Ultrasound-negative pressure cavitation extraction of phenolic compounds from blueberry leaves and evaluation of its DPPH radical scavenging activity

Abstract

Traditional extraction methods for natural products from biomass have many drawbacks such as low extraction yields, time-consuming, plenty of organic solvent consumption and being harmful to environment and human beings. In the present study, we developed an efficient extraction method called ultrasound-negative pressure cavitation extraction (U-NPCE) for extraction of bioactive compounds from blueberry leaves. The optimization of the extraction process was based on single factor experiments and Box–Behnken design (BBD). The optimal extraction conditions were ethanol concentration (v/v) 68.61%, ultrasonic power 0.36W/cm2, negative pressure −0.07Pa, extraction time 15min, solid/liquid ratio 1:30g/mL and extraction temperature 50°C. Under the optimal extraction condition, the mass transfer kinetics model indicated that U-NPCE has higher extraction yields for total phenols (TP), total flavonoids (TF) and total procyanidins (TPA) and the time consumption were 3.33 and 3.67 times shorter than that of ultrasound-assisted extraction (UAE) and negative pressure cavitation extraction (NPCE) respectively. Moreover, extracts of U-NPCE (22.5μg/mL) have stronger DPPH radical scavenging activity than those of UAE (30μg/mL) and NPCE (32.5μg/mL). The results indicated that U-NPCE was more efficient than UAE and NPCE for extraction of polyphenols from blueberry leaves and extracts has much higher TP, TF and TPA contents and DPPH radical scavenging activity.