First, the basic principle of the freeze dryer.
Freeze dryer is a drying technology that freezes aqueous materials into a solid state by reducing the temperature and vacuuming, and then converts the solid ice directly into gaseous water vapor through sublimation, so as to remove water and retain the material. In the freeze drying process, the water in the material is directly sublimated from an unstable ice crystal state to a gaseous state, and this process does not appear liquid water, so it is also called "sublimation drying".
2. Features and advantages of freeze dryer.
1.Preservation of the original flavor and nutrients of food: Since freeze-drying is carried out in a low temperature and vacuum environment, it can effectively prevent the loss of nutrients and flavor in food, so as to maintain the original taste and nutritional value of food.
2.Extend the shelf life of food: By removing moisture, the rate of microbial reproduction can be significantly reduced, thereby extending the shelf life of food. Depending on the type of food, freeze-dried food can last for months or even years.
3.Energy saving and environmental protection: The energy required for the freeze-drying process is relatively low, and there is no chemical residue, which meets the requirements of modern green and environmentally friendly industrial development.
4.Convenient and fast: The freeze-dried food is small in size, light in weight, easy to carry and transport, and provides convenience for long-distance food transportation and travel.
5.Wide range of applications: The freeze dryer is not only suitable for the preservation of fruits, vegetables, meat and other foods, but also can be used in biological products, medicines, chemical raw materials and other fields.
3. The application of freeze dryer in the field of food preservation.
1.Vegetables and fruits preservation: Through freeze-drying technology, vegetables and fruits can retain their original color, taste and nutrients for a long time. For example, common freeze-dried fruits and vegetables are freeze-dried strawberries, freeze-dried blueberries, freeze-dried carrots, etc.
2.Meat preservation: Freeze-dried meat removes most of the water, significantly extending shelf life. At the same time, the rehydrated meat still tastes delicious and the nutrients are retained.
3.Convenience foods: such as instant soups, ready-to-eat vegetables, dehydrated drinks, etc., are all convenience foods produced by freeze-drying technology. These foods can be quickly restored by simply adding water, which is convenient and fast.
4.Coffee and tea: After freeze-drying, coffee, tea and other beverages are lightweight, easy to carry, and can maintain their original flavor for a long time.
5.Other foods, such as condiments, candies, etc., can also be preserved by freeze-drying technology.
IV. Conclusions. As an advanced food preservation technology, freeze dryer has a wide range of application prospects. With the continuous improvement of people's requirements for food safety and quality, it is believed that freeze drying technology will play an increasingly important role in the food industry in the future.