Table 3.

Emerging technologies used for bioactive compound extraction from tomato processing by-products, type of biomass, target functional compounds recovered, experimental conditions, and main research findings.

Technology	Material	Target	Experimental Condition	Optimal Condition	Main Research Findings	References
HPH 1	Tomato peels	•Lycopene •Polyphenols •Proteins	•Number of passes: 1–10 •P: 100 MPa •Solvent: Water	•P: 100 MPa •Number of passes: 10	•Proteins (+70.5%) •Polyphenols (+32.2%) •Extracts antioxidant activity (+23.3%) •Lycopene recovered (up to 56.1% of that initially present in the peels)	[15]
PEF 2	Industrial tomato waste	•Lycopene	•E: 1–5 kV/cm •WT: 5–10 kJ/kg •Solvent: Acetone, Ethyl lactate	•E: 5 kV/cm •WT: 5 kJ/kg • Acetone	•Extraction rate (+27–37%) •Lycopene recovery yield (+12–18%) •Antioxidant power (+18.0–18.2%)	[11]
	Industrial tomato peels	•Lycopene •Proteins •Phenolic compounds	•E: 1.0–5.0 kV/cm •WT: 5.7–22.8 kJ/kg •n: 0–500 pulses	•PEF: 2 kV/cm for 700 pulses •PEF: 5 kV/cm for 1.5 µs •PEF: 1.0 kV/cm for 7.5 µs	•Carotenoid extraction yield (+56.4%) •Concentration of total phenolic compounds (+56.16 mg gallic acid/kg) •Protein recovery (1.45 mg/g tomato waste) •Lycopene recovery (0.143 mg/g tomato waste)	[83]
	Tomato peels	•Lycopene	•E: 0.5–5 kV/cm •WT: 0.5–20 kJ/kg •Solvent: Acetone •T: 20–50 °C	•E: 5 kV/cm •WT: 5 kJ/kg •Solvent: Acetone •T: 50 °C	•Total carotenoids (+47%) • Antioxidant power (+68%)	[84]
	Tomato pulp and peels	•Lycopene	•E: 3–7 kV/cm •WT: 0.54 to 13.50 kJ/kg •n: 5 to 100 pulses of 3 µs •Solvent: Hexane: Ethanol: Acetone	•E: 5 kV/cm •30 pulses of 3 µs •Solvent: Hexane: Ethanol: Acetone (50:25:25)	•Total carotenoids (+39%) •Reduced hexane consumption (from 45 to 30%) without changing the carotenoid extraction yield	[85]
SB 3—PEF	Tomato peels	•Lycopene	•E: 0.25–0.75 kV/cm •WT: 1 kJ/kg •Time: 1 min •T: 50–70 °C •Solvent: Acetone	•E: 0.5 kV/cm •WT: 1 kJ/kg •T: SB at 60 °C	•Carotenoid content 0.379 mg/g fw	[17]
UAE 4	Tomato pomace	•Pectin	•Frequency: 37 kHz •Time: 15, 30, 45, 60, and 90 min •T: 60 °C and 80 °C •Solvent: Ammonium oxalate/oxalic acid	•Frequency: 37 kHz •Sonication time: 90 min, •T: 80 °C	•Pectin yield 31.2% by CE (1440 min) and 36% by UAE (15 min)	[86]
	Industrial tomato waste	•Lycopene	CSE •T: 20, 40, and 60 °C •Time: 10, 20, 30 and 40 min •Solvent: Hexane: Acetone: Ethanol (2:1:1) UAE • Power: 50, 65 and 90 W •Time: 1, 2, 5, 10, 15, 20 and 30 min	•Solvent/solid ratio: 50:1 (v/w) •T: 60 °C •Time: 40 min •Solvent/solid ratio: 35:1 (v/w) •Power: 90 W •Time: 30 min	•To recover about 80% of lycopene UAE extraction time was 10 min, CSE extraction time at least 20 min •UAE of lycopene requires lower time, temperature, and amount of solvent than CSE	[87]
	Tomato Pomace	•Lycopene	•T: 40, 55, 70 °C •Solvent mixture: 30, 65, 100 v/v •Solvent/solid ratio: 50, 75, 100 •Extraction time: 20, 35, 50 min •Frequency: 40 kHz •Power: 100 W	•T: 63.4 °C •Proportion of ethyl acetate in solvent mixture: 30% v/v •Solvent/solid ratio: 100 mL/20 g •Time: 20 min	•UAE lycopene recovered 1.33 mg/g dw (+9.4%) higher than that of CSE (1.209 mg/g dw)	[88]
	Tomato Pomace	•Lycopene	•T: 40, 55, 70 °C •Time: 20, 35, 50 min • Amplitude: 20,30,48, 65% • Time: 30, 50, 70 s •V: 32, 45, 60, 90 mL	•T: 65 °C •Time: 20 min • Solvent/solid ratio: 72 mL/g •Amplitude: 65% •Time: 33 s •V: 90 mL	•UAE lycopene recovered 1.53 mg/g	[89]
HPPE 5 + UAE + CSE 6 (Soxhlet)	Tomato pomace	•Pectin •Polyphenols •Fatty acid	HHPE •T: 80 °C •P: 300 MPa •Time: 10, 20, 30, and 45 min •Solvent: Nitric acid CSE • Solvent: Mixture chloroform and methanol (50:50, v/v) at solvent boiling temperature		•Simultaneous extraction of different compounds, (decreased yield of individual compounds) •HHPE, UAE, and CSE used in combination allow decreasing the extraction time	[90]
UAE MAE 7 OHAE 8 UAME 9 UAOHE 10	Tomato peels	•Pectin	•Sonication power: 450, 600 and 750 W •Time: 2, 4, 6, 8, 10, 12, 14, and 16 min •Microwave power: 540 W applied for 4 min	•US (450 W, 8 min) •MW (540 W)	•OHAE pectin extraction yield increased 9.30% •MAE pectin extraction yield increase of 25.42% •UAME can be used as an efficient pectin extraction technique from tomato by-products	[91]
UAE	Tomato seeds	•Oil	•Power: 550 W, 37 kHz •Time: 30, 60, and 90 min • T: 70 °C •Solvent: Hexane •Water immersion: 25–40 °C	•Power: 550 W, 37 kHz •Time: 90 min •T: 40 °C	•UAE oil extraction yield increases up to 28.11% (15.91% more than that of untreated samples)	[92]
SFE 11 CO2	Industrial tomato peels by-product	•β-carotene •Lycopene	•T: 50–80 °C •P: 30–50 MPa •Flow rates: 3–6 g CO2/min Time: 105 min	•P: 40 MPa •T: 80 °C •Flow rates: 4 g CO2/min •Time: 105 min	•Extraction yield of 28.38–58.8% for β-carotene, and 32.02–60.85% for lycopene •Lycopene recovered 0.728 mg/g dw	[93]
	Tomato peels	•Lycopene	•T: 70, 74, 80 °C • P: 20, 40 MPa •Time: 155 min	•Time: 155 min •P: 40 MPa •T: 74 °C	•Lycopene recovered 5.28 mg/g dw	[94]
	Tomato Pomace	•Oil	•T: 40, 50, 60, 80 °C •Tim: 2–8 h •P: 210–280 bar	•P: 280 bar •T: 40 °C •Tim: 2.5 h	•Yield of tomato seed oil was 0.25 g/g (solubility 14 mg/dm3)	[95]
	Tomato pomace	•Lycopene	•P: 30–50 MPa •T: 40–80 °C •Peel/seed ratio: 30/70 and 70/30	For peel/seed ratio: 70/30 •P: 50 MPa •T: 80 °C For peel/seed ratio: 30/70 • P: 50 MPa •T: 60 °C	•Maximum lycopene recovered: 0.358 mg of extract/kg of raw material (measured) and 0.320 mg of extract/kg of raw material (predicted) •Lycopene recovery is affected by peel/seed proportion, pressure, and temperature.	[96]
MAE	Tomato peels Tomato peels	•Phenolic compounds •Lycopene •Beta-carotene	•T: 25, 55, and 90 °C •Time: 5 and 10 min • Solvent: Methanol and HCl •Time: 30, 60, and 90 s •Power: 180, 300, and 450 W	•1% HCl to 50 or 70% methanol for phenolic acids T: 90 °C •MAE condition is 300 W for 60 s	•The average total phenolic content 0.053 g/mg •Extraction time does not affect TF, TP, and phenolic compound recovery, and temperature and solvent have a significant effect on polyphenols yield •Lycopene recovered 0.0574 mg/g dw •Beta-carotene recovered 0.0483 mg/g dw	[97]
UAE MAE	Tomato seeds	•Oil	•Pre-processing with hot water 40 °C for 24 h and UAE 550 W, 37 kHz •T: 25–40 °C •Time: 30 and 60 min •Extraction for MAE: powers of 250 and 600 W Time: 90 min Solvent: Hexane	•Ultrasound: 60 min •Microwave: 600 Watts •T: 40 °C •Pre-processing with hot water 40 °C for 24 h	•Extraction efficiency up to +23.03% •Extraction time decrease of 1.5 min with MAE and 30 min with UAE	[98]

¹. HPH, high-pressure homogenization ². PEF, pulsed electric field ³. SB, steam blanching ⁴. UAE, ultrasound-assisted extraction ⁵. HPPE, high pressure processing extraction ⁶. CSE, conventional solvent extraction ⁷. MAE, microwave-assisted extraction ⁸. OHAE, ohmic heating-assisted extraction ⁹. UAE-MAE, ultrasound-assisted extraction-microwave-assisted extraction ¹⁰. UAOHE, ultrasound-assisted ohmic heating extraction ¹¹. SFE, supercritical fluid extraction.