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. 2021 Apr 30;26(9):2632. doi: 10.3390/molecules26092632

Table 2.

Summary of the main recent findings showing the effects of the pulsed electrical field (PEF) technology on anthocyanin extraction from agri-food by-products.

Waste/By-Product Extraction Process Parameters Major Findings Reference
Raspberry by-product Electric field intensity: 1 and 3 kV/cm
Specific energy input: 1, 6, and 12 kJ/kg
Frequency: 20 Hz
Pulse width: 20 μs
  • -

    Improved anthocyanin extraction (up to 25.7%);

  • -

    PEF process intensification did not increase anthocyanin extraction;

  • -

    Mild PEF (1 kV/cm and 6 kJ/kg) was sufficient to achieve higher anthocyanin extraction.

 [47]
Sweet cherry by-product Electric field intensity: 0.5, 1, and 3 kV/cm
Specific energy input: 10 kJ/kg
Frequency: 5 Hz
Pulse width: 20 μs
  • -

    No effect on the number and type of anthocyanins extracted;

  • -

    Improved anthocyanin extraction (up to 38.4%);

  • -

    PEF process intensification did not increase anthocyanin extraction;

  • -

    Cyanidin-3-glucoside content reduced as the electric field intensity increased.

 [48]
Sour cherry by-product Electric field intensity: 1, 3, and 5 kV/cm
Specific energy input: 10 kJ/kg
Frequency: 10 Hz
Pulse width: 20 μs
  • -

    Improved anthocyanin extraction (up to 54%);

  • -

    PEF process intensification did not increase anthocyanin extraction.

 [99]
Blueberry by-product Electric field intensity: 10–35 kV/cm
Pulse number: 2–14
Pulse width: 2 μs
  • -

    PEF process intensification improved anthocyanin extraction (up to 20 kV/cm and 10 pulses);

  • -

    High electric field intensity (>20 kV/cm) and pulse number (>10 pulses) drastically reduced anthocyanin extraction;

  • -

    PEF technology was more effective than US.

 [100]
Blueberry by-product Electric field intensity: 3 kV/cm
Specific energy input: 1, 5, and 10 kJ/kg
Frequency: 10 Hz
Pulse width: 20 μs
  • -

    No effect on the number and type of anthocyanins extracted;

  • -

    Improved anthocyanins extraction (up to 75%);

  • -

    Anthocyanin extraction increased with PEF process intensification;

  • -

    No evidence of individual anthocyanin degradation due to PEF application.

 [46]
Blueberry by-product Electric field intensity: 1, 3, and 5 kV/cm
Specific energy input: 10 kJ/kg
Frequency: 10 Hz
Pulse width: 20 μs
  • -

    Improved anthocyanin extraction (up to 111%);

  • -

    Anthocyanin extraction increased with PEF process intensification.

 [101]
Blueberry by-product Electric field intensity: 1, 3, and 5 kV/cm
Specific energy input: 10 kJ/kg
Frequency: 10 Hz
Pulse width: 20 μs
  • -

    No effect on the number and type of anthocyanins extracted;

  • -

    Improved anthocyanin extraction (up to 95%);

  • -

    Anthocyanin extraction increased with PEF process intensification.

 [102]
Blueberry pomace Electric field intensity: 10, 15, and 20 kV/cm
Specific energy input: up to 41.03 kJ/kg
Pulse number: 10, 50, and 100
Pulse width: 2 μs
  • -

    Anthocyanin extraction increased with PEF process intensification;

  • -

    PEF technology was more effective than US and high voltage electrical discharges.

 [103]
Peach pomace Electric field intensity: 0.8–10 kV/cm
Specific energy input: 0.02–20 kJ/kg
Frequency: 0.1 Hz
Pulse width: 4 μs
  • -

    Improved anthocyanin extraction (up to 11.8-fold);

  • -

    PEF process intensification significantly reduced anthocyanin extraction.

 [98]
Grape pomace Electric field intensity: 1.2, 1.8, and 3.0 kV/cm
Specific energy input: 18 kJ/kg
Pulse number: 200–2000
Pulse width: 100 μs
  • -

    Improved anthocyanin extraction (up to 18.9%);

  • -

    The increase in electric field intensity (1.2–3.0 kV/cm) had no effect on anthocyanin extraction.

 [104]
Grape pomace Electric field intensity: 13.3 kV/cm
Specific energy input: 0–564 kJ/kg
Frequency: 0.5 Hz
  • -

    Improved anthocyanin extraction (up to 5.3-fold);

  • -

    Anthocyanin extraction increased with PEF process intensification;

  • -

    PEF technology was more effective for anthocyanin extraction than US (up to 22%) and high voltage electrical discharges (up to 55%).

 [105]
Grape peel Specific energy input: 289.8 (PEF-I) and 37.8 W (PEF-II)
Pulse number: 25.2 (PEF-I) and 9.7 (PEF-II)
Frequency: 10 Hz
Pulse width: 6 μs
  • -

    Improved anthocyanins extraction (up to 4-fold);

  • -

    PEF-I treatment was more effective for anthocyanin extraction than US.

 [106]
Plum peel Specific energy input: 228 (PEF-I) and 17.8 W (PEF-II)
Pulse number: 25.2 (PEF-I) and 9.7 (PEF-II)
Frequency: 10 Hz
Pulse width: 6 μs
  • -

    PEF technology was not able to increase anthocyanin extraction compared to control.

 [106]