Microwave Irradiation Enhances the Germination Rate of Tartary Buckwheat and Content of Some Compounds in Its Sprouts

Tartary buckwheat (Fagopyrum tataricum) seeds were irradiated with microwaves at various power levels of 200, 400, 600 and 800 W for 10 or 30 s. The irradiated grains were germinated for 3, 5, and 7 days and harvested. The germination rate of the tartary buckwheat seeds and contents of some compounds in the sprouts were investigated. The results showed that the exposure to 600 W microwaves for 10 s resulted in the highest final germination rate after 7 days of germination, which was 2 times that of the control. The exposure of seeds to 800 W for 30 s showed the lowest germination rate (approximately 10%), which decreased by 87% compared with the control (p<0.05). The exposure at 600 W for 30 s stimulated the total flavones content, reduced the sugar and soluble protein contents, and increased the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity. The highest free amino acid content (11 mg/g) was observed in 5-day sprouts exposed to 800 W for 10 s. Moreover, the microwave treatment had a positive effect on the catalase (CAT) and superoxide dismutase (SOD) activity.