Intensification of extraction of curcumin from Curcuma amada using ultrasound assisted approach: Effect of different operating parameters

Curcumin, a dietary phytochemical, has been extracted from rhizomes of Curcuma amada using ultrasound assisted extraction (UAE) and the results compared with the conventional extraction approach to establish the process intensification benefits. The effect of operating parameters such as type of solvent, extraction time, extraction temperature, solid to solvent ratio, particle size and ultrasonic power on the extraction yield have been investigated in details for the approach UAE. The maximum extraction yield as 72% was obtained in 1 h under optimized conditions of 35 °C temperature, solid to solvent ratio of 1:25, particle size of 0.09 mm, ultrasonic power of 250 W and ultrasound frequency of 22 kHz with ethanol as the solvent. The obtained yield was significantly higher as compared to the batch extraction where only about 62% yield was achieved in 8 h of treatment. Peleg’s model was used to describe the kinetics of UAE and the model showed a good agreement with the experimental results. Overall, ultrasound has been established to be a green process for extraction of curcumin with benefits of reduction in time as compared to batch extraction and the operating temperature as compared to Soxhlet extraction.     

Green ultrasound-assisted extraction of carotenoids based on the bio-refinery concept using sunflower oil as an alternative solvent

A green, inexpensive and easy-to-use method for carotenoids extraction from fresh carrots assisted by ultrasound was designed in this work. Sunflower oil was applied as a substitute to organic solvents in this green ultrasound-assisted extraction (UAE): a process which is in line with green extraction and bio-refinery concepts. The processing procedure of this original UAE was first compared with conventional solvent extraction (CSE) using hexane as solvent. Moreover, the UAE optimal conditions for the subsequent comparison were optimized using response surface methodology (RSM) and ultra performance liquid chromatography – diode array detector – mass spectroscopy (UPLC–DAD–MS). The results showed that the UAE using sunflower as solvent has obtained its highest β-carotene yield (334.75 mg/l) in 20 min only, while CSE using hexane as solvent obtained a similar yield (321.35 mg/l) in 60 min. The green UAE performed under optimal extraction conditions (carrot to oil ratio of 2:10, ultrasonic intensity of 22.5 W cm^?2, temperature of 40 °C and sonication time of 20 min) gave the best yield of β-carotene.     

Comparison of ultrasound-assisted extraction with conventional extraction methods of oil and polyphenols from grape (Vitis vinifera L.) seeds

Ultrasound-assisted extraction (US) carried out at 20 KHz, 150 W for 30 min gave grape seed oil yield (14% w/w) similar to Soxhlet extraction (S) for 6 h. No significant differences for the major fatty acids was observed in oils extracted by S and US at 150 W. Instead, K₂₃₂ and K₂₆₈ of US- oils resulted lower than S-oil. From grape seeds differently defatted (S and US), polyphenols and their fractions were extracted by maceration for 12 h and by ultrasound-assisted extraction for 15 min. Sonication time was optimized after kinetics study on polyphenols extraction. Grape seed extracts obtained from seeds defatted by ultrasound (US) and then extracted by maceration resulted the highest in polyphenol concentration (105.20 mg GAE/g flour) and antioxidant activity (109 Eq αToc/g flour).     

Kinetic improvement of olive leaves’ bioactive compounds extraction by using power ultrasound in a wide temperature range

In this study, the effect of temperature and ultrasonic application on extraction kinetics of polyphenols from dried olive leaf was investigated. Conventional (CVE) and ultrasonic-assisted extraction (UAE) were performed at 10, 20, 30, 50 and 70 °C using water as solvent. Extracts were characterized by measuring the total phenolic content, the antioxidant capacity and the oleuropein content (HPLC–DAD/MS–MS). Moreover, Naik’s model was used to mathematically describe the extraction kinetics. The experimental results showed that phenolic extraction was faster in UAE (ultrasonic-assisted extraction) than in CVE (conventional extraction), being extraction kinetics satisfactorily described using Naik model (include VAR > 98%). Besides, the total phenolic content, the antioxidant capacity and the oleuropein content were significantly (p < 0.05) improved by increasing the temperature in both CVE and UAE. Oleuropein content reached 6.57 ± 0.18 being extracted approximately 88% in the first minute for UAE experiments.     

Comparisons between conventional,ultrasound-assisted and microwave-assisted methods for extraction of anthraquinones from Heterophyllaea pustulata Hook f. (Rubiaceae)

This work reports a comparative study about extraction methods used to obtain anthraquinones (AQs) from stems and leaves of Heterophyllae pustulata Hook (Rubiáceae). One of the conventional procedures used to extract these metabolites from a vegetable matrix is by successive Soxhlet extractions with solvents of increasing polarity: starting with hexane to eliminate chlorophylls and fatty components, following by benzene and finally ethyl acetate. However, this technique shows a low extraction yield of total AQs, and consumes large quantities of solvent and time. Ultrasound-assisted extraction (UAE) and microwave-assisted extraction (MAE) have been investigated as alternative methods to extract these compounds, using the same sequence of solvents. It was found that UAE increases the extraction yield of total AQs and reduces the time and amount of solvent used. Nevertheless, the combination UAE with benzene, plus MAE with ethyl acetate at a constant power of 900 W showed the best results. A higher yield of total AQs was obtained in less time and using the same amount of solvent that UAE. The optimal conditions for this latter procedure were UAE with benzene at 50 °C during 60 min, followed by MAE at 900 W during 15 min using ethyl acetate as extraction solvent.     

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

In this study, extraction of essential oil, polyphenols and pectin from orange peel has been optimized using microwave and ultrasound technology without adding any solvent but only “in situ” water which was recycled and used as solvent. The essential oil extraction performed by Microwave Hydrodiffusion and Gravity (MHG) was optimized and compared to steam distillation extraction (SD). No significant changes in yield were noticed: 4.22 ± 0.03% and 4.16 ± 0.05% for MHG and SD, respectively. After extraction of essential oil, residual water of plant obtained after MHG extraction was used as solvent for polyphenols and pectin extraction from MHG residues. Polyphenols extraction was performed by ultrasound-assisted extraction (UAE) and conventional extraction (CE). Response surface methodology (RSM) using central composite designs (CCD) approach was launched to investigate the influence of process variables on the ultrasound-assisted extraction (UAE). The statistical analysis revealed that the optimized conditions of ultrasound power and temperature were 0.956 W/cm² and 59.83 °C giving a polyphenol yield of 50.02 mg GA/100 g dm. Compared with the conventional extraction (CE), the UAE gave an increase of 30% in TPC yield. Pectin was extracted by conventional and microwave assisted extraction. This technique gives a maximal yield of 24.2% for microwave power of 500 W in only 3 min whereas conventional extraction gives 18.32% in 120 min. Combination of microwave, ultrasound and the recycled “in situ” water of citrus peels allow us to obtain high added values compounds in shorter time and managed to make a closed loop using only natural resources provided by the plant which makes the whole process intensified in term of time and energy saving, cleanliness and reduced waste water.     

Effect of acoustic frequency and power density on the aqueous ultrasonic-assisted extraction of grape pomace (Vitis vinifera L.) – A response surface approach

Aqueous ultrasound-assisted extraction (UAE) of grape pomace was investigated by Response Surface Methodology (RSM) to evaluate the effect of acoustic frequency (40, 80, 120 kHz), ultrasonic power density (50, 100, 150 W/L) and extraction time (5, 15, 25 min) on total phenolics, total flavonols and antioxidant capacity. All the process variables showed a significant effect on the aqueous UAE of grape pomace (p < 0.05). The Box–Behnken Design (BBD) generated satisfactory mathematical models which accurately explain the behavior of the system; allowing to predict both the extraction yield of phenolic and flavonol compounds, and also the antioxidant capacity of the grape pomace extracts. The optimal UAE conditions for all response factors were a frequency of 40 kHz, a power density of 150 W/L and 25 min of extraction time. Under these conditions, the aqueous UAE would achieve a maximum of 32.31 mg GA/100 g fw for total phenolics and 2.04 mg quercetin/100 g fw for total flavonols. Regarding the antioxidant capacity, the maximum predicted values were 53.47 and 43.66 mg Trolox/100 g fw for CUPRAC and FRAP assays, respectively. When comparing with organic UAE, in the present research, from 12% to 38% of total phenolic bibliographic values were obtained, but using only water as the extraction solvent, and applying lower temperatures and shorter extraction times. To the best of the authors’ knowledge, no studies specifically addressing the optimization of both acoustic frequency and power density during aqueous-UAE of plant materials have been previously published.     

Optimisation of ultrasound assisted extraction of phenolic compounds from Sparganii rhizoma with response surface methodology

The present study reports on the extraction of phenolic compounds from sparganii rhizome. Box–Behnken Design (BBD), a widely used form of response surface methodology (RSM), was used to investigate the effect of process variables on the ultrasound-assisted extraction (UAE). Three independent variables including ethanol concentration (%), extraction time (min) and solvent-to-material ratio (mL/g) were studied. The results showed that the optimal UAE condition was obtained with an ethanol concentration of 75.3%, an extraction time of 40 min and a solvent-to-material ratio of 19.21 mL/g for total phenols, and an ethanol concentration of 80%, an extraction time of 33.54 min and solvent-to-material ratio of 22.72 mL/g for combination of ρ-hydroxybenzaldehyde, ρ-coumaric acid, vanillic acid, ferulic acid, rutin and kaempferol. The experimental values under optimal conditions were in good consistent with the predicted values, which suggested UAE is more efficient process as compared to solvent extraction.     

Ultrasound induced green solvent extraction of oil from oleaginous seeds

Ultrasound-assisted extraction of rapeseed oil was investigated and compared with conventional extraction for energy efficiency, throughput time, extraction yield, cleanness, processing cost and product quality. A multivariate study enabled us to define optimal parameters (7.7 W/cm² for ultrasonic power intensity, 40 °C for processing temperature, and a solid/liquid ratio of 1/15) for ultrasound-assisted extraction of oil from oilseeds to maximize lipid yield while reducing solvent consumption and extraction time using response surface methodology (RSM) with a three-variable central composite design (CCD). A significant difference in oil quality was noted under the conditions of the initial ultrasound extraction, which was later avoided using ultrasound in the absence of oxygen. Three concepts of multistage cross-current extraction were investigated and compared: conventional multistage maceration, ultrasound-assisted maceration and a combination, to assess the positive impact of using ultrasound on the seed oil extraction process. The study concludes that ultrasound-assisted extraction of oil is likely to reduce both economic and ecological impacts of the process in the fat and oil industry.     

Effects of various factors of ultrasonic treatment on the extraction yield of all-trans-lycopene from red grapefruit (Citrus paradise Macf.)

The effects of various factors, including the extraction time, temperature, solvent/material ratio, the ultrasonic intensity and duty cycle of ultrasonic irradiation on the extraction yield of all-trans-lycopene from red grapefruit by ultrasound-assisted extraction (UAE) were investigated. In comparison with conventional solvent extraction (CSE), UAE showed a pronounced greater extraction yield and reduced extraction time effectively with a peak value at 30 min. The extraction yield was significantly influenced by temperature and the optimum condition was 30 °C. The extraction yield increased with increasing of solvent/material ratio until equilibrium was arrived at the optimal ratio of 3:1 (mL/g). The extraction yield increased first and then decreased with an increase in ultrasonic intensity. The extraction yield of UAE increased with the increase of duty cycle, whereas pulsed ultrasound with proper intervals was more efficient than continuous ultrasonication. The degradation via isomerisation of all-trans-lycopene under ultrasonic treatment was also observed with the formation of 9,13′-di-cis-, 9,13-di-cis-, 15-cis-, 13-cis- and 9-cis-lycopene isomers which were tentatively identified by HPLC-PAD.     

Aqueous ionic liquid based ultrasonic assisted extraction of eight ginsenosides from ginseng root

We developed an aqueous ionic liquid based ultrasonic assisted extraction (ILUAE) method for the extraction of the eight ginsenosides (ginsenoside-Rg1, -Re, -Rf, -Rb1, -Rc, -Rb2, -Rb3 and -Rd) from ginseng root. A series of l-alkyl-3-methylimidazolium ionic liquids differing in composition of anions and cations were evaluated for extraction efficiency. The results indicated that the ILUAE method has a remarkable ability to improve the extraction efficiency of ginsenosides. In addition, the ILUAE procedure was also optimized on some ultrasonic parameters, such as the IL concentration, solvent to solid ratio and extraction time. Under these optimal conditions (e.g., with 0.3 M [C₃MIM]Br, solvent to solid ratio of 10:1 and extraction time of 20 min), this approach gained the highest extraction yields of total ginsenosides 17.81 ± 0.47 mg/g. Compared with the regular UAE, the proposed approach exhibited 3.16 times higher efficiency and 33% shorter extraction time, which indicated that ILUAE has a broad prospect for sample preparation of medicinal plants.     

A possible general mechanism for ultrasound-assisted extraction (UAE) suggested from the results of UAE of chlorogenic acid from Cynara scolymus L. (artichoke) leaves

The use of ultrasound-assisted extraction (UAE) for the extraction of chlorogenic acid (CA) from Cynara scolymus L., (artichoke) leaves using 80% methanol at room temperature over 15 min gave a significant increase in yield (up to a 50%) compared with maceration at room temperature and close to that obtained by boiling over the same time period. A note of caution is introduced when comparing UAE with Soxhlet extraction because, in the latter case, the liquid entering the Soxhlet extractor is more concentrated in methanol (nearly 100%) that the solvent in the reservoir (80% methanol) due to fractionation during distillation. The mechanism of UAE is discussed in terms of the effects of cavitation on the swelling index, solvent diffusion and the removal of a stagnant layer of solvent surrounding the plant material.     

Effect of ultrasonic treatment on the polyphenol content and antioxidant capacity of extract from defatted hemp,flax and canola seed cakes

The effectiveness of ultrasonic extraction of phenolics and flavonoids from defatted hemp, flax and canola seed cakes was compared to the conventional extraction method. Ultrasonic treatment at room temperature showed increased polyphenol extraction yield and antioxidant capacity by two-fold over the conventional extraction method. Different combinations of ultrasonic treatment parameters consisting of solvent volume (25, 50, 75 and 100 mL), extraction time (20, 30 and 40 min) and temperature (40, 50, 60 and 70 °C) were selected for polyphenol extractions from the seed cakes. The chosen parameters had a significant effect (p < 0.05) on the polyphenol extraction yield and subsequent antioxidant capacity from the seed cakes. Application of heat during ultrasonic extraction yielded higher polyphenol content in extracts compared to the non-heated extraction. From an orthogonal design test, the best combination of parameters was 50 mL of solvent volume, 20 min of extraction time and 70 °C of ultrasonic temperature.     

Effects of various factors of ultrasonic treatment on the extraction recovery of drugs from fish tissues

In the present research, a combined extraction method of ultrasound-assisted extraction (UAE) in conjunction with solid phase extraction (SPE) was applied to isolation and enrichment of selected drugs (metoprolol, ticlopidine, propranolol, carbamazepine, naproxen, acenocumarol, diclofenac, ibuprofen) from fish tissues. The extracted analytes were separated and determined by ultra-high performance liquid chromatography with UV detection (UHPLC–UV) technique. The selectivity of the developed UHPLC–UV method was confirmed by comparison with ultra-high performance liquid chromatography–tandem mass spectrometry (UHPLC–MS/MS) analysis.The important parameters, such as composition of type and pH of extraction solvent, solid/liquid rate volume of extraction solvent and number of extraction cycles were studied. The ultrasonic parameters, such as time, power and temperature of the process were optimized by using a half-fraction factorial central composite design (CCD). The mixture of 10 mL of methanol and 7 mL of water (pH 2.2) (three times) was chosen for the extraction of selected drug from fish tissues. The results showed that the highest recoveries of analytes were obtained with an extraction temperature of 40 °C, ultrasonic power of 300 W, extraction time of 30 min.Under the optimal conditions, the linearity of method was 0.12–5.00 μg/g. The determination coefficients (R²) were from 0.979 to 0.998. The limits of detection (LODs) and limits of quantification (LOQs) for the extracted compounds were 0.04–0.17 μg/g and 0.12–0.50 μg/g, respectively. The recoveries were between 85.5% and 115.8%.     

Aqueous ionic liquid based ultrasonic assisted extraction of four acetophenones from the Chinese medicinal plant Cynanchum bungei Decne

In this study, an aqueous ionic liquid based ultrasonic assisted extraction (ILUAE) method for the extraction of the four acetophenones, namely 4-hydroxyacetophenone (1), 2,5-dihydroxyacetophenone (2), baishouwubenzophenone (3) and 2,4-dihydroxyacetophenone (4) from the Chinese medicinal plant Cynanchum bungei was developed. Three kinds of aqueous l-alkyl-3-methylimidazolium ionic liquids with different anion and alkyl chain were investigated. The results indicated that ionic liquids (ILs) showed remarkable effects on the extraction efficiency of acetophenones. In addition, the ILUAE, including several ultrasonic parameters, such as the ILs concentration, solvent to solid ratio, power, particle size, temperature, and extraction time have been optimized. Under these optimal conditions (e.g., with 0.6 M [C₄MIM]BF₄, solvent to solid ratio of 35:1, power of 175 W, particle size of 60–80 mesh, temperature of 25 °C and time of 50 min), this approach gained the highest extraction yields of four acetophenones 286.15, 21.65, 632.58 and 205.38 μg/g, respectively. The proposed approach has been evaluated by comparison with the conventional heat-reflux extraction (HRE) and regular UAE. The results indicated that ILUAE is an alternative method for extracting acetophenones from C. bungei.     

Optimization of ultrasonic-assisted extraction (UAE) of betulin from white birch bark using response surface methodology

Betulin is an abundant naturally occurring triterpene, which makes it a potentially important raw material for a precursor of biologically active compounds. The objective of the current study was to determine the optimum UAE conditions for betulin from B. papyfera bark. The optimum conditions were evaluated with fractional factorial design and optimized using response surface methodology. High yields of betulin were observed from white birch bark by UAE technology. The solvent concentration and the ratio of material to solvent were the most significant parameters on betulin extraction as evaluated through FFD. The extraction conditions were further investigated with central composite design. The fitted second-order model revealed that the optimal conditions consisted of 98% ethonal concentration, 1:42 the ratio of white birch bark to solvent, extraction temperature 50 °C, ultrasonic frequency 5 kHz and extraction time 3 h. Under the optimized condition, the maximum productivity of betulin predicted is 23.17%. The extraction productivity and purity of betulin under the optimized extraction conditions were great higher than that of the non-optimized condition. The present study demonstrates that ultrasound is a great efficiency tool for the fast extraction of betulin from white birch bark.     

Enhancement of ultrasound-assisted extraction of sulforaphane from broccoli seeds via the application of microwave pretreatment

In this study, microwave pretreatment and grinding treatment were used to enhance sulforaphane formation, then ultrasonic-assisted extraction (UAE) was applied to extract sulforaphane using simultaneous hydrolysis and extraction method. The effects of various parameters, which were ultrasonic time, ultrasonic power, solid-water ratio and solid-ethyl acetate ratio on the extraction rate of sulforaphane were investigated. The results showed that microwave pretreatment enhanced sulforaphane formation. Excessive size reduction did not increase or even reduced extraction rate of sulforaphane. Simultaneous hydrolysis and extraction significantly increased extraction rate of sulforaphane compared to hydrolysis followed by extraction. UAE accelerated mass transfer and the solubilization of the targeted compounds due to the acoustic cavitation effect, thus enhanced enzymatic hydrolysis of glucoraphanin and the extraction rate of sulforaphane. The extraction rate of sulforaphane using UAE with simultaneous hydrolysis and extraction was 4.07-fold of the conventional extraction method. UAE was an effective method to extract sulforaphane from broccoli seeds since it led to higher yield of sulforaphane in a much shorter extraction time.     

Ultrasonic extraction of steroidal alkaloids from potato peel waste

Potato processors produce large volumes of waste in the form of potato peel which is either discarded or sold at a low price. Potato peel waste is a potential source of steroidal alkaloids which are biologically active secondary metabolites which could serve as precursors to agents with apoptotic, chemopreventive and anti-inflammatory properties. The present study investigated the relative efficacy of ultrasound assisted extraction (UAE) and solid liquid extraction (SLE) both using methanol, to extract steroidal alkaloids from potato peel waste and identified optimal conditions for UAE of α-solanine, α-chaconine, solanidine and demissidine. Using response surface methodology optimal UAE conditions were identified as an amplitude of 61 μm and an extraction time of 17 min which resulted the recovery of 1102 μg steroidal alkaloids/g dried potato peel (DPP). In contrast, SLE yielded 710.51 glycoalkaloid μg/g DPP. Recoveries of individual glycoalkoids using UAE yielded 273, 542.7, 231 and 55.3 μg/g DPP for α-solanine, α-chaconine, solanidine and demissidine respectively. Whereas for SLE yields were 180.3, 337.6, 160.2 and 32.4 μg/g DPP for α-solanine, α-chaconine, solanidine and demissidine respectively. The predicted values from the developed second order quadratic polynomial equation were in close agreement with the experimental values with low average mean deviation (E < 5%) values. Predicted models were highly significant (p < 0.05) for all parameters studied. This study indicates that UAE has strong potential as an extraction method for steroidal alkaloids from potato peel waste.     

Instant controlled pressure drop technology and ultrasound assisted extraction for sequential extraction of essential oil and antioxidants

The instant controlled pressure drop (DIC) technology enabled both the extraction of essential oil and the expansion of the matrix itself which improved solvent extraction. The sequential use of DIC and Ultrasound Assisted Extraction (UAE) triggered complementary actions materialized by supplementary effects. We visualized these combination impacts by comparing them to standard techniques: Hydrodistillation (HD) and Solvent Extraction (SE). First, the extraction of orange peel Essential Oils (EO) was achieved by HD during 4 h and DIC process (after optimization) during 2 min; EO yields was 1.97 mg/g dry material (dm) with HD compared to 16.57 mg/g dm with DIC. Second, the solid residue was recovered to extract antioxidant compounds (naringin and hesperidin) by SE and UAE. Scanning electron microscope showed that after HD the recovered solid shriveled as opposite to DIC treatment which expanded the product structure. HPLC analyses showed that the best kinetics and yields of naringin and hesperidin extraction was when DIC and UAE are combined. Indeed, after 1 h of extraction, DIC treated orange peels with UAE were 0.825 ± 1.6 × 10^?2 g/g of dry material (dm) for hesperidin and 6.45 × 10^?2 ± 2.3 × 10^?4 g/g dm for naringin compared to 0.64 ± 2.7 × 10^?2 g/g of dry material (dm) and 5.7 × 10^?2 ± 1.6 × 10^?3 g/g dm, respectively with SE. By combining DIC to UAE, it was possible to enhance kinetics and yields of antioxidant extraction.