Effect of Ultrasonic Induction On the Main Physiological and Biochemical Indicators and GABA Content of Maize During Germination

GABA (γ-aminobutyric acid) is an inhibitory neurotransmitter in mammalian cerebrospinal fluid that has a variety of health benefits, which accumulated in sprouted grains. In this study, ultrasonication (US) of maize sprouts was used to alter their GABA content. The analysis indicated that the respiration of the ultrasonic-treated maize was significantly enhanced during germination, resulting in a 27% increase in shoot length, as well as a 4.03% higher dry matter consumption rate, and 2.11% higher starch consumption rate. Furthermore, optimum sonication resulted in 22.83% more reducing sugar, 22.52% more soluble protein and 30.55% higher GABA content. These changes were likely related to accelerated metabolism which caused reduced dry matter, starch, reducing sugars, soluble protein, free amino acids, and glutamic acid. GABA content and GAD activity of maize treated with ultrasound were all higher compared to the control group throughout the germination process, indicating that ultrasound treatment could promote the germination of maize, accelerate the process of germination and shorten the time of GABA enrichment in germinating maize. The results of this study can be applied to increase GABA content in germinating maize.