In addition to ensuring proper temperature and humidity control in the drying process of Pleurotus eryngii, it is also necessary to cut Pleurotus eryngii into 2-4 mm thin slices to ensure the quality of drying.
Processing steps of Pleurotus eryngii
The slice size of Pleurotus eryngii is about 2-4 mm, the thinner the slice, the higher the drying efficiency. This is mainly because the thinner the slices, the larger the contact area between the surface moisture and the hot air, thereby increasing the drying rate. In addition, when the slices are thinner, the moisture inside the mushroom slices has a shorter migration path, which is conducive to the evaporation of moisture on the outer surface. Improved drying efficiency. When the slice is too thick, the water evaporation path is long, and the internal water migration and evaporation speed is relatively slow.
Pleurotus eryngii drying process
The drying of Pleurotus eryngii slices is very similar to that of most traditional Chinese medicinal materials and flowers. It starts from the low temperature section, and then slowly adjusts the temperature. According to the size and water content of the mushroom slices, the drying process lasts for 15-20 hours. Production experience shows that under the conditions of fixed wind speed, material size and material accumulation layer, the drying time of Pleurotus eryngii shortens with the increase of hot air temperature, especially in the medium temperature range. In this range, the higher the temperature The faster the heat transfer rate, the shorter the drying time.
According to the characteristics of the material, adjust the temperature and humidity, adopt the drying mode of air source heat pump gradient cooling, use the drying temperature of 60 ℃ for 3 hours, and then lower the temperature to 55 ℃ for another 3 hours. Finally, at a drying temperature of 50° C., dry the Pleurotus eryngii to constant weight. There are two main advantages of doing this: freshly picked Pleurotus eryngii has a high moisture content, and gradually heating and cooling down can ensure that the surface of the Pleurotus eryngii does not wrinkle. The hot air drying method with gradient cooling has lower energy consumption and lowers production costs. Taking a set of 7P machine as an example, it can hold about 1500 catties of fresh Pleurotus eryngii slices, and the drying time for each batch is 15-20 hours. The moisture content of the dried Pleurotus eryngii slices is about 10%, the shape is complete, and the color is milky white Slightly yellow, with a light fragrance.