How long can edible fungi be preserved at room temperature?

Storage and fresh-keeping characteristics and varieties of Pleurotus ostreatus

Mushrooms are rich in amino acids and proteins and taste delicious. However, the postharvest respiration of mushrooms is exuberant, which can only be used for short-term storage because of the rapid opening of umbrellas, browning, deterioration and deterioration of quality at room temperature. Dried mushrooms are easy to preserve, but their nutritional value decreases, and serious losses will be caused if they are not processed in time. Therefore, measures should be taken before postharvest storage, transportation, sales and processing to prevent the quality of mushrooms from declining. There are many varieties of mushrooms, such as Pleurotus ostreatus, Lentinus edodes, bisporus mushroom, Flammulina velutipes, straw mushroom and so on.

II. Harvesting

1. Timely harvest: mushrooms are harvested too early, the cover is not long, affecting the yield, too late the bacteria are not tolerant to storage, and the quality is declining. Pleurotus ostreatus should be fully expanded in the cap, the color becomes lighter, there is a white antler in the depression, the edge is just rolled up, but not a large number of spores are harvested, the harvest is too late, the stalk is hard, the edge is broken, the texture becomes tough, often with bitter and strange taste, and the edible quality is declining. Lentinus edodes should be harvested before the umbrella is opened. Pleurotus ostreatus is generally harvested when the cover is not more than 4cm and the umbrella is not opened. If the harvest is too late, it is easy to open the umbrella and turn brown, thus shortening the storage period. Flammulina velutipes should stop growing in the stalk, the diameter of the cap is up to 1.5ltel 2.0cm, the edge of the cap begins to be harvested at ordinary times, and the mushroom body is weightless too late.

2. Harvest method: do not spray water to maintain toughness on the harvest day, but stopping water prematurely will make the bacterial cap dry and brittle, and some can spray a small amount of water in the early morning. When harvesting, turn a single mushroom upward to harvest, tilt the cover outward, and do not come out directly from the bacterial bed. Clamp the receptacle with the fingers of the left hand, and cut off the base of the receptacle with the right hand with a knife; when the fruiting body is clustered, such as Pleurotus ostreatus, you can cut it with a knife close to the bed from the base of the stalk; Flammulina velutipes can gently hold the mushroom and pull it out. After harvest, put the mushroom stalk up into the basket, precool or repair the mushrooms in a frozen place as soon as possible, or repair them immediately after harvest and reload the basket. For the varieties with larger individuals and shorter stalks, shortening the stalks can prolong the storage life. For example, the stalk of Pleurotus ostreatus is 2cm long and 3cm long after harvest. The stalk length of Pleurotus ostreatus is usually 5 Mel 10 mm when harvested. The main edible part of Flammulina velutipes is stalk, which should not be cut short. When trimming, remove the open umbrella mushrooms, diseased mushrooms, insect mushrooms and damaged mushrooms that are not suitable for storage. Refrigerate the repaired mushrooms as soon as possible.

III. Storage and fresh-keeping conditions

The suitable conditions for storage of ground mushrooms are 0 ℃ and 95% relative humidity. The water loss of mushrooms is related to black stalk and umbrella opening. Packing with thin film or keeping relative humidity higher than 95% can reduce water loss. Controlled atmosphere storage can inhibit the browning of mushrooms, and controlling 4% oxygen in 2 Murray and 10% carbon dioxide in 5 Murray is beneficial to keep mushrooms white and prolong storage life. Salt water, citric acid, ascorbic acid, sulfur dioxide or steam heat treatment can passivate the activity of polyphenol oxidase and prevent enzymatic browning, and metal containers should be avoided in storage and transportation to prevent non-enzymatic browning.

IV. Storage, fresh-keeping and treatment

1. Controlled atmosphere storage: (1) the mushrooms are stored in a 0.04 Murray 0.06 mm thick polyethylene bag by controlled atmosphere, and the low oxygen and high carbon dioxide environment is created by breathing the mushrooms themselves. The packing bag should not be too large. Generally, it is appropriate to hold a capacity of 2 Murray 4 jin, and the quality will remain unchanged for 5 days under 0 ℃. (2) filled with carbon dioxide, the mushrooms were packed in a polyethylene bag 0.04murmur0.06mm thick, filled with nitrogen and carbon dioxide, and kept at 2muri 4% and 5murmur10% respectively, which could inhibit umbrella opening and browning at 0 ℃. (3) the mushrooms were packed in a polyethylene bag with a thickness of 0.06 ℃ and 0.08 mm thick, and the oxygen content was reduced by vacuum, which could be kept for 7 days at 0 min.

2, ice storage method: add ice to cool the mushroom body during transportation, put a layer of plastic film in the packaging container, put 6cm thick crushed ice at the bottom, place an ice bag in the middle, place mushrooms around it, fold the surrounding film inward when it is 80% full, cover the film with crushed ice about 5cm thick, and finally cover it for transportation.

3. Cylinder storage method: put 4cm deep cold water at the bottom of the washed cylinder, set up a wooden frame and put the mushroom code on it, then seal it with plastic film and store it at a low temperature.

4. Drug treatment: (1) saline. After harvest, mushrooms are washed with 0.6% cold salt water and soaked for 10 minutes, which can precool and prevent browning and drain water for storage. If washed with salt water, then rinsed with 0.1% ascorbic acid or 0.1% citric acid and stored, the effect is better. Drain and refrigerate in a plastic bag. (2) sodium pyrosulfite. After harvest, wash the sundries with 0.02% sodium pyrosulfite, then put it in 0.05% sodium pyrosulfite for half an hour, rinse with clean water, drain and store, which has a good color protection effect.

5. Irradiation

Gamma ray irradiation can prevent discoloration of fresh mushrooms, inhibit respiration and parachute opening, with a dose of 200 Mel 300 rad.