Optimization for Extraction of Essential Oil from Needles of Abies firma by ResponseSurface Methodology

In September 2020, needles of introduced 20-year Abies firma were collected from Jinning Caoyutang Forest Park, Zhejiang province.Essential oil from needles were prepared by steam distillation with water as solvent, and response surface methodology (RSM) was used to optimizethe extraction process. Taking the yield of essential oil as objective, four single factors were tested like particle size, soaking time, distillation timeand distillation speed. The extraction process of A. firma essential oil by steam distillation was optimized through Box Behnken design of responsesurface methodology, and a prediction model of quadratic polynomial regression equation was established. The optimal extraction process of theessential oil from A. firma needles was as follows: 200 mesh of particle size, 37 minutes of soaking, 108 minutes of distillation, and 2.8 mL/min ofthe distillation speed. Under this condition, the maximum yield of essential oil was 0.714%, which was in good conformity with the predicted value of0.716%, indicating that the extraction process was reliable.