A Detailed Guide to Post-Harvest Handling and Processing Methods for Wine Cap Mushroom

Wine cap mushroom, also known as King Stropharia, is a domesticated wild mushroom species, and in recent years there has been a trend of gradual expansion. Its mushrooms have a delicate fragrance, crisp and tender flesh, good palatability, high yield, high selling price, and very considerable economic benefits. However, its fresh products have a short storage time and are not easy to preserve. If not sold fresh in time, huge losses will be caused. In order to ensure that economic benefits are not lost, the salting processing and dried product processing techniques for wine cap mushroom are now introduced.

1. Salting processing of wine cap mushroom

1. Harvesting. The mushroom bodies of wine cap mushroom used for salted export should be harvested at 6-7 maturity, that is, when the cap is bell-shaped and the partial veil has not yet ruptured. Use a bamboo strip to scrape off the soil and sand from the mushroom base, and wash clean.

2. Blanching. Place the cleaned mushroom bodies of wine cap mushroom into boiling water with 5% table salt and blanch by boiling for 8-12 min. The specific boiling time should depend on the size of the mushroom bodies, and boiling should continue until the mushroom bodies are cooked but not mushy and the center of the mushroom bodies is thoroughly cooked. The "sink-float method" can be used for testing, that is, stop the heat for a moment; if the mushroom bodies sink, they are cooked, and if they float, they are raw; or place the mushroom bodies into cold water; cooked mushrooms sink and raw mushrooms float. After boiling is completed, scoop them out,

and quickly place them into cold water or running water to cool until thoroughly cold. Use an aluminum pot or stainless steel pot for blanching and boiling, and never use an iron pot, so as to avoid browning of the mushroom body color and affecting quality.

3. Salting. First prepare a 40% saturated saltwater solution, that is, weigh 40 kg of refined table salt and dissolve it in 100 kg of boiling water, then cool. Then scoop the boiled and cooled wine cap mushroom out of the water, place it into a clean large vat, pour in saturated saltwater until the mushroom bodies are submerged, and press bamboo strips and heavy objects on top to prevent the mushroom bodies from being exposed above the saltwater surface, which would cause discoloration and spoilage. After pressing and covering, sprinkle a layer of surface salt to protect color and prevent spoilage. When the surface salt dissolves, sprinkle another layer, and repeat this until the surface salt no longer dissolves.

4. Transferring to another vat for storage. After wine cap mushroom has been salted in concentrated saltwater for about 10 days, it should be transferred to another vat once, with saturated saltwater poured in again, pressed and covered, and surface salt sprinkled until the saltwater concentration in the vat stabilizes at 24 Baume degrees, after which it can be packed into barrels for storage and export. After processing is completed, the saltwater can be used to recover table salt by heating and evaporation for reuse.

5. Consumption of saltwater wine cap mushroom. Salted wine cap mushroom can generally be kept fresh for about 3 months. When eating, scoop the mushroom bodies out of the saltwater, place them in clean water to soak and desalt, and then they can be cooked and eaten; the saltwater mushrooms can also be placed in 1% citric acid solution and soaked for 7 min to desalt, then removed and rinsed clean with clean water. When cooking, salt may be omitted to avoid increasing the saltiness.

2. Dried product processing of wine cap mushroom

The mushroom bodies of wine cap mushroom have a relatively high water content and are not suitable for processing by sun-drying. It is advisable to use a drying machine or an electric heating forced-air dryer for mechanical drying in a drying room. The process is as follows:

1. Grading and loading onto trays. For wine cap mushroom used for drying, watering should be stopped 2 days before harvest. Use a bamboo strip to scrape off the scales on the mushroom bodies and the soil and sand from the mushroom base. Keep the stipe as needed or cut off all or part of the stipe with stainless steel scissors. After washing, drain the water in a ventilated place, or spread them in the sun to dry for 2-4 h. Sort and grade according to the size of the mushroom bodies and the degree of dryness and wetness, and place them on baking trays with the gills facing down. Before baking, preheat the drying machine (room) to 45-50 degrees C. After the temperature drops slightly, arrange the fresh mushroom trays on the tray racks in the drying room. Place large and wet mushrooms on the middle layer of the racks, small and dry mushrooms on the top layer of the racks, and opened-cap mushrooms on the bottom layer of the racks. After arranging them, close the drying room door, start the machine, and carry out baking and drying.

2. Temperature adjustment and shape setting. The starting temperature for baking mushrooms picked on sunny days is 35-40 degrees C; for mushrooms picked on rainy days, it is 30-35 degrees C. After the mushroom bodies are heated, the surface moisture evaporates rapidly. At this time, all air inlet windows and exhaust windows should be opened to discharge water vapor with the maximum ventilation volume, promoting the whole gill layer to become fixed and upright in shape. Then immediately lower the temperature to 26 degrees C and maintain it for 4 h to prevent the gill layer from falling over, damaging the mushroom shape, turning black in color, and reducing commercial value.

3. Dehydration of mushroom bodies. After maintaining 26 degrees C for 4 h, begin to raise the temperature, increasing the baking temperature by 2-3 degrees C per hour, maintaining this for 6-8 h until reaching 51 degrees C, then hold constant, promoting large-scale evaporation of moisture from the mushroom bodies. When raising the temperature, open and close the air windows in time and adjust the relative humidity to 10% to ensure that the gill layer remains upright and the color is fixed. During the temperature-raising stage, also appropriately adjust the positions of the upper and lower baking trays so that the drying degree of the mushroom bodies is uniform.

4. Overall drying. From constant temperature at 51 degrees C, slowly raise to 60 degrees C over about 6-8 h. When dried to 80% dryness, take out the baking trays and air them for 2-3 h, then put them back on the racks for baking. Close both air windows completely and bake for 2 h. When the mushroom stipe breaks easily when lightly bent by hand and gives a crisp sound, the baking is finished. Generally, 9 kg of fresh mushrooms can be processed into 1 kg of dried mushrooms.

5. Finished product sub-packaging. Pack the dried wine cap mushroom after baking according to grade into plastic food bags, with each bag containing 500 g or 1000 g of dried product, seal the bag opening, and store for preservation or export. The dried product of wine cap mushroom can also be put into woven bags lined with plastic film, and after sealing the bag opening, placed into corrugated boxes or specially made bamboo or wooden boxes, with each box containing 5 kg of dried product, which is convenient both for preservation and for export.