Effect of magnetic field‐assisting germination on bioactive substances and antioxidant activities of quinoa

Nowadays people pay more and more attention to the healthy function of grain. Quinoa is rich in bioactive substances and is easy to grow. In order to further improve the content of bioactive substances in quinoa, this study adapted magnetic field-assisting germination to process quinoa and compared it with ordinary germinated quinoa. The contents of gamma-aminobutyric acid (GABA), total phenols, flavonoids, and saponins of quinoa under different treatments were determined; and the antioxidant activity indexes of quinoa under different treatments were further measured, which included DPPH free radical scavenging rate, ferric ion-reducing antioxidant power (FRAP), and ABTS free radical scavenging rate. The results showed that the contents of bioactive substances and antioxidant activities of common and magnetic germinating quinoa were significantly higher than those of not germinating quinoa, and increased with the increase in germinating time; and the increase in bioactive substances and antioxidant activities of magnetic germinating quinoa were significantly higher than those of common germinating quinoa. The maximum values of bioactive substance content and antioxidant activity index of germinated quinoa assisted by magnetic field were as follows: GABA 61.93 mg/100 g; total phenol 2.90 mg/g; flavonoids 3.12 mg/g; saponins 8.12 mg/g; DPPH free radical scavenging rate 88.04%; FRAP 8.39 mu mol TE/DW; and ABTS free radical scavenging rate 69.97%. In conclusion, the magnetic field-assisting germination can achieve a large and steady increase in the content of bioactive components and antioxidant activity of quinoa. This study aims to provide theoretical guidance for the processing and application of quinoa. Novelty impact statement Magnetic field treatment is an innovative and efficient method for germination without contact and ion residue. Compared with not germinated quinoa and ordinary germinated quinoa, magnetic field-assisting germination can achieve a large and steady increase in the content of bioactive components and antioxidant activity of quinoa, which is convenient for the subsequent processing and research of germinated quinoa to obtain the functional food needed by people.