1. Selection of raw materials. Before dehydration, the best ones should be strictly selected, the inferior ones should be removed, and the parts with diseases, insects, rot, and shriveled shall be removed. 80% of the maturity is appropriate, and those overripe or not ripe should also be picked out. Remove seeds from melons, and other types of vegetables can be washed with clean water and then placed in a cool place to dry, but should not be exposed to the sun.
2. Cutting, blanching and cutting the washed raw materials into slices, wires, strips, and other shapes according to product requirements. When pre-cooking, it varies according to the raw materials. For those that are easy to cook, put them in boiling water, and for those that are not easy to cook, put them in boiling water for a while. Generally, the blanching time is 2 to 4 minutes. Leafy vegetables are best not blanched.
3. Cool and drain. The pre-cooked vegetables should be cooled immediately (usually washed with cold water) to drop to normal temperature quickly. After cooling, to shorten the drying time, you can use a centrifuge to shake off the water; you can also use a simple manual method to squeeze and drain. After the water is drained, you can spread it out and let it cool for a while to prepare for drying.
4. Drying. Different temperatures, times, and moisture content during drying should be determined according to different varieties. Drying is generally carried out in a drying room. There are roughly three types of drying rooms: the first is a simple drying room; the first simple drying room adopts countercurrent blast drying; the second is a drying room with dual tunnels and a combination of forward and reverse airflow; The third is a van-type stainless steel hot air dryer, the drying temperature range is 65 ℃ - 85 ℃, drying at different temperatures, and gradually cooling. When using the first and second drying rooms, evenly spread the vegetables in the tray, and then put them on the pre-set racks to keep the room temperature at about 50 °C, and at the same time, keep turning them to speed up the drying, generally drying time is about 5 hours.
5.5, sorting, packaging. After the dehydrated vegetables meet the requirements of the Food Sanitation Law, they can be packed in plastic bags, sealed and boxed, and then sold.