Recovery of hesperidin and narirutin from waste Citrus unshiu peel using subcritical water extraction aided by pulsed electric field treatment

The objective of this study was to identify whether the efficacy of extracting hesperidin and narirutin from Citrus unshiu peel by-products can be increased by combining pulsed electric field (PEF) and subcritical water extraction (SWE). The samples were treated with a PEF at a strength of 3 kV/cm for 60 and 120 s. Subsequent SWE was conducted at extraction temperatures of 110-190 degrees C for 3-15 min. The concentration of hesperidin was highest at 46.96 +/- 3.37 mg/g peel (dry basis) after PEF treatment at 120 s, combined with SWE at 150 degrees C for 15 min, while that of narirutin peaked at 8.76 +/- 0.83 mg/g after PEF treatment at 120 s, integrated with SWE at 190 degrees C for 5 min. The concentrations of both hesperidin and narirutin increased with PEF treatment time. The PEF increased the amounts of hesperidin and narirutin extracted by 22.1% and 33.6%, respectively. This study demonstrate the potential of PEF pretreatment for enhancing the SWE of flavonoids from C. unshiu peel.

Automated summary

This study demonstrated the potential of combining pulsed electric field (PEF) and subcritical water extraction (SWE) for enhancing the extraction of flavonoids from Citrus unshiu peel by-products. The concentrations of hesperidin and narirutin increased with PEF treatment time, and the combination of specific PEF and SWE parameters resulted in the highest extraction yields. PEF treatment increased the amounts of hesperidin and narirutin extracted by 22.1% and 33.6%, respectively.