Analysis of technical problems of freeze-dried fruits

　　Analysis of technical problems of freeze-dried fruits
　　Fruit is a kind of food with high added value, and freeze-dried fruit will have a very broad market prospect. However, at present, the development of freeze-dried fruits using freeze-drying machines has encountered bottlenecks. The reasons for this are mainly the following three reasons.
　　First, the difference between different fruits is relatively large
　　There are many kinds of fruits, even if they are similar fruits, if the growing environment is different, the climate will be different, which will cause great differences. Therefore, the technical parameters of the fruit freeze-drying process are difficult to categorize and set a unified standard process. If different kinds of fruits have different enzymes, their color protection process is very different, and the fruit is also very particular. The different thickness of the plate will cause the quality of the dried products after zui to be different. Choose a specific freeze-drying process for different fruits.
　　Second, the freeze-drying process takes a long time and consumes a lot of energy
　　Vacuum freeze drying is considered to be a dry method that is expensive for zui. The cost of vacuum freeze-dried food is about 5 to 7 times that of hot air drying, 7 to 8 times that of quick-frozen food, and 7 times that of spray drying. The pre-freezing energy consumption in the vacuum freeze-drying process only accounts for 4% to 14%, and the total energy consumption of the vacuum pump, heating plate and cold trap during the drying process accounts for 86% to 96%. Due to the high investment cost of equipment and high energy consumption in the production process, some manufacturers are discouraged and restrict the practical application and development of freeze-drying technology.
　　Third, the appropriate technical parameters are more difficult to determine the parameters of the vacuum freeze-drying process, which has a decisive impact on the quality of freeze-dried fruit. The freeze-drying process, including pre-freezing, primary drying, secondary drying and storage stages, is a fairly complex heat and mass transfer process; and these processes are closely related to the nature of the fruit. Therefore, it is necessary to determine a variety of thermophysical properties of fruits, to understand the factors affecting heat and mass transfer during the freeze-drying process, in order to develop a reliable procedure, using an optimized freeze-drying control process to produce high-quality freeze-dried products.
　　However, the freeze-dried fruit is fast-frozen, vacuum-dehydrated, preserves the original color, aroma, taste, nutrients and the appearance of the original material, and has good rehydration, and does not contain any additives, it is ideal. High-end foods that are natural and hygienic. As food safety issues become more serious, the space for subsequent development is beyond imagination.