Optimization of spray-drying conditions and quality assessment of dry extract from Perilla frutescens (L.) Britton leaves

Context: Perilla frutescens and its dried extract have been employed in food and pharmaceutical manufacturing due to the plant's biological activities, which include antibacterial, anti-allergic, anticancer, antiviral, antioxidant, and antidepressant properties. Despite numerous studies on preparing dry extracts from various medicinal herbs, no research has been conducted to optimize spray-drying conditions specifically for P. frutescens. Aims: To optimize the spray-drying parameters using BCPharSoft software and evaluate the quality of P. frutescens dry extract. Methods: D-optimal design based on four independent variables carrier type (Glucidex, Glucidex: Arabic gum 9:1, Glucidex: Arabic gum 8:2), carrier mass (10, 15, and 20 g), inlet air temperature (160, and 180℃) and flow rate (12, and 14 rpm/min) was applied to investigate the cause-effect relations and optimized preparation process. The drying performance, moisture content, total phenol, and total flavonoid content were investigated as four dependent variables. Results: All independent variables had significant effects on the dependent variables. The optimal parameters of the preparation process included using carrier Glucidex: Arabic gum at a ratio of 9:1, carrier mass of 19 g, inlet air temperature of 161°C, and flow rate of 12 rpm/min. The drying performance, moisture content, total phenol, and flavonoid content of the optimized P. frutescens dry extract were found to be 10.42%, 4.80%, and 90.57 mg GA/g, and 53.55 mg QE/g, respectively. Conclusions: Dried P. frutescens extract has been efficiently produced using the spray-drying technique, establishing a foundation for future manufacturing of pharmaceuticals and functional foods derived from P. frutescens.