegetables often adopt the method of low-temperature preservation for the raw materials and the prepared vegetables. This preservation method is not only safe and hygienic, but also can better preserve the nutrition of the dishes. For the latter, the effect of secondary heating on the nutrition of dishes is not as great as people think. After secondary heating, some heat sensitive nutrients such as vitamin C will be partially lost. "However, this kind of loss is relatively limited. First, from the perspective of scope, some non heat sensitive nutrients will not be lost; second, from the perspective of degree, even heat sensitive nutrients will generally only be lost in part after secondary heating, rather than all." Ruan Guangfeng added. Fan Zhihong, associate professor of the Department of nutrition and food safety, School of food, China Agricultural University, stressed in an interview with the media: