Detailed Explanation of Shiitake Mushroom Roasting and Storage Techniques

Bag-cultivated shiitake mushrooms have become a major pillar industry for economic development in many mountainous rural areas, but during the shiitake cultivation process, due to untimely management, or encountering abnormal climate and large temperature differences, deformed mushrooms or low-quality shiitake mushrooms (collectively called "cull mushrooms") are easily formed. If these low-quality mushrooms are not processed and are directly sold on the market as fresh mushrooms, the price is very low and sales are sluggish. If they are roasted into dried mushrooms, not only can their value increase, but sales are also good.

1. Raw material processing. Trim the stems of fresh mushrooms; the length of stem trimming should be determined according to the mushroom shape, mushroom flesh, mushroom quality and mushroom cap, and can be divided into three grades: removing the bran, trimming half the foot, and trimming flat foot. Generally speaking, for shiitake mushrooms with a small cap, thin flesh and long stems, it is best to remove the bran (keeping the whole foot); for mushrooms with a large and round cap, thin flesh and soft, loose quality, half the foot may be taken (that is, half of the stem is trimmed off), with a range of about 1--1.5 cm; for those with a large and round cap and thick, hard flesh, it is best to trim flat foot, that is, trim off the foot, leaving about 0.5 cm. According to the cap size, flesh thickness, cap roundness and quality, cutting and retaining the mushroom stems at different lengths has a great influence on the price of the finished dried mushrooms and the yield rate of dried mushrooms.

2. Roasting method. The key is to properly control the temperature during the roasting process. After trimming the stems of shiitake mushrooms to different lengths, spread them on drying trays, push the drying trays into the drying oven of the dryer, close the oven door tightly and start the fire to begin drying. The temperature at the initial dehydration stage must not be lower than 30°C; it is best to start drying at 32°C; dry for 6 hours within the range of 40°C--50°C; after stopping the fire for 1 hour, dehydrate for another 6 hours under the condition of 45°C--50°C hot air temperature; stop the fire for 2 hours and sort the mushrooms. Finally, dehydrate at 50°C--60°C until completely dried. During roasting, the temperature should not be raised too quickly; the temperature increase per hour must not exceed 3°C--5°C.

During the roasting process, sorting the mushrooms is also a link that cannot be ignored, because the mushroom flesh varies in thickness, and its water content differs greatly, so the required roasting time naturally varies. Therefore, after the second fire stoppage, each tray must be checked one by one; those found already dried should be picked out first and put into plastic bags, and the undried ones should be pushed back into the oven to continue drying. In this way, some shiitake mushrooms can be prevented from becoming scorched due to excessive roasting, which would affect the quality of the dried mushrooms.

3. Storage of dried mushrooms. After shiitake mushrooms are dried, if they are not properly stored, they can easily absorb moisture again. Especially in the rainy season, when the temperature is high and humidity is high, mildew and insect damage are more likely to occur. Therefore, after shiitake mushrooms are dried, they should be quickly graded and put into plastic bags, and then a small packet of anhydrous sodium chloride should be added, so as to prevent the sugar in the mushroom body from seeping out and causing discoloration, and at the same time prevent moths and other insects from laying eggs and hatching. In order to prevent shiitake mushrooms and other insect pests, the storage room can also be fumigated with carbon disulfide for 24 hours before storage, and storage can be carried out after the residual gas is expelled.