China has always been a big producer and consumer of walnut. At present, the method of manual peeling or mechanical peeling is still used in the primary processing of walnut raw materials in China. The drying time is long, the mold breeding is serious, and the rot rate is as high as 10% to 15%. With the expansion of walnut planting area and the increase of yield year by year, rapid drying after harvest is particularly important.
Walnut drying technology
Walnuts after harvest first need to be peeled and processed, followed by rinsing and drying, the most critical step: drying.
The first stage – timely into the warehouse dehumidification
Deglazed within 8 hours into the warehouse on the shelf dehumidification baking, dehumidification temperature of 30-35 ℃, baking time of 12-15 hours, the shell surface moisture loss, the color from black to brown when the end of dehumidification.
The second stage – color initial baking
After the end of moisture removal into the color initial baking, the temperature rises to 50 ℃, baking time of 12 hours, drying characteristics for the completion of cracking open the kernel fruit no water vapor, kernel has been fixed color, 70% dry, but still able to take off the kernel coat.
The third stage – fire dry kernel
After the end of the color drying period into the dry kernel period, the temperature is controlled at 30 ℃, about 16 hours, at this time the water content of the kernel up to about 10%.
Dry kernel stage can be abandoned at the end of the fire, and with a burlap bag on the grill on the kernel full coverage, insulation for a few hours to promote the upper layer of kernels within the moisture continues to evaporate, to achieve the upper and lower layers of kernel drying relatively uniform.
Post time: Aug-06-2024
