Optimization of microwave-assisted extraction process of Hordeum vulgare L. by response surface methodology

This study attempted to find optimum extract range of active ingredient for barley sprouts (Hordeum vulgare L.). Extracts from Hordeum vulgare L. were made by microwave extraction method and total polyphenol content (IPC), total flavonoid content (TFC), DPPH radical scavenging activity (DPPH) were measured with extract of Hordeum vulgare L.. Response surface methodology (RSM) was applied to a extraction process, and central composite design (CCD) was also used for this process to examine the optimum condition. Independent variables (X_n) are concentration of ethanol (Xi: 0, 25, 50, 75, 100%), microwave power (X₂: 60, 120, 180, 240, 300 W), extraction time (Xs: 4, 8, 12, 16, 20 min). Dependent variables (Y.,) are IPC (Yi), TFC (Y₂), DPPH radical scavenging (Y₃). It is formed by sixteen conditions to extract The R² value of dependent variables is ranged from 0.90 to 0.97 (p<0.05). Experiments values within the optimal range (40% of ethanol concentration, 120 W of microwave power, 18 min of extraction time) were 3.74 mg GAE/g (IPC), 3.00 mg RE/g (TFC), 35.43% (DPPH), respectively. Under the optimized conditions, predicted value showed no significant difference comparing with the experimental values.