Semi-Pilot Scale Extraction of Pinocembrin and Galangin from Populus alba L. × berolinensis K. Koch via Enzymatic Pretreatment and Ultrasonication

In this investigation, pinocembrin and galangin were efficiently extracted from the male inflorescence ofPopulus albaL. ×berolinensisK. Koch through an enzymatic pretreatment–ultrasonic-assisted strategy (EP-UAS), and the feasibility of their pilot-scale application was validated. The optimal parameters (ethanol volume fraction, cellulase dosage, incubation temperature, incubation time, pH, liquid‒solid ratio, ultrasonic irradiation power during incubation, duty cycle, ultrasonic irradiation power and time during extraction) affecting pinocembrin and galangin yields were systematically explored. The Box–Behnken design (BBD) results provided optimal parameters for the EP-UAS process. Under the optimal conditions, the actual yields of pinocembrin and galangin were 2158.33 ± 0.13 μg/g and 1257.96 ± 0.06 μg/g, respectively. Stability, recovery and reproducibility were determined under the above optimized conditions to evaluate the proposed EP-UAS method. Moreover, laboratory-scale experimental results revealed that the conditions selected via single-factor and response surface experiments were also applicable to pilot-scale production, facilitating industrialization.