Table 1.

Research papers and reviews focusing on green and sustainable separation of natural products from agro-industrial waste published from January 2006 to December 2017 (ISIS Web of Knowledge)

Year	Crop	Waste stream	Target compounds	Geographical location	Green or sustainable separation approach	References
2017	Olives	Olive kernels	Phenolic compounds and oil	France and Spain	Aqueous liquid solid extraction (LSE), mechanical expression (ME), supercritical CO2 (SC-CO2) and gas-assisted mechanical expression (GAME)	Gas-assisted mechanical expression (GAME) for the selective recovery of lipophilic and hydrophilic compounds from olive kernel [145]
2017	Figs	Leaves	Bioactive compounds	China	Deep eutectic solvent with microwave and ultrasound extraction Time: 10 min (MW) and 60 min (US) Temperature: 40–80 °C Power: 250 W (MW) and 700 W (US)	Enhanced and green extraction polyphenols and furanocoumarins from Fig (Ficus carica L.) leaves using deep eutectic solvents [136]
2017	Polygonum multiflorum	Herbal raw materials	Stilbene glycoside and anthraquinones	China	Ionic liquids with ultrasonic extractor Time: 1–120 min Power: 40–120 W	Sequential extraction and separation using ionic liquids for stilbene glycoside and anthraquinones in Polygonum multiflorum [131]
2017	Several sources	Not defined	Mostly bioactive compounds	Spain	Review Critical overview about the greenness of water as extraction solvent	Water as green extraction solvent: Principles and reasons for its use [146]
2017	Pomelo	Flavedo	Essential oil	China	Microwave irradiation Power: 240–700 W Time: 24 min	A process to preserve valuable compounds and acquire essential oils from pomelo flavedo using a microwave irradiation treatment [52]
2017	Selaginella doederleinii	Not defined	Biflavonoids	China	Ionic liquids and microwave-assisted extraction Power: 300–700 W Time: 30–50 min Temperature: 40–60 °C	Optimization of ionic liquid-assisted extraction of biflavonoids from Selaginella doederleinii and evaluation of its antioxidant and antitumor activity [132]
2017	Pogostemon cablin	Leaves	Essential oils	Indonesia	Microwave-assisted hydrodistillation (MAHD) and solvent-free microwave extraction (SFME) Power: 600 W (MAHD) and 264 W (SFME) Time: 66 min (MAHD) and 45 min (SFME); solvent: water	Comparison of conventional and microwave-assisted distillation of essential oil from Pogostemon cablin leaves: analysis and modeling of heat and mass transfer [147]
2017	Juglans regia L.	Fresh male flowers and unripe walnut seeds	Phenolic content and water-soluble polyphenols	Italy	Microwave-assisted extraction Frequency: 2.45 GHz Max. power: 500 W Solvent: ethanol/water Temperature: 60–100 °C Time: 6–30 min	Process intensification by experimental design application to microwave-assisted extraction of phenolic compounds from Juglans regia L. [148]
2017	Walnuts	Walnut de-pellicle	Flavonoids	China	Macroporous resins Pretreated with 5% HCl and 5% NaOH solutions	Recovery of flavonoids from walnuts de-pellicle wastewater with macroporous resins and evaluation of antioxidant activities in vitro [149]
2017	Ginseng	Roots	Bioactive compounds	Brazil	Sequential extraction system using ethanol followed by water Temperature: 333 K Time: 5–240 min	Techno-economic evaluation of obtaining Brazilian ginseng extracts in potential production scenarios [150]
2017	Food ingredients and natural products	Not defined	Nutraceutics, cosmetic, pharmaceutical, and bioenergy applications	France	Review current knowledge on ultrasound-assisted extraction	Ultrasound-assisted extraction of food and natural products. Mechanisms, techniques, combinations, protocols and applications. A review [151]
2017	Coffee	Coffee chaff	Antioxidants	Portugal	Solid–liquid extraction and multi-frequency multimode modulated (MMM) Frequency: 19.8 kHz Power: 250 and 500 W Time: 60–600 s	Multi-frequency multimode modulated technology as a clean, fast, and sustainable process to recover antioxidants from a coffee by-product [152]
2017	Apples	Wild apple fruit dust	Bioactive compounds, polyphenolic antioxidants	Serbia	Microwave-assisted extraction Time: 15–35 min Ethanol conc.: 40–80% Irradiation power: 400–800 W	Microwave-assisted extraction of wild apple fruit dust production of polyphenol-rich extracts from filter tea factory by-products [153]
2017	Wood	Wood biomass	Lignin oligomers	China	Microwave-assisted treatment with deep eutectic solvent Solvent: choline chloride and oxalic acid dehydrate Temperature: 80 °C Power: 800 W Time: 3 min	Efficient cleavage of lignin-carbohydrate complexes and ultrafast extraction of lignin oligomers from wood biomass by microwave-assisted treatment with deep eutectic solvent [137]
2017	Wood	Oak wood from cooperage by-products	Furanic compounds, cis- and trans- B-methyl-y-octalactones, terpenes and norisoprenoids, benzenic compounds	Spain	Pressurized liquid extraction Solvent: water, ethanol/water (80:20) and ethyl lactate Temperature: 60–120 °C Pressure: 10.34 MPa Flush volume: 60% Purging time: 80 s	Extraction of natural flavorings with antioxidant capacity from cooperage by-products by green extraction procedure with subcritical fluids [154]
2017	P. armeniaca, P. persica, P. domestica, Triticum aesativum	Fruit and vegetables seeds and peels	Phenolic compounds	Pakistan	Ultrasonic water bath Solvent: 65% (v/v) ethanol (methanol and acetone) Extraction time: 30 min Temperature: 50 °C	Extraction and quantification of phenolic compounds from Prunus armeniaca seed and their role in biotransformation of xenobiotic compounds [71]
2017	Lignocellulose materials	Lignocellulosic biomass such as crops or forestry residues	High value-added bio-based products (e.g., bioethanol, biogas, acetic acid, acetic acid, or activated carbon)	Mexico and Pakistan	Review Focus on transformation based on syngas platform (thermochemical platform) and sugar platform (biochemical platform)	Lignocellulose: a sustainable material to produce value-added products with zero-waste approach [155]
2017	Olives	Olive by-product (paté)	Fatty acids and phenolic compounds	Spain and Italy	Soxhlet extraction (percolation with petroleum ether, under reflux)	Macro and micro functional components of a spreadable olive by-product (pate) generated by new concept of two-phase decanter [156]
2017	Tucumã palm fruit	Tucumã’s endocarp	Cellulose	Brazil and USA	Alkaline extraction (135 °C, autoclave, 2 bar, 2 min, 20% of aqueous NaOH, 1:30 straw to liquor (g/ml), 30 min)	New approach for extraction of cellulose from tucuma’s endocarp and its structural characterization [115]
2017	Grapes	Seeds	Resveratrol	China	Subcritical water extraction Pressure: 0.5–1.5 MPa Time: 20–30 min Temperature: 130–170 °C	Optimization of subcritical water extraction of resveratrol from grape seeds by response surface methodology [100]
2017	Mango, rambutan, santol	Peels	Antioxidant activity	Thailand	Solid–liquid extraction Ethanol (95%)	Study effect of natural extracts on the antioxidant activity in pork balls [157]
2017	Tomatoes	Pericarps without seeds	Nutrient-rich antioxidant ingredients	Portugal, Spain, Ireland	Microwave extraction (600 rpm, 200 W) Time: 0–20 min Temperature: 60–180 °C Ethanol conc.: 0–100% Solid/liquid ratio: 5–45 g/l	Valorization of tomato wastes for development of nutrient-rich antioxidant ingredients: a sustainable approach towards the needs of today’s society [158]
2017	Citrus latifolia, Rubus sp., Origanum vulgare and Heterotheca inuloides	Peel and broken down vegetable material	Fatty acids and antioxidants compounds	Mexico, Belgium	SC-CO2 Extraction time: 1 h Flow: 25 g/min Pressure: 10–40 MPa Temperature: 35–60 °C Co-sol.: 0–8 g/min Percent flow: 0–32%	Thermodynamics and statistical correlation between supercritical CO2 fluid extraction and bioactivity profile of locally available Mexican plant extracts [159]
2017	Pomegranates	Peels	Carotenoids	Greece	Ultrasound-assisted extraction (139 W, 20 kHz); solvents: vegetable oils Extraction time: 10–60 min Temperature: 20–60 °C	Green ultrasound-assisted extraction of carotenoids from pomegranate wastes using vegetable oils [72]
2017	Pomegranates	Both edible and non-edible parts	Polyphenols	Greece	Semi-automatic extractor Solvents: H2O, β-CD, HP-β-CD Extraction time: 363 min Temperature: 25 °C	Green extraction of polyphenols from whole pomegranate fruit using cyclodextrins [121]
2016	Quince	Leaves	Natural dyes and bioactive compounds	Romania	Aqueous extraction Extraction time: 60–240 min Temperature: 4–100 °C	Dyeing and antibacterial properties of aqueous extracts from quince (Cydonia oblonga) leaves [160]
2016	Corn	Steep liquor	Vanillic acid, p-coumaric acid, ferulic acid, sinapic acid and quercetin	Spain, Portugal, and Italy	Liquid–liquid extraction Solvents: chloroform (56 °C, 60 min) Ethyl acetate (25 °C, 45 min)	A multifunctional extract from corn steep liquor: antioxidant and surfactant activities [161]
2016	Palm	Oil palm empty fruit bunches	Cellulose with polypropylene as biocomposite material	Malaysia, Pakistan	Ultrasonic treatment (40 kHz) solvent: hydrogen peroxide Extraction time: 1–3 h Room temperature	Autoclave and ultra-sonication treatments of oil palm empty fruit bunch fibers for cellulose extraction and its polypropylene composite properties [73]
2016	Tomatoes	Seeds and peels	Carotenoids/proteins	Tunisia and Germany	Supercritical CO2 extraction 80 °C, 400 bar, 4 g CO2/min for 2 h	Biorefinery cascade processing for creating added value on tomato industrial by-products from Tunisia [82]
2016	Black tea	Black tea processing waste	Antioxidant and antimicrobial phenolic compounds	Turkey and USA	Solvent extraction Solvents: H2O, ethanol Extraction time: 2 h Temperature: 70 °C	Black tea processing waste as a source of antioxidant and antimicrobial phenolic compounds [46]
2016	Rapeseed	Rapeseed oil cakes	Protein- and lignin-rich fractions	France	Ultrafine miffing and electrostatic separation Solvents: NaOH, diethylether, hexane Extraction time: 5 h Temperature: 60 °C	Chemical- and solvent-free mechanophysical fractionation of biomass induced by tribo-electrostatic charging: separation of proteins and lignin [139]
2016	Sunflower	Seeds	Sunflower protein-based ingredients	USA	Review Green pigmentation associated with the interaction of sunflower protein and oxidized chlorogenic acid (CGA) by outlining the sunflower oil and protein meal market, CGA reactions contributing to greening, methods for CGA extraction, and the effect of processing on sunflower protein quality and the greening reaction	Chlorogenic acid oxidation and its reaction with sunflower proteins to form green-colored complexes [162]
2016	Passion fruit	Peels	Pectin	Malaysia	Acidic and enzymatic extraction Citric solution, celluclast Extraction time: 30–120 min Temperature: 35–85 °C	Comparison of acidic and enzymatic pectin extraction from passion fruit peels and its gel properties [107]
2016	Red grape	Pomace	Polyphenols and anthocyanin pigments	Greece	Ultrasound-assisted extraction (140 W, 37 kHz) Solvent: aqueous glycerol Extraction time: 60 min Temperature: 45 °C	Development of a green process for the preparation of antioxidant and pigment-enriched extracts from winery solid wastes using response surface methodology and kinetics [74]
2016	Orange and lemon	Fresh and waste peel	Pectin and d-limonene	Portugal and Italy	Microwave Solvent: water Extraction time: 1 h Temperature: 80 °C	Eco-friendly extraction of pectin and essential oils from orange and lemon peels [53]
2016	Coffee	Spent coffee grounds	Oil	China	Ultrasonication extraction Solvent: hexane Extraction time: 15–75 min	Effect of oil extraction on properties of spent coffee grounds-plastic composites [98]
2016	Tomato	Waste of tomato paste plants	Lycopene	Iran and Canada	Microemulsion technique (MET) Solvents: water, saponin: glycerol, surfactant: lycopene Extraction time: 30 min Temperature: 25 °C	Enhanced lycopene extraction from tomato industrial waste using microemulsion technique: optimization of enzymatic and ultrasound pre-treatments [163]
2016	Red capsicum (Capsicum annuum)	Processing residue	Carotenoids	India	Enzymatic liquefaction Pectinase, viscozyme L, cellulose extraction Time: 1 h Temperature: 60 °C	Enzyme-assisted extraction of carotenoid-rich extract from red capsicum (Capsicum annuum) [108]
2016	Rice	Husk	Cellulose	India	Eco-friendly method montmorillonite, LiOH, H2O2 Extraction time: 6 h Temperature: 80 °C	Extraction of cellulose from agricultural waste using montmorillonite K-10/LiOH and its conversion to renewable energy: biofuel by using Myrothecium gramineum [122]
2016	Tea (yarrow and rose hip)	By-products from filter-tea factory	Chlorophylls and carotenoids	Serbia	Supercritical fluid extraction Extraction time: 5 h Temperature: 40 and 60 °C Pressure: 100–300 bar CO2 flow rate: 0.194 hk/h	Extraction of minor compounds (chlorophylls and carotenoids) from yarrow-rose hip mixtures by traditional versus green technique [83]
2016	Corn, sugarcane, sorghum, pearl millet, green gram, groundnut sesame	Bagasse, stover, stalk and shell	Para-coumaric acid (pCA)	India and USA	Alkaline hydrolysis pH 3, alkali conc.: 0.5–4 M Hydrolysis duration: 4–24 h Sugaring-out for separation of pCA from hydrolysate	Extraction of p-coumaric acid from agricultural residues and separation using ‘sugaring out’ [116]
2016	Winery	Grape wastes and by-products	Antioxidant compounds and polyphenols	Denmark, China, France and Brazil	Review Conventional (solid liquid extraction, heating, grinding, etc.) and non-conventional (pulsed electric fields, high voltage electrical discharges, pulsed ohmic heating, ultrasounds, microwave-assisted extractions, sub- and supercritical fluid extractions, as well as pressurized liquid extraction) methods	Green alternative methods for the extraction of antioxidant bioactive compounds from winery wastes and by-products: a review [164]
2016	1st to 3rd generation biodiesel feedstocks	Mostly microalgae	Biodiesel	Malaysia and Japan	Review Integration of enzymatic reactors with supercritical fluid technology	Green biodiesel production: a review on feedstock, catalyst, monolithic reactor, and supercritical fluid technology [84]
2016	Jatropha curcas, oil palm	Seeds, empty fruit bunch	Bio-oil	Malaysia	Microwave extraction Solvent: water Extraction time: 60–140 min Power: 200–700 W	Green bio-oil extraction for oil crops [54]
2016	Green tea	Green tea residue	Protein	The Netherlands	Alkaline protein extraction Solvent: NaOH Extraction time: 2 h Temperature: 95 °C	Improving yield and composition of protein concentrates from green tea residue in an agri-food supply chain: effect of pre-treatment [117]
2016	Eucalyptus wood	Eucalyptus chips	Hemicelluloses	Uruguay	Green liquor extraction Solvents: water and green liquor (Na2CO3, Na2S, and NaOH) extraction time: 30–150 min temperature: 100–160 °C	Integrated forest biorefineries: green liquor extraction in eucalyptus wood prior to kraft pulping [123]
2016	Watermelons	Juice	Lycopene	Brazil	Microfiltration, diafiltration, reverse osmosis α-Al2O3 membranes T1-70 (35 °C) Polyamide composite membranes (35 °C, 60 bar)	Integrated membrane separation processes aiming to concentrate and purify lycopene from watermelon juice [140]
2016	Larch wood	Sapwood, heartwood, bark and branches	Phenolic compounds	Slovenia	Pressurized hot water Extraction time: 30 min Temperature: 100 °C	Isolation of phenolic compounds from larch wood waste using pressurized hot water: extraction, analysis and economic evaluation [165]
2016	Tomatoes	Pomace	Lycopene	Iran	Microemulsion technique H2O and surfactants Extraction time: 30 min Temperature: 35 °C	Microemulsion-based lycopene extraction: effect of surfactants, co-surfactants, and pretreatments [166]
2016	Melons	Rind	Carbohydrates, phenolic compounds, and fatty acids	Spain	Solvent extraction Solvent: cyclohexane, ethanol Extraction time: 2 h Microwave radiation: 190 °C, 20 min, 200 W	Microwave heating for the catalytic conversion of melon rind waste into biofuel precursors [167]
2016	Tomatoes, fungus Blakeslea trispora	Processing waste	Lycopene	Greece	Review Emphasis on final product safety and ecofriendly processing (solvent extraction, SFE, MAE, high-pressure processing, ultrasound, electrical methods)	Natural origin lycopene and its “green” downstream processing [168]
2016	Oranges	Peel	Pectin	Italy	Conventional hydrodistillation, MAE, US Solvents: water Extraction time: 5–155 min Temperature: 90–333 °C	Novel configurations for a citrus waste based biorefinery: from solventless to simultaneous ultrasound and microwave-assisted extraction [55]
2016	Lemons, olives, onion, red grape, coffee, and wheat	Peel, leaves, solid wastes, pomace, spent filter and bran	Polyphenolic compounds	Greece	Ultrasound extraction (140 W, 37 kHz) eutectic mixtures Extraction time: 90 min Temperature: 80 °C	Novel glycerol-based natural eutectic mixtures and their efficiency in the ultrasound-assisted extraction of antioxidant polyphenols from agri-food waste biomass [75]
2016	Potatoes	Peels	Polyphenolic antioxidants	Greece	Ultrasound extraction (140 W, 37 kHz) Solvents: ethanol and glycerol Extraction time: 90 min Extraction temperature: 50–80 °C	Optimization of a green ultrasound-assisted extraction process for potato peel (Solanum tuberosum) polyphenols using bio-solvents and response surface methodology [76]
2016	Grapes	Seeds	Grape seed oil	Croatia	Supercritical CO2 Extraction time: 90 min Temperature: 35–64 °C Pressure: 158–441 bar CO2 flow rate: 1.94 kg/h	Optimization of supercritical CO2 extraction of grape seed oil using response surface methodology [85]
2016	Crocus sativus	Petals (underutilized bulk agro-waste)	Phenolic compounds	Iran	Subcritical water extraction Extraction time: 20–60 min Temperature: 120–160 °C	Optimization of the subcritical water extraction of phenolic antioxidants from Crocus sativus petals of saffron industry residues: Box–Behnken design and principal component analysis [101]
2016	Bananas	Peels	Antioxidants	Malaysia and Turkey	Solvent extraction Solvents: acetone, ethanol, hexane, methanol, H2O Extraction time: 1–5 h	Optimization of extraction parameters on the antioxidant properties of banana waste [47]
2016	Pea vine	Pea vine waste	Potential platform molecules (5-hydroxy furfural; ethanoic acid); sugars (levoglucosenone, rhamnose, xylose, fructose); biopolymer with pectinaceous and starch-like characteristics	United Kingdom	Pseudo-subcritical water extraction Temperature: 125–175 °C Pressure: 20–60 bar Flow rate: 1–5 ml/min	Potential utilization of unavoidable food supply chain wastes-valorization of pea vine wastes [6]
2016	Keratin-containing products stored in large waste deposits	Processing waste	Keratin	Romania	Review Keratins solubilization (protected and unprotected methods) followed by dehydro-thermal, physical-type bonding or chemical treatments	Practical ways of extracting keratin from keratinous wastes and by-products: a review [169]
2016	Taxus baccata L.	Case study based on European yew	10-deacetylbaccatin III (10-DAB)	Germany	Review Theoretical approach in thermodynamics and process modelling as an alternative process design	Process design for integration of extraction, purification and formulation with alternative solvent concepts [170]
2016	Olives	Olive mill waste water	Biophenols (hydroxytyrosol and tyrosol)	Italy	Liquid–liquid extraction Solvents: n-hexane, EtOAc	Quick assessment of the economic value of olive mill waste water [171]
2016	Olives	Olive mill waste water	Tyrosol	Spain, United Kingdom and Spain	Hydrophobic ionic liquids Solvents: ILs Extraction time: 2 h Temperature: 303–323 K	Recovery of tyrosol from aqueous streams using hydrophobic ionic liquids: a first step towards developing sustainable processes for olive mill wastewater (OMW) management [133]
2016	Cupuassu	Seeds	Cupuassu butter (phenolic content/tocopherols/fatty acids)	Brazil	Supercritical CO2 extraction Temperature: 50 and 70 °C Pressures: 20–40 MPa	Supercritical CO2 extraction of cupuassu butter from defatted seed residue: experimental data, mathematical modeling and cost of manufacturing [86]
2016	Coffee	Spent coffee grounds	Oil fraction	Portugal, Brazil, Portugal	Supercritical CO2 Extraction time: 1 h Temperature: 55 °C Pressure: 250 bar Flow rate: 15 kg/h	The green generation of sunscreens: using coffee industrial sub-products [87]
2016	Ginger	Not defined	Essential oil, phenolics, fibers and phenolic acids	France	Microwave hydrodiffusion and gravity processing (MHG) and UAE Solvents: water Extraction time: 83 and 90 min Temperature: up to 100 and 50 °C	Towards a “dry” bio-refinery without solvents or added water using microwaves and ultrasound for total valorization of fruit and vegetable by-products [56]
2016	Passion fruit	Passion fruit seeds and passion fruit seed cake (the residue from the seed oil production by cold pressing)	Oil and extract with promising antioxidant and antimicrobial activities	Brazil and USA	SFE, LPE, MAC, UE Solvents: sCO2, hexane, ethyl acetate, ethanol, H2O Extraction time: 45 min–7 days temperature: room temp.− 50 °C	Valorization of passion fruit (Passiflora edulis sp.) by-products: sustainable recovery and biological activities [88]
2016	Wood	Broken pallets, crates, and waste timber from building and demolition works	Renewable energy source	Romania	Review Overview of the technical and economic opportunity of using wood waste as a renewable energy source	Wood waste as a renewable source of energy [172]
2015	Plants of spontaneous flora, cultivated plant, and wastes resulted in agricultural and food industry	General bio-derived materials	Polyphenols	Romania	Review Microwave-assisted extraction (MAE), supercritical fluid extraction (SFE), and ultrasound-assisted extraction (UAE)	A comparative analysis of the ‘green’ techniques applied for polyphenols extraction from bioresources [173]
2015	Onion	Onion solid wastes	Polyphenol- and pigment-enriched extracts with antioxidant activity	Greece	Ultrasound extraction (140 W, 37 kHz) Extraction time: 60 min Temperature: 45 °C	A green ultrasound-assisted extraction process for the recovery of antioxidant polyphenols and pigments from onion solid wastes using Box–Behnken experimental design and kinetics [174]
2015	Six types of plant fibers (bast, leaf, seed, straw, grass, and wood) and animal fibers and regenerated cellulose fibers	Seed (coir) and animals (chicken feather) as they are secondary or made from waste products	Fibers	Sweden	Review Dew, stand, cold and warm water, steam, enzyme, mechanical, ultrasound chemical and Surfactant retting	A review of natural fibers used in biocomposites: plant, animal and regenerated cellulose fibers [175]
2015	Non edible vegetables	Seeds	Biodiesel	Egypt	Review	A review on green trend for oil extraction using subcritical water technology and biodiesel production [102]
2015	Neem	Neem seed cake (NSC)	Neem Protein (NP)	USA	Alkaline extraction Solvents: H2O and NaOH Extraction time: 60 min Temperature: 75 °C	Bio-based polymeric resin from agricultural waste, neem (Azadirachta indica) seed cake, for green composites [118]
2015	Oranges	Peel	Essential oil, polyphenols and pectin	Algeria and France	MHG, UAE, MAE Solvents: “in situ” water Extraction time: 25 and 3 min Temperature: 59 °C	Bio-refinery of orange peels waste: a new concept based on integrated green and solvent free extraction processes using ultrasound and microwave techniques to obtain essential oil, polyphenols and pectin [57]
2015	Corn, sugarcane, sorghum, soybean, rice, barley, potato, other lignocellulose, vegetable oils, oilseed	By-products (bagasse, straw, cobs, stalks, stover, grass etc.)	Biofuel, 1,3-propanediol, succinic acid, adhesives, solvents, surfactants, ethyl lactate, erucic acid, amylose ethers, among others	Denmark	Review Focus on integrating sustainability assessment procedures and tools (LCA and evaluation approaches)	Biorefining in the prevailing energy and materials crisis: a review of sustainable pathways for biorefinery value chains and sustainability assessment methodologies [144]
2015	Agro-industrial products	Agro-industrial co-products	Phenolic compounds	Brazil	Solid-state fermentation, even as friendly enzyme-assisted extractions	Biotransformation and bioconversion of phenolic compounds obtainment: an overview [176]
2015	Cashew-nut	Husk	Natural dyes	India	Enzyme-assisted extraction cellulase and pectinase Solvent: water Extraction time: 60–180 min pH 9.5	Cashew-nut husk natural dye extraction using Taguchi optimization: green chemistry approach [109]
2015	Beet	Sugar beet pulp	Monosaccharides present in hydrolyzed SBP pectin: l-rhamnose, l-arabinose, d-galactose and d-galacturonic acid	United Kingdom	Centrifugal partition chromatography ascending mode, 1000 rpm Mobile phase flow rate: 8 ml/min	Centrifugal partition chromatography in a biorefinery context: separation of monosaccharides from hydrolyzed sugar beet pulp [141]
2015	Mangoes (Mangifera indica L.) and rye grains (Secale cereals L.)	Peels and grains	Alk(en)ylresorcinols (ARs)	Germany	Ultrasound-assisted extraction Solvent: dichloromethane Extraction time: 15 s cooled in ice bath	Development and validation of an HPLC method for the determination of alk(en)ylresorcinols using rapid ultrasound-assisted extraction of mango peels and rye grains [78]
2015	Olives	Waste from olive oil production	High-added value compounds (polyphenols, fatty acids, coloring pigments (chlorophylls and carotenoids), tocopherols, phytosterols, squalene, volatile and aromatic compounds)	Spain, France, Morocco and Portugal	Review Conventional (solvent, heat, grinding) and non-conventional methodologies (ultrasounds, microwaves, sub- and supercritical fluid extractions, pressurized liquid extraction, pulsed electric fields and high voltage electrical discharges)	Emerging opportunities for the effective valorization of wastes and by-products generated during olive oil production process: non-conventional methods for the recovery of high-added value compounds [142]
2015	Asparagus	Dried segments (residues)	Antioxidant compounds	China	Solid–liquid extraction Solvents: acetone, methanol or ethanol Extraction time: 2 h Temperature: 70 °C	Extraction and analysis of antioxidant compounds from the residues of Asparagus officinalis L. [177]
2015	Grapes	Skin	Anthocyanins	Korea	Deep eutectic solvents (DESs) Extraction time: 45 min room temperature	Highly efficient extraction of anthocyanins from grape skin using deep eutectic solvents as green and tunable media [138]
2015	Green tea	Green tea leaf residue	HG pectin, RGII pectin, organic acids, cellulose and hemi-cellulose	The Netherlands	Alkaline extraction Solvents: 0.1 M NaOH Extraction time: 2 h (protein), 5 min–24 h (carbohydrates or lignin) Temperature: 95 °C	How does alkali aid protein extraction in green tea leaf residue: a basis for integrated biorefinery of leaves [119]
2015	Papaya (Carica papaya L.)	Processing waste	Lycopene	China	Ultrasound extraction (600 W, 40 kHz) Solvents: ethanol/ethyl acetate Extraction time: 15–40 min Temperature: 20–70 °C	Optimization of ultrasound-assisted extraction of lycopene from papaya processing waste by response surface methodology [77]
2015	Carrots, green beans, leeks and celeriac	Vegetable waste streams (rejected carrots, carrot steam peels, green beans cutting waste, leek cutting waste and celeriac steam peels)	Pectin	Belgium	Alcohol insoluble residue Solvents: ethanol and acetone	Pectin characterization in vegetable waste streams: a starting point for waste valorization in the food industry [178]
2015	Berries of A. melanocarpa	Black chokeberry wastes	Antioxidants	France	Extraction-adsorption process Extraction time: 2–8 h Temperature: 22 °C	Pilot scale demonstration of integrated extraction-adsorption eco-process for selective recovery of antioxidants from berries wastes [179]
2015	Cashew nuts (CNS)	Shells	Anacardic acid	Tanzania	Review Focus on natural anacardic acids from CNS and other plants and their semi-synthetic derivatives as possible lead compounds in medicine	Potential biological applications of bio-based anacardic acids and their derivatives [180]
2015	Soy, sugarcane, tea	Soy sauce residues, sugarcane bagasse and tea dregs	Hemicelluloses	China	Ionic liquid Solvents: ionic liquids Extraction time: 1–5 h Temperature: 70–100 °C	Quantitative industrial analysis of lignocellulosic composition in typical agro-residues and extraction of inner hemicelluloses with ionic liquid [134]
2015	Tomatoes	Processing tomato	Nutritional bioactive compounds, lycopene	Italy	Biocompatible technology extraction	Recovery of tomato bioactive compounds through a biocompatible and eco-sustainable new technology for the production of enriched “nutraceutical tomato products” [181]
2015	Citrus sinensis (Hamlin, Valencia, Pera riu and Pera Natal)	Albedo and flavedo	Flavanone	Brazil	Enzymatic process tannase, pectinase and cellulase Extraction time: 30 h Temperature: 40 °C pH 5	Simultaneous extraction and biotransformation process to obtain high bioactivity phenolic compounds from Brazilian citrus residues [110]
2015	Sunflower	Seeds	Oil- (fatty acids and their antioxidant capacities) and water-soluble phase (proteins, carbohydrates and phenolics)	Slovenia	Subcritical water extraction Extraction time: 5–120 min Temperature: 60–160 °C Pressure: 30 bar	Simultaneous extraction of oil- and water-soluble phase from sunflower seeds with subcritical water [103]
2015	Cereals, root crops, fruits, vegetables, oilseeds, meat, dairy products	Food waste	Nutritionally interesting compounds, chemicals and biofuels	Brazil	Review Sub- and supercritical technologies	Sub- and supercritical fluid technology applied to food waste processing [89]
2015	Agricultural biomass	By-products such as durian peel, mango peel, corn straw, rice bran, corn shell and potato peel	Bio-fuel, water soluble sugars and phenolic compounds	Malaysia and Nigeria	Review Sub-critical water	Sub-critical water as a green solvent for production of valuable materials from agricultural waste biomass: a review of recent work [182]
2015	Sugarcane	Sugarcane waste (rind, leaf and bagasse)	Wax/long-chain aldehydes and n-policosanols (nutraceutical compounds) triterpenoids	UK and Brazil	Supercritical CO2 (scCO2) Extraction time: 4 h Temperature: 50 °C Pressure: 350 bar Flow rate: 40 g/min	Sugarcane waste as a valuable source of lipophilic molecules [183]
2015	Mangoes	Peel	Pectin	Germany and Saudi Arabia	Hot-acid extraction Extraction time: 90 min pH 1.5	The arabinogalactan of dried mango exudate and its co-extraction during pectin recovery from mango peel [184]
2015	Coffee	Spent coffee grounds	Tannin compounds	Malaysia	Alkaline extraction Solvent: NaOH Extraction time: 30–90 min Temperature: 60–100 °C	The influence of extraction parameters on spent coffee grounds as a renewable tannin resource [185]
2014	Eucalyptus globulus wood	Trimmings of Eucalyptus globulus wood veneers	Phenolic compounds	Spain	Aqueous two-phase extraction PEG 2000 and ammonium sulphate Extraction time: 30–390 min Temperature: 25–65 °C	Aqueous two-phase systems for the extraction of phenolic compounds from eucalyptus (Eucalyptus globulus) wood industrial wastes [124]
2014	Pomegranates	By-products after winemaking of pomegranate	(poly)phenolic compounds	Spain, Mexico and Italy	Extraction with MeOH 70% (v/v) and sonication	Assessment of pomegranate wine lees as a valuable source for the recovery of (poly)phenolic compounds [186]
2014	Citrus	Peel, pulp and seeds	Several value-added products, such as essential oils, pectin, enzymes, single cell protein, natural antioxidants, ethanol, organic acids, and prebiotics	Greece and Sweden	Review	Biotransformation of citrus by-products into value added products [187]
2014	Olives	Olive solid waste	Natural dye	Tunisia	Aqueous extraction in closed flasks Solvent: NaOH Extraction time: 15–120 min Temperature: 30–90 °C	Development and optimisation of a non-conventional extraction process of natural dye from olive solid waste using response surface methodology (RSM) [125]
2014	Coffee	Waste coffee grounds	Biodiesel production	United Kingdom	Suspended in fresh heptane room temperature	Effect of the type of bean, processing, and geographical location on the biodiesel produced from waste coffee grounds [188]
2014	Grapevine and hazelnut	Grapevine waste and hazelnut skins	Polyphenols content	Italy and France	UAE and MAE Solvents: ethanol, methanol, acetone, butanone, β-cyclodextrin Extraction time: 5–40 min Temperature: 20–60 °C	Efficient green extraction of polyphenols from post-harvested agro-industry vegetal sources in Piedmont [58]
2014	Bamboo	Raw bamboo culm	Lignin	Malaysia	Review Chemical and steam explosion methods	Extraction and preparation of bamboo fibre-reinforced composites [189]
2014	Spruce	Spruce sawdust	Carboxylic acids	Finland	Alkaline extraction Solvents: Na2CO3 or Na2S.9H2O Extraction time: 30 min + 30 min; Temperature: 80 °C up to 160 °C and 210 °C	Production of carboxylic acids from alkaline pretreatment byproduct of softwood [120]
2014	Variety of biomass sources (rapeseed, soybean, palm oil and nonedible feedstocks)	Preferably 2nd–4th generation feedstock (non-edible materials as bagasse, oil waste, microalgae, cyanobacteria and microbes)	Biodiesel	Malaysia	Review Supercritical fluid process and catalytic in situ or reactive extraction process	Integration of reactive extraction with supercritical fluids for process intensification of biodiesel production: prospects and recent advances [90]
2014	Cherries	Cherry seeds	Total phenolic content	Brazil and France	Pressurized fluid extraction (PFE) Solvent: anhydrous ethanol Extraction time: 2–10 min Temperature: 40–80 °C	Isolation by pressurized fluid extraction (PFE) and identification using CPC and HPLC/ESI/MS of phenolic compounds from Brazilian cherry seeds (Eugenia uniflora L.) [190]
2014	Corn	Corn stover	Lignin	USA	Protic ionic liquid (PIL) Extraction time: 24 h Temperature: 90 °C	Lignin extraction from biomass with protic ionic liquids [135]
2014	Oranges	Peel	d-limonene	United Kingdom	Microwave-assisted extraction 200 W, closed vessel Solvent: hexane Temperature: 70–110 °C	Microwave-assisted extraction as an important technology for valorising orange waste [59]
2014	Sweet Limes	Peel	Antioxidant phenolics	Pakistan	Enzymatic treatment Incubation time: 30–120 min Temperature: 30–75 °C pH 5 to 8	Optimization of enzyme-assisted revalorization of sweet lime (Citrus limetta Risso) peel into phenolic antioxidants [111]
2014	Artichoke	Artichoke scraps	Phenolic compounds	Italy	Ultrasound-assisted extraction (UAE) Time: 60 min Solvent: water	Phenols and antioxidant activity in vitro and in vivo of aqueous extracts obtained by ultrasound-assisted extraction from artichoke by-products [79]
2014	Cachrys pungens Jan (Umbelliferae)	Aerial parts of Cachrys pungens Jan (Umbelliferae)	Bioactive compounds	Italy	Solvent extraction Solvents: methanol Extraction time: 72 h room temperature dark conditions	Phytotoxic activity of Cachrys pungens Jan, a Mediterranean species: separation, identification and quantification of potential allelochemicals [191]
2014	Wheat	Wheat straw	Major organic components (e.g., N-heterocycles, fatty acids, phenols and lignins)	Canada	Fast pyrolysis steel shots 475 °C	Wheat straw biomass: a resource for high-value chemicals [192]
2013	Cranberries	Cranberry juice and pomace	Polyphenolics	Canada and Mexico	Pilot scale methods Solvents: ethanol Extraction time: 24 h	Bioactivities of pilot-scale extracted cranberry juice and pomace [48]
2013	Fruits, vegetables, eggs, shrimp	Plant residues, industrial and post-harvest materials	Carotenoids	Mexico	Review Novel environmentally friendly solvents (e.g., ethyl lactate, bioethanol, vegetal oil, commercial enzymes)	Carotenoids extraction and quantification: a review [193]
2013	Tomatoes	Peels	Lycopene	Italy	Enzymatic-assisted extraction Temperature: 45 and 60 °C pH 4–5 and 9–10.5	Environmentally friendly lycopene purification from tomato peel waste: enzymatic-assisted aqueous extraction [112]
2013	Coffee	Coffee residue left after the preparation of the brew (spent coffee grounds—SCG)	Polysaccharides	Portugal	Alkali extraction Solvent: H2O and 4 M NaOH Extraction time: 3 h Temperature: 20–120 °C	Extractability and structure of spent coffee ground polysaccharides by roasting pre-treatments [194]
2013	Coffee	Spent coffee grounds	Lipids, oil	Iran	Soxhlet, UAE, MAE, SFE Solvents: petroleum benzene and n-hexane Soxhlet: 6 h, boiling temperature UAE: 45 min, ambient conditions MAE: 30 s, 200 and 800 W SFE: 200–250 bar, 40–60 °C, modifier (water, ethanol, hexane)	Extraction of lipids from spent coffee grounds using organic solvents and supercritical carbon dioxide [60]
2013	Forest Industry	Forest residues, including bark	Bioactive molecules	Canada	Review Green alternatives for the design, formulation, and manufacture of new products with applications in various markets (cosmetics, natural health products, biocides, adhesives, coatings)	Forest extractives, the 4th pathway of the forest biorefinery concept [195]
2013	Coffee	Spent coffee grounds (SCG)	Lipid fraction	Portugal and Brazil	Supercritical carbon dioxide Extraction time: 1 h Temperature: 55 °C Pressure: 250 bar CO2 flow rate: 15 kg/h	From coffee industry waste materials to skin-friendly products with improved skin fat levels [91]
2013	Walnuts	Green husk	Natural compounds with antioxidant and antimicrobial properties	Spain and Portugal	Solvent extraction Solvents: water, methanol, ethanol Extraction time: 45 min room temperature	Influence of solvent on the antioxidant and antimicrobial properties of walnut (Juglans regia L.) green husk extracts [49]
2013	Coffee	Spent coffee	Antioxidants	Spain	Soxhlet, SPE, filter coffeemaker Solvents: water, ethanol, methanol Extraction time: 6–165 min Temperature: 80–100 °C	Influence of extraction process on antioxidant capacity of spent coffee [50]
2013	Tomatoes	Peel	Fatty acids	France	Depolymerization 1.5 M KOMe overnight treatment at room temperature	Interfacial properties of functionalized assemblies of hydroxy-fatty acid salts isolated from fruit tomato peels [196]
2013	Coffee	Spent coffee grounds (SCG)	Polysaccharides	Portugal	Microwave superheated water extraction Extraction time: 5 min Temperature: 200 °C	Microwave superheated water extraction of polysaccharides from spent coffee grounds [61]
2013	Turkish red pine timber	Waste barks	Natural dye	Turkey	Natural dyestuff extraction machine Solvents: water and ethanol Extraction time: 24 h (osmosis)	Natural dye extraction from waste barks of Turkish red pine (Pinus brutia Ten.) Timber and eco-friendly natural dyeing of various textile fibers [126]
2013	Cotton, jute, flax, hemp, ramie and natural colorants	Wastes and manufacturing by-products	Fibres, polysaccharides, dyes and pigments, polyphenols, oils and other biologically active compounds	India	Review Conventional maceration, soxhlet, MAE, SFE, ultrasonic extraction	Perspectives for natural product based agents derived from industrial plants in textile applications: a review [197]
2013	Coffee	Spent coffee grounds	Natural antioxidants	Italy	Solvent extraction Solvents: H2O, ethanol, Extraction time: 30 min Temperature: 60 °C	Recovery of natural antioxidants from spent coffee grounds [198]
2013	Feijoa fruits	Primarily skin and some flesh	Total soluble solids (TSS), pectin fibre content, total extractable PP content (TEPC) and total antioxidant activity	New Zealand	Accelerated solvent extraction Solvents: (acidified) water, ethanol Temperature: 20 or 50 °C	Utilisation potential of feijoa fruit wastes as ingredients for functional foods [127]
2012	Green tea	Green tea waste	Noncaffeine tea polyphenols	China	Water bath 20 min 90 °C	A novel way of separation and preparation non-caffeine tea polyphenols from green tea waste [199]
2012	Larch	Larch wood-derived lignocellulosic residue	Arabinogalactan, pectin, and crystalline glucose	Russia	Water extraction Extraction time: 2–3 h Temperature: 60–80 °C	An eco-friendly technology for polysaccharide production from logging and sawing waste [128]
2012	Olives	Olive leaves	Oleuropein	Greece	SFE and PLE SFE: 30 MPa, 50 °C, 9.6 kg/h PLE: 10.34 MPa, 10 min, 40–150 °C Solvents: H2O and EtOH	Development of a green extraction procedure with super/subcritical fluids to produce extracts enriched in oleuropein from olive leaves [92]
2012	Wood	Wood barks, obtained from pulp mills as industrial wastes	Natural phenolic polymers of tannins and lignin	France	Aqueous extraction urea and sulfite used as water-additives Extraction time: 1 h under reflux Temperature: 75 °C	Development of green adhesives for fibreboard manufacturing, using tannins and lignin from pulp mill residues [129]
2012	Wheat	Wheat milling by-products	High quality oil and vitamin E	Italy	Review Solvent extraction, mechanical pressing or the eco-friendly supercritical carbon dioxide (SC-CO2) extraction technology	Durum wheat by-products as natural sources of valuable nutrients [200]
2012	Tree bark	Waste product from paper pulp industries	Antioxidants	Sweden	SFE, PFE, SLE Solvents: scCO2, ethanol, H2O Extraction time: 30 min–24 h Temperature: 70–180 °C	Extraction of antioxidants from spruce (Picea abies) bark using eco-friendly solvents [93]
2012	Timber	Empty fruit bunches	Fiber	Malaysia	Perspective paper	Fiber resin matrix composites: nature’s gift [201]
2012	Oranges	Peel	Essential oil	United Kingdom	Steam distillation and microwave irradiation SD: water, 1 h MW: 12.5 min, 200 °C, power gradient from 400 to 1200 W	p-cymenesulphonic acid: an organic acid synthesized from citrus waste [202]
2012	Black tea	Black tea wastes	Pancreatic lipase-inhibiting polyphenols	Japan	Hot-compressed water (HCW) ion-exchange water extraction temperature: 100–200 °C	Polyphenols extracted from black tea (Camellia sinensis) residue by hot-compressed water and their inhibitory effect on pancreatic lipase in vitro [203]
2012	Green tea	Green tea waste	Polyphenols	China	Liquid–liquid extraction Solvents: H2O, glyceryl, triacetate, n-butanol, ethyl acetate Extraction time: 12 h + 2 h	Recovery of tea polyphenols from green tea waste by liquid–liquid extraction [204]
2012	Citrus	Peels	Polymethoxy flavonoids	China	Solvent extraction Solvents: methanol and ethanol Extraction time: 1–3 h Temperature: 65–85 °C	Study on the extraction technique of poly-methoxyflavonoids from citrus peels by using response surface methodology [205]
2011	Coffee	Husks	Caffeine	Spain	Supercritical CO2 Extraction time: 20 min Temperature: 323 K Pressure: 60 bar CO2 flow rate: 2–3 g/min	Extraction of caffeine from Robusta coffee (Coffea canephora var. Robusta) husks using supercritical carbon dioxide [94]
2011	Oranges	Peel	Essential oils	France and Tunisia	Microwave steam diffusion (MSDf) Extraction time: 12 min Temperature:100 °C	Microwave steam diffusion for extraction of essential oil from orange peel: kinetic data, extract’s global yield and mechanism [62]
2011	Grape	Skins	Anthocyanins	Spain	Microwave-assisted extraction Solvents: H2O, methanol Extraction time: 5–20 min Temperature: 50–100 °C	Microwave-assisted extraction of anthocyanins from grape skins [63]
2011	Tea (green, oolong and black)	Tea residues (green, oolong and black tea residues)	Phenolic compounds	Japan	Microwave-assisted extraction water under autohydrolytic conditions Extraction time: 2 min Temperature: 110–230 °C	Microwave-assisted extraction of phenolic compounds from tea residues under autohydrolytic conditions [64]
2011	Sea Buckthorn (Hippophae rhamnoides	By-Products of juice production	Flavonoids	France	Solvent-free microwave hydrodiffusion and gravity (MHG) without addition of solvent or water atmospheric pressure	Solvent free microwave-assisted extraction of antioxidants from sea buckthorn (Hippophae rhamnoides) food by-products [206]
2011	Wheat	Wheat straw	Energy and CO2 secondary metabolites including fatty acids, wax esters and fatty alcohols	England	Supercritical CO2 extraction Temperature: 40–100 °C Pressure: 100–300 bar CO2 flow rate: 40 g/min	Use of green chemical technologies in an integrated biorefinery [95]
2011	Olives	By-products generated during storage of extra virgin olive oil	Phenolic compounds, hydroxytyrosol, tyrosol, decarboxymethyl oleuropein aglycone, and luteolin	Italy and Spain	Solid–liquid and liquid–liquid extraction Solvents: n-hexane, methanol, H2O Extraction time: 1 h	Wastes generated during the storage of extra virgin olive oil as a natural source of phenolic compounds [207]
2010	Tomatoes	Ground tomatoes without seeds	Lycopene	France and Algeria	Solvent extraction Solvent: d-limonene	Carotenoid extraction from tomato using a green solvent resulting from orange processing waste [208]
2010	Tea plant	Tea stalk and fiber wastes	Caffeine	Turkey	Supercritical CO2 ethanol as co-solvent Extraction time: 1–5 h Temperature: 50–70 °C Pressure: 250 bar semi-continuous flow	Effect of ethanol content on supercritical carbon dioxide extraction of caffeine from tea stalk and fiber wastes [96]
2010	Portuguese elderberry	Pomace	Anthocyanins	Portugal	Supercritical CO2 extraction Solvents: CO2, water, ethanol Extraction time: 40 min Temperature: 313 K	Effect of solvent (CO2/ethanol/H2O) on the fractionated enhanced solvent extraction of anthocyanins from elderberry pomace [97]
2010	Green tea	Green tea waste	Polyphenols, total catechins, and reducing sugars	South Korea and USA	Solvents: cold water (25 °C), hot water (90 °C), sulfuric acid, hydrochloric acid and methanol Extraction time: 20 min 250 rpm	Effects of cellulase from Aspergillus niger and solvent pretreatments on the extractability of organic green tea waste [130]
2010	Tea	Tea waste	Caffeine	Iran	Subcritical water extraction Temperature: 100–200 °C Pressure: 20–40 bar water flow rate: 1–4 g/min	Isolation of caffeine from tea waste using subcritical water extraction [104]
2010	Citrus sudachi	Peels	Flavones	Japan	Microwave-assisted extraction Solvents: methanol extraction time: 10 to 12 min	Microwave-assisted extraction and methylation of useful flavones from waste peels of Citrus sudachi [209]
2010	Mate (Ilex paraguariensis)	Mate residue	Compounds with antioxidant properties, such as phenolic acids and methylxanthines, such as caffeine	Brazil	Solvent extraction Solvent: methanol, H2O, ethanol sonication for 15 min room temperature	Phenolic acids and methylxanthines composition and antioxidant properties of mate (Ilex paraguariensis) residue [210]
2010	Rice	Rice bran	Phenolic compounds as well as other valuable materials	Japan	Subcritical water Preheated oil: 100–180 °C, 10 min Preheated water bath: 180–360 °C, 10 min and 220 °C for 2–30 min	Production of phenolic compounds from rice bran biomass under subcritical water conditions [105]
2009	Citrus	Peels	Essential oil	France and Algeria	Microwave hydrodiffusion gravity Extraction time: 15 min atmospheric pressure 500 W	A new process for extraction of essential oil from citrus peels: microwave hydrodiffusion and gravity [65]
2009	Kiwifruit	By-products derived from kiwifruit processing	Phenolics and pectin polysaccharides	New Zealand	Solvent extraction Solvents: water, ethanol Extraction time: 1 h room temperature	Evaluation of the extraction efficiency for polyphenol extracts from by-products of green kiwifruit juicing [211]
2009	Palm	Black liquor of oil palm waste	Lignin	Malaysia	Solvent extraction Chemical extractions: di-ethyl ether, alcohol-benzene mixture treatment with H2SO4 for 30–45 min	Exploring the antioxidant potential of lignin isolated from black liquor of oil palm waste [212]
2009	Turkish tea plants	Tea stalk and fiber wastes	Caffeine	Turkey	Supercritical carbon dioxide Extraction time: 1–10 h Temperature: 55–75 °C increasing pressure up to 250 bar semi-continuous flow	Extraction of caffeine from tea stalk and fiber wastes using supercritical carbon dioxide [99]
2009	Rice	Rice bran	Oil (value-added materials such as amino acids, organic acids, and water-soluble saccharides)	Japan	Subcritical water preheated oil bath: 100–180 °C Preheated salt bath: 200–360 °C Reaction time: 5 min	Sub-critical water treatment of rice bran to produce valuable materials [106]
2009	Several biomass	Residues rich in lignocellulosics	Bio-based chemicals (e.g., succinic, lactic, fumaric l-malic, l-aspartic acids)	England	Review Focus on green chemical conversion of lignin into higher value chemicals	The integration of green chemistry into future biorefineries [21]
2009	Apple	Industrially generated apple pomace	Antioxidants and polyphenols	Ireland	Pressurized liquid extraction accelerated solvent extractor static extraction of 5 min Temperature: 75–193 °C	The optimization of extraction of antioxidants from apple pomace by pressurized liquids [213]
2008	Chicory, citrus, cauliflower, endive, and sugar beet	Plant by-products (chicory roots, citrus peel, cauliflower florets and leaves, endive, and sugar beet pulps)	Pectins	France and Finland	Enzymatic extraction Extraction time: 4 h Temperature: 50 °C	Extraction of green labeled pectins and pectic oligosaccharides from plant by-products [113]
2008	Tea (green, oolong, and black)	Green, oolong, and black tea residues	Polysaccharides, polyphenols, arabinose, galactose, xylose, catechins	Japan	Microwave heating Solvent: water Temperature: 110–230 °C	Microwave heating of tea residue yields polysaccharides, polyphenols, and plant biopolyester [66]
2008	Plant lipids	Plant oils and other natural lipidic phases	Phytosterols, vitamins	Czech Republic	Review Enzymes as efficient natural catalysts	Plant products for pharmacology: application of enzymes in their transformations [114]
2007	Broccoli	Broccoli seeds	Natural sulforaphane	China and Australia	Liquid–liquid and solid-phase extraction Solvents: ethanol, hexane, ethyl acetate	Separation and purification of sulforaphane from broccoli seeds by solid phase extraction and preparative high-performance liquid chromatography [214]
2006	Tea	Tea waste	Caffeine	Turkey	Solid–liquid extraction solvents: hot water and chloroform Temperature: 370 K and 293 K	Solid–liquid extraction of caffeine from tea waste using battery type extractor: process optimization [215]