The best way to preserve oyster mushrooms

I believe that many people in life are more concerned about how to preserve some food and what is the best way to use it. In fact, fungi like oyster mushrooms are crispy and delicious, but they are not easy to preserve. If they are not preserved properly, they may cause surface ulcers, which are not edible. For fungi and vegetables that are difficult to store, we must learn the correct harvesting and storage methods.

1. Harvest

When harvesting, twist the individual mushroom bodies upwards and pick them by hand. When picking, the mushroom caps should tilt outwards and cannot be pulled directly from the mushroom bed. Use the fingers of your left hand to hold the stipe tightly, and use the right hand to hold the knife to cut off the base of the stipe. Then trim the mushroom stems neatly, cut off the excessively long stems, and place them in the basket with the stems facing upwards. Sort the mushrooms into grades in the pergola, and select out the mushrooms with open umbrellas, diseased mushrooms, and mushrooms with insects that are not suitable for storage.

2. Storage Method

1. Low temperature storage: After harvesting, remove impurities from the mushrooms, put them in a plastic bag (it is best to punch a few holes) and tie the bag, then store them in a cold storage at 3~4℃, which can keep them fresh for 7~10 days. Or use plastic frames. At the same temperature, if the relative humidity of the air is controlled at 80%~85%, the mushrooms can also be kept fresh for about 7 days.

After picking, the mushrooms are selected and graded, and then rinsed with clean water. If the mushrooms turn yellow or brown, rinse them in a 0.01% sodium metabisulfite aqueous solution for 3 to 5 minutes. Quickly pre-cool the mushroom bodies with ice water to reduce the temperature of the mushroom bodies to 0~3℃ as soon as possible, drain the water, put them in ventilated plastic frames and put them in a cold storage. The temperature of the cold storage should be controlled at 0~3℃ and the relative humidity should be 90%~95%. Pay attention to ventilation and control the CO2 concentration in the cold storage to not exceed 3%. This storage method can store fresh mushrooms for 8 to 10 days.

2. Controlled atmosphere storage in film bags: Oyster mushrooms can withstand high concentrations of CO2, and can be stored in controlled atmosphere by using ordinary polyethylene plastic bags. A 0.5 kg storage bag is made of 0.025 mm thick polyethylene film. The O2 content in the bag can meet the breathing needs of the mushroom body, and the oxygen supply is about 1%. The CO2 in the bag reaches equilibrium within 24 hours, which is 4%~5%. A cardboard box should be placed inside the bag to absorb condensation. It can stay fresh for 7 days at room temperature. If this method is used for too long, the CO2 concentration in the bag will be too high, which will affect the flavor of the fresh mushrooms.

After the mushrooms are rinsed and graded, they are drained, cooled with air conditioning, and then packaged in plastic bags. The gas composition in the bag was adjusted so that the O2 concentration was about 1% and the CO2 concentration was 2%~5%. Under this atmosphere control parameter, the growth of the mushroom cap and stem was extremely slow and obviously inhibited, the mushrooms rarely opened, and the color of the mushrooms was pure white. This storage method has been used commercially abroad.

3. Radiation storage: After removing impurities from the oyster mushrooms, put them into ordinary polyethylene plastic bags, irradiate them with 60Co γ rays with a dose of 1000 Ge, and then store them in a cold storage at 0℃. After one month of storage, the effect is good, the weight does not decrease, and the commodity value does not decrease.

The mushrooms were rinsed, graded and drained, then packed in porous polyethylene plastic bags and irradiated with 60Co gamma rays at a dose of 2000-3000 Ge. The irradiated mushrooms have less water evaporation and lower weight loss rate, which significantly inhibits the browning, membrane breakage and cap opening of the mushrooms. The irradiated mushrooms can be stored for 4 to 5 days at room temperature (16-18°C) and a relative humidity of 65%. If stored at low temperatures, the time can be longer.

4. Storage with solid preservatives: Use glycerin or gelatin as a coating support stabilizer, soak the fresh mushrooms in the stabilizer for 3 to 5 minutes, pick them up and drain. Using sodium dithionite as a deoxidizer, mix 1 gram of sodium dithionite and a small amount of activated carbon in a paper bag, and put them together with 400 grams of mushroom bodies into a high-pressure polyethylene plastic bag. Tie the bag tightly with thread and store it at 17-20℃. After 6 days of storage, its color and freshness remain unchanged.