Preservation, storage and processing of edible fungi

The fresh edible mushrooms after picking are perishable at room temperature and are easily damaged during the packaging and transportation process, resulting in lower quality and loss. In the peak season of production, edible fungus should be sold fresh. In the hot season, it is necessary to collect and process edible mushroom products and must be kept fresh and stored. In order to regulate and enrich the market supply of edible fungi and meet the needs of domestic and foreign markets, we must do a good job in the processing of edible fungi. Now introduce the most commonly used fresh storage and processing methods of edible fungi. (I) Preservation Storage Method 1. Refrigeration Method: Temperature is the most important factor affecting the respiration of agricultural products. At 5°C to 35°C, the respiratory intensity is increased by 3 times for each 10°C rise in temperature, resulting in a higher ambient temperature. However, the refrigerating temperature should not be too low, usually it is controlled between 0 and 8°C. Ice cooling is most commonly used in production. Salt or calcium chloride is added to the ice and the ice is placed above the edible mushrooms. 2. Modified atmosphere storage method: The principle is to reduce the concentration of oxygen and increase the concentration of carbon dioxide, thus inhibiting the respiration. Oxygen levels below 1% can inhibit the opening of edible mushrooms and stimulate the opening of umbrellas at 5%. High concentrations of carbon dioxide can inhibit the opening of umbrellas, but too high a concentration can promote the anaerobic respiration of edible fungi and cause poisoning. Air-conditioning methods: (1) Put the edible fungus into a container with a certain degree of transparency to allow it to naturally reduce oxygen; (2) Artificially reduce oxygen, that is, charge carbon dioxide and nitrogen. Combination of air conditioning and cold storage is better. 3, radiation treatment method: the application of 60 gamma or 137 palladium gamma radiation emitted from the radiation source for radiation treatment of edible fungi, can make the body of water and other substances ionize, generate free radicals or ions, can effectively suppress the open umbrella , Delay the process of discoloration of bacteria, kill or inhibit the activities of spoilage microorganisms and pathogens, so as to play a role in preservation, combined with better cold storage. The radiation dose is suitable for 200,000 rads. 4, phytohormone treatment: some hormones can inhibit the breathing of edible fungi, delay aging, extend the preservation time; some hormones can also suppress open umbrella. The hormones that can be used are: Chlorhexidine (CCC), 2.4-D, Qingxin (MH), Indoleacetic acid (IAA), Naphthaleneacetic acid (NAA), and Bijiu (N-dimethylaminosuccinamide). The use concentration varies from species to species, typically from a few to several hundred ppm. (2) Common processing method 1. Dry processing method: The dry processing process is the evaporation process of moisture contained in the edible mushroom body. When the edible mushroom comes into contact with the dry hot air, the surface moisture is distributed to the external environment and forms a one from inside to outside. The difference in the gradient of moisture content, the greater the gradient difference, the faster the moisture moves outward, and vice versa, the slower, until the water content inside and outside the same, the movement of moisture stops. Dry processing is a widely used method of processing and preservation, and not all edible fungi must be dry processed. For example, if the dried mushrooms are dried, their flavor and flavor are not as good as those of fresh mushrooms; Pleurotus ostreatus, Hericium erinaceus, and oyster mushrooms are generally eaten freshly; although the mushroom can be dried, it should be steamed in the pot for 10 minutes before being dried; Mushrooms, black fungus and white fungus are mainly dried. One method of drying is to dry it, thinly spread the fresh mushroom (ear) on the bamboo or bamboo curtain, and expose it to the sun when it is exposed to the sun. Pay attention to diligent turning when spreading the sun, and be careful to prevent breakage. Generally, fresh mushrooms can be sun-dried in two large sunny days, dried in plastic bags, and quickly sealed for storage. Another method is drying. Put the fresh mushrooms in the oven, drying cage or drying room and heat them with electricity, charcoal fire or far outside line. Keep the temperature at 60-65°C, and control the fluctuation of the temperature not more than 7°C. If the drying room is used for drying, it should be ventilated and vented every 5-6 hours. The time is 10-15 minutes. After drying, bagging and storage. 2. Preservation processing method: Put the edible fungus into a high concentration of salt concentrate. The high osmotic pressure generated by the salt causes the microorganisms carried inside and outside the edible mushroom to be in a physiologically dry state. The protoplasm shrinks and these microorganisms are not killed. It is dead, but it can't move. It ensures that the edible fungus doesn't rot for a long time. There are mushrooms, oyster mushrooms, oyster mushrooms, and hericium erinaceus that are marinated. The specific processing steps are: (1) Selection of raw material mushrooms: Fresh mushrooms should be harvested in a timely manner to remove impurities, remove mold and be harmed by pests and diseases. Mushrooms should be removed from the base of the mushroom. Pleurotus ostreatus should be divided into bundles one by one, and the aging part of the stem should be cut off. The mushroom should be cut to hard roots. (2) Precooking: Immerse edible fungus in 5% to 10% of refined salt water, boil for 5-7 minutes, remove and drain water. (3) Salting: According to the ratio of 12.5 to 15 kilograms of 50 kg edible fungus, first put a layer of salt in the bottom of the tank, add a layer of edible mushrooms after pre-cooking, and then put salt, so repeatedly, until full cylinder. The boiled and cooled saturated brine is poured into the cylinder, and the edible fungus is capped and pressurized so that it is completely immersed in salt water. At the same time, the prepared conditioning solution is added so that the pH value of the saturated saline is about 3.5. (4) Management: The cylinder should be inserted with a rubber tube, inflated 2 to 3 times a day, so that the salt water up and down cycle, 10 days cylinder 1 time, 20 days can be marinated. (5) Packing: After pickling, it can be removed and stored in drums. The buckets must be filled and saturated brine must be added. The pH must be adjusted to 3.5. 3, cans processing method: the fruiting body of the mushroom is sealed in the container, after high temperature treatment, most of the microorganisms will be extinguished, and at the same time prevent external microorganisms from invading again, to obtain long-term preservation of edible fungi at room temperature. All edible fungi can be processed into canned foods, but the most processed are mushrooms, straw mushrooms, white fungus, and hedgehog. There are eleven processes throughout the process: (1) Selection of canned containers. There are generally 3 types of tin cans, glass jars and soft cans, and suitable containers can be selected according to the production process and market demand. (2) Selection and processing of raw material mushrooms. The edible fungus is required to be fresh, free from pests and diseases, and has a normal color and the umbrella is complete. The stipe should be cut flat and the length of the handle should not exceed 0.8 cm. (3) Color protection and rinsing of mushroom body. The selected edible fungus was poured into a 0.03% sodium thiosulfate solution, and the mud was washed and demineralized. The mixture was then removed and poured into 0.1% sodium thiosulfate solution supplemented with appropriate amounts of vitamins C and E. Rinse with running water to prevent deterioration after canning. (4) Heat to boil. First put tap water in the container, heat it to 80°C, add 0.1% citric acid, boil it, pour it into boiling water and precook for 8 to 10 minutes, continuously remove the floating foam. (5) Grading. After pre-cooking, remove edible mushrooms, cool in cold water, and grade them by size. (6) canning. Each can can not be filled too full, to leave 8 to 10 mm from the cover of the gap, usually 500 grams of empty cans should be added 240 to 250 grams of edible mushrooms, 180 to 185 grams of soup injection. Soup recipe: 97.5 kg of clear water, 2.5 kg of salt, 50 g of citric acid, heated above 90°C, and filtered with gauze. The temperature of the soup is not lower than 70°C. (7) Exhaust. The most common method is to heat the exhaust gas, ie, set the cans to 86 to 90°C for 8 to 15 minutes to eliminate the air in the tank. (8) Sealing cans. At present, double rolling seam sealing machine can be used for sealing. (9) Sterilization. Edible fungus cans are usually sterilized by high pressure steam. Different edible fungi and different tank numbers, sterilization temperature is different. Such as canned mushroom sterilization temperature of 113 ~ 121 °C, time 15 to 60 minutes, and Straw mushroom sterilization can be 130 °C. (10) Cooling. The sterilized cans are immediately cooled in cold water and the temperature drops as fast as possible. (11) Print the package. Canned cans shall be printed on the lid and stored in packaging.