Table 3.

Overview of extraction processes for winery waste.

Winery Waste	Conditions and Technique of Extraction	Compounds	Remarks	References
Red grape skins	SLE, Central Composite Design using ethanol (38.06–96.93% ethanol) acidified with citric acid (0.01 to 2.64%), at 13.06–71.9 °C for 11.36 to 78.6 min	Total anthocyanins, total polyphenols, and antioxidant activity	The optimized parameters were 0.85% citric acid concentration, 85% ethanol concentration, temperature 57.39 °C, extraction time 52.14 min. 25 mg cyanidin 3 glucoside/g 37.41 mg gallic acid/g 17.2 mM Trolox/g	[133]
Grape pomace, skin and seed	SLE, 70% ethanol at room temperature, 20 min at 3500 rpm	Total polyphenols	650 ± 32µg gallic acid/g 550 ± 23 µg gallic acid/g 480 ± 34 µg gallic acid/g	[134]
Grape pomace	PEF, 1.2 kV/cm, 18 kJ/kg	Polyphenols	Depending on the temperature utilized, higher extraction yields	[135]
Grape pomace	PEF, power supply 40 kV—10 kA, frequency 0.5 Hz, 0–564 kJ/kg of energy input	Anthocyanins	Compared to UAE, the anthocyanins are 22% greater	[131]
Vine shoots	PEF, 13.3 kV/cm, 0–1500 pulses, 50 °C, 50–762 kJ/kg/3 h diffusion	Polyphenols	Total polyphenols may have increased up to twofold above untreated samples. Resveratrol (0.032 mg/g), kaempferol (0.156 mg/g), and epicatechin (1.747 mg/g)	[136]
Pomace (seeds, stalks, and skin)	UAE, time of 2.5, 5, and 10 min, pulse treatment 5 s on/5 s off, temperature 25, 40 and 55 °C, ultrasound amplitude 20, 30 and 40%, water, 5 g/L	Anthocyanins	25% increase in total anthocyanins Optimum conditions were temperature of 55 °C, ultrasound amplitude of 40%, 6 min of treatment	[137]
Grape pomace	UAE, temperature of 17 ± 3 °C, liquid-solid ratio of 5:1 mL/g, water as solvent, power of 50–150 W; time of 5–25 min, frequency of 40–120 kHz	Polyphenols	Optimum conditions were power of 150 w, time of 25 min, frequency of 40 kHz 12% to 38% of phenolic compounds	[138]
Grape pomace	UAE, 5 g sample/100 mL solvent, power 200 W, 40:1 (solvent: solid), 1:1 (water: ethanol), 45 °C, 10 min extraction, and 30 min stirring	Polyphenols	Ultrasound as an independent technique reduced polyphenol yields, but when combined with shaking extractions, yields of 2079.33 mg/100 g were obtained.	[139]
Vine shoots	UAE, 24 kHz, 400 W, 50 °C, 3 h diffusion (1010–3428 kJ/kg)	Polyphenols	An increase in total polyphenol yields up to 45%. Epicatechin (0.671 mg/g), kaempferol (0.097 mg/g), and resveratrol (0.024 mg/g)	[136]
Grape skins	MAE, 100–540 W, 3–10 min, 0–50, solvent (0–50% ethanol in water)	Polyphenols	The best polyphenol extraction was achieved using 540 W for 3 min and 50% ethanol.	[140]
Grape skins	MAE, 2458 MHz, 1000 W/L, (8–92%) ethanol, 30 min	Total polyphenols	104 mg gallic acid/g	[141]
Grape skins	MAE, power of 100–500 W, solvent (50–80% methanol in water) time of 5 and 20 min, temperature of 50 and 100 °C	Anthocyanins	Compared to conventional extraction, the optimal extraction conditions (500 W, 100 °C, and 40% methanol in water extraction solvent) resulted in a 5 h to 5 min reduction in extraction time.	[142]
Grape pomace	MAE, power of 1000 W, time of 10 min, distilled water solution acidified with 2% (m/v) citric acid in a ratio of 1:3	Total polyphenols, total anthocyanins, antioxidant activity	6.68 ± 0.05 mg gallic acid/g 1.32 ± 0.03 mg malvidin-3,5-diglycoside/g 23.84 ± 0.57 μmol Trolox/g	[143]
Grape seeds	SFE, Box-Behnken design, 80–120 bar pressure, 4–6 kg/h CO2 flow rate, 10–20% (w/w) co-solvent percentage	Polyphenols Proanthocyanidin fractionation (FI and FII)	Optimized conditions were: pressure 80 bar, temperature 40 °C, flow rate 6 kg/h and 20% co-solvent. The total phenolic content of 7132 mg gallic acid/100 g. FI (>1000 mg catechin/100 g) and FII (>800 mg catechin/100 g)	[144]
Grape pomace, skin and seed	SFE, 70% ethanol, a flow rate of 2 mL/min, 60 °C, and 250 bar	Total polyphenols	570 ± 10 µg gallic acid/g 603 ± 14 µg gallic acid/g 336 ± 28 µg gallic acid/g	[134]
Grape pomace	PLE, 60–140 °C, ethanol/water (30:70; 70:30, v/v)	Total polyphenols	When a mixture of ethanol/water at a ratio of 70% was utilized at 140 °C, the yield of polyphenol was significantly increased for both wet (16.2 g gallic acid/100 g) and dry (7.28 g gallic acid/100 g) grape pomace extracts.	[136]
Grape pomace	PLE, ethanol and water mixtures (acidified or not) (50% w/w), pure ethanol and acidified water at 40–100 °C	Total anthocyanins, total phenolic compounds	The best PLE conditions for bioactives extraction (50% ethanol-water pH 2.0, 40 °C) resulted in 10.21 mg of malvidin-3-O-glucoside/g and 35.30 mg gallic acid/g	[145]