Effect of magnetic field pretreatment on germination characteristics, phenolic biosynthesis, and antioxidant capacity of quinoa.

ABSTRACT

The development of quinoa-based functional foods with cost-effective methods has gained considerable attention. In this study, the effects of magnetic field pretreatment on the germination characteristics, phenolic synthesis, and antioxidant system of quinoa (Chenopodium quinoa Willd.) were investigated. The results showed that the parameters of magnetic field pretreatment had different effects on the germination properties of five quinoa varieties, in which Sanjiang-1 (SJ-1) was more sensitive to magnetic field pretreatment. The content of total phenolics and phenolic acids in 24-h germinated seeds increased by 20.48% and 26.54%, respectively, under the pretreatment of 10 mT magnetic fields for 10 min compared with the control. This was closely related to the activation of the phenylpropanoid pathway by increasing enzyme activities and gene expression. In addition, magnetic field improved 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2'-Azinobis-(3-ethylbenzthiazoline-6-sulphonate) (ABTS) free radicals scavenging capacities and increased peroxidase (POD), catalase (CAT), superoxide dismutase (SOD), ascorbate peroxidase (APX) and glutathione peroxidase (GSH-Px) activities. This study suggests that magnetic field pretreatment enhanced gene expression of phenylalanine ammonia lyase (PAL), 4-coumarate-CoA ligase (4CL), chalcone synthase (CHS) and chalcone isomerase (CHI), increased antioxidant enzyme activity and phenolics content. Thereby lead to an increase in the antioxidative capacity of quinoa.