Optimization Of Processing Conditions To Extract Bioactive Compounds From Perilla Leaves

Abstract

Perilla leaves (Perilla frutescens) are commonly used in Vietnam due to their various beneficial health effects. In this study, ultrasound assisted extraction (UAE) was used to extract bioactive compounds from perilla leaves. Plackett-Burman design (PBD) at two-level with seven independent variables including ultrasound temperature and duration, solid-to-solvent ratio, ethanol concentration, pH, drying temperature, and particle size was utilized to screen the significant factors affecting the total phenolic content (TPC), anthocyanin content and 2,2-diphenyl- 1- picrylhydrazyl (DPPH) radical scavenging activity. Optimization was then carried out using a central composite design (CCD) with the two factors screened previously, namely drying temperature (40, 43, 50, 57, 60 °C) and solvent/solid ratio (26, 30, 40, 50, 54). The optimal conditions were determined as follows: pH of 1, drying temperature of 50.28 °C and solvent/solid ratio of 37.67 (mL/g). Under these optimal conditions, TPC, anthocyanins content and antioxidant activity were predicted to be 23.63 mg gallic acid equivalent (GAE)/g dry basis (DB), 601.87 μg cyanidin-3-glucoside equivalent (CGE)/g DB and 37.87 mg Trolox equivalent (TE)/g DS, respectively. The experimental results are consistent with the predicted values, which were 23.49 mg GAE/g DB, 596.67 μg CGE/g DB, and 37.74 mg TE/g DB, respectively confirming that the model was valid for optimization of the extraction conditions