Drying technology of Lentinus edodes

Lentinus edodes is not only a famous and valuable edible fungus in the world, but also a traditional export commodity in China. Lentinus edodes contains unique flavor, rich nutrition, tender and smooth meat, is one of the commonly used ingredients of Chinese and foreign famous dishes, and is known as the king of dishes. At the same time, Lentinus edodes is also a famous medicinal fungus, which has high medicinal value, such as replenishing qi, not hungry, activating wind and breaking blood. Modern medicine has proved that long-term consumption of Lentinus edodes can strengthen the physique, soften blood vessels, lower cholesterol, and have the effect of preventing and fighting cancer. Therefore, Lentinus edodes is very popular in the international market and has become the second largest edible mushroom in the world. The production and processing of Lentinus edodes can bring great economic and social benefits and have broad market prospects.

For the primary processing of Lentinus edodes products, at present, the vast majority of professional mushroom farmers and small-scale processing units adopt a relatively extensive traditional processing method, that is, simple drying and soil kiln drying, and then directly enter the market @ # @ 136 products. The products processed in this way are not competitive in the market, but also waste good raw materials of Lentinus edodes. After China's entry into WTO, the international market has higher and higher requirements for the quality of products. In order to make Lentinus edodes products go abroad and be competitive in foreign markets, it is necessary to actively adopt advanced processing technology and production equipment, establish a set of scientific quality control methods and operating norms, and improve the processing quality of products.

1. Preparation of materials

(1) the method of harvesting forbids watering one day before harvest and harvests in time. Thick mushrooms should be harvested when they are mature, and generally the harvest should not exceed that of medium well. During harvest, the mushroom membrane should be naturally broken, the cover has not been opened, the edge of the mushroom is rolled up, and the mushroom body with no pathological changes and no deformities is extended. When harvesting, gently pinch the fungal handle with your fingers and twist it, do not touch the bacterial fold, handle it gently, and the backlog should not be too thick. Avoid contact with pressure distortion or damage when handling or placing in bamboo baskets.

(2) before treatment, the mushroom root was cut off and the mushroom stalk was left with 1cm~2cm. First sort out the flower mushroom, thick mushroom and thin mushroom, then pack them in the plate according to the variety and size, and expose the 2h~3h in the sun to remove part of the moisture. When loading the plate, you should make the cover face up and the stalk face down, put it evenly, and do not overlap the backlog, so as to prevent damage to the mushroom and affect the quality. Lentinus edodes must be baked within 6 hours after harvest. If there are cold storage conditions, the preservation time can be extended appropriately.

two。 Drying chamber drying

(1) put the shiitake mushrooms into the drying room and put them on the grill and send them into the drying room for baking. The large and thick ones with high moisture content should be put on the upper layer, and the small and thin ones with low water content on the lower layer. Generally put 8 ~ 10 layers. If it is placed too much, it is easy to make the heating temperature of the upper, middle and lower materials uneven. The spacing of each layer should be 30cm.

(2) the Lentinus edodes can be dried only when the temperature of the drying room is raised to 35 ℃. Two wet bulb thermometers should be hung near the window in the room. When drying, it must be at a low temperature, and then gradually increase the temperature. The temperature is usually increased by 1 ℃ ~ 3 ℃ in 1 hour, and the maximum temperature should be controlled in the range of 80 ℃ ~ 85 ℃. It is generally required to bake at 35 ℃ ~ 40 ℃ for 6 h → 40 ℃ ~ 60 ℃ and 8h~10h → for 60 ℃ for 2 h. The higher the moisture content of Lentinus edodes, the longer it takes to bake at low temperature. If the temperature rises suddenly at the beginning of the baking, it is bound to cause the tissue to lose water too quickly, and it is easy to make the lid of Lentinus edodes out of shape, fold upside down, crack the cap, blacken the color, destroy the activity of enzymes, and make Lentinus edodes lose its original flavor. After Lentinus edodes is sent into the drying room, it should be baked continuously until it is dry, the heating can not be interrupted, and the temperature should not be suddenly high or low, otherwise the color of Lentinus edodes will turn black and the quality will decline.

(3) in the drying process of Lentinus edodes, in addition to the need to strictly control the heating temperature, timely moisture drainage is also an important link. The upper part of the drying room must be provided with a tide hole. The outlet of the small drying chamber is 10cm × 12cm, the medium drying chamber is 15cm × 20cm, and the large drying chamber is 20cm × 40cm. According to the need, some can set up 2 tide holes. If the surrounding environment is not conducive to the discharge of moisture, an exhaust fan should be installed, and the discharge hole had better be directly connected to the outside. The general principle of dehumidification is: in the early stage of Lentinus edodes baking, when the temperature of the drying room is 35 ℃ ~ 40 ℃, all the dehumidification holes or fans should be turned on; when the temperature rises to 40 ℃ ~ 60 ℃, the dehumidification 3h~4h will be fine. After 60 ℃, all the drainage holes can be closed, and there is no need to drain moisture. If the moisture is excessive, it is easy to make Lentinus edodes pale white. If the Lentinus edodes baked with water-soaked yellow, it means that the moisture discharge is not good, or the furnace temperature is not enough, especially the halfway heat is more likely to cause this phenomenon.

(4) ventilation in order to adjust the indoor temperature and ensure the hot air circulation in the drying room, it must be ventilated to the room at any time. Therefore, two ventilation holes of 20cm × 20cm should be set in the lower part of the drying chamber. If the air supply is not smooth, a blower should be installed. The air sent to the drying room had better be purified first.

(5) when baking to 16h~18h, the door of the drying room can be opened to check whether the drying degree of Lentinus edodes is qualified. During the inspection, press with your finger at the junction of the bacterial cap and the stalk, if only the trace shows that the drying is qualified; if the hand feels soft and the bacterial fold is also soft, it is necessary to continue drying. The characteristics of qualified dried products are: special flavor of Lentinus edodes; fold yellow, fold erect, complete, not inverted; water content of mushroom body does not exceed 13%; Lentinus edodes maintains its original shape, cover is round and flat, and maintains natural color.

(6) graded packaging and ① screening. First, Lentinus edodes and debris with a diameter of less than 3cm and more than 7cm are screened with a thin iron sieve, and the rest are graded and packaged as internal products. Cut the mushroom stalk with ②. Cut off the unqualified mushroom stalk as required by the regulations. ③ sorting. Pick out damaged mushrooms and deformed mushrooms. ④ grading. Classified according to the requirements of export products, divided into three categories: flower mushroom, thick mushroom and thin mushroom, a total of 12 grades

See Table 1. ⑤ sub-package. Weigh it after classification, put it in plastic bags and pack the cartons according to the required quality. Lentinus edodes must be packed in plastic bags within 6 hours after drying to prevent mildew and deterioration caused by moisture absorption. Dried shiitake mushrooms that can not be packed in time should be packed in large plastic bags and tied tightly. It is strictly forbidden to pack in breathable bags such as nylon woven bags or gunny bags. Packaged products should be stored in a dry room.

Table 1 grading table of Lentinus edodes

Name | feature | cover diameter cm |

Pleurotus ostreatus | large curling edge, obvious pattern, meat thickness | 4-6 |

Pleurotus ostreatus | Mushroom body thickness | 340 |

Pleurotus ostreatus | Pleurotus ostreatus body is semicircular | 2-3 |

Diced mushrooms | Mushroom body is round | 1x 2 |

Thick mushroom | thick mushroom meat, large edge of roll, cross-cut amount > 1cm | 4-6 |

Medium thick mushroom | rich mushroom meat | 340 |

Pleurotus ostreatus | Mushroom Meat thickness | 2-3 |

Thick diced mushrooms | thick mushroom meat | 1x 2 |

Extra-large thin mushroom | full open umbrella, thin umbrella meat | > 7 |

Pleurotus ostreatus | flat cover | 4-7 |

Pleurotus ostreatus | flat cover | 340 |

Pleurotus ostreatus | flat cover | 2-3 |

3. Dryer drying

For small processing enterprises in rural areas, tunnel dryer is an ideal dehydration and drying equipment for Lentinus edodes. At present, the more advanced model has chain circulating tunnel dryer, which can automatically control temperature, continuous operation, fast drying speed, easy to operate, diesel, raw coal and other fuels can be used. The chain circulating tunnel dryer is composed of mechanical power and thermal power. When working, as long as the speed regulation motor, blower and heater are turned on and the valve is properly adjusted, the material plate can be run in parallel, uniform speed and multi-level circulation to dry the product. Because the drying mode of the equipment adopts flow circulation hanging plate, the material does not need to be turned over, and the drying is uniform, so the processed Lentinus edodes products are of good quality and high grade. In addition, the dryer adopts indirect heating, which has no pollution and high thermal efficiency. Compared with the kiln drying, the drying time of the chain circulating tunnel dryer is reduced by nearly 40%.

4. Use and maintenance of drying equipment

(1) when the Lentinus edodes dried by the dryer reaches the standard, the machine should be stopped after a cease-fire to avoid overheating and deformation of the pipe.

(2) if the furnace is damaged, it must be repaired in time. The thickness of refractory bricks should be 6cm and should be coated with refractory mud.

(3) after each furnace is dried and cooled, each smoke should be pulled back and forth several times in time to prepare for the next furnace drying.

(4) there should be certain standards for the use of coal or firewood to ensure the time and quality of baking.

(5) the necessary equipment such as blower and exhaust fan should pay attention to maintenance and repair, and there should be a certain amount of spare parts so as not to affect the normal operation.

(6) the electrical equipment should be standard and safe, and the connection of power supply circuit should be firm and reliable. When drying, it is necessary to ensure normal power supply to avoid economic losses caused by temporary power outages.

(7) the chimney must be installed outdoors and the height should be more than 4m to ensure the total pulling force of the flue. Fire should be prevented.

In the production and processing of Lentinus edodes, we should not only need strict quality management, but also pay attention to economic accounting. Lentinus edodes must be purchased according to quality standards and dried as soon as they are collected. Finished and semi-finished products should do a good job of anti-theft, anti-rat, anti-insect, anti-moisture work. The remaining mushroom stalks and deformed mushrooms without drying value should be drowned immediately, and can be processed into Lentinus edodes candied fruit, Lentinus edodes stalk pine, Lentinus edodes soy sauce and other products, so as to improve the development and utilization value of their by-products and increase the economic benefits of enterprises.