1.Drying standards and quality requirements. Drying standard: the shell can be flat by hand, the flesh is dry and russet, shiny, wrinkled, the core is easily cracked with teeth bite, and the section is grayish with grass and trees. Quality requirements: the same grade should be dry and even, the fruit pedicle is complete, the shape is smooth, the pulp has no scorching taste, no mildew, no insects, no more than 5 broken shell rate

2.In order to select the mature, round fruit, the fractionated longan fruit was suspended and soaked in 0.1% potassium permanganate solution for 5 minutes, and then wash it.

3.The first stage drying is to put the trays on the shelf. After preprocessing the fruit of the tile on the foil material thickness 15 mm to 20 mm. Then closed the feeding door, side feeding door, outdoor outlet and wet outlet of the drying room, open the fan, steam valve and electric steam regulating valve, make the hot air temperature control in 45 ℃ and maintain for a period of time 1 material at this time in a relatively closed space of doing fruit slow evaporation of moisture is equivalent to the process of filming. Then open the air outlet and the outlet hot air temperature control in 75*80C drying 32 to 36 hours of air effect drying to 8 dry after filling bags or pile back into the cold storage or short time storage and then the next batch of air effect drying operation. Could wait for the completion of the performance processing according to the customer's demand for the second stage of drying operations.

4.The second stage is to remove the shelf in the drying room, replaced with trolley. The semi-dry fruit is placed on the tray of the trolley and then the trolley is pushed into the drying room. The inlet and outlet door and side outlet door are closed and the fan, steam valve and electric steam control valve are opened so that the hot air temperature in the drying room is maintained between 60 and 70C. After the material is dried in the drying room, the side outlet door is opened and the material out of the drying room becomes a finished product.

5.

In the whole drying process, hot air counter-current drying process is generally adopted for drying operations. The forward direction of the material trolley is opposite to the flow direction of dry and hot air. However, due to the particularity of the structure of the drying room, a certain outlet can be opened or closed according to different drying processes, so that hot air can also form a cross-flow longan drying speed is fast and quality is good.

The dried longan was divided into three grades according to the size of the fruit particles with the fruit diameter. The super grade is 2.914.2cm; the first grade fruit diameter is 2.312.75cm; The secondary fruit diameter is 2.162.30cm.

The general super fruit accounts for 10%~20% of the total fruit. First grade fruit accounts for 55%~80%. Secondary fruit accounts for 15%~20%. There were also two grades of fruit diameter 2.00~2.30cm above the first grade.

Longan were packed in sealable glued cartons lined with plastic film bags. Fill the container with dried fruits by shaking while loading. Then seal the mouth of plastic bags with 25~40kg each. For long distance transportation, use extra wooden cases and iron nails to fasten the lid.

This process can be used to process fresh longan fruit in large quantities in the mature season of longan.