Vacuum Freeze Drying Chamber

Project Name: Zhengzhou Haoxiangni Co., Ltd.

Completed on: May 18,2019, in Xinzheng City, Zhengzhou, Henan, China.

The construction period is 120 days, and the debugging and cooling period is 45 days.

This project is specifically designed for large-scale jujube cultivation bases, agricultural product deep-processing enterprises, and leading food production companies. It meets the processing demands of freeze-dried jujubes on a large scale, ensuring that the produced freeze-dried jujubes retain the original nutrients, color, and flavor of the jujubes. These products can be widely applied in various fields such as snack foods, healthy meal replacements, baking ingredients, and maternal and infant foods. Through the cluster configuration of 10 core sets of equipment, the project achieves a breakthrough in the daily processing capacity of freeze-dried jujubes. Coupled with customized parallel refrigeration units, it ensures the stability and energy efficiency of the production process, enabling enterprises to establish a full-process processing capability from raw material handling to finished product output.

The system features 10 sets of 200m³ vacuum freeze-drying units, each with an effective freeze-drying capacity designed for large-scale production. The chamber is constructed from food-grade 304 stainless steel, offering corrosion resistance, easy cleaning, and compliance with food hygiene standards. Equipped with intelligent vacuum and temperature control systems, the equipment precisely regulates vacuum levels (≤10Pa) and shelf temperatures (-50℃ to +50℃) during freeze-drying, meeting the process requirements of different freeze-drying stages for jujubes. Additionally, the automated feeding and discharging system significantly enhances production efficiency and reduces labor intervention costs. The 10 units can operate independently or in coordinated mode, flexibly accommodating various batch sizes and specifications for freeze-dried jujube production.

Process Flow of Fruit Freeze-Drying Products

The core principle of freeze-drying fruits is to directly vaporize the moisture from solid ice into a gaseous state under vacuum conditions, achieving dehydration and preservation while maximizing the retention of the original nutrients, color, flavor, and morphology of the fruit flesh. The specific process flow is summarized as follows:

1. Raw material pretreatment: Select high-quality fruits with appropriate ripeness, free from diseases, pests, and damage. After cleaning, sorting, core removal (optional), and cutting (optional), impurities and substandard materials are removed to ensure uniform quality of the raw materials.

2. Pre-freezing treatment: The pretreated pulp is evenly spread on the lyophilization tray and transferred into the pre-freezing chamber of the quick-freezer or lyophilization equipment. It is rapidly frozen at low temperatures of-35°C to-45°C, converting all internal moisture in the pulp into solid ice, thereby laying the foundation for subsequent sublimation drying.
3. Sublimation Drying: The pre-frozen pulp is transferred into the vacuum freeze-drying chamber. The vacuum system is activated to achieve the preset vacuum level, while the shelf heating system gradually increases the temperature. This process enables the solid ice within the pulp to sublimate directly into water vapor under vacuum conditions. The water vapor is then cooled and condensed into liquid water by the condensation system before being discharged. This stage constitutes the critical phase of freeze-drying, requiring precise control of vacuum levels and heating rates to prevent pulp deformation or nutrient loss.
4. Desiccation: After the majority of free water in the pulp has sublimated, the process enters the desiccation stage. The shelf temperature is further increased to remove the bound water adsorbed within the pulp, reducing the moisture content to below 5%, thereby enhancing the product's shelf life and storage stability.
5. Post-processing: After drying is completed, allow the lyophilized pulp to return to room temperature, then perform sealed packaging in a clean environment. Simultaneously, conduct final product inspection and sorting to remove non-conforming products, ultimately obtaining high-quality lyophilized pulp.