Green Extraction Technology Research Articles

Biochemical Composition and Phycoerythrin Extraction from Red Microalgae: A Comparative Study Using Green Extraction Technologies

Porphyridium spp. is a debated family that produces phycoerythrin (PE) for use in multiple industrial applications. We compared the differences in the biochemical composition and phycoerythrin yield of P. cruentum and P. purpureum by conventional and green extraction technologies. The protein content in P. cruentum was 42.90 ±1.84% w/w. The omega-3 fatty acid (FA) was highlighted by eicosapentaenoic acid (EPA, C20:5, ω-3, ~9.74 ± 0.27% FA) and arachidonic acid (ARA, C20:4, ω-6, ~18.02 ± 0.81% FA) represented the major omega-6 fatty acid. Conversely, P. purpureum demonstrated a higher lipid content (17.34 ± 1.35% w/w) and an FA profile more saturated in palmitic (C16:0, 29.01 ± 0.94% FA) and stearic acids (C18:0, 50.02 ± 1.72% FA). Maceration and freeze/thaw were the conventional methods, whereas microwave (MW) and ultrasound (US) served as green procedures for PE extraction under the factorial-design methodology. Aqueous solvents, extraction-time and power were the main factors in the statistical extraction designs based on Response-Surface Methodology (RSM). Overall, the PE extraction yield was higher (2-to 6-fold) in P. cruentum than in P. purpureum. Moreover, green technologies (US > MW) improved the PE recovery in comparison with the conventional methods for both of the microalgae. The maximum PE yield (33.85 mg/g) was obtained under optimal US conditions (15 min and buffer solvent (PBS)) for P. cruentum. Finally, we proved the biochemical differences between the red microalgae and ratified the advantages of using green extraction for PE because it reduced the processing times and costs and increased the economic and functional-applications of bioactive compounds in the industry.

Antioxidant Molecules from Plant Waste: Extraction Techniques and Biological Properties

The fruit, vegetable, legume, and cereal industries generate many wastes, representing an environmental pollution problem. However, these wastes are a rich source of antioxidant molecules such as terpenes, phenolic compounds, phytosterols, and bioactive peptides with potential applications mainly in the food and pharmaceutical industries, and they exhibit multiple biological properties including antidiabetic, anti-obesity, antihypertensive, anticancer, and antibacterial properties. The aforementioned has increased studies on the recovery of antioxidant compounds using green technologies to value plant waste, since they represent more efficient and sustainable processes. In this review, the main antioxidant molecules from plants are briefly described and the advantages and disadvantages of the use of conventional and green extraction technologies used for the recovery and optimization of the yield of antioxidant naturals are detailed; finally, recent studies on biological properties of antioxidant molecules extracted from plant waste are presented here.

Techno-economic analysis of catechin mix manufacture from Camellia sinensis leaves using green extraction technology

This work designed, modeled and performed economic analysis of the base case extraction and recovery of catechin mix (CM) from Camellia sinensis leaves (CSL) using deep eutectic solvent (DES) and microwave assisted extraction (MAE) with the assistance of SuperPro Designer software. Techno- -economic analysis of three commercial scales of manufacture was also investigated and compared using profitability parameters. Sensitivity and uncertainty analyses were further carried out on the most viable commercial scale to determine input variable(s) of highest significance on the profitability of the process. The 3.30 kg CM/batch is the most economically desirable scale with return on investment of 324.65%, payback period of 0.31 years, internal rate of return of 163.83% and net present value of $1,059,595,224. Out of the input variables selected for the sensitivity and uncertainty analyses, CSL and DES costs have the least effect on the selected profitability parameters of the process.

Enhancing the potential exploitation of Salvia miltiorrhiza Bunge: Extraction, enrichment and HPLC-DAD analysis of bioactive phenolics from its leaves

Salvia miltiorrhiza Bunge leaves, a crop waste, have potential as a source of bioactive phenolics. In this work, ultrasound-assisted extraction (UAE) was employed as a green extraction technology to extract phenolics from S. miltiorrhiza leaves. UAE parameters were optimized using response surface methodology (RSM) based on Box-Behnken design, achieving the total phenolics from S. miltiorrhiza leaves (SMLTP) yield of 71.16 ± 0.57 mg gallic acid equivalent per g of dry material (mg GAE/g DM) under optimal conditions. Afterwards, NKA-2 resin was selected to enrich SMLTP, the data for adsorption of SMLTP on NKA-2 resin fitted well with pseudo-second-order and Langmuir models. A NKA-2 resin-based chromatography procedure was optimized by studying breakthrough curves and desorption curves to enrich SMLTP from crude extract. A lab-scale enrichment experiment was performed under optimal conditions, the content of SMLTP in the product was 78.33 ± 0.61 %, which was 3.7 times higher than that in the crude extract, the recovery yield of SMLTP was 82.14 ± 1.62 %. Finally, HPLC-DAD analysis showed the contents of five major phenolic compounds including caffeic acid, rutin, isoquercitrin, rosmarinic acid, and salvianolic acid B significantly increased through enrichment. Certainly, this study will enhance S. miltiorrhiza industry to be more ecologic and economic.

Microwave-assisted extraction of antioxidative anthraquinones from roots of Morinda citrifolia L. (Rubiaceae): Errata and review of technological development and prospects

In this paper, the errata for a published paper, titled “Microwave-assisted extraction of antioxidative anthraquinones from roots of Morinda citrifolia”, authored by Surasak Hemwimon, Prasert Pavasant, and Artiwan Shotipruk, in the Journal of Separation and Purification Technology, Volume 54, 2007, Pages 44–50, were presented. Since microwave-assisted extraction (MAE) is an emerging green technology that attracts considerable research interest, the paper has been cited by more than 220 articles. These articles were also reviewed to evaluate the impact of the error and the impact of the paper to the research community. Additionally, we have reviewed the most recent articles in the related fields and provided feedbacks on the development of MAE technology and anthraquinones research. Prospects of green extraction technology in the context of the 21st century circular bioeconomy was also discussed.

Macroalgae as a Source of Valuable Antimicrobial Compounds: Extraction and Applications.

In the last few decades, attention on new natural antimicrobial compounds has arisen due to a change in consumer preferences and the increase in the number of resistant microorganisms. Macroalgae play a special role in the pursuit of new active molecules as they have been traditionally consumed and are known for their chemical and nutritional composition and their biological properties, including antimicrobial activity. Among the bioactive molecules of algae, proteins and peptides, polysaccharides, polyphenols, polyunsaturated fatty acids and pigments can be highlighted. However, for the complete obtaining and incorporation of these molecules, it is essential to achieve easy, profitable and sustainable recovery of these compounds. For this purpose, novel liquid–liquid and solid–liquid extraction techniques have been studied, such as supercritical, ultrasound, microwave, enzymatic, high pressure, accelerated solvent and intensity pulsed electric fields extraction techniques. Moreover, different applications have been proposed for these compounds, such as preservatives in the food or cosmetic industries, as antibiotics in the pharmaceutical industry, as antibiofilm, antifouling, coating in active packaging, prebiotics or in nanoparticles. This review presents the main antimicrobial potential of macroalgae, their specific bioactive compounds and novel green extraction technologies to efficiently extract them, with emphasis on the antibacterial and antifungal data and their applications.

Rana chensinensis Ovum Oil Based on CO2 Supercritical Fluid Extraction: Response Surface Methodology Optimization and Unsaturated Fatty Acid Ingredient Analysis.

Rana chensinensis ovum oil (RCOO) is an emerging source of unsaturated fatty acids (UFAs), but it is lacking in green and efficient extraction methods. In this work, using the response surface strategy, we developed a green and efficient CO2 supercritical fluid extraction (CO2-SFE) technology for RCOO. The response surface methodology (RSM), based on the Box–Behnken Design (BBD), was used to investigate the influence of four independent factors (pressure, flow, temperature, and time) on the yield of RCOO in the CO2-SFE process, and UPLC-ESI-Q-TOP-MS and HPLC were used to identify and analyze the principal UFA components of RCOO. According to the BBD response surface model, the optimal CO2-SFE condition of RCOO was pressure 29 MPa, flow 82 L/h, temperature 50 °C, and time 132 min, and the corresponding predicted optimal yield was 13.61%. The actual optimal yield obtained from the model verification was 13.29 ± 0.37%, and the average error with the predicted value was 0.38 ± 0.27%. The six principal UFAs identified in RCOO included eicosapentaenoic acid (EPA), α-linolenic acid (ALA), docosahexaenoic acid (DHA), arachidonic acid (ARA), linoleic acid (LA), and oleic acid (OA), which were important biologically active ingredients in RCOO. Pearson correlation analysis showed that the yield of these UFAs was closely related to the yield of RCOO (the correlation coefficients were greater than 0.9). Therefore, under optimal conditions, the yield of RCOO and principal UFAs always reached the optimal value at the same time. Based on the above results, this work realized the optimization of CO2-SFE green extraction process and the confirmation of principal bioactive ingredients of the extract, which laid a foundation for the green production of RCOO.

Enhanced extraction of essential oil from Cinnamomum cassia bark by ultrasound assisted hydrodistillation

Cinnamon essential oil with many bioactivities is an important raw material for the production of various chemicals, and the conventional hydrodistillation (HD) for cinnamon oil extraction always require a longer extraction time. In this work, ultrasound-assisted hydrodistillation extraction (UAHDE) technique was employed to enhance the extraction efficiency of essential oils from cinnamon barks. The parameters with significant effects on the essential oil extraction efficiency (ultrasound time, ultrasound power, extraction time, liquid–solid ratio) were optimized, and the proposed UAHDE was compared with the conventional HD extraction in terms of the extraction time, extraction yield, and physicochemical properties of extracted oils. Compared to the HD extraction, the UAHDE resulted in a shorter extraction time and a higher extraction yield. Using GC–MS analysis, the UAHDE provided more valuable essential oil with a high content of the vital trans-cinnamaldehyde compounds compared with the HD. Scanning electron micrograph (SEM) confirmed the efficiency of ultrasound irradiation for cinnamon oil extraction. In addition, the analysis of electric consumption and CO2 emission shows that the UAHDE process is a more economic and environment-friendly approach. Thus, UAHDE is an efficient and green technology for the cinnamon essential oil extraction, which could improve the quantity and quality of cinnamon oils.

Applications of Nonconventional Green Extraction Technologies in Process Industries: Challenges, Limitations and Perspectives

This study reviewed five different nonconventional technologies which are aligned with green concepts of product recovery from raw materials on industrial scale, with minimal energy consumption and chemical use. Namely, this study reviewed supercritical fluid extraction (SCFE), pressurized liquid extraction (PLE), microwave-assisted extraction (MAE), ultrasound extraction (UAE) and pulsed electric fields extraction (PEFE). This paper provides an overview of relevant innovative work done in process industries on different plant matrices for functional value-added compounds and byproduct production. A comparison of the five extraction methods showed the supercritical CO2 (SC-CO2) process to be more reliable despite some limitations and challenges in terms of extraction yield and solubility of some bioactive compounds when applied in processing industries. However, these challenges can be solved by using ionic liquids as a trainer or cosolvent to supercritical CO2 during the extraction process. The choice of ionic liquid over organic solvents used to enhance extraction yield and solubility is based on properties such as hydrophobicity, polarity and selectivity in addition to a safe environment.

RP-HPLC-PDA-ESI-MS/MS screening of bioactive compounds from Degla-Beida dates: Conventional and green extraction technologies

Date fruits have vital therapeutic properties, in the way that they represent an inexhaustible source of bioactive compounds such as polyphenols. Therefore, the objective of this work was to evaluate the phytocomposition by High Performance Liquid Chromatography (RP-HPLC-PAD-ESI-MS/MS) of the optimized microwaveassisted extraction (MAE) phenolic extract by using the response surface methodology (RSM) compared to the ultrasound-assisted and conventional extractions (UAE and CE), and to test its antioxidant activity in vitro. The resulting regression model indicated that a quadratic polynomial model was best suited for the spectrophotometrically determined total phenolics. The maximum total phenolic content, TPC, (4.27±0.09 mg GAE/g DW) was obtained with a 50% (v/v) ethanol’s concentration, a 700 W microwave power and an extraction time of 2.42 minutes. HPLC analysis revealed the presence of organic sugars and acids, nucleoside, carotenoids, proanthocyanidins, lignans, flavonols, flavones, saponin and sterol glucosides. The MAE phenolic extract showed 58.72±0.29% DPPH radical scavenging activity and a 1.88±0.09 mg AscAE/mL reducing power.

Clean technologies applied to the recovery of bioactive extracts from Camellia sinensis leaves agricultural wastes

This study deals with the valorisation of tea leaves from the agricultural pruning remains using clean technologies with low environmental impact. Leaves with null commercial interest were dismissed during the pruning season, however with a sequential combination of microwave hydrodiffusion and gravity (MHG), ultrasound-assisted (US) and pressurized hot water (AH) extractions was possible to recover bioactive compounds. An initial pre-treatment was performed using MHG at selected irradiation powers to facilitate the liberation of antioxidants through the cell membrane. The solid phases were processed by three ways: i) ultrasound bath system (80°C, 80KHz, from 15 to 60min); ii) AH technology (non-isothermal treatment with maximum temperature from 140 to 200°C); and iii) a sequence of the three aforementioned technologies. Both raw material and liquors were analysed to determine fundamental physicochemical, phytochemical or biological properties. Leaves debris showed positive results in bioactive compounds with a maximum value of total phenolic around 130mg GAE/g extract in the sequential combination. Antioxidant capacity ranged from 0.3 to 0.9g Trolox/g extract. The combination of green extraction technologies guarantees an efficient recovery of bioactive compounds, creating the possibility of new products that improve the wellbeing.

Phytochemicals from Castanea spp. buds and green extraction technologies: the Finnover project

Green economy is a sustainable development tool based on the valorization of economic, natural and social resources. It is recognized as a tool to be applied to all the production sectors (goods and services), as well as for the conservation and sustainable use of natural resources. The FINNOVER project (“Innovative strategies for the development of cross-border green supply chains”) proposes a technical-economic path for the creation and development of new supply chains for the eco-sustainable extraction and use of natural bioactive compounds. In this study, an innovative extraction and re-use strategy to obtain value-added products from botanical by-products was developed as an alternative to waste incineration or composting. It was applied to Castanea sativa bud extract production as a case study, but it could be analogously applied for other herbal preparations. Castanea spp. and their preparations have been widely used for hundreds of years as medicinal plants in composite formulae. Bioactive compounds (botanicals) are quite variable in the plant material, according to genotype (intraspecific chemodiversity), different collection stages, pedoclimatic conditions of sampling sites (wild or cultivation zones), agrotechniques, and post-harvest handling. This research aimed to compare the bioactive compound pattern of Castanea spp. bud preparations (herbal preparations derived from embryonic fresh plant tissues as buds and sprouts) with the composition of extracts derived from the bud-waste management process. Molecules were extracted by the encoded traditional method (maceration in hydroglyceroalcoholic solution) and by green extraction technologies (Pulsed Ultrasound-Assisted Extraction). HPLC methods were used to identify and quantify the main bioactive compounds, and to obtain a specific profile to assess the contribution of every single bioactive class to the total phytocomplex. The established protocol was simple, sensitive and reliable and it could be used for the evaluation and quality control of natural products and relative eco-sustainable extracts. The valorization of bud marcs, which remain after the bud-preparation production, could have a significant economic impact for the commercial producers, representing an important innovation in this sector.

Hunting Molecules in Complex Matrices with SPME Arrows: A Review

Thirty years since the invention and public disclosure of solid phase microextraction (SPME), the technology continues evolving and inspiring several other green extraction technologies amenable for the collection of small molecules present in complex matrices. In this manuscript, we review the fundamental and operational aspects of a novel SPME geometry that can be used to “hunt” target molecules in complex matrices: the SPME Arrow. In addition, a series of applications in environmental, food, cannabis and forensic analysis are succinctly covered. Finally, special emphasis is placed on novel interfaces to analytical instrumentation, as well as recent developments in coating materials for the SPME Arrow.

A greener alternative using subcritical water extraction to valorize the brown macroalgae Ecklonia maxima for bioactive compounds

This work aimed to optimize the subcritical water extraction (SWE) parameters from the brown macroalga Ecklonia maxima for yields, total phenolic content (TPC), antioxidant activity (ABTS), sulphate content and alginate yields using response surface methodology (RSM). A central composite experimental design evaluated the impact of temperature (100–180 °C), extraction time (5–30 min) and solvent to feed (S/F) ratio (10–50 mL g−1) operated at 40 bar. The predicted model accuracy for all the variables was good with R2 values ranging from 0.76 to 0.97. All response variables showed a high dependence on the hydrolysis temperature followed by S/F ratio and extraction time. The optimized levels for the total phenolic content coupled with antioxidant activities and yield was 180 °C, extraction time of 23.75 min and a S/F ratio of 30 mL g−1 with an yield of 76.02 ± 0.51%, TPC of 41.20 ± 0.42 GAE g−1 and antioxidant activity of 1.81 ± 0.01 mmol TE g−1. The optimized levels for the polysaccharide fractions were 120 °C for 5 min at S/F ratio of 30 mL g−1 giving a yield of 58.25 ± 0.93%, sulphate content of 48.53 ± 1.19 mg SO42− g−1 and 15.65 ± 0.42% alginate. These results show that there is a variance in optimal operational conditions based on the target compounds of interest and it links operational conditions to both functional properties and product type. Overall, SWE is a promising green extraction technology for isolating bioactive compounds from E. maxima which can find potential applications in food and cosmetic industry.

Biochemical analysis and potential applications of aqueous and solid products generated from subcritical water extraction of microalgae Chlorella pyrenoidosa biomass

Subcritical water extraction (SWE) technology has become useful as a green extraction technology for generating various biochemical and bioactive compounds from a wide range of biomass feedstocks, including microalgae. SWE processes result in two different product phases: an aqueous phase containing solubilized or immiscible bioactive compounds from the extract, and solid-phase biomass debris containing residual or unextracted bioactive molecules in the matrix. While most SWEs of microalgal biomass focus on maximizing lipid production for biofuel application, the present work seeks to explore opportunities to identify and characterize compounds obtained from both the aqueous and solid phases. SWE of Chlorella pyrenoidosa biomass was carried out under varying conditions of temperature (170–370 °C), extraction time (1–20 min), and microalgal biomass loading (1–15%). Analysis of aqueous and solid-phase samples collected under varying SWE conditions showed a higher protein concentration of 4.13 mg mL−1 in the aqueous phase compared with carbohydrate (1.35 mg mL−1) for the optimum extraction conditions. About 17.52 mg g−1 of amino acids and 12.72 mg g−1 of organic acids were obtained from the aqueous phase with glutamic acid and lactic acid being the highest. The findings from this work would be useful in identifying and harnessing important microalgal biochemical from SWE process to develop new and improved bioproduct technologies.

Recyclable menthol-based deep eutectic solvent micellar system for extracting phytochemicals from Ginkgo biloba leaves

Abstract With an emphasis on human health, the demand for natural products is progressively increasing and sustainable extraction technologies for phytochemicals are receiving greater attention. In the present study, we established a naturally recyclable two-phase aqueous micellar system comprising menthol-based hydrophobic deep eutectic solvent (DES) in water. Typical representative phytochemicals from Ginkgo biloba leaves included flavonoid glycosides, terpene lactones, and bioflavonoids. These compounds have differing polarities and were selected as targets for the evaluation of our novel menthol-based aqueous DES as a green and sustainable extraction technology for partitioning various compounds. Components of the aqueous DES system and extraction process were systematically studied, and the following optimal conditions were identified: menthol–acetic acid ratio of 1:1 (mol/mol), DES–water ratio of 1:1 (v/v), solid–liquid ratio of 15:1 (mg/mL), extraction power of 200 W, and extraction time of 10 min. The two-phase system easily separated compounds with differing polarity into the upper (DES-rich phase) and lower (water phase) phases after extraction. Analyses of the related mechanisms indicated that micelle formation of menthol-based DES in water was the dominant separating process and that this process provided large contact areas between target compounds and extraction solvent, thereby promoting extraction from G. biloba leaves. Moreover, this aqueous DES system could efficiently be recovered and reused in regeneration studies. This novel menthol-based aqueous DES system provides a sustainable extraction technology for various phytochemicals from plant materials.

Graphene oxide-assisted ethanol reflux extraction of total flavonoids from Ginkgo biloba leaves: study of kinetics and mechanism

Ginkgo biloba leaves (GBL) contain many biologically active compounds such as flavonoids and terpene trilactones. In this study, graphene oxide (GO)-assisted ethanol reflux extraction (GERE) was adopted to extract the Ginkgo flavonoids (GF) from GBL, and the kinetics and mechanism of GF extraction were studied. SEM, XRD and FT-IR results all showed that GO could disrupt the cellulose structure and reduce the crystallinity of GBL. Through the obtained experimental data, it can be seen that So–Macdonald model was suitable to describe the extraction kinetics with high values of the coefficient of determination (R2 ≥ 0.994) and low values of the residual sum of squares (RSS ≤ 0.00022). The optimum leaching conditions of GERE were 70% (v/v) of ethanol concentration, 16 mL/g of liquid to solid ratio, 1.5 mg/g of GO dosage and 140 rpm of stirring speed at 70°C for 4 h by the single factor experiments. Under these conditions, the equilibrium yield of GF by GERE reached 82.63%, about 5.60% higher than the conventional ethanol reflux extraction (ERE). The value of the apparent activation energy obtained was 3.69 kJ/mol for GERE, 6.35% lower than that for ERE at a temperature within the range of 40–70 °C. HPLC results indicated that GO could not decompose flavonoids. The higher yield of GF can be attributed to the catalytic hydrolysis to the cell wall by GO, which can decrease the apparent activation energy and accelerate the leaching of GF at the fast diffusion stage. GERE method is an efficient and green extraction technology and So–Macdonald model satisfactorily described the extraction kinetics of Ginkgo flavonoids.

Green and efficient extraction of total glucosides from Paeonia lactiflora Pall. ‘Zhongjiang’ by subcritical water extraction combined with macroporous resin enrichment

In this work, a green and efficient method of subcritical water extraction (SWE) combined with macroporous resin purification (MRP) of the total glucosides (TGP) from Paeonia lactiflora Pall. ‘Zhongjiang’ was established. The hydrolysis of albiflorin and paeoniflorin in subcritical water was initially studied. Albiflorin and paeoniflorin were stable in subcritical water at 180 °C for 10–30 min but unstable at high temperatures (T ≥ 220 °C) for a long time (time ≥ 40 min). Then, the response surface methodology (SMR) was used to optimise the SWE process for an enhanced extraction yield of TGP. The best extraction conditions obtained were as follows: extraction time 22 min, extraction temperature 158 °C, and liquid-to-solid ratio 21 mL/g. Under the optimal conditions, the maximum extraction yield of TGP reached 7.08%. In addition, the efficient AB-8 macroporous resin purification method of TGP was established from the SWE crude extract. The optimised loading amount was 1.6 BV (bed volume) of the TGP crude extract, and the desorption conditions were as follows: eluting 3 BV with ultrapure water, and then eluting with 20% ethanol at 2 BV·h−1 to collect 12 BV eluate. After the AB-8 resin treatment, the TGP content increased from 32.5% in the crude extract to 89.6% (albiflorin ≥ 25%, paeoniflorin ≥ 63%), and the recovery rate of TGP reached 84.2%. These results indicate that SWE combined with MRP is a simple, green, and effective technology for the TGP extraction from P. lactiflora ‘Zhongjiang’.

IFST Winning Articles

IFST Winning Articles

Antioxidant composite films with chitosan and carotenoid extract from Chlorella vulgaris: optimization of ultrasonic-assisted extraction of carotenoids and surface characterization of chitosan films

Recently, there is an increasing interest towards the application of bioactive natural polymer based packaging materials instead of synthetic polymers. Therefore, the aim of this work was to investigate to edible, biodegradable and antioxidant chitosan film incorporated with carotenoid extracts from Chlorella vulgaris. Firstly, green extraction technology, ultrasonic-assisted extraction (UAE) was applied for the extraction of lutein, β-carotene, and α-carotene from Chlorella vulgaris. Response surface methodology (RSM) was used for optimizing the extraction parameters of α-carotene, β-carotene and lutein. The maximum yields of lutein, β-carotene, and α-carotene were 4.844 ± 0.780, 0.258 ± 0.020 and 0.275 ± 0.040 mg g−1, respectively. Secondly, the produced chitosan films were characterized by FT-IR and SEM techniques. And also the release study of chitosan films was investigated according to the total phenolic content and antioxidant capacity methods. Moreover, the addition of carotenoid extract significantly improved biodegradable films that can be used as a packaging material and patches because of its antioxidative properties.