Essential oil of nutmeg pericarp

The composition of the volatile oil extracted by hydro-distillation from nutmeg pericarp and the component retention indices were determined by gas chromatography–mass spectrometry GC-MS The oil contains 16 monoterpenes (60%), nine monoterpene alcohols (29%), eight aromatic ethers (7%), three sesquiterpenes (1%), six esters (1%) and eight other minor components. The components are similar to those in nutmeg and mace oils but differ substantially in concentrations. The sabinene, myristicin and safrole concentrations are much lower while the terpinen-4-ol and α-terpineol contents are much higher than in nutmeg and mace oils. © 1999 Society of Chemical Industry     

Ultrasound and microwave assisted extraction of diosgenin from fenugreek seed and fenugreek-supplemented cookies

Fenugreek has been recognized as the most important medicinal plant. The presence of diosgenin in fenugreek seed is known to have promising health benefits. In the present work the extraction of diosgenin from the fenugreek seed was performed and its supplementation in cookies was done. The ultrasound-assisted extraction (UAE) and microwave-assisted extraction (MAE) methods have been applied for extraction of diosgenin. In case of UAE, the maximum diosgenin was obtained from fenugreek seed powder with 80 % ethanol solution for 50 min, whereas the maximum diosgenin in MAE was obtained at 80 % ethanol solution for 4 min. Overall, the extract yield of UAE was higher than MAE. The UAE method with an ethanolic concentration of 80 % was considered as optimum for the determination of diosgenin in cookies. The diosgenin content of the cookies supplemented with fenugreek seed powder increased with its increase and the diosgenin content ranged from 0.099 to 0.191 g diosgenin equivalent/100 g of cookies. Further research on the incorporation of fenugreek seed powder and diosgenin in ready-to-eat foods are of great value because of health benefits of diosgenin and market demand of ready-to-eat foods.     

Microwave-Assisted Extraction of Anthocyanins from Black Currant Marc

This paper reports on the process optimization study of anthocyanin extraction from black currant marc by microwave-assisted extraction (MAE) using acidic solvents. Maximum yields of anthocyanins were achieved at pH?2 with an extraction time of 10 min with a microwave power of 700 W. The anthocyanin yields in MAE were compared with those obtained by conventional solvent extraction (CE) using citric or hydrochloric acids, and citric acid and water with a sulfur concentration of 50 ppm. A significant reduction of extraction time was achieved using MAE; maximum anthocyanin yield was obtained after 10 min using MAE, while using CE only after 300 min. Furthermore, the amount of solvent used halved; the mass ratio of marc to solvent was 1:40 in CE and 1:20 in MAE. Additionally, the final anthocyanin concentration in the solvent phase of MAE increased by 20 % compared to the conventional extraction with hydrochloric acid at pH?2 and temperature of 80 °C. The results suggest that microwave-assisted extraction is a more efficient technique for the extraction of valuable compounds from black currant residue.     

Determination of Ochratoxin A in Bread: Evaluation of Microwave-Assisted Extraction Using an Orthogonal Composite Design Coupled with Response Surface Methodology

An analytical method using microwave-assisted extraction (MAE) and liquid chromatography (LC) with fluorescence detection (FD) for the determination of ochratoxin A (OTA) in bread samples is described. A 2⁴ orthogonal composite design coupled with response surface methodology was used to study the influence of MAE parameters (extraction time, temperature, solvent volume, and stirring speed) in order to maximize OTA recovery. The optimized MAE conditions were the following: 25 mL of acetonitrile, 10 min of extraction, at 80 °C, and maximum stirring speed. Validation of the overall methodology was performed by spiking assays at five levels (0.1–3.00 ng/g). The quantification limit was 0.005 ng/g. The established method was then applied to 64 bread samples (wheat, maize, and wheat/maize bread) collected in Oporto region (Northern Portugal). OTA was detected in 84 % of the samples with a maximum value of 2.87 ng/g below the European maximum limit established for OTA in cereal products of 3 ng/g.     

Determination of Polyamines in Baby Food by Gas Chromatography-Mass Spectrometry: Optimization of Extraction and Microwave-Assisted Derivatization Using Response Surface Methodology

The present work evaluates the feasibility of microwave-assisted acylation combined with previous ion-pair extraction for the determination of the polyamines spermidine and spermine in baby food by GC-MS. In this way, extraction and derivatization reaction times were simultaneously optimized using a central composite rotational design. From response surface analysis, we verified maximum analytical response for spermidine and spermine employing 1 M hydrochloric acid solution as extraction solvent under shaking during 35 min, followed by acylation derivatization using a household microwave at 600 W for only 5 min. Limits of detection and quantification of 5 and 10 μg kg^?1 were achieved, and recoveries from 72 to 112% and RSD values ≤16% were obtained under repeatability and within-reproducibility conditions for both polyamines, at levels of 250 and 500 μg kg^?1. The validated GC-MS method was applied for 20 baby food samples commercially available in Brazil, thus resulting in the first report on spermidine and spermine in baby food.     

Development of an Aqueous Polyethylene Glycol-Based Extraction and Recovery Method for Almond (<Emphasis Type="Italic">Prunus armeniaca L</Emphasis>.) Protein

A novel method for protein extraction from sweet almonds with aqueous polyethylene glycol (PEG) as solvent and recovery from the extraction solution was developed. The extraction yields of different solvents, such as sodium hydroxide, sodium chloride, PEG 200, PEG 400, and PEG 600 aqueous solutions, were investigated and PEG 200 showed the highest extraction efficiency. The PEG-based microwave-assisted extraction (MAE) parameters were then optimized using response surface methodology. Under optimum condition, PEG 200 concentration of 25 % (w/w), liquid to solid ratio of 22 mL g^?1, microwave power of 120 W, extraction temperature of 45 °C, and extraction time of 4 min, the average extraction yield was 93.75?±?3.15 %. Subsequently, the almond protein was recovered from the extraction solution containing PEG with an isoelectric point-ethanol synergy precipitation protocol. The combined technique integrated the speed of isoelectric point precipitation with the completeness of alcohol precipitation. The recovery of almond protein was 98.81 % with a time of 3–5 min. The proposed PEG-based MAE and synergy precipitation protocol provide a rapid and effective method for almond protein extraction and recovery and have the potential to be used for other plant proteins.     

Evaluation of a Microwave-Assisted Extraction Method for Lignan Quantification in Flaxseed Cultivars and Selected Oil Seeds

An optimized microwave-assisted extraction (MAE) method was evaluated through repeatability, recovery and efficiency testing. The repeatability tests, performed by three users over time, were not significantly different. The recovery of lignan throughout the extraction, preparation and analysis steps is 97.5% with a coefficient of variation <1%. The MAE method is efficient for extracting lignans from the plant matrix, and it achieves significantly higher extraction yields than the two established reference methods. The applicability of the MAE method was demonstrated by extracting lignans from a variety of plant samples. The secoisolariciresinol diglucoside (SDG) content of seven flaxseed cultivars grown in Saint-Mathieu-de-Beloeil, QC, in 2009 ranged from 14.6 to 18.9 mg SDG per gram of seed. Flax hulls produced in Winchester, ON, in 2010 were very rich in lignan; their SDG content was 40.0 mg/g of flax hull. Sesame seeds contained 0.18–1.89 mg SECO (aglycone of SDG) per gram of seed, with significant differences among black, white and brown sesame seed. Chia seeds contained 0.99–1.29 mg SECO per gram of seed, with significant differences among batches of seeds. Sunflower seeds had 0.046 mg SECO per gram of sample and almonds had 0.029 mg SDG per gram of sample. The optimized and evaluated MAE method is recommended for the general analytical quantification of lignans in plant samples.     

Application and Optimization of Microwave-Assisted Extraction and Dispersive Liquid–Liquid Microextraction Followed by High-Performance Liquid Chromatography for the Determination of Oleuropein and Hydroxytyrosol in Olive Pomace

In the present study, a new method based on microwave-assisted extraction and dispersive liquid–liquid microextraction (MAE–DLLME) followed by high-performance liquid chromatography (HPLC) was proposed for the separation and determination of oleuropein (Ole) and hydroxytyrosol (HyT) from olive pomace samples. The effective factors in the MAE–DLLME process such as microwave power, extraction time, the type and volume of extraction, and dispersive solvents were studied and optimized with the aid of response surface methodology (RSM) based on a central composite design (CCD) to obtain the best condition for Ole and HyT extraction. At the optimized conditions, parameter values were 220 W microwave power, 12 min extraction time, 60 μL extracting solvent, and 500 μL dispersive solvent. The calibration graphs of the proposed method were linear in the range of 10–500,000 μg L^?1, with the coefficient of determination (R²) higher than 0.99 for Ole and HyT. Repeatability of the method, described as the relative standard deviation (RSD), was 4.12–5.63% (n?=?6). The limits of detection were 35 and 20 μg L^?1 for Ole and HyT, respectively. The recoveries of these compounds in the spiked olive pomace sample were from 93 to 98%. The proposed method, MAE–DLLME–HPLC–UV, was an accurate, rapid, and reliable method when compared with previous methods.     

Extraction of caffeine and catechins using microwave-assisted and ultrasonic extraction from green tea leaves: an optimization study by the IV-optimal design

In this research, optimal conditions for extraction of caffeine and polyphenols were established from Iranian green tea leaves. In the first step, caffeine was extracted with efficacy about 86% versed to 4.5% of EGC + EGCG. The EGCG + EGC was extracted from partially decaffeinated green tea leaves through microwave-assisted extraction (MAE) and ultrasound-assisted extraction (USE) with efficiency levels of 95 and 85%, respectively. The best results for the MAE process were obtained with 7.8 min and three number of extraction cycles and for the USE process were as followed: time 57 min, temperature 65 °C, and the number of extraction cycles 3. The total phenol content values at the best conditions of MAE and the USE processes were 125 ± 5 and 96 ± 6 mg gallic acid/g DW. The 50% inhibition (IC₅₀) on 1,1-diphenyl-2-picrylhydrazyl (DPPH) were 56 and 66 mg/g of phenol for the MAE and USE processes.     

Optimization of green extraction methods for cinnamic acid and cinnamaldehyde from Cinnamon (<Emphasis Type="Italic">Cinnamomum cassia</Emphasis>) by response surface methodology

The major compounds of cinnamon are cinnamic acid and cinnamaldehyde, for which the conditions of microwave-assisted extraction (MAE), ultrasound-assisted extraction (UAE), and reflux extraction (RE) were optimized using response surface methodology for comparing their efficiencies in terms of extraction yield, consumption of time and energy, and CO₂ emission. The results indicated MAE superiority to UAE and RE owing to the highest yield of target compounds (total yield: 0.89%, cinnamic acid: 6.48 mg/100 mL, and cinnamaldehyde: 244.45 mg/100 mL) at optimum MAE conditions: 59% ethanol, 147.5 W microwave power and 3.4 min of extraction time. RE resulted in comparable yields with the highest consumption of time, energy, and solvent, and least CO₂ emission. Therefore, it is concluded that MAE is the most efficient method for green extraction of cinnamic acid and cinnamaldehyde from cinnamon powder compared to UAE and RE.     

Optimization of Conditions for Organic Acid Extraction from Edible Plant Material as Applied to Radish Sprouts

In recent years, there has been growing interest in the influence of sprouts on health. Fruit and vegetables are the main sources of organic acids for humans; however, little is yet known about organic acids in sprouts. In this study, the selection of the optimal parameters for extraction of organic acids from fresh, edible sprouts is reported. Two extraction techniques: microwave-assisted (MAE) and ultrasound-assisted were compared. The experimental conditions were optimized in terms of extraction time, temperature, and composition of extraction solution. To determine the influence of time and temperature of extraction or sample cooling, solvents used for extraction, on the analytical signal in isotachophoretic separation, the methods of experimental planning fractional factorial design: 3^k?1 were used (three factor, three-level design). The optimal conditions for extraction of organic acids from radish sprouts were MAE, 90 °C; 18 min; and 0.01 M NaOH as a solvent.     

微波辅助萃取冬枣环磷酸腺苷工艺研究

研究利用微波辅助萃取MAE(microwave-assisted extraction)提取冬枣中环磷酸腺苷的新方法。以高效液相色谱法HPLC(high performance liquid chromatography)定量测定所萃取的环磷酸腺苷。采用正交试验考察浸泡时间、处理时间、微波功率和料液比对环磷酸腺苷提取率的影响,确定最佳工艺条件为:微波功率200W、浸泡时间6h、处理时间3min、料液比1:20。     

Development of a Microwave-Assisted Extraction Method for the Determination of Organochlorine Pesticides in Mussel Tissue

A method for the multiresidue analysis of 16 organochlorine insecticides in mussel tissue was developed. The method was based on the microwave-assisted extraction of the mussel tissue by the use of acetonitrile followed by the solid phase extraction (SPE) cleanup of the extracts and subsequent analysis by GC/MS in the selected ion monitoring (SIM) mode. Microwave-assisted extraction (MAE) operational parameters (extraction temperature and time, extractant volume) were optimized with respect to extraction efficiency of the target compounds. Recoveries >70 % with percent relative standard deviation (RSD%) <20 % were obtained for all compounds under the selected parameters. The Florisil cleanup step was efficient enough in the removal of co-extracted substances so that no adverse effect on the chromatographic system was observed. The proposed method was used for the analysis of mussel samples from aquacultures in Greece. Overall the proposed method was efficient, fast, and had low solvent consumption.     

小麦胚芽VE的微波萃取工艺和神经网络模型的研究

本文研究了微波萃取小麦胚芽中维生素E的方法。考察了溶剂浓度，微波萃取时间，液固比，预浸取时间对萃取率的影响。与常规萃取方法相比，当小麦胚芽5g，液固比6：1(V／W)，微波功率468W时，微波萃取时间2min，乙醇浓度50％时，维生素E的萃取率可达到16．65mg／100g，其效率远大于常规萃取方法。因此微波萃取小麦胚芽中维生素E具有时间短，效率高的特点。本文还运用取得的实验数据建立了小麦胚芽中VE微波萃取的BP神经网络模型。并验证了模型的正确性。     

微波辅助提取苦杏仁甙的工艺研究

以无水乙醇为溶剂,采用微波辅助法提取苦杏仁中的苦杏仁甙,以高效液相色谱法（HPLC）定量测定苦杏仁甙的提取得率,采用正交试验考察了料液比、提取时间、提取温度对苦杏仁甙提取得率的影响,确定了微波功率为500W条件下的最佳提取工艺条件为料液比1：6,提取温度75℃,时间15min,提取2次,苦杏仁甙的提取得率为4.09。     

罗汉果皂苷的微波提取(英文)

中药罗汉果是广西特产,本文采用微波辅助提取技术,从罗汉果中提取罗汉果皂苷,并优化出最佳的微波提取功率、微波辐射时间、固液比及原料的粉碎度。结果表明,最佳的微波辐射时间是5min、微波功率是495W、原料的粉碎度为不小于0.15mm及固液比为1:30,和传统的加热提取相比较,微波辅助提取的提取时间短,但具有较高的提取率。微波辅助提取的提取时间为5min时,提取率达76.56%,而传统的加热提取时间为2h时,提取率为68.46%。     

Optimization of microwave-assisted extraction with saponification (MAES) for the determination of polybrominated flame retardants in aquaculture samples

The efficiency of microwave-assisted extraction with saponification (MAES) for the determination of seven polybrominated flame retardants (polybrominated biphenyls, PBBs; and polybrominated diphenyl ethers, PBDEs) in aquaculture samples is described and compared with microwave-assisted extraction (MAE). Chemometric techniques based on experimental designs and desirability functions were used for simultaneous optimization of the operational parameters used in both MAES and MAE processes. Application of MAES to this group of contaminants in aquaculture samples, which had not been previously applied to this type of analytes, was shown to be superior to MAE in terms of extraction efficiency, extraction time and lipid content extracted from complex matrices (0.7% as against 18.0% for MAE extracts). PBBs and PBDEs were determined by gas chromatography with micro-electron capture detection (GC-muECD). The quantification limits for the analytes were 40-750 pg g(-1) (except for BB-15, which was 1.43 ng g(-1)). Precision for MAES-GC-muECD (%RSD < 11%) was significantly better than for MAE-GC-muECD (%RSD < 20%). The accuracy of both optimized methods was satisfactorily demonstrated by analysis of appropriate certified reference material (CRM), WMF-01.     

Conventional and Microwave-Assisted Extraction of Mucilage from <Emphasis Type="Italic">Opuntia ficus-indica</Emphasis> Cladodes: Physico-Chemical and Rheological Properties

Cactus pear cladodes processing has potential value for mainstream industries and is equally important for marginal rural communities in arid regions. This work is focused on physico-chemical and rheological properties of Opuntia ficus-indica (OFI) peeled cladodes extracted by conventional method “CE” and using microwave-assisted extraction “MAE.” MAE gave the highest yield extraction (8.13 %, w/w) within the lowest extraction time (500 W/7 min) and provided more protein (×1.03) and carbohydrates (×1.51) than CE. The monosaccharides detected by gas chromatography were arabinose, galactose, rhamnose, xylose, and galacturonic acid. The dialyzed mucilage solution characterized by SEC/MALS/VD/DRI (size-exclusion chromatography coupled with online multi-angle light scattering, viscometer detectors, and differential refractive index) revealed fractions with molecular weight (M _w ) ranging from 15.3–15.7?×?10⁶ g mol^?1 for the CE extracts and about 16.7–17.5?×?10⁶ g mol^?1 for the MAE extracts. Dynamic oscillatory testing has been used to study the rheological properties of mucilage solution within the concentration of 0.50–3.00 % (w/v) at 25 °C. The rheological profiles of CE and MAE showed similar behavior. At low frequency and low mucilage concentration (<2.00 %), the viscous component (G") predominated over the elastic component (G'), while for higher frequencies, the behavior is reversed (G'?>?G"). If safely controlled, alternative energies like microwaves could extract soluble polymers with comparable properties to commercial ones, conventionally extracted.     

Microwave assisted fluidized bed drying of nutmeg mace for essential oil enriched extracts: An assessment of drying kinetics,process optimization and quality

The drying mechanism of the myristicin enriched nutmeg mace has been optimized in a microwave assisted fluidization bed dryer (MWFBD) through multiple linear regression (MLR) and artificial neural network (ANN) modeling. The developed drying technique overcomes the non-uniformity heating problems in microwave heating and prolonged drying in fluidized bed drying. During the novel method of drying selected input variables were drying air temperature (DT) (40–50 °C) and microwave power (MP) (480–800 W) and output variables involving colour, oil yield, and myristicin quantity have been investigated by a continuous air velocity of 5.1 m/s. Six mathematical models about one to four conditions have fitted with an experimental design. Suitable enforcement of such models was evaluated through statistical measures. The coefficient of determination (R²) of MLR varied from 0.89 to 0.98, and the sum of squared error (SSE) varied within 6 × 10⁻³ to 158.18, while R² of ANN fluctuated from 0.82 to 0.95, and the mean squared error (MSE) varied between 0.006 and 0.1450, which shows MLR design performance superior than ANN design. The processing conditions of 48.24 °C DT and 637.431 W MP with a drying time of 1.3 h were identified as optimum conditions with a desirability value of 0.98 to obtain maximum oil yield (13.38%) and good colour (L* (20.83), a* (17.34), b* (8.62)) of nutmug mace. Moreover, no myristicin (5.92%) degradation was observed compared with the sun and convective drying. Among the tested models, page and logarithmic models gave a better prediction of moisture ratio.     

Optimization of microwave-assisted extraction with saponification (MAES) for the determination of polybrominated flame retardants in aquaculture samples

The efficiency of microwave-assisted extraction with saponification (MAES) for the determination of seven polybrominated flame retardants (polybrominated biphenyls, PBBs; and polybrominated diphenyl ethers, PBDEs) in aquaculture samples is described and compared with microwave-assisted extraction (MAE). Chemometric techniques based on experimental designs and desirability functions were used for simultaneous optimization of the operational parameters used in both MAES and MAE processes. Application of MAES to this group of contaminants in aquaculture samples, which had not been previously applied to this type of analytes, was shown to be superior to MAE in terms of extraction efficiency, extraction time and lipid content extracted from complex matrices (0.7% as against 18.0% for MAE extracts). PBBs and PBDEs were determined by gas chromatography with micro-electron capture detection (GC-μECD). The quantification limits for the analytes were 40–750 pg g^?1 (except for BB-15, which was 1.43 ng g^?1). Precision for MAES-GC-μECD (%RSD?<?11%) was significantly better than for MAE-GC-μECD (%RSD?<?20%). The accuracy of both optimized methods was satisfactorily demonstrated by analysis of appropriate certified reference material (CRM), WMF-01.