Dehydrated vegetables processing technology
Dehydrated vegetables are divided into AD vegetables and FD vegetables two.
AD vegetables, also known as dried vegetables. Drying dehydration using the mechanism to make dehydrated vegetables collectively referred to as AD vegetables.
FD vegetables, also known as frozen vegetables. The use of freeze-dehydration mechanism to make dehydrated vegetables collectively referred to as FD vegetables.
Drying methods are natural drying and artificial dehydration two categories. Artificial dehydration including hot air drying, microwave drying, puffing dry, infrared and far infrared dry, vacuum drying and so on. At present, more and more applications of dehydrated vegetables are hot air drying and dehydration and freeze drying. The vacuum dehydration method is an advanced drying and drying method for vegetables. The products can retain the original color, fragrance and taste of fresh vegetables, Shape, but also has the ideal fast rehydration. Now the hot air drying dehydrated vegetables and frozen vacuum drying dehydrated vegetables processing process and methods are described below.
Hot air drying varieties of processing processes and methods
1, the choice of raw materials Selection of vegetables with rich meat quality, dehydration should be strictly selected to the poor prior to the removal of pests, rot, shriveled part. In order to Bacheng maturity is appropriate, too mature or unfamiliar should also be singled out, in addition to melons to seed flesh, the other types of vegetables available water rinse, and then placed in the shade to dry, but not in the sun exposure.
2, cutting, blanching will wash the raw materials according to product requirements were cut into pieces, wire, bar and other shapes. Pre-cooking time, due to different raw materials vary, easy to cook through the boiling water boiled cooked, not easy to cook through the boiling water (water temperature above 150 ℃) in a little cook a moment, the general blanching time of 2 to 4 minutes. Leaf is best not to blanch treatment.
3, cooling, drainage, pre-boiled vegetables should be immediately cooled (usually cold water shower), so that it quickly dropped to room temperature. After cooling, in order to shorten the drying time, can be used centrifuge rejection of water, can also be used simple manual method of pressure Lek, until the water Lek to do, you can spread out a little cool sun to prepare for plate baking.
4, drying should be based on different varieties to determine the different temperature, time, color and drying moisture content. Drying is generally carried out in the drying room. Drying room roughly three kinds: the first simple drying room, the use of counter-current blast drying; The second is a two-story double tunnel, combined with the counter-current drying room; The third is the stainless steel hot air dryer, bake Dry temperature range of 65 ℃ -85 ℃, at different temperatures drying, cooling gradually. The first and second drying room, the vegetables evenly spread in the tray, and then placed on a pre-set drying rack, and keep the room temperature around 50 ℃, while constantly turning, to speed up the drying, the general drying Time is about 5 hours.
5, sorting, packaging dehydrated vegetables tested to meet the food hygiene law requirements, can be packed in plastic bags, and sealed, boxed, and then listed.
Frozen vacuum drying varieties of processing
1, the selection of raw materials Leaf vegetables from harvesting to processing should not exceed 24 hours, the artificial selection of the yellow, rotten part; root vegetables and other artificial selection of foreign goods, rotting part, and classification.
2, the removal of vegetable surface dirt and other impurities. For the removal of pesticide residues, the general need to use 1.55% -1% hydrochloric acid solution or 0.05% -0.1% potassium permanganate or 600 mg / kg bleach soak for a few minutes sterilization, and then rinse with water.
3, peeled roots and vegetables should be peeled. Chemical lye peeled raw materials loss rate is low, but the export products generally require artificial peeling or mechanical peeling, peeled immediately after the water or into the color protection solution to prevent browning.
4, cut into the shape of the vegetables will be cut into a certain shape (tablets, flakes), cut into pieces after the easy browning of the vegetables should be immersed in the color solution.
5, blanching generally use hot blanching, water temperature changes with the variety of vegetables, usually 100 ℃ or more; time for a few seconds to several minutes to species. Blanching, you can add some salt in the water, sugar, organic acids and other substances to change the color and increase the hardness of vegetables.
6, the cooling should be immediately after the end of cooling blanched cooling (water or ice water cooling), the shorter the better cooling time.
7, Drain and cool, the vegetable surface will stay some water droplets, which is unfavorable to freezing, easy to block the frozen vegetables, not conducive to the next vacuum drying. Methods commonly used centrifugal dry type.
8, the frozen material quickly frozen after freezing, freezing temperature is generally below -30 ℃, for the next vacuum drying to prepare.
9, the vacuum drying pre-frozen vegetables into the vacuum container by the vacuum system will reduce the window pressure to three-phase point below the heating system to heat the material, so that the material gradually evaporates moisture until the end of the water until dry.
10, sub-measurement freeze-dried products should be immediately seized, excluding impurities and other goods, according to the exact requirements of weighing packaging, into the bag to be sealed.
11, the packaging with double-layer plastic bags vacuum packaging. As the product of oxidation and browning, nitrogen packing available, packaged into the outer carton storage. Vegetable dewatering machine production process
Use vegetable washing machine or artificial vegetables, to ensure that dehydrated vegetables without soil without impurities.
Need to use a professional vegetable machine, in accordance with the requirements of the specifications of vegetables
Vegetable dehydration is divided into drying dehydration (AD vegetables), frozen dehydration (FD vegetables)
After the dehydration of vegetables, into the two-storey bag, sealed with a vacuum sealing machine will be fresh. And then into a woven bag.
Finally, dehydrated vegetables into the zero-degree cold storage room to save. Can save about six months.