Method for Preparing and Conditioning Granular Burdock Roots Through Combined Uniform Drying By Using Radio Frequency Pretreatment and Microwave Pulse Spouting

A method for preparing and conditioning granular burdock roots through combined uniform drying by using radio frequency (RF) pretreatment and microwave pulse spouting, the method comprising:

• performing pretreatment on burdock roots to generate burdock slices;
• immersing the burdock slices into an aqueous solution containing about 0.1%-1.0% ascorbic acid and about 0.1%-1.0% sodium chloride in a mass concentration for about 10-60 minutes;
• performing blanching on the burdock slices for about 1-10 minutes by using about 0.1%-1.0% D-isoascorbic acid sodium solution at a temperature of about 70° C.-95° C.;
• pre-drying the burdock slices by using RF for about 20 minutes with an RF power of about 1.5-2 w/g at a hot wind with a temperature of about 50° C., a distance between electrodes being about 20.5 centimeters (cm);
• performing a first drying on the burdock slices through the microwave pulse spouting at about 0-10 minutes, a microwave power being about 1.0-1.5 w/g at the hot wind temperature of about 70-75° C., and a spouting frequency being about 2 seconds at an interval of about 6 seconds;
• performing a second drying on the burdock slices for about 25 minutes, the microwave power being about 1.5-2.0 w/g at a hot wind temperature of about 65-70° C., and a spouting frequency being about 2 seconds at an interval of about 6 seconds;
• and
• performing a third drying on the burdock slices for about 5 minutes, the microwave power being about 1.0-1.5 w/g at a hot wind temperature of about 70-75° C., and a spouting frequency being about 2 seconds at an interval of about 8 seconds.