Dehydrated vegetable processing technology
writer :Jiade Food ; Date:2016-10-18 15:10
Dehydration dried method with natural drying and artificial dehydration. Artificial dehydration include hot air dried, microwave dried, dried, infrared and far infrared ray dried, vacuum dried, etc. More vegetables dehydration dried application is currently hot air drying dehydration and frozen vacuum drying dehydration, vacuum frozen encapsulation-dehydration is a kind of advanced current vegetables dehydration dry process, the product can keep fresh vegetables original color, aroma, taste and shape, but also has the ideal compound water quickly. Now the hot air drying and dehydrated vegetables frozen vacuum drying process and method of the dehydrated vegetables processing are presented here.
Varieties of hot air drying processing process and methods:
1, raw material. Chooses to have rich succulent varieties of vegetables, dehydrated before should go YanGeXuan better, eliminate diseases and pests, decay, dry parts. At maturity eighty percent advisable, cooked or not cooked should also be singled out, except melons to seed the pulp, other types of vegetables available clear water is rinsed clean, then put in the shade to dry, but unfavorable exposure in the sun.
2, cutting, blanching. Will clean raw materials according to the product requirements, respectively, sliced, wire, strip shape, etc. Pre-cooking, different raw material varies, easily cooked steam cooked in boiling water, easily cooked with boiling water (the water temperature is in commonly 150 ℃ or above) in the boil for a minute, blanching time is 2 ~ 4 minutes. Leaf vegetables had better not blanching treatment.
3, cooling, waterlogging caused by excessive rainfall. Vegetables should be performed immediately after the pre-cooking process cooling (usually use cold water shower), make its rapid drop to normal temperature. After cooling, to shorten the drying time, centrifuge dumped water are available, and also can use simple manual method pressure drain, after waiting for water drain all, dries, can spread out a little bit for the plate.
4, drying. Should be determined according to different varieties of different temperature, time, colour and lustre and drying the moisture content. Drying generally carried out within the chamber. Chamber to roughly three types: the first kind of simple and easy drying room, reflux drum wind drying; The second is to use double tunnels, along the upstream combination of drying room on the second floor; The third is van stainless steel hot air dryer, drying temperature range of 65 ℃, 85 ℃, at different drying temperature, cooling. Using the first and the second chamber, put vegetables evenly stalls in the disk, and then to set in advance good drying rack, keep the room temperature is 50 ℃ or so, at the same time keep turning, make it speed up the drying process, general drying time is about 5 hours.
5, sorting, packaging. The test meet the requirements of food hygiene law, dehydrated vegetables can be packing in plastic bags, and sealing, packing, and then listed.
Variety of frozen vacuum drying process:
1, raw material. Leaf vegetables from harvesting to processing should not be more than 24 hours, artificial selection on yellow, rotting part; Root vegetables artificial pick cull, decay, and grading.
2, cleaning. Remove vegetable surface dirt and other impurities. To remove pesticide residues, general need 1.55% - 1% hydrochloric acid solution or 0.05% - 1.55% potassium permanganate or 600 mg/kg bleach sterilization soak for a few minutes, then rinse with water purification.
3, peel them. Root vegetables should be peeled. Chemical alkali peeling raw material loss rate is low, but the general requirements of artificial leather or export products of mechanical peeling, must immediately after peeling or color liquid, into clean water to prevent Browning.
4, segmentation molding. Cut vegetables into a certain shape (grain, sheet), Browning easily after segmentation of vegetables should be immersed in the color liquid.
5, blanching. Generally USES hot water blanching, water temperature change with vegetable varieties, general is above 100 ℃; Time for a few seconds to a few minutes. When blanching, can add some salt in the water, sugar, organic acids and other substances, to change the color and increase the hardness of vegetables.
6, cooling. Blanching should immediately after the cooling water (water or ice), the cooling time as short as possible.
7, drain well. Stranded some water droplets on the surface after cooling, the vegetables, which is harmful to freeze, easy to make after frozen vegetables into pieces, not conducive to the vacuum drying. Methods general centrifugal dry type.
8 and freeze. Drain after material fast freezing, freezing temperature generally under - 30 ℃, to prepare for the next step of vacuum drying.
9, vacuum drying. After preliminary frozen vegetables in a vacuum container by using vacuum system pressure below the triple point within the window, the heating system heating for material, make the material moisture evaporation, until dry moisture to the finish.
10, sorting measuring. Freeze drying products shall be immediately after the sorting, removing impurity and cull, and accurate weighing, according to the requirements of the packing into the bag for sealing.
11, packaging. Packed in double plastic bag vacuum packing. Because of the oxidation products Browning, available nitrogen filled packaging, package in carton outside warehousing storage. Vegetable dehydrator process.