＂Tiangong Recipe＂： Space food is more than just ＂supplementing nutrition＂

　　Figure ①: Space ice cream in the Astronaut Center. Figure ②: Jing Haipeng and Chen Dong dine in space. Photo 3: Canned cheesecake prepared to celebrate Jing Haipeng’s 50th birthday in space. Figure ④: Aerospace 3D food printer developed by Astronaut Center. Figure ⑤: Astronaut Center discusses the assembly scheme of space food.

　　Figure 1 Figure 4 Photo by our reporter Tang Zhongke; Figure ② is provided by China Astronaut Center; Figure 3 Xinhua News Agency; Figure ⑤ is provided by Zang Peng.

　　The research and application of space food plays an important role in the development of manned spaceflight project in China.

　　As a special food for special people in a special environment, what other factors should be considered besides providing necessary energy and nutrition for space food? How are these space foods made? How to make space recipes? How does it taste? Recently, the reporter walked into the space nutrition and food research room of China Astronaut Center to explore the mystery.

　　Ground-based space diet

　　"Tiangong" recipes are very popular.

　　Three meals a day and extra meals.

　　"Breakfast includes porridge, rice cake, marinated eggs, cabbage and mango juice." Zang Peng, an assistant researcher in the Space Nutrition and Food Research Office of China Astronaut Center, introduced the recipes on the first day of the space mission assembly stage (right). "Lunch and dinner are also two staple foods, three dishes, a side dish, a canned fruit and a soup. There are also many kinds of snacks and snacks: chocolate, chicken wings, almonds, dried beans and yogurt drinks. "

　　"However, this is only the recipe for the first day, and it will be adjusted in the next four days. A cycle of diet is different every day. There are more than 100 kinds of foods that astronauts can enjoy this time. " Yan Peng said. Moreover, this recipe should refer to the workload of this mission and the verification results of many ground experiments, and then be adjusted according to the sex and age of astronauts.

　　In addition to the load limit, the recipe arrangement is also related to the characteristics of space food. "Unlike the cooked food we usually eat, space food is mostly processed food, and the loss of nutrients in food is greater than that in cooked food, so we need to pay more attention to the problem of nutrient balance." Yan Peng said.

　　Astronauts’ favorite dishes: cabbage rabbit meat, pine nut corn, braised bamboo shoots and spicy peanuts.

　　Because it is a processed food, the taste of space food is an important topic. In the process of food development and evaluation, the Astronaut Center will invite "sensory evaluators" to evaluate the newly developed space food. After passing the evaluation, the astronauts will be asked to test the taste again.

　　Zang Peng mentioned that at present, astronauts are more interested in several dishes. "You can have more when you have a special task." Such as cabbage rabbit meat, pine nut corn, braised bamboo shoots, spicy peanuts and so on.

　　Is space food delicious? Zang Peng smiled. "Meat food is not much different from the taste we often eat. There is still a certain gap between other foods and cooked foods. This is the characteristic of processed food, but overall it tastes good."

　　Space food is more than just "supplementing nutrition"

　　Some people may ask, is it worth the effort to study space food? Why can’t you directly supplement the whole nutrient preparation and save the trouble of food production and transportation? Zang Peng explained that the space diet is not as simple as complete nutrition. In order to keep astronauts in good working condition in orbit, the diet should be consistent with the ground as far as possible, that is, "the space diet is grounded". At the same time, the process of eating can also temporarily free astronauts from their busy work. They can communicate while eating and relax in their leisure time.

　　Braised pork chops with red sauce, shredded pork with fish flavor and ice cream … …

　　"Tiangong" cuisine is a difficulty in research and development.

　　Space food is generally divided into six categories, namely "three foods and three products": staple food, non-staple food, ready-to-eat food, drinks, condiments and functional food. Among them, dishes in non-staple food have always been a difficult point in space food research and development, Zang Peng said.

　　Innovate sterilization method to ensure color and fragrance

　　"Green leafy vegetables are still difficult to take to the sky." Zang Peng said that space food needs a shelf life of 12 months, and generally needs to be heated and sterilized. The sensory conditions such as color, fragrance and so on of the heated vegetables are not ideal. At present, the main dishes in China are roots and fungi, such as carrots, potatoes, yams and fungus, which are common space ingredients.

　　"A space fish-flavored shredded pork needs to be fried for dozens of kilograms." In front of the "cauldron" where "shredded pork with fish flavor" is fried, Zang Peng said, "In order to ensure the quality, space food is industrialized." Take fish-flavored shredded pork as an example. Auricularia auricula, bamboo shoots and meat are treated separately in advance and then added to the feeding port of the "cauldron". The time and heat required for cooking are controlled by the machine.

　　"The fish-flavored shredded pork cooked here is half-cooked." It turns out that space food needs to be sterilized after packaging, and the heating process in sterilization will cook the food until it is "cooked". Zang Peng said, "In the past, high-temperature sterilization was used for space food, but this practice would make the taste of dishes worse. Now we prefer to use multi-stage heating sterilization or a combination of cold and hot sterilization to improve the color and flavor of dishes as much as possible."

　　Space ice cream tastes great.

　　"Our space ice cream was made in this machine." In the food processing workshop of the laboratory, Zang Peng said that the ice cream eaten by Jing Haipeng and Chen Dong was actually frozen and sublimated, and the water molecules that had turned into ice were quickly pulled away. With a bite, the space ice cream has no difference in taste except for the icy feeling of ordinary ice cream, and the taste is quite good.

　　Space pork chop is "boring, not spitting skin"

　　Because the spacecraft is afraid of oil and debris, some seemingly ordinary home-cooked dishes are not so simple to make.

　　Zang Peng said that taking "braised pork chops" as an example, it is necessary to manually pick out the bones and broken bones and remove the grease when making them. As far as grease removal is concerned, in addition to removing fat before cooking, bread crumbs should be wrapped and baked in the oven after making. Space pork chops can be understood as boneless meat, which can be "stuffy".

　　By the same token, cookies in space are bite-sized, and cookie crumbs will not be eaten all over the sky.

　　There is tea to drink every day in the "Tiangong".

　　This time in space, Jing Haipeng and Chen Dong basically make tea every day.

　　Zang Peng said that this is the first time that Chinese has made tea in space. There are two kinds of tea prepared this time: one is similar to the tea bag we usually use; The other is tea powder. "Tea powder can be understood as similar to ‘ Guo Zhen ’ The same ‘ Tea Jane ’ For example, there is lemon tea flavor. " Both "soaking" methods are the same, which is not complicated. After rehydrating the tea bag with a special water gun, it can be heated in an electric heating box.

　　3D "printing" the new future

　　"Tiangong" cooking is not a dream.

　　In the space nutrition and food research laboratory of China Astronaut Center, there is a 3D food printer. Zang Peng introduced that this is the first generation of 3D food printer they developed. China Astronaut Center is trying to let astronauts "cook" their own food in the sky.

　　Zang Peng said that the early foreign space food was in the shape of a hose, and every time you eat, you need to squeeze the food into your mouth like "squeezing toothpaste". With the successful deployment of refrigerators on spacecraft in the United States, the difference between the diet of foreign astronauts and the ground is getting smaller and smaller.

　　At present, China’s space foods are all processed "cooked food". In order to reduce the weight, some foods are dehydrated on the ground first. In space, astronauts rehydrate food first, and then put it into an electric heating box to heat it. "The laver egg soup package on the market now is derived from this space dehydration technology."

　　If printing food in space can be realized, astronauts can take flour to the sky and then "punch" fresh steamed bread through a 3D printer.

　　■ Tips

　　History of space food in China

　　The research and development of space food in China started from the "Dawn" space program in the 1970s, and more than 50 varieties of space food warehouses in three categories, namely, normal rations, emergency rations and life-saving rations, have the ability to form a four-day recipe cycle configuration.

　　In 1980s, the basic research on the relationship between nutrition and bone loss in weightlessness and the protective measures were carried out by using simulated weightlessness animal model.

　　The manned spaceflight project was launched in 1992. On the basis of previous research, four applied basic research and product development systems, namely, space nutrition, astronaut substance metabolism, space food and space food packaging, were established, forming the basic framework of space nutrition and food engineering research.

　　Cartography of this edition: Cai Huawei