Food freeze dryer processing freeze-dried food production process: raw material selection → finishing → pre-freezing → vacuum freeze-drying → post-processing → packaging and storage. In the technological process of freeze-dried food processing, taking fruits and vegetables as an example, the main steps are as follows:
Step 1. Selection of raw materials: All vegetable raw materials come from legal channels, and must ensure that the raw materials are fresh, free of peculiar smell, and no rotting phenomenon. The pesticide residues and pollutant limits should comply with the corresponding national standards and industry standards;
Step 2. Cleaning: Clean the soil and debris, and remove some old leaves;
Step 3. Cut shape: cut into different shapes according to customer requirements;
Step 4. Blanching: Put the cut vegetables into the boiling tank in time, and complete the blanching at the specified time and temperature. The water temperature is above 85 ℃, the materials are put in, and the blanching is maintained at 90 ℃ for 3 minutes;
Step 5. Cooling: After cooking, pick up and cool in time to prevent accumulation;
Step 6. Ingredients: according to the product and customer requirements, add salt or no salt, and no other food additives;
Step 7. Loading: Put the cooled ingredients into the standard metal tray in time and enter the quick-freezing warehouse. If the temperature of the material is above 20°C, the fan can be cooled in time before entering the freezing warehouse;
Step 8. Pre-freezing: the temperature of the freezer is controlled below -18°C and the freezing time is 1.5 hours;
Step 9. Vacuum freeze-drying: After the freezing is completed, quickly move it into the food freeze-drying machine together with the metal plate, and complete the vacuum freeze-sublimation drying process under the specified operation; the vacuum degree in the pre-production to mid-term vacuum freeze-sublimation drying process should be less than 1.5 Torr, Drying varies with the number of materials and the thickness of the tray. The curve is set from 20°C-70°C-62°C. The drying temperature in the later stage is controlled at 65°C, and 1 hour before the oven is released, the drying temperature is reduced to 62°C;
Step 10. Inner packaging: After the vacuum freeze-drying is completed, first check whether the room is clean, and open it for sterilization and dehumidification one hour in advance; the products leaving the freeze-drying room must be sealed and packaged within 60 minutes to prevent moisture and pollution;
Step 11. Outer packaging: Pack it into the outer packaging box according to the specified requirements, pay attention to the correct labeling of the outer packaging box, and the label is complete and correct.
