Operating Steps of Fruit Freeze-Dryer

Applications of Fruit Freeze-Dryers:

In addition to producing directly edible products such as freeze-dried fruit slices and dried fruit, fruit freeze-dryers can also be used to prepare food ingredients like fruit powder, fruit jam, and fruit juice powder, which are widely applied in baking, beverages, confectionery, and other fields. Freeze-drying technology also plays an important role in traditional Chinese medicine preparations and biological products. For example, some Chinese medicinal herbs can be freeze-dried into powder for easier storage and formulation. Biologically active substances such as enzymes and vaccines are often preserved using freeze-drying methods. In scientific research experiments in biology, chemistry, and medicine, freeze-dryers are used for sample preparation and preservation, such as freeze-drying cells, tissues, proteins, etc., to maintain their activity and stability.

Determination Steps for Fruit Freeze-Dryer:

1. Preparation:

Equipment check: Ensure all components of the freeze-dryer are operating normally.

Material preparation: Select fresh, moderately ripe, pest- and disease-free fruits. Wash, peel, remove pits/seeds, and cut into uniform small pieces. Pre-treatment steps such as blanching or sulfur treatment may be applied.

Container preparation: Choose suitable food-grade containers that can be sealed and facilitate the sublimation of water.

2. Pre-freezing stage:

Place the prepared fruit material into the freezing chamber or pre-freezing device of the freeze-dryer. Set an appropriate pre-freezing temperature, generally between -20°C and -40°C, to freeze the water in the fruit into ice crystals.

Once the core temperature of the fruit reaches the pre-freezing temperature, maintain it for a period to ensure complete freezing. The pre-freezing time is typically 12–24 hours.
3. Freeze-drying stage:

Start the freeze-dryer: Turn on the vacuum system to gradually increase the vacuum level inside the drying chamber, generally reaching a vacuum range of 10–30 Pa. Simultaneously, start the heating system to warm the frozen fruit, causing the ice crystals to sublime directly into water vapor.

Sublimation drying: During the sublimation drying phase, control the heating temperature and vacuum degree so that the ice crystals in the fruit sublime slowly. The heating temperature is generally controlled between 0°C and 30°C to avoid excessive temperatures that could cause melting or spoilage. This stage lasts a relatively long time, typically 24–72 hours, depending on the fruit type and thickness.

Desorption drying: After most of the ice crystals have sublimed, proceed to the desorption drying phase. At this point, raise the heating temperature appropriately, generally to 30–50°C, to further remove residual moisture in the fruit until the desired dryness is achieved. Desorption drying typically takes 6–12 hours.

4. Completion and inspection:
End freeze-drying: When the fruit freeze-drying process is complete, first turn off the heating system. Then slowly restore the pressure inside the drying chamber to atmospheric pressure balance. Remove the freeze-dried fruit.

If you are interested in our fruits Freeze Dryer or have any inquiries, please feel free to contact us. As professional manufacturers specializing in freeze-drying machines, we offer various specifications of products, including home use freeze dryer, laboratory-scale freeze dryer, pilot-scale freeze dryer, and production scale freeze dryer. Whether you require equipment for home use or larger industrial-scale equipment, we provide the highest quality products and services to meet your needs.