Table 2.
Effect of non-thermal technologies on F&V by-products pigments (anthocyanins, betalains, carotenoids and chlorophylls).
| Non-Thermal Technology | By-Product | Findings | Reference | |
|---|---|---|---|---|
| Anthocyanins | Electro-technologies | Winery wastes and by-products (pomace) | Recovery of polyphenols (>20%) at E = 13.3 kV/cm (0–564 kJ/kg) V = 40 kV (0–218 kJ/kg) | [95,99] |
| High pressure | Wine by-products | Recovery of 41% at 600 MPa, 60 min/solvent (50–50% ethanol in water) | [99,109] | |
| High pressure | Wine by-products | Recovery of 22–83% at 200–600 MPa, 30–90 min, solvent (20–80%; 100–0% ethanol in water) | [99,110] | |
| Pulsed electric fields | Blueberry pomace (press cake) |
Increase of Delphinidin, Cyanidin, Petunidin, Peonidin, and Malvidin. 51%, 71% and 95% at 1 kV/cm, 3 kV/cm, and 5 kV/cm, respectively | [107] | |
| Pulsed electric fields | Blueberry by-product | Anthocyanin extraction increased (>30%) with PEF process intensification (1–35 kV/cm; 1–10–41 kJ/kg; 10 Hz, 2–100 pulses, 2 μs | [105,106,111,112] | |
| Pulsed electric fields | Grape by-product (pomace and peel) |
Improved anthocyanin extraction (up to 18.9%) at 1.2, 1.8, and 3.0 kV/cm, 18 kJ/kg, 200–2000 pulses, 100 μs | [106,108] | |
| Pulsed electric fields | Plum by-product | No increase anthocyanins at 37.8–289.8 W, 0.7–25.2 pulses, 10 Hz, 6 μs | [106,108] | |
| Pulsed electric fields | Peach by-product | Improved anthocyanin extraction (up to 11.8-fold) at 0.8 kV/cm, 0.2 kJ/kg; 0.1 Hz 4 μs | [106,113] | |
| Pulsed electric fields | Raspberry by-product | Increase 27.5% at 1 kV/cm, 6 kJ/kg, 20 Hz and 20 μs | [106,114] | |
| Pulsed electric fields | Sour cherry by-product | Improved anthocyanin extraction (up to 54%); 1 kV/cm, 10 kJ/kg, 10 Hz, 20 μs | [106,115] | |
| Pulsed electric fields | Sweet cherry by-product | Improved anthocyanin extraction (up to 38.4%) at 0.5 kV/cm, 10 kJ/kg, 5 Hz, 20 μs | [106,116] | |
| Pulsed electric fields | Winery wastes and by-products (grapes) | Increase of anthocyanins: 3-fold at 3 kV/cm 50 pulses; 1.6 and 2-fold ↑ 5 kV/cm 1 ms | [99,117] | |
| Pulsed electric fields | Winery wastes and by-products (grapes) | Increase of 51–62% at 0.8–5 kV/cm, 1–100 ms, 42–53 kJ/kg | [99,117] | |
| Pulsed electric fields | Winery wastes and by-products (grapes) | Increased anthocyanin content (1.6–1.9 fold more) at 5 kV/cm, 1 ms, 48 kJ/kg | [99,118] | |
| Pulsed electric fields | Winery wastes and by-products (pomace) | Increase of Anthocyanins (2-fold more) at 13.3 kV/cm, 0–564 kJ/kg | [99,101] | |
| Pulsed electric fields + ultrasounds |
Blueberry by-products | Increase of anthoycanin extraction (3 fold more) (PEF: 60% ethanol 1:6 and 20 kV/cm; Ultrasounds: 1:6, 40 °C, 60 min at 125 W) | [119] | |
| Subcritical/critical Fluid Extraction |
Grape skin | Recovery of 85% at 100–130 bar, pH of 2–4, 25–30% ethanol, 25–50 mL/min CO2 flow, and 3–10% extract flow ratio | [99,120] | |
| Ultrasounds | Eggplant by-product | US-assisted extraction (15–45 min) was preferable to conventional solid-liquid extraction due to the lower temperature (25 °C) used and higher delphinidin 3-O-rutinoside content (1.5 fold more). | [82] | |
| Ultrasounds | Jabuticaba by-products | The highest concentration at 1.1 W/cm2, 3 min, 10 KHz | [106,121,122] | |
| Ultrasounds | Pomegranate peel | 116 W sonication power with 80% duty cycle for 6 min for extraction of 22.51 mg cyanidin-3-glucosides/100 g pomegranate peel. | [106,123] | |
| Betalains | Pulsed electric fields | Opuntia stricta peels | Total colorants to ≈80 mg/100 g FW (20 kV, frequency of 0.5 Hz, number of pulses of 50) | [124] |
| Pulsed electric fields | Red pricky pear peels | Increase of 2.4 fold colorants (betanin and isobetanin) at 8–23 kV/cm 50–300 pulses + aqueous extraction | [125] | |
| Ultrasound | Opuntia stricta peels | Total colorants to ≈80 mg/100 g FW (400 W power at 24 kHz frequency for 5–15 min) | [124] | |
| Carotenoids | Electro-technologies | Olive kernel | Recovery of polyphenols (2-fold more) E = 13.3 kV/cm (0–141 kJ/kg), V = 40 kV (0–141 kJ/kg) | [54,89] |
| Microemulsion (Ultrasounds + enzyme) |
Tomato pomace | Recovery of lycopene (>20%). The optimal conditions (tomato pomace: double distilled water 1:6): combined ultrasound (20–37 W, amplitude 90% and sonication temperature of 10 °C for 15 min) and enzyme pretreatments (0.2 mL/kg, 30 min, pH 4, 35 °C), saponin as a natural surfactant, and glycerol as a co-surfactant. | [55,126] | |
| Pulsed Electric Fields | Tomato waste | Recovery of 12–18% of lycopene in acetone and ethyl lactate extracts at 5 kJ/Kg and 5 kV/cm (20 °C). | [55,105,127] | |
| Supercritical Fluid Extraction | Broccoli by-products | Decrease of beta-carotene (>10%) compared with conventional treatment at 400 bars, 5% of ethanol | [79] | |
| Supercritical fluid extraction | F&V waste: -sweet potato, tomato, apricot, pumpkin and peach peels -green, yellow and red peppers |
Total carotenoid recovery values were greater than 90% w/w, with β-carotene being the most successfully extracted compound (TCRs 88–100% w/w), at 350 bar, 15 g/min CO2, 15.5% (v/v) ethanol as co-solvent, 30 min of extraction time) | [128,129] | |
| Ultrasound | Orange processing waste | Optimization of β-carotene extraction with enzyme assisted technology at 20 kHz, 500 W and 25 °C | [129,130] | |
| Ultrasound | Red pricky pear peels | Increase of 2.6 fold colorants (betanin and isobetanin) at 400 W 5–15 min + aqueous extraction | [125] | |
| Ultrasound | Tomato pomace | Lycopene increase (>10%) at 25–40 °C, 0–10 min, 0–100 kPa; 58–94 μm; Hexane %: 25–75 | [55,131,132] | |
| Ultrasounds | Tomato peel | 5-fold lower all-trans lycopene content by ultrasounds (30 min 0 °C) compared to thermal extraction (75 °C, 1–2 h). | [14] | |
| Chlorophylls | Electro-technologies | Olive kernel | Recovery of polyphenols (>30%) E = 13.3 kV/cm (0–141 kJ/kg), V = 40 kV (0–141 kJ/kg) | [54] |
| Supercritical Fluid Extraction | Broccoli by-products | Increase of chlorophylls (>10%) at 400 bars, and 5% of ethanol | [79] |