Pulsed electric field-ultrasonic assisted extraction combined with macroporous resin for the preparation of flavonoids from Pericarpium Citri Reticulatae

Pericarpium Citri Reticulatae (PCR) has long been perceived as a condiment and medicine in East Asian countries especially China. To establish a cost-effective method with the potential for industrial implementation to enhance extraction and purification of PCR flavonoids, four extraction methods (hot water extraction (HWE), ultrasound-assisted extraction (UAE), pulsed electric field-assisted extraction (PEF-AE), pulsed electric field combined with ultrasound-assisted extraction (PEF-UAE)) and five macroporous resins (AB-8, NKA-9, D-101, HPD-100, and HPD-950) were investigated and compared in this study. Results of total flavonoid content (TFC) and monomer flavonoid composition revealed that PEF-UAE was the most efficient extraction process. Response surface methodology (RSM) was employed to determine the optimum conditions of PEF-UAE (ultrasonic power 340 W, ultrasonic time 30 min, electric field strength 3 kV/cm, and 81 pulses). Under the optimum conditions, the PCR flavonoids extracted by PEF-UAE yielded the highest contents of total flavonoid, nobiletin, and tangeretin in all PCR flavonoid samples. Among the five macroporous resins, AB-8 was used to purify PCR flavonoids due to its higher adsorption and desorption capacities. A maximum purification efficiency was achieved under 6 h of adsorption time and 298 K of temperature, indicated by 2.47-fold, 2.78-fold, and 2.43-fold increases in the contents of hesperidin, nobiletin, and tangeretin, respectively. The purified PEF-UAE flavonoid extract also demonstrated the superior α-glucosidase inhibitory and radical scavenging activities. This study offered a prerequisite for the future utilization of PEF-UAE and AB-8 to produce PCR flavonoids for food and medicine applications. Novelty impact statement Pulsed electric field combined with ultrasound can significantly increase the extraction rate of flavonoids from Pericarpium Citri Reticulatae . The purification mechanism of AB-8 for Pericarpium Citri Reticulatae flavonoids has been explained. The Pericarpium Citri Reticulatae flavonoids extracted by pulsed electric field combined with ultrasound showed the best biological activities.