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Innovative ultrasound sonication pretreatment sparger-based microwave assisted extraction method for enhanced essential oil extraction from lemon grass
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Litsea cubeba fruit, which has the highest content of essential oils in the plant, is an important woody oil plant resource. In this study, the influence of the solvent-free microwave extraction (SFME) and hydrodistillation (HD) techniques on the extraction of L. cubeba fruit essential oils was investigated in terms of yield, kinetics, and chemical composition, where the former conditions were optimized by the response surface design. The maximal essential oil yield was obtained under the optimal SFME process conditions (442 W and 24 min), where the irradiation time was the most important variable (p < 0.0001). Regardless of the extraction method used, the influence of harvesting time on L. cubeba fruit essential oils were quantitatively and qualitatively analyzed afterwards, where the SFME essential oil from July showed its superiority over the others regarding its higher extraction yield and better bioactivities. Compared with the HD method, the SFME approach could significantly enhance the yield of essential oils extracted from June to August by nearly 47% with the advantages of saving energy and low environmental impact. Interestingly, the SFME method could selectively extract monoterpene hydrocarbons such as D-limonene with relation to different compositions and bioactivities. Moreover, SFME essential oil showed a better inhibitory effect on tyrosinase and melanogenesis, indicating its skin-whitening potential as a new promising natural cosmetic ingredient.
Oil has extensively been extracted from oil-bearing crops and traded globally as a major food commodity. There is always a huge demand from the fats and oils industries to increase oil yield because of profitability benefits. If extraction is conducted under mild operating conditions to preserve and improve the oil quality, then it would be an added value. Ultrasound that works on the cavitational action helps to fulfil the gap. Ultrasound is gaining tremendous interest as an alternative to replace the current conventional extractions approach because of its multiple benefits. Cavitation generated by ultrasound eases the release of oil from cell matrices, thereby allowing the extraction to be carried out under mild processing conditions. The effect enhances the oil yield whilst preserving the quality of the oil. In ultrasound, green solvents can be used to replace toxic organic solvents. Recent up-to-date approaches utilised a combination of ultrasound with enzyme, microwave and supercritical technology to further enhance the oil extraction. This review highlights a comprehensive work of the impact of ultrasound and ultrasound in combination with other technologies on oil extraction, which emphasises the extraction yield and physicochemical properties of the oil, such as fatty acid composition, oxidative stability with the retention of the lipophilic phytochemicals and iodine, saponification values and colour parameters. Understanding of ultrasonication techniques for oil extraction served to be essential and useful information for the fats and oils scientists from academia and industries to explore the possibility of employing a sustainable and mild approaches for extracting oil from various crops.
The work was designed to utilize the integration of microwave assisted extraction preceded by ultrasonic pre-treatment to enhance the extraction yield of essential oil. It called sequential ultrasonic microwave assisted extraction (SUMAE) method. The target plant was Lavandula coronopifolia Poir which has unique therapeutic properties. Comparisons in terms of extraction yield, antioxidant properties, chemical composition, antimicrobial properties, and environmental effects of the proposed method were performed by microwave extraction as a base method. Ultrasonic power, microwave power, and extraction time were selected as independent variables in order to optimize the extraction conditions using response surface methodology (RSM) with the central composite design (CCD). Essential oil yield was considered as the response. The highest yield was equivalent to 1.15% (w/w) which obtained under the following conditions: 150 W of ultrasonic power, 800 W of microwave power, and 40 min of extraction time. The value has increased by about 82% compared to the base method. The chemical composition results of the active ingredients showed that the number of compounds in SUMAE method is much higher than the one in the microwave method. Moreover, according to DPPH and FRAP results, the essential oils extracted by SUMAE method had more antioxidant properties The study of antimicrobial properties showed that the active ingredients obtained from the suggested extraction method have the highest antimicrobial properties. Besides that it is more environmental friendly than microwave-assisted extraction method.
Graphic abstract
Essential oils can be extracted from the leaves and stalk of aromatic grass plants, namely the citronella grass ( Cymbopogon nardus ) and lemongrass ( Cymbopogon citratus ), which grow primarily in the tropical and subtropical regions of the world. The word lemon denotes its unique lemon-like aroma, which is largely contributed by the existence of citral. This organic compound is an amalgamation of two stereoisomeric monoterpene aldehydes, in which the trans isomer geranial content is predominant over its cis isomer neral. The essential oil of lemongrass has been utilised since the old-times in traditional medicine as a natural remedy to improve circulation, control menstrual cycles, enhance digestion or improve immunity. It is also used to produce perfumes, flavours, detergents, and pharmaceuticals. Basically, citronella grass and lemongrass essential oil can be obtained by various extraction methods, such as conventional solvent extraction, ultrasound-assisted extraction (UAE), steam distillation, hydrodistillation (HD), microwave-assisted hydrodistillation (MAHD), and supercritical fluid extraction (SFE) with CO 2 . SFE is considered as the most selected consumer and environmentally friendly essential oil extraction method because its traceless solvent in the product. The quality of the essential oil from aromatic grass strongly depends on the extraction method and operating conditions. However, the chemical composition of the essential oil of C. nardus and C. citratus also varies with the geographical origin, cultivation practices, plant age, photoperiod, harvest period, cultivars, and extraction methods. The chemical markers which have consistently been identified in the essential oil of aromatic grass are aldehydes, hydrocarbon terpenes, alcohols, ketones, and esters. This article presents the recent information on extraction methods of aromatic grass essential oil, chemical composition and its potential in industrial applications.
The genus Cymbopogon (Greek words 'kymbe' meaning boat and 'pogon' meaning beard), commonly known as lemongrass, belongs to the Poaceae family. It comprises a large number species, but only two have economic importance as cultivated plants: C. citratus and C. flexuosus. However, C. citratus is more resistant to drought and low temperatures and because of that can be cultivated over large areas therefore it is commercially more important. C. citratus leaves are widely used as a lemon flavor ingredient in herbal teas, prepared either by decoction or infusion, or in finished herbal products such as capsules, tablets and creams. Even though essential oils are known for being used for fragrance and as an important ingredient in Asian cuisine, they are also used in other industries (pharmaceutical and cosmetic) due to their bioactive compounds that show various therapeutic effects. The chemical composition of C. citratus essential oil varies widely depending on genetic diversity, habitat and agronomic treatment of the culture, as well as on the part of the plant, maturity stage and extraction method. However, the essential oil of C. citratus mainly consists of the citral, which is a mixture of two isomeric acyclic monoterpene aldehides: geranial (trans-citral) and neral (cis-citral). C. citratus possesses good antibacterial activity, it could be used as alternative treatment for enteric fever, to cure infectious diseases related to the respiratory system, as well as for oral hygiene, it helps by removing bacteria from the oral cavity and prevents teeth and gum diseases such as peridontitis, plaque and gingivitis. Furthermore, C. citratus showed high contents of total phenolic and total flavonoids, as well as high free radical scavenging capacity with potential as an antioxidant. C. citratus shows good antiinflamatory, anti-diabetic, hypolipidemic, renoprotective and cardioprotective, as well as anticancer activities. Apart from this, C. citratus possesses vasorelaxant, sedative and antitusive potential. Furthermore, the compound citral is used in perfume industry as well as for cleaning wounds and treatment of skin diseases in forms of gels, or functional paper microencapsulated with essential oil, which can be used for hand hygiene.
Economic and pharmacological significance of the essential oils of members of the genus Cymbopogon is rapidly increasing. Lemongrass (Cymbopogon flexuosus), wild lemongrass (C. citratus), palmarosa (C. martinii) and citronella (C. winterianus) are the elite essential oil producing aromatic grasses of the genus Cymbopogon. Lemongrass essential oil is mainly comprises of cyclic and acyclic monoterpenes. Citral (a racemic mixture of two isoforms geranial and neral) is the major constituent which gives a characteristic lemon like aroma to lemongrass oil. Lemongrass oil and citral are mainly used in flavors, fragrances, cosmetics and pharmaceuticals. Beside citral is also used for the synthesis of vitamin B and ionones. In this chapter we have thoroughly discussed the various aspects of lemongrass essential oil like biosynthesis, accumulation, chemical compositions and biological properties. C li c k h e r e t o b u y AB B Y Y P D F Trans fo r m e r 2 .0 w w w .A B B Y Y .c o m C li c k h e r e t o b u y AB B Y Y P D F Trans fo r m e r 2 .0 w w w .A B B Y Y .c o m
Oil from sandalwood is commonly obtained by a conventional distillation process which requires great energy, significant amount of solvents, and quite a long process time. Therefore, the use of new 'green technique' for extracting essential oil with minimum/low energy, solvents, and time need to be considered. One extraction method which has been succesfully developed is microwave hydrodistillation method. This research employs a method developed from microwave hydrodistillation, that is microwave air-hydrodistillation for optimizing the extraction of essential oil. The purpose of this study is to examine the effect of the presence and absence of additional air flow to the microwave hydrodistillation method. The material used in this study includes sandalwood powder. The extractions by microwave hydrodistillation and microwave air-hydrodistillation methods were done on the power of 600W; the ratio of the raw material to be extracted and the solvent was 0.05 g mL-1 and the extraction time was 120 minutes. In the extraction by microwave air-hydrodistillation, the rates of air flow used were 0.1, 0.5, 1.5, 3.0, and 5.0 L/min. The results of the research show that the extraction of sandalwood oil by microwave air-hydrodistillation is faster and produces higher yields and recovery accumulation compared to the extraction by microwave hydrodistillation method. The testing of the physical properties of the sandalwood oil indicates that essential oil obtained by microwave hydrodistillation and microwave air-hydrodistillation has the same quality (refractive index and specific gravity). Further, the testing of the chemical properties of the sandalwood oil shows that essential oil obtained by microwave air-hydrodistillation has better quality (flavor) compared to the oil obtained by microwave hydrodistillation.
This article examines the essential oils that are the central tools of aromatherapy and uses them as a case study for different approaches to material culture. It considers the conceptual and political implications of thinking of essential oils as, in turn, commodities, materials and essences. I argue that both cultural studies and aromatherapy have something to learn from each other. Classic materialist approaches might do well to focus more attention on the material properties and effects of things. Aromatherapy, on the other hand, could benefit from the enriched political understanding associated with classic materialist critique. New materialist strains of cultural studies may also find the vibrancy of matter that underpins many CAM/New Age practices worthy of examination.
Recently, mushroom polysaccharides have been explored to attribute to vital biologically important functions, and several extraction techniques can be employed, therefore, polysaccharides were extracted from the edible mushroom Calocybe indica to explore its functionality. Multiple enzymes viz., cellulase, pectinase, and protease (1:1:1) at temperature 47 °C and pH 4.64 with an extraction time of 2 h yielded 7.24 % polysaccharide content. The thermograph curve of polysaccharides showed two-stage decomposition at a different temperature range and decomposition of polysaccharides initiated with an onset temperature of 226.77 °C and a maximum peak at 248.90 °C. Hydrodistillation processed Eucalyptus globulus leaf oil was characterized using the chromatography technique and eucalyptol, p-cymene, Γ-terpinene, 4-epi-cubebol, spathulenol, viridiflorol, and p-mentha-1,5-dien-8-ol was observed as major components. As well, we formulated nanoemulsion using mushroom polysaccharide and eucalyptus leaf oil with 140.8 nm and evaluated synergistic antimicrobial and antibiofilm activity. MIC and MBC values for Pseudomonas aeruginosa, E. coli, and S. typhi were 12.50–3.125 and 6.25–1.56, and for S. aureus were 6.25, 6.25, 3.125, and 3.125, 3.125, 1.56 and for C. albicans the values were 12.50,12.50, 6.250 and 6.25,6.25, and 3.125 μl/mL respectively. The polysaccharides, essential oil, and nanoemulsion showed remarkable antibiofilm activity against S.aureus with inhibition of 57.42 ± 0.19, 59.62 ± 0.15, and 69.34 ± 0.19 %, while E. coli showed the least antibiofilm activity. However, all three tested samples showed significant (p < 0.05) differences against tested pathogenic microorganisms with inhibition of biofilm formation. Therefore, it could be inferred that the synergistic properties of essential oils with mushroom polysaccharides are a promising strategy to enhance antimicrobial efficacy and control foodborne pathogens.
The genus Cymbopogon is important from the point of view of their essential oils. Essential oils from these species are widely used in flavours, fragrances, cosmetics, soaps, detergents and perfumery owing to their typical lemon-like aroma. Essential oil of Cymbopogon citratus was extracted by hydrodistillation and characterized using Gas chromatography/mass spectrometry (GC-MS) and Fourier Transform Infrared (FTIR).The oil was also subjected to physico-chemical analysis, the physical and chemical properties evaluated were Boiling point (74oC), Specific gravity (0.8960), Refractive index (1.4838) and pH (6.00) at 25oC. Saponification value(109.76) and Acid value (0.55) mg KOH/g oil. Iodine value (100g of I2/g oil) 105, Ester value (189.21), Residue on evaporation (10%) at 100oC.The chemical composition of the essential oil analyzed by GC-MS showed citral (31.1%), β-Myrcene (14.2%), citronellal (9.8%), limonene oxide (7.7%), eraniol (7.3%) and linalool (6.2%) as the major compounds. The FTIR spectra revealed the presence of n-alkane, conjugated alkene, primary amide, amine, aldehyde, primary and secondary alcohols. The results obtained from the physico-chemical parameters, and functional groups identified by FTIR as well as the compounds identified by GC-MS revealed that the oil has medicinal and nutritive values as well as industrial applications in the pharmaceutical, perfumery and cosmetic industries .Keywords: Characterization, Citral, Cymbopogon citratus, Essential oil, FTIR, GC-MS
Recently, microwave hydrodiffusion and gravity (MHG) pushed the confines of the microwave assisted extraction (MAE) further toward an innovative, quick, efficient, and eco-friendly process for plant secondary metabolites extraction. The goal of this study was to optimize the microwave hydrodiffusion and gravity (MHG) process for the extraction of the essential oils (EO) from Tunisian cumin (Cuminum cyminum L.) seeds. The effects of different parameters: microwave irradiation time (8, 12, and 16 min), microwave irradiation power (150, 200, and 250 W), and moisture content (40, 50, and 60%), on the extraction yield were achieved using the response surface methodology (RSM) with central composite design (CCD). In order to elucidate the efficiency of the MHG, it was compared with conventional hydrodistillation (HD) in terms of kinetic, quantity and quality of obtained EO, environmental impact, and energy consumption. Results showed that, under the optimum conditions defined by the central composite face-centered (CCF) and calculated by the analysis of variance (ANOVA) (16 min of microwave irradiation time, 203.30 W of microwave irradiation power, and 44.67% of moisture content), the yield of cumin essential oil obtained with MHG was 1.579 ± 0.05%. Meanwhile, compared with the HD process, the MHG successfully improved the EO yield (1.579 ± 0.05% versus 1.550 ± 0.07% with HD) in shorter extraction time (16 min versus 150 min with HD), less electrical consumption, lower carbon dioxide emissions (CO2), and smaller volume of waste water. Using the GC-FID and GC–MS analysis, the MHG provided more valuable EO with high amount of oxygenated compounds compared with the HD. Scanning electron micrograph (SEM) confirmed the efficiency of MHG for EO extraction. Thus, MHG appeared like rapid process, green technology, and desirable alternative protocol to enhance the quantity and the quality of the essential oil extracted from the medicinal and aromatic plants (MAPs).
This work was designed to utilize the integration of ultrasonic-microwave assisted preceded by enzymolysis pre-treatment to enhance the extraction efficiency of essential oil (EO) from wild Lavandula pubescens (Lp). Cellulase (C-ase), hemicellulase (H-ase) and mixed enzymes (C-ase/H-ase) were used at 10 mg/100 mL of the liquid phase. Gas chromatography mass spectrometry (GC-MS) system was used for chemical composition analyses of Lavandula pubescens essential oil (Lp-EO). C-ase pre-treatment achieved the highest yield (0.50%) of EO and highest ratio of carvacrol (29.22%) as the main compound in comparison to other treatments. Changes in the morphological structure of Lp tissues were tracked using Scanning electron microscope (SEM). Free radical-scavenging activity was assessed using DPPH•-SA and ABTS•+SA assays. The optimal extraction conditions were enzyme concentration of 14.82mg/100mL, sonication time of 38.18min, and microwave power at 333W. At these conditions, the maximum %yield, %DPPH•-SA, and ABTS•+SA were 0.67%, 65.40% and 0.025 (as mM Trolox), respectively. Results exhibited that the isolated Lp-EO could be used as anti-free radical and anti-bacterial agents in the biological systems.
Background
How to extract the bioactive compounds efficiently and safely is a central issue in modern food and pharmaceutical industry. Mechanochemical assisted extraction is an innovative effective and eco-friendly extraction technology, which has shown a great prospect in the industry and biotechnological research. By this method, mechanochemical pretreatment allowed physical and chemical transformations of target compound to improve its water solubility and accelerated extraction efficiency markedly.
Scope and approach
This review gives an overview of applications, possible mechanisms and important parameters of MAE. Furthermore, the comparison between MAE and other techniques is also presented. So far, several researches have evaluated the effect of MAE for extraction of bioactive compounds (e.g. flavonoids, magnolol, rutin and polysaccharides) and compared MAE with other extraction techniques (e.g. heat-reflux extraction and superfine grinding extraction).
Key findings and conclusions
The current studies demonstrated that MAE had many advantages such as high efficiency and selectivity, simpler manipulation and significant reduction of the organic solvent consumption. It is a potential alternative technique to the conventional extraction method in the industrial production. Moreover, since MAE is performed under relatively low temperature, it can reduce or avoid the loss of thermolabile compounds.
The second edition of this book is virtually a new book. It is the only comprehensive text on the safety of essential oils, the first review of essential oil/drug interactions, and it provides detailed essential oil constituent data not found in any other text. Much of the existing text has been re-written, and 80% of the text is completely new. There are 400 comprehensive essential oil profiles and almost 4000 references. There are new chapters on the respiratory system, the cardiovascular system, the urinary system, the digestive system and the nervous system. For each essential oil there is a full breakdown of constituents, and a clear categorization of hazards and risks, with recommended maximum doses and concentrations. There are also 206 Constituent Profiles. There is considerable discussion of carcinogens, the human relevance of some of the animal data, the validity of treating an essential oil as if it was a single chemical, and the arbitrary nature of uncertainty factors. There is a critique of current regulations.
Two important challenges need to be addressed to realize a practical biorefinery for the conversion of biomass to fuels and chemicals: (i) effective methods for the degradation and fractionation of lignocelluloses and (ii) efficient and robust chemical methods for the conversion of bio-feeds to target products via highly selective catalytic reactions. Ultrasonic energy promotes the pretreatment and conversion process through its special cavitational effects. In this review, recent progress and methods for combining and integrating sonication into biomass pretreatment and conversion for fuels and chemicals are critically assessed. Ultrasonic energy combined with proper solvents allows destruction of the recalcitrant lignocellulosic structure, fractionation of biomass components, and then assists many thermochemical and biochemical reactions, with increased equilibrium yields of sugars, bio-ethanol and gas products by 10–300%. Sonication promotes hydrolysis, esterification and transesterification in biodiesel synthesis and leads to reduced reaction time by 50–80%, lower reaction temperature, less amounts of solvent and catalyst than comparable unsonicated reaction systems. For algal biomass, sonication benefits the disruption, lysis and content release of macro and microalgae cells, and reduces the time required for subsequent extraction and chemical/biochemical reactions, with efficiencies typically being improved by 120–200%. High-frequency ultrasound of 1–3 MHz allows harvesting of microalgae, liquid product separation and in-situ process monitoring of biomass reactions, while high-intensity ultrasound at 20–50 kHz activates heterogeneous and enzymatic catalysis of the biomass reactions. The use of ultrasound in conversion of biomass to biofuels provides a positive process benefit.
A gas chromatography flame ionization detection method for the quantification of bioactive marker compounds (neral, geranial, geraniol, limonene, citronellal, and beta-myrcene) in the essential oil of Cymbopogon citratus (lemon grass) was developed. Four procedures for the extraction of essential oils from C. citratus were compared including solvent extraction, steam distillation extraction, accelerated solvent extraction, and supercritical fluid extraction. Solvent extraction by sonication with nonpolar solvents showed comparable results to the steam distillation method. Several commercial products prepared from C. citratus and Cymbopogon flexuosus were analyzed and compared.
Dried and ground leaves of lemon grass (Cymbopogon citratus Stapf.) were used as a matrix for supercritical extraction of essential oil with CO(2). The objective of this study was to analyze the influence of pressure on the supercritical extraction. A series of experiments were carried out, for 360 min, at 50 degrees C and at different pressures: 90, 100, 110 and 120 bar. Extraction conditions were chosen to maximize citral content in the extract oil. The collected extracts were analysed by GC-MS and their composition was compared with that of the essential oil isolated by hydrodistillation and by steam distillation. At higher solvent density the extract aspect changes passing from a characteristic yellow essential oil to yellowish semi-solid mass because of the extraction of high molecular mass compounds. The optimum conditions for citral extraction were 90 bar and 50 degrees C, at these conditions citral represent more than 68% of the essential oil and the extraction yield was 0.65% while the yield obtained from hydrodistillation was 0.43% with a content of citral of 73%.
Development and optimization of microwave assisted process for extraction of nutmeg mace essential oil. Department of Post-Harvest Technology and Agricultural Processing
- N Sagarika
- Sagarika N.