Pre processing determines the upper limit of finished product quality. This includes cleaning, trimming, cutting, blanching (enzyme inactivation and color protection), and concentration (increasing solid content and reducing subsequent sublimation water volume - this is the most economical energy-saving method). Plate/fabric single-layer uniform, non overlapping, thickness determined according to material characteristics (generally 10-20 mm). The uniformity of plating directly determines batch consistency; The tray is recommended to be made of 316L or food grade aluminum alloy with guide holes.

Overview of Vacuum Freeze Drying Equipment:
After freezing the material at low temperature, the ice is directly sublimated into water vapor and discharged in a vacuum environment, thereby removing moisture without almost damaging the tissue structure and thermosensitive components. Raw material receiving inspection → pre-treatment (cleaning/cutting/blanching, etc.) → batching/concentration (depending on category) → draining/homogenizing → palletizing (fabric) → pre freezing → vacuum freeze-drying (primary drying+secondary drying) → out of box reheating → post-treatment (cutting/crushing) → metal detection → weighing and packaging (nitrogen filling/deoxidation) → coding traceability → inspection and storage.
Vacuum freeze-drying equipment production line process:

Pre freezing (key to success or failure) objective: The material is completely frozen/vitrified, with the center temperature reaching the set value and maintained for 1-2 hours. Suggest cooling down the program, slowing down the rate near the eutectic point, and controlling the ice crystal size. Incomplete pre freezing → Boiling, foaming, and "spraying" during vacuum pumping, contaminating the box and condenser. The eutectic point/melting point must be measured using DSC or resistance method, and cannot be determined based on experience. Vacuum freeze-drying for one-time drying (without free water): The box pressure is typically 10-50 Pa, and the shelf temperature is controlled at 3-5 ℃ below the melting point to prevent collapse. Secondary drying (removal of bound water): further depressurization+moderate heating, and removal of bound water by desorption. Endpoint criterion: It is recommended to use the Pressure Rise Test to determine the endpoint of a drying process online, which is more reliable than a fixed timer and can avoid energy waste caused by over drying. The endpoint moisture content is determined by category: fruits and vegetables are generally ≤ 5%, and high-fat materials such as coffee are ≤ 3%.
Vacuum freeze-drying equipment packaging:

After exiting the box and undergoing post-processing, it is necessary to first warm it up before exposing it to air, otherwise it will condense and regain moisture. The crushing/cutting area needs to be controlled for humidity (RH ≤ 40%) and dust removal, and freeze-dried powder generally has strong moisture absorption. Packaging and storage high barrier film+nitrogen or deoxidizer, oxygen and moisture resistant; It is recommended to add natural antioxidants to easily oxidizable materials such as coffee, animal organs, and nuts. Storage at room temperature and cool or -18 ℃, depending on the category.