1. Pretreatment
Before freeze-dried fruit is produced, it must first be pretreated. This involves selecting fresh, pest-free, and appropriately ripe fruit, then washing, peeling, core-removing, and slicing it. When slicing, ensure the slices are uniform in thickness to achieve consistent drying results during the subsequent freezing and drying processes.
2. Freezing
The pretreated fruit slices are then rapidly frozen. This step aims to quickly convert the moisture in the fruit into ice crystals, preventing them from growing during the drying process and affecting the taste and quality of the product. The freezing temperature is typically below -30°C, and the freezing time depends on the type of fruit and the thickness of the slices.
3. Vacuum Drying
The frozen fruit slices are then dried in a vacuum drying chamber. Under vacuum, the ice crystals sublime directly into water vapor, removing moisture from the fruit. This step requires controlling the temperature and vacuum level appropriately to ensure the fruit slices retain their original shape and color while minimizing nutrient loss. The drying time depends on the type of fruit, the thickness of the slices, and the capabilities of the drying equipment.
4. Packaging
After drying, freeze-dried fruit needs to be packaged. The packaging material should be airtight and oxygen-barrier to prevent moisture, oxidation, and deterioration during storage. The packaging should also include information such as the production date, expiration date, and storage conditions to ensure proper storage and consumption.
