Optimization of Hydrothermal Acid Controlled Extraction of Luteolin from Perilla Stem by Response Surface Methodology

In order to improve the resource utilization of Perilla stem, the hydrothermal acid control method was used to extract luteolin from Perilla stem. Taking the extraction amount of luteolin as the response value, response surface method was used to optimize the optimum extraction conditions. The phase structure of Perilla stem before or after hydrothermal acid control was analyzed by FTIR and SEM characterization.The results showed that under the optimal conditions of hydrothermal time of 120 min, hydrothermal temperature of 230 ℃, solid-liquid ratio of 1:20 g/mL and citric acid concentration of 1%, luteolin (901.049 ± 0.60) μg/g could be extracted from 2.0 g Perilla stem. The model was feasible. FTIR analysis showed that hydrothermal acid control could destroy the functional groups C−O−C and C=O in the lignocellulosic of Perilla stem. SEM showed that hydrothermal acid control could reduce the mass transfer resistance of active substances such as luteolin and facilitate the dissolution of luteolin.