Table 2 Comparison of different green extraction techniques along with their examples
Summary | Examples | References | |||
|---|---|---|---|---|---|
Bioactive compounds | Source | Solvent/enzyme | Yield | ||
Supercritical fluid extraction (SFE) | |||||
Generally, CO2 is used Conducted under room temperature and at high pressure Environment friendly Time-saving process Recycle and reuse of the supercritical fluid | Lycopene | Tomato waste | Liquid CO2 | 729.98 mg/kg | Kehili et al. (2017) |
Total phenolic content | Orange pomace (dry) | Pure ethanol Ethanol/water (9:1) | 21.2 GAE/g of extract 20.7 GAE/g of extract | Espinosa-Pardo et al. (2017) | |
Polyphenol content | Seed fraction | 7.7 mgGAE/g | Manna et al. (2015) | ||
Skin fraction (Grape pomace) | 11.9 mgGAE/g | ||||
Pulsed electric field | |||||
Less time-consuming Conducted under room temperature or heat and at atmospheric pressure Water, aqueous and non-aqueous solvents along with moderate quantity Reduction in energy cost | Anthocyanin | Grape by-products | Water and ethanol | 14.05 mg Cy-3-glu eq./g dry matter | Corrales et al. (2008) |
Total phenolic Total anthocyanin content | Blueberry press cake | 50% ethanol and 0.5 HCl | +63% +78% | Bobinaitė et al. (2015) Boussetta et al. (2012) | |
Polyphenols | Grape seeds | Ethanol | 9 g/100 g GAE | ||
Microwave-assisted extraction | |||||
Cost-effective technique Water, aqueous and non-aqueous solvents along with moderate quantity or none High yield and short extraction time Operated under room temperature and at atmospheric pressure | Total phenolic | Red grape pomace | Water | 52,645 ppm GAE in dry extract | Drosou et al. (2015) |
Total phenolic content | C. sinensis peels | Acetone in water (20–80%) | 12.09 mgGAE/g DW | Nayak et al. (2015) | |
Total carotenoid yield | Gac peels | Ethyl acetate | 262.3 ± 3.5 mg/100 g DW | Chuyen et al. (2017) | |
Ultrasound-assisted extraction | |||||
Reduction in the time, energy and power usage Conducted under room temperature or heat and at atmospheric pressure Water, aqueous and non-aqueous solvents along with moderate quantity Higher yield Use of renewable plant resources Quick return of investment Safety and security Reduction of unit operations | Carotenoids (all-trans-lycopene, β-carotene) | Tomato pomace | Hexane and ethanol | 7.49 to 14.08 mg/100 g dw | Luengo et al. (2014) |
Total phenolic | Red grape pomace | Water | 50,959 ppm GAE in dry extract | Drosou et al. (2015) | |
Naringin (Flavonoid) | Grapefruits solid waste | Ethanol | 24–36 mg/g dw | Garcia-Castello et al. (2015) | |
Phenols, antioxidant, anthocyanins | Grape seeds | Ethanol | 5.41 mg GAE/100 ml 2.29 mg/ml | Ghafoor et al. (2009) | |
Natural colour | Pomegranate rinds | Water | 20% | Sivakumar et al. (2011) | |
Enzyme-assisted extraction | |||||
High rate of extraction Used water as solvent (Eco-friendly) High cost of enzyme for large volume of samples Unsuitable for heat-labile compounds | Carotenoids | Pumpkin | Pectinex UltraSP® | 2 mg/100 g | Ghosh and Biswas (2015) |
Anthocyanins | Crocus sativus | Pectinex® | 6.7 mg/g | Lotfi et al. (2015) | |
Carotenoid | Capsicum annuum | Viscozyme L®, cellulose and pectinase | 41.72–279.83 mg/100 g | Nath et al. (2016) | |