Hot air drying of Dehydrated vegetables processing process and methods
writer :Jiade Food ; Date:2016-10-18 15:42
(1) selection of raw materials. Should choose the organization of dense, coarse fiber, less fresh and full of vegetables for work. Dehydrated vegetables, should be strictly selected superior to inferior, remove the pests and rot, dry part. The eight should be mature, over cooked or not should be singled out.
(2) dressing and cleaning. According to the freshness, size, quality and maturity of the raw materials, the selection and classification. In addition to the melon seed pulp, other types of vegetables can be washed clean, and remove the petiole, stem leaf, and then without direct sunlight to dry the surface of the water. Will be washed raw materials according to the requirements of products, respectively, cut into pieces, silk, and other shapes. For potatoes and carrots, etc., to use 1%~2% sodium hydroxide at room temperature or boiling water treatment 5~10min, in order to remove the skin; some vegetables have to be classified bundle, so that uniform, in order to facilitate the boiling hot.
(3) boiling hot. Vegetables, after being properly cooked, relatively easy to dry the dry products in addition to the original state of the water easily. The vegetables cooked hot, most microorganisms and eggs attached to kill on the vegetables, the green vegetables is more fresh and green. The length of cooking time is different according to the kinds of vegetables, varieties, maturity and texture. When the boiling pot of water, should be kept in a boiling state, and constantly changes, so that uniform heating. Some vegetables in order to keep the original flavor, spicy or sweet smell, does not have to be pre cooked or evaporation. Soaking method can be used without the vegetable varieties. There are 2 main types of immersion method: one is to organize the fresh vegetables, immersed with baking soda 5 1000 boiling water, mix well, and keep the water boiling, immersed in 1~2min, the fresh vegetables to two mature, remove becomes translucent, soda water and then immersed in containing 2.5%, to heat and cool, Lek to the water, sacking the pressure to the water, to be baked; the other is to take off has 20%~85% water vegetables dipped in the solution containing at least one solute (salt in liquid or salt, sugar I, the number of solution should be already dehydrated vegetables all absorbed. So that the final salt content of vegetables reached 3%~15%, sugar content of not more than 15% (referring to the use of salt, sugar, salt and sugar, the content of salt, water content of 6%~25%.
(4), water cooling. After the pretreatment, the vegetables should be cooled immediately (usually with cold water), so that it should be quickly reduced to the normal temperature. After cooling, in order to shorten the drying time, can be used to dump water, also can use simple manual method. When the water drain as much as possible, you can spread out a little drying, stay for baking tray.
(5) drying. According to different varieties, to determine the different temperature, time, color and drying of water content. Drying is generally carried out in the drying room. Drying room roughly 3: first is a simple drying room, using counter current drying; drying room is second with two layers of double tunnel, CIS countercurrent combination; third is the van of stainless steel hot air drying machine, drying temperature range of 65~85 DEG C, different drying temperature, gradually cooling down. By first, second kinds of drying room, the vegetables evenly on the tray, and then put a good pre drying rack, keep the temperature at 50 degrees Celsius, turning the general drying time is about 5h. When the temperature is not timely, it is necessary to make timely adjustments. To the body moisture content of vegetables dropped to about 20% in 0.1%, sorbic acid is sprayed evenly on the surface or end bearing sodium antiseptic antistaling agent.
(6) closure. The dried vegetables into a large operation box structure tight seal around the 10h temporary, dried vegetables moisture keep uniform.
(7) pressing block. The dried vegetable, the volume is bigger, must carry on the compression in the package. General dehydrated vegetables in the final stage of dehydration, the temperature of 60~65 degrees Celsius, ranging from cooling immediately pressed block, can not be re heated. Otherwise, in order to reduce the fragmentation, the pressure should be sprayed with hot steam before, and then hot air drying, very easy to cause loss of vitamin C. Packaged vegetables should be stored together with desiccant.
(8) sub inspection, packing. Dehydrated vegetables tested meet the food hygiene requirements, can be packed in a plastic bag, and seal, trade mark, export quality and production period, into the shop to have moistureproof paper box, stored in a cool, dry, dark place, in preparation for listing.