Preservation and processing of the hottest Agaricu

Preservation and processing of Agaricus bisporus

the processing technology of Agaricus bisporus mainly includes preservation processing, quick freezing processing, canning processing, salting processing and drying processing. The main products are fresh mushrooms, quick-frozen mushrooms, canned mushrooms, salted mushrooms and dried (sliced) mushrooms. In addition, there are seasoned mushrooms, mushroom sauce, mushroom seasoning, mushroom concentrate, mushroom beverage, mushroom preserves and mushroom (polysaccharide) health products, mushroom beautifying products and other products. Several main technologies are introduced

1. Can storage processing. The vast majority of mushroom products in China are processed into cans and are mainly exported. Canning is to seal mushrooms in containers, and after certain high-temperature treatment, kill microorganisms that can cause canned mushrooms to decay and produce viruses and diseases; On the other hand, we should try our best to ensure that the shape, color, nutrition, flavor and texture of mushrooms will not be lost, so it is crucial to master the sterilization temperature and time. Canning process includes canning package preparation, raw material treatment, canning, venting, sealing, sterilization and cooling

2. Salting processing. Put fresh mushrooms into high concentration salt solution after precooking and cooling. The high osmotic pressure produced by salt makes the water and soluble substances contained in mushroom tissue exude from cells, and the salt water infiltrates. The salt content of mushroom body gradually balances with the salt solution. At the same time, it also stops the growth and development of microorganisms inside and outside the mushroom body due to the physiological drying state of high salt concentration, playing a role in corrosion prevention. Mushroom salting processing is divided into primary salting method and secondary salting method. The concentration of table salt solution for salting is 20 ~ 22 Baume degrees (100kg of water plus 40kg of table salt, heated and dissolved). In the one-time method, add 75kg salt solution and 125kg pre boiled and cooled mushrooms, add standard salt cover, measure the concentration of salt water every day, and turn it under the fixture on the experimental machine once. If the concentration of salt water decreases, add table salt to 20 ~ 22 Baume degrees. After 96 ~ 144 hours, when the brine concentration is stable at 18 Baume degrees, graded packaging can be carried out. The secondary method is to pour the semi-finished products obtained by salting for 48 hours in the primary method into the tank, and add 22 Pomerol salt solution to salt for 48 hours. When the brine concentration is stable at 18 Baume degrees, carry out graded packaging. The packaging shall be in accordance with the standards required by the foreign trade department, and more clean and sanitary plastic barrels with tight seals shall be selected. The concentration of salt water shall be kept at 18 Baume degrees, and the salt water shall be clear, yellow and bright without impurities. When packaging, first add 3kg of 23% citric acid with 0.2% citric acid into the barrel The lifting guide wheel adjusts the salt water with an incorrect degree of 0 ~ 22 Baume. It is graded, weighed and canned according to the grade of mushrooms, and then added with the above salt water to cover and seal tightly, which can be preserved for a long time or transported for long-distance sale

3. Quick freezing processing. The pretreated mushrooms are quickly frozen at - 30 ~ - 35 ℃ or lower, packaged in plastic containers, or quickly frozen after packaging, and then stored at - 18 ℃ for refrigeration, so as to inhibit the growth and development of microorganisms, prevent corruption, and achieve the purpose of long-term preservation. The quick-frozen processing technology includes raw material selection, handle cutting, cleaning, color protection, scalding, cooling, grading, selection and finishing, packaging, quick-frozen and cold storage

4. Dry processing. Drying mainly uses heat energy or freeze-drying to dehydrate mushrooms and increase the concentration of soluble substances to the extent that microorganisms are difficult to use, so as to achieve the purpose of long-term preservation. The moisture content of dried mushroom products is generally required to be 7% - 8%

the drying method of dried mushroom slices is to use a mushroom slicer to cut the cleaned mushrooms into 3.0 ~ 3.5mm thick slices longitudinally, soak them in 0.1% sulfite bleach for 5 ~ 10 minutes, and evenly lay them on the baking sieve or the conveyor belt of the toaster. Do not overlap them. First dry them at 50 ~ 55 ℃, and then increase them to 65 ~ 70 ℃, and gradually cool them down at the end. Generally, it can be dried until the mushroom slices are crushed when pinched. The first-class product is required to be white to gray white in color, with complete film type, and the second-class product is slightly fragmented and light yellow in color. Products are packaged and stored after classification

mushroom freeze-drying method is also called vacuum freeze-drying or sublimation drying. The advantage is that the mushrooms do not need to be killed, and the mushrooms with clean pretreatment can be used for processing, and the products can better maintain the original color, aroma, taste, shape and nutritional value. The principle of freeze-drying is to freeze the water in the mushroom raw material into ice crystals, then reduce the pressure to a certain value, supply the sublimation heat, and directly vaporize and sublimate the ice crystals under high vacuum to deform time) 6 kinds of curves and relevant experimental data are removed. At the end of drying, immediately fill the drying chamber with dry air and nitrogen to restore normal pressure, and then package. The product dried by this method has a brittle texture, so we should pay attention to the selection of appropriate packaging materials. For long-term preservation, vacuum packaging is often used, and nitrogen is filled in the packaging bag. The freeze-drying process of mushrooms includes: cleaning the raw materials, sending them into the closed container of the freeze-drying system, freezing at -20 ℃, and then slowly heating up at a high precision, especially the microcomputer controlled pressure experimental machine. After about 10 hours, the mushrooms are dehydrated and dried due to sublimation. The water loss rate of mushrooms accounts for 90% of the weight of fresh mushrooms, and the water content of products is 7% - 8%. The product has good thickening property. It can be restored to its original state as long as it is soaked in hot water for a few minutes. The rehydration rate can reach 80%. Except that the hardness is slightly inferior to that of fresh mushrooms, its flavor is almost the same as that of fresh mushrooms

(source: China Agriculture)