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Processing measures for dehydrated organic vegetables
- Jul 04, 2018 -

In summer, the growth and development of organic vegetables are in high temperature and storm season. Although organic vegetables can still blossom and pod at about 35 C, the fruit setting rate is declining because of the gradual deterioration of environmental conditions.

The main varieties of water vegetables are carrot, edible fungi, cabbage, cabbage and ginger.

Dehydration drying methods include two types: natural drying and artificial dehydration. Artificial dehydration includes hot air drying, microwave drying, puffing and drying, infrared and far-infrared drying, vacuum drying and so on. At present, most of the application of dehydration and drying of vegetables is hot air drying and freezing vacuum drying, and freezing vacuum dehydration is an advanced method of dehydration and drying of vegetables. The product can not only retain the original color, aroma, taste and shape of fresh vegetables, but also have ideal quick rehydration. The process and method of hot air drying dehydrated vegetables and frozen vacuum drying dehydrated vegetables are introduced below.

1. Process and method of hot air drying dehydrated vegetable processing

1, raw material selection: choose a vegetable variety with rich meat quality. Before dehydration, we should strictly select the best and get rid of the bad, and eliminate the pests, rotten and shrunken parts. With 80% maturity as suitable, too mature or unripe should also be picked out, except melon seeds to seed, other types of vegetables can be rinsed with clean water, and then put in the shade to dry, but it is not suitable for exposure under the sun.

2. Cutting and blanching: the raw materials are cut into slices, silk and strips according to the requirements of the product. When cooked, the boiling water is easy to boil and boiled in boiling water. The boiling time is usually 2 to 4 minutes. Leaf vegetables are best not treated with blanching.

3, cooling, leachate: pre cooked vegetables should be cooled immediately (usually by cold water infusion), so that it quickly dropped to normal temperature. After cooling, in order to shorten the drying time, the centrifuge can be flung with water, and a simple manual method is used to press the drain. After the water is exhausted, a little cold can be opened to prepare the plate for baking.

4, drying: different temperature, time, color and moisture content should be determined according to different varieties. The drying is usually carried out in the baking room. There are roughly three kinds of drying rooms: the first simple drying room, the dry air drying, the second kind of drying room with two layers of double tunnel and CIS countercurrent; the third is the hot air dryer of the wing type stainless steel, the drying temperature range is 65 - 85 C, drying at different temperatures and gradually reducing the temperature. When the first and second kinds of baking rooms are used, the vegetables are evenly distributed in the plate, and then put on the pre set baking frame to keep the room temperature about 50 degrees centigrade. At the same time, it should be constantly turned to make it dry. The general drying time is about 5 hours. 5. The inspection and packaging of dehydrated vegetables can meet the requirements of food hygiene law. They can be packed in plastic bags, sealed and packed, and then listed.

Two. Process and method of processing frozen vacuum drying dehydrated vegetables

1, selection of raw materials: leaf vegetables from harvesting to processing should not exceed 24 hours, artificial selection of the yellow and rotten parts; rhizome vegetables selected out of the same products, rotten parts, and classification.

2, cleaning: remove the soil and other impurities on the surface of vegetables. In order to remove pesticide residues, 0.5% - 1% hydrochloric acid solution or 0. 05% - 0. 1% Potassium Permanganate or 600 mg / kg bleach powder are usually soaked for several minutes to sterilize and rinse with water purification.

3, peeling: rhizomatous vegetables should be treated with skin. The loss rate of chemical alkaline solution is low, but the export products usually require artificial skin or mechanical peeling. After peeling, it must be immediately put into clean water or color protection solution to prevent browning.

4. Cut into parts: cut the vegetables into a certain shape (grain, sheet). After the cut, browning vegetables should be immersed in the protection liquid.

5, blanching: generally hot water blanching, water temperature changes with vegetable varieties, generally 80 degrees - 100 degrees; time is several seconds to several minutes. Salt, sugar, organic acids and other substances can be added to the water to change the color and hardness of vegetables.

6, cooling: after blanching, it should be cooled immediately (water cooling or ice water cooling), and the shorter the cooling time, the better.

7, drain: after cooling, the vegetable surface will stay some water droplets, which is unfavorable to the freezing. It is easy to make the frozen vegetables into blocks, which is not conducive to the next vacuum drying.  The method is usually centrifuged and dry.

8, freezing: quick drying of materials after freezing, freezing temperature below 30 degrees below normal, ready for the next vacuum drying.

9, vacuum drying: the prefrozen vegetables are placed in a vacuum container by vacuum system to drop the pressure from the window to the three phase point and heat the material to the material, so that the moisture of the material is evaporated gradually until the end of the water.

10. Sub inspection and measurement: after freeze-drying, the products should be inspected immediately, and the impurities and the out of class products should be removed.

11, packing: vacuum packing with double plastic bag. Due to oxidation and browning of products, they can be packed in nitrogen, then put into the outer carton and stored in storage.

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