Combined effect of pulse electric field and probe ultrasound technologies for obtaining phenolic compounds from orange by-product

Orange peel by-product is a known source of bioactive compounds with several health benefits. This study focuses on optimizing the conditions for pulsed electric field (PEF) technology as a pretreatment to obtain extracts rich in phenolic compounds from the orange peel. A Box-Behnken design of 15 experiments with 3 independent factors (field energy, number of pulses and pulse width) was performed. The phenolic content was extracted by ultrasound technology and analyzed by HPLC-ESI-TOF-MS. Optimum conditions were 1.4 kV/cm and 30 pulses of 110 μs achieving a recovery of 40.8 mg/g dry weight of phenolic compounds, 27.5% higher than obtained without PEF. Besides, hesperidin and narirutin content increased by 29.4 and 38.9%, respectively. For the antioxidant assays also significative increments (≥53%) were achieved. The combination of optimized PEF pre-treatment with ultrasound extraction has let to obtain orange peel enriched extracts in polyphenols with higher antioxidant activity.