What technologies and procedures are needed for dehydrated vegetable processing?

The main varieties of dehydrated vegetables are carrots, edible fungi, cabbage, kale and ginger.

Dehydration and drying methods include natural drying and artificial dehydration. Artificial dehydration includes hot air drying, microwave drying, puffing and drying, infrared and far infrared drying, vacuum drying and the like. At present, the application of vegetable dehydration and dry preparation is hot air drying and dehydration and freeze vacuum drying dehydration. The frozen vacuum dehydration method is an advanced vegetable dehydration method. The product can retain the original color, fragrance and taste of fresh vegetables. Shape, and has the ideal rapid rehydration. The process and method for processing hot air dried dehydrated vegetables and frozen vacuum dried dehydrated vegetables are described below.

1. Process and method for processing hot air drying and dehydrated vegetables

1. Selection of raw materials The vegetables with rich fleshy quality should be selected carefully before dehydration, and the parts of insects, decay and cognac should be removed. It is appropriate to use 80% maturity. Over-ripe or unripe should also be picked out. In addition to melon seeds, other types of vegetables can be washed with water and then dried in a cool place, but should not be exposed to sunlight.

2, cutting, blanching will wash the raw materials according to product requirements are cut into pieces, silk, strips and other shapes. When pre-cooking, it varies according to the raw materials. It is easy to boil and is cooked in boiling water. It is not easy to cook and boil in boiling water for a while. Generally, the blanching time is 2-4 minutes. Leafy vegetables zui are not blanched.

3, cooling, draining pre-cooked vegetables should be immediately cooled (usually cold water shower), so that it quickly drops to room temperature. After cooling, in order to shorten the drying time, you can use the centrifuge to drown water, or you can use the simple manual method to press the leaching. After the water is drained, you can spread it out and cool it to prepare the plate for baking.

4, drying should be based on different varieties to determine different temperatures, time, color and moisture content during drying. Drying is generally carried out in a drying room. There are three types of drying rooms: * a simple drying room, which uses countercurrent blast drying; the second is a two-story double tunnel, combined with counter-current flow drying room; the third is a box stainless steel hot air dryer, drying The temperature range is from 65 ° C to 85 ° C, and it is dried at different temperatures and gradually cooled. When using the * and the second drying room, spread the vegetables evenly in the dish, then put them on the pre-set drying rack, keep the room temperature at about 50 °C, and keep turning to make it dry faster, generally drying time. It is about 5 hours.

5, separate inspection, packaging dehydrated vegetables after testing to meet the requirements of the Food Sanitation Law, can be packaged in plastic bags, sealed, boxed, and then listed.

Second, the process and method of processing frozen vacuum drying dehydrated vegetables

1. The selection of raw materials for leafy vegetables should not be processed for more than 24 hours, and the yellow and rotten parts should be manually selected; the root vegetables should be manually selected and exported, and part, and graded.

2. Wash and remove the soil and other impurities on the vegetable surface. In order to remove pesticide residues, it is generally necessary to sterilize with 1.55%-1% solution or 0.05%-0.1% potassium permanganate or 600 mg/kg for several minutes, and then rinse with purified water.

3, peeled root vegetables should be peeled. The loss rate of chemical lye peeling raw materials is low, but the export products generally require manual peeling or mechanical peeling. After peeling, they must be put into clear water or color protection liquid immediately to prevent browning.

4. Dividing and forming the vegetables into a certain shape (grain, flake), and the vegetables that are easy to brown after being cut should be immersed in the color protection liquid.

5, blanching is generally hot water blanching, water temperature varies with vegetable varieties, generally 80 ° C -100 ° C; time is a few seconds to a few minutes. When blanching, add some salt, sugar, organic acid and other substances in the water to change the color and increase the hardness of the vegetables.

6. Cool down immediately after cooling blanching (water or ice water), the shorter the cooling time, the better.

7. After draining and cooling, some water droplets will be trapped on the surface of the vegetables, which is unfavorable for freezing. It is easy to make the frozen vegetables into pieces, which is not conducive to vacuum drying in the next step. The method generally uses centrifugal drying.

8. The material after freezing and draining is quickly frozen, and the freezing temperature is generally below -30 °C, which is ready for vacuum drying in the next step.

9. Vacuum drying The pre-frozen vegetables are placed in a vacuum container. The pressure in the window is lowered to below the triple point by means of a vacuum system, and the heating system supplies heat to the material, so that the moisture of the material gradually evaporates until it reaches the end of the moisture.

10. Sub-inspection and measurement The products after freeze-drying should be immediately inspected, and the impurities and other foreign products should be removed, and accurately weighed according to the packaging requirements, and put into the bag to be sealed.