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.