One, dehydration drying methods are natural sun drying and artificial dehydration two categories. Artificial dehydration including hot air drying, microwave drying, puffing drying, infrared and far infrared drying, vacuum drying. At present, the application of vegetable dehydration drying is more hot air drying dehydration and freezing vacuum drying dehydration, freezing vacuum dehydration method is currently an advanced vegetable dehydration drying method, the product can retain the original color, aroma, taste, shape of fresh vegetables, but also has the ideal rapid rehydration. Now the hot air drying dehydrated vegetables and freezing vacuum drying dehydrated vegetables processing process and method is introduced as follows.
Two, hot air drying of dehydrated vegetables processing process and methods:
1, raw materials selection selection of vegetable varieties with rich meat, dehydration should be strictly selected before the best to remove the bad, remove the disease, insect, rot, shriveled part. To eighty percent maturity is appropriate, overcooked or undercooked should also be picked out, in addition to melons to the seeds and flesh, other types of vegetables can be rinsed with water, and then placed in a cool place to dry, but should not be exposed to the sun.
2, cutting, blanching and rinsing the clean raw materials according to product requirements were cut into slices, silk, strips and other shapes. Pre-cooking, depending on the raw materials, easy to cook through the blanching in boiling water, not easy to cook through the boiling water in a few moments, the general blanching time is 2 to 4 minutes. Leafy vegetables are best handled without blanching.
3, cooling, draining pre-cooked vegetables should be cooled immediately after processing (generally using cold water shower), so that it quickly reduced to room temperature. After cooling, in order to shorten the drying time, centrifuges can be used to shake the water, can also be used in a simple manual method of pressure leaching, to be drained of water, can be spread out a little cooler, in order to be ready to load the tray baking.
4, drying should be determined according to different varieties of different temperatures, time, color and moisture content when drying. Drying is generally carried out in the drying room. There are three kinds of drying room: the first simple drying room, the use of counter-current air drying; the second is a two-story double tunnel, the combination of counter-current drying room; the third is a compartment-type stainless steel hot air dryer, drying temperature range of 65 ℃ -85 ℃, drying at different temperatures, and gradually cooling. When using the first and second type of drying room, the vegetables are evenly spread on the plate, and then put on the pre-set drying racks to maintain the room temperature of about 50 ℃, and at the same time, it should be constantly turning, so that it accelerates the drying, the general drying time of about 5 hours.
5, sub-inspection, packaging dehydrated vegetables by inspection to meet the requirements of the Food Sanitation Law, can be divided into plastic bags, and sealed, boxed, and then listed.