Effects of ultrasonic waves, microwaves, and thermal stress treatment on the germination of Tartary buckwheat seeds

The effects of ultrasonic waves, microwaves, thermal stress, thermal stress combined with ultrasonic waves and thermal stress combined with microwaves on the germination of Tartary buckwheat seeds from Ningxia and Sichuan were compared. On the seventh d of germination, the highest germination rate of Tartary buckwheat from Ningxia treated with ultrasonic waves was 87.33%, which was 4.66% higher than that of the control (p < .05). The highest germination rate of the microwaves treatment of Tartary buckwheat from Sichuan was 86.67%, which was 4.67% (p < .05) higher than that of the control. The ultrasonic waves and microwaves treatments increased the content of flavonoids and reducing sugars and enhanced the DPPH and ABTS radical scavenging activities. In addition, the ultrasonic waves and microwaves treatments had positive effects on the activities of catalase and phenylalanine ammonia lyase. PRACTICAL APPLICATIONS: Tartary buckwheat is highly valued as food and for its nutritional and health benefits. The germination of Tartary buckwheat seeds can improve its food quality and nutritional value. Germinated buckwheat has higher contents of phenolics and flavonoids. Two such high‐speed, high efficiency and low energy consumption of heating methods, microwaves and ultrasonic waves processing technologies, are highly significant for the seed germination. In this study, two types of Tartary buckwheat seeds were treated with ultrasonic waves, microwaves, and thermal stress. In addition, the present study reflected the relationship between the germination characteristics and various physiological and biochemical indices. We found that these results are important for the seed germination of Tartary buckwheat and provide the best means of expanding the use of Tartary buckwheat and related products.