Preparation of germinated brown rice with high γ-aminobutyric acid content and short root by magnetic field treatment

This study aimed to prepare germinated brown rice (GBR) with high γ-aminobutyric acid (GABA) content and short root length. Brown rice (BR) was exposed to 10 mT magnetic field at 25 °C for 60 min, followed by incubating in GABA solutions (0–10 mM, 30 °C) for 24 h. After treatment, GABA content in GBR significantly increased from 16.43 to 25.64–50.54 mg/100 g, while root length was shorter than 3.0 mm. Although GABA-aminotransferase activity was reduced by 4.61%–16.14%, the absorption of exogenous GABA caused by higher electrical conductivity, increased cell membrane permeability and more root hairs was the dominant reason for GABA accumulation. The hyperaccumulation of GABA conversely retarded the positive effect of M on α-amylase activity, starch structure, and anti-oxidase activity, thus maintaining the root length at 2.03–2.45 mm. Overall, this study provided an efficient method for preparing GBR with high GABA content and short root.