The main varieties of dehydrated vegetables include carrots, edible mushrooms, cabbage, wild cabbage, ginger, etc. The way of dehydration can be divided into two types:drying in the sun and drying artificially. In fact, artificial dehydration includes hot air drying, microwave drying, puffing dry, infrared and far infrared drying, vacuum drying and so on. Among them, air dried dehydration and freeze dried dehydration are widely used presently. In this article, Zhengzhou Rich Foods would like to introduce the manufacturing technique of air dried vegetables.
Step 1. Raw material selection
Usually we choose those vegetables with fleshy texture. Before dehydration, we will carefully select the inferior quality, and remove the diseased and decayed parts.
As for the ripeness, vegetables with eighty percent ripeness is most suitable.Thus neither overripe or underdone vegetables should be singled out. For melon vegetables, we need to discard seeds from the pulp. For other vegetables, clean them with water and then let it dry in the shade instead of drying in the sun.
Step 2. Cutting and blanching
According to the product requirements, cut the raw materials into slices, shreds, strips and other shapes.
During pre-cooking stage, due to different raw materials, the blanching way is different. Those who are easy to be cooked stay less time in boiling water. While, those who are not easy to be cooked need longer time. Usually the time is between two and four minutes. In addition, there is no need blanching leaf vegetables.
Step 3. Cooling and draining
After pre-cooking process, vegetables should be immediately cooled in the manner of cold water shower. Therefore, they can quickly dropped to room temperature. After cooling, in order to shorten drying time, we can throw the water with a centrifuge. While, simple manual method of leaching is also available. After draining, you can spread those vegetables for cooling thoroughly . And then put them on baking plate for drying.
Step 4. Drying
According to different species, the temperature, time, color and drying moisture content could be different. Drying process generally is carried out in the drying room.
There are three types of drying room. The first type is simple drying room, which mainly adopts counter-current blast drying; the second of drying room is the combination of a two-story double tunnel and the reverse flow.
The third is stainless steel hot air dryer with van body. The temperature inside ranges from 65 to 85 degree centigrade. Then vegetables will be dried at different temperature and cool down gradually.
When using the first and second drying room, we need to spread those vegetables evenly on plates and put them in a preset rack and keep the temperature at 50 degree centigrade. Meanwhile,vegetables should be constantly turned to speed up drying, generally the drying time is about 5 hours.
Step 5. Checking and packaging
When dehydrated vegetables are tested to meet the requirements of the Food Sanitation Law, they will be sub-packed in plastic bags, sealed and packing. Now those air dried vegetables are ready to enter the market.