Effect of ultrasound and microwave pretreatment on sprouting, GABA, bioactive compounds, and other physicochemical properties of sorghum

Abstract

Aim of this study is to see how ultrasound (US) and microwave (MW) pretreatments affect γ-aminobutyric acid (GABA) and physicochemical parameters of sorghum sprouts. Before sprouting, the sorghum was treated with the US at different time intervals (10, 15, 20 min) and MW at various power levels (10%, 30%, 50%). Sample treated by the US for 15 min showed the highest sprouting percentage of 97.33%. Both treatments induced stress in grain resulting in GABA accumulation substantially from the control where US for 15 min and MW at 10% power level had the highest of 87.14 and 66.97 μg/g, respectively. US treatment for 20 min showed the highest total phenolic content (TPC) of 21.26 mg GAE/100 g, while on 10 min of treatment, it showed the highest antioxidant activity of 84.53% DPPH inhibition. The water absorption capacity and oil absorption capacity were the highest of 0.86 g/g and 0.98 g/g in the MW-treated sample at 10% output power respectively. In conclusion, the ultrasound treatment successfully accelerated the sprouting rate and GABA content while retaining total phenolic content, making it beneficial for developing functional foods.