How to Dry Walnut/Dehydrate Walnut in a Dehydrator

Jul 16, 2021

Introduction to walnut：

Walnut is rich in nutrients. Walnut like sunshine, cold resistance, drought resistance, disease resistance, like fertile and humid sandy loam, like water, fertilizer, like Yang, suitable for most of the land growth.

Walnut processing steps：

1. Peeling
Walnut began to mature from late August to early September. At this time, the pericarp changes from dark green to yellowish green or light yellow. Some of the involucres are cracked and a small number of fruits drop, which can be harvested for processing. Green walnut can't be exposed to the sun. The dried walnuts are not easy to peel. The walnuts should be stacked in a cool place or indoor with a height of 30-50cm and covered with walnut leaves or grass. After 3-5 days, when the green skin is removed from the shell, it is peeled by hand or cut with a knife. Generally 4.5kg walnut can produce 1kg dry walnut.
2. Rinsing and drying
After peeling, the walnut should be washed with water in time, because the vascular bundles at the base of walnut will contract after a long time, and the washing water is easy to enter into the shell, causing the kernel to change color and even rot. Put the walnuts in the basket, then put them into the water, and stir them with a bamboo broom for 5 minutes each time. Wash 2-3 batches of walnuts for once.
Wet walnut shell clean soil and black dirt, and then bleach. Use 1 kg bleach powder and 6-8 kg warm water to dissolve, filter out the residue, and then add 60-80 kg clear water to dilute to bleach solution. After the walnut is put into the bleach solution, continuously stir it to see if the shell changes from cyan red to yellow white. Then remove the white spots of the residual bleach powder by repeatedly washing with clean water until it is light white. Bleaching is carried out in a vat instead of an iron bucket to prevent the walnut shell from turning green. Each time 80 kg walnut is rinsed, the bleaching time is 8-10 minutes. After the walnut is fished out, add 0.5kg bleaching powder into the bleaching solution and reuse for 7-8 times.
Walnut bleached can be cool for half a day, after most of the water evaporated and then spread sun. It can also be dried at 40 ℃ - 50 ℃. The sign of sun drying is that the skin color of the kernel changes from milky white to light yellow brown, and the diaphragm is easy to break. Dried walnuts should be stored in a well ventilated and dry room.
3. Take the kernel
When taking kernel by hand, place the walnut suture parallel to the ground, and knock evenly. Do not knock hard or repeatedly. Generally, 38 kg of kernel can be taken per 100 kg.
4. Soaking in fragrance solution
Mix 20% Dupi, 5% clove, 25% fennel, 20% licorice, 15% star anise, 10% Zanthoxylum bungeanum and 5% Xiangpian, add 10 times of water, heat to boil, keep warm for 30 minutes, and filter out the extract. Add 2-5% salt and 0.03-0.05% monosodium glutamate to the extract. Immerse the walnut kernel in the fragrance liquid made by the above method for 1 hour, remove and drain.

Walnut drying process：

The walnut kernel is put into a special 304 stainless steel grid plate, each plate is 7.5 kg, and each car is 12 disks. The 6p drying and dehumidification integrated machine is equipped with 25 cubic meters drying room, which can be put into 8 material trucks at a time, and can feed 600kg at a time. The drying time is between 15-20 hours. The soaked walnut kernel is dried at 60 ℃ to 70 ℃ until the moisture content is below 10%.

Recommendation of walnut dryer/drying machine

Commercial 100-3000kg/h large amount of dehydration wide application and easy operation

Heat pump drying machine use the principle of inverse Carnot cycle. It absorbs low-temperature heat energy in the air, which becomes high-temperature heat energy after efficient heat collection and integration by the heat pump system, and is transported to the drying room for cyclic heating and drying of materials.It refers to exhausting the hot and humid air in the drying room directly to the outside of the drying room through dehumidification device, and then replenishing natural fresh air.

Hot air circle drying machine belongs to high temperature heat pump unit. Its working principle is: the working fluid of the heat pump is compressed by the compressor, becomes high temperature and high pressure gas, enters the condenser, condenses and liquefies the heat, and is used for air heating in the drying room. The moisture in the material is vaporized and evaporated by the form of hot air, and the evaporated water vapor is discharged by the moisture discharge system, thereby achieving the purpose of drying the drying material.