Influence Of Extraction Parameters Research Articles

Supercritical carbon dioxide chelation extraction of heavy metal ions from drilling fluid waste: Experiment and simulation

This study evaluates the application of supercritical carbon dioxide chelation extraction technology for treating heavy metal ions (Zn2+ and Cr3+) in drilling fluid waste. Through a combination of experimental and molecular dynamics simulation methods, the influence of extraction parameters (temperature, pressure, duration, and chelating agents) on the extraction efficiency are investigated. Findings show that increased duration and pressure significantly improve extraction efficiency, while temperature has a complex effect, initially increasing efficiency but plateauing and slightly decreasing at higher temperatures. The optimum extraction condition with pressure of 220 bar, temperature 348.15 K and an extraction duration of 70 min using ethylene diamine tetraacetic acid (EDTA) as the chelating agent has been determined. Importantly, molecular simulation analysis revealed that citric acid outperforms EDTA in terms of Zn2+ and Cr3+ aggregation by forming larger aggregates with greater numbers of molecules while reducing overall aggregate count. Furthermore, optimization of extraction pressure in the EDTA system shows potential benefits. These results suggest that supercritical carbon dioxide chelation extraction technology has strong potential for environmentally friendly and reliable waste management in the drilling industry. This study represents a significant step forward in developing sustainable solutions for heavy metal removal from drilling fluid waste.

Ultrasonic-assisted extraction of polyphenolics from Schrebera swietenioides Roxb.: An optimization using response surface methodology

Schrebera swietenioides Roxb is an important medicinal plant used for the treatment of various diseases by the indigenous communities. However, this plant is still underexplored in the modern scientific era. Specifically, the leaves of the plant are reported to contain various medicinal properties such as antioxidant, antimicrobial, anti-inflammatory, and antipyretic activity. Herewith, the present work demonstrates and optimizes the extraction process usingan ultrasonic system and comopared the results with conventional extraction methods. Optimization was performed by combining first and second-order polynomial designs at different levels using Plackett-Burman and Central-Composite designs. A total of 31 experiments were conducted at different levels, including ultrasonic power (10–40 %), solvent-to-sample ratio (20–50 mL/g), solvent concentration (50–80 %), and HCl normality (0.2–1 N). The findings of the study suggest a significant (p<0.05) influence of extraction parameters on the extraction yield of the response variables, including total phenol (TPC), total flavonoid (TFC), total tannin (TTC), and the antioxidants activity. Further, the predicted values demonstrated good agreement with the experimental values, exhibiting a high (R2>95%) coefficient of determination and a non-significant lack of fit. At the optimized condition, the experimental values of TPC, TFC, TTC and antioxidants (DPPH, ABTS, FRAP) activity were found near the model predicted values. The HPLC-PDA analysis identified ten polyphenolic compounds, among which rutin hydrate (12.991±0.003 mg/g DW), followed by phloridzin (6.660±0.001 mg/g DW), and chlorogenic acid (3.380±0.008 mg/g DW) were the most prominent compounds. Furthermore, the optimized extract showed effective antibacterial activity against Bacillus subtillis, Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus species. In conclusion, the obtained results indicate that the proposed optimization strategy can be utilized to enhance the yield of polyphenolics from the target species with possibility of its application in therapeutics values.

Optimized microwave-assisted extraction of total phenolic and flavonoid contents from defatted seeds and press residue of Opuntia ficus-indica (l.) mill

Phenolic content of Opuntia ficus indica (OFI) was estimated in samples of seeds and press residue (cake) generated through mechanical oil extraction process. A microwave-assisted extraction (MAE) method was investigated for the optimization of the extracted total phenolic (TPC) and total flavonoid contents (TFC). The influence of extraction parameters on the yields of TPC, TFC were modelled using a second-order regression equation. The optimal MAE conditions were: 61.65 % ethanol concentration, 633.42 W microwave power, 3.59 min irradiation time and 46.28 mL/g solid-to-liquid ratio (SLR) for phenolics extraction, and 54.97 %, 580.04 W, 3.20 min and 47.40 mL/g for flavonoids extraction from defatted seeds powder. The extracts obtained under these conditions showed a TPC and TFC of 416.311±1.154 mg gallic acid equivalent (GAE) per100 g dry weight (DW) and 52.67±0.72 mg quercetin equivalent (QE)/100 g DW, respectively. Regarding press residue, the optimal conditions were 60.26%, 643.89 W, 3.85 min and 47.28 mL/g for phenolics extraction, and 67.96 %, 464.41 W, 2.46 min and 41.04 mL/g for flavonoids extraction; with a TPC and TFC of 400.11±3.14 mg GAE/100 g DW and 38.75±0.16 mg QE/100g DW, respectively. The results of the present study confirmed that OFI seeds and press residues could be considered as a non-negligible source of phenolics with a good antioxidant activity and revealed that MAE is a reliable method for optimizing yields of recovered phytochemicals from such agricultural products derivatives and by-products, with an intent to be scaled-up for industrial, nutraceutical or pharmaceutical applications.

Parameter evaluation of extraction using microwave hydrodistillation ultrasonic-pretreatment on yield of black pepper oil

Black pepper is one of Indonesia's agricultural commodities, contributing foreign exchange to the country. However, the economic value of this commodity has decreased. It is influenced by the lack of diversified black pepper products, which of course, have a higher value than raw material marketing. One product diversification that can be developed is black pepper oil. In obtaining essential oils, appropriate methods and technology are needed so that the resulting product is of high quality and the process is carried out efficiently. The latest methods in extraction that are being developed are microwave and ultrasonic technology. Therefore, in this study, black pepper oil extraction was carried out using the microwave hydrodistillation method, whereas previously, ultrasonic pretreatment was given for the material. In this case, observations were made on the influence of extraction parameters. Based on the research, it was found that increasing the distiller size flask and ambient temperature could increase the percentage of essential oils yield. At the same time, the longer extraction time caused a decrease in yield. Decreasing the material particle size and increasing microwave power could cause an increase in yield up to a certain point. The best results in black pepper oil extraction were obtained under extraction conditions using a distiller size of 1000mL, extraction time of 60 minutes, at an ambient temperature of 30 oC, the particle size of 60 mesh, at a power of 450 W with a yield of 1.056%, with the characteristics of having a clear greenish colour and anRI of 1.480. These specifications comply with ISO 3061:2008 for essential oil from black pepper. Thus, these parameters can be considered in the black pepper oil extraction process to produce marketable products. As a suggestion for further research, modeling, and process scale-up can be developed.

Optimization of the Parameters Influencing the Antioxidant Activity and Concentration of Anthocyanins Extracted from Red Onion Skins Using a Central Composite Design

This study aimed to extract bioactives from red onion skins for use as edible colorants that are both natural and functional. The extraction of bioactive chemicals from red onion skins using a conventional solvent extraction was optimized using a Central Composite Design (CCD). The influence of extraction parameters, such as ethanol and citric acid concentrations, extraction temperature, and time, on anthocyanin content and antioxidant activity (DPPH method) was studied. A quadratic model was suggested for all of the parameters examined and employed. Citric acid concentration (0.05–2.64%), ethanol concentration (6.36–73.63%), operation temperature (16.47–58.52 °C), and extraction duration (10–234.54 min) were the variables studied in the coded form of the experimental plan. The best conditions for maximum anthocyanins and antioxidant activity recovery were: 60% ethanol, 0.87% citric acid, 179.99 min, and 25 °C. The anthocyanins concentration varied from 0.45 to 1.43 mg C3G/g DW, while the antioxidant activity varied from 24.29 to 37.20 mM TE/g DW, according to the experimental design. Overall, it should be emphasized that the extraction process can be enhanced by settling the operating factors to maximize the model responses. The current findings demonstrate that extracts from red onion skins would be useful in developing functional food products.

Valorization of Aloe vera Skin By-Products to Obtain Bioactive Compounds by Microwave-Assisted Extraction: Antioxidant Activity and Chemical Composition.

Aloe vera skin (AVS) is a major by-product of Aloe processing plants all over the world. In this study, response surface methodology was used to optimize microwave-assisted extraction (MAE) of bioactive compounds from AVS. The influence of extraction parameters, such as ethanol concentration (%Et), extraction temperature (T), time (t) and solvent volume (V), on extraction yield (Y), total phenolic content (TPC), antioxidant activity (DPPH and FRAP methods) and aloin content, was studied. Optimum extraction conditions were determined as 80% ethanol, 80 °C, 36.6 min and 50 mL and optimized extracts showed interesting contents of polyphenols and antioxidant performance. The phenolic profile was determined by HPLC-DAD/MS and some major phenolic compounds, such as aloin A, aloin B, aloesin, aloe-emodin, aloeresin D, orientin, cinnamic acid and chlorogenic acid, were quantified while eight other compounds were tentatively identified. Moreover, structural and thermal properties were studied by FTIR and TGA analyses, respectively. The obtained results suggested the potential of AVS as a promising source of bioactive compounds, thus increasing the added value of this agricultural waste.

Ultrasound‐assisted extraction of essential and toxic elements from pepper in different ripening stages using Box–Behnken design

The influence of extraction parameters on the ultrasonically assisted extraction (UAE) of K, Na, Ca, Mg, Zn, Cu, Fe, Mn, Cr, Se, Mo, Li, Al, B, Pb, Hg, Cd, As, and Ni was studied to determine the conditions when a minimum of essential and maximum of toxic elements is leached from peppers, depending on its ripening stage. The effect of process variables was investigated by using Box–Behnken design. Each essential element had a different optimal condition for minimal leaching, while the toxic elements were predominantly extracted with acetic acid solution as extractant. The highest correlation between extraction conditions and concentration of extracted elements was found for aqueous extracts of mature green pepper. The concentration of acetic acid highly influenced the leaching of elements and a strong correlation between the concentration of Al, B, Fe, and Mn, and the UAE experimental conditions were observed. Practical applications This study investigates the leaching of minerals and heavy metals present in vegetables to the most commonly used media (water and acetic acid) during processing and canning. The data from this study may be useful for improving the quality of processed pepper products due to new information on how different parameters influence these losses (ripening stage of peppers, medium/solvent used for preparation, or storage, applied temperatures, time, mass to volume ratio). Essential elements are better preserved during the processing of intermediate breaker and mature red pepper compared to green mature fruits. Better retention of essential elements in the breaker and mature red pepper (that are mostly used in industrial processing) can be achieved by reducing the contact time with water, as well as mass to volume ratio. Leaching of toxic elements Al, Hg, and As can be improved with an acetic acid solution.

Chemometric Optimization of Biologically Active Compounds Extraction from Grape Marc: Composition and Antimicrobial Activity.

The article focuses on the optimization of the extraction process of biologically active compounds (BAC) from grape marc—a by-product of the wine industry. The influence of temperature, specifically 30 °C, 45 °C and 65 °C, and ethanol concentration in solutions, specifically 0–96% (v/v) on the extraction yield of polyphenols, flavonoids, tannins and anthocyanins, were investigated. The composition of individual polyphenols, anthocyanins and organic acids, antioxidant activity (DPPH and ABTS) and CIELab chromatic characteristics of the grape marc extracts (GME), were characterized. The microbiostatic and microbicidal effects in direct contact of GME with pathogenic microorganisms, Bacillus subtilis, Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, were determined in vitro. The influence of extraction parameters on the total polyphenol content (TPC), total flavonoid content (TFC), tannin content (TC), total anthocyanin content (TAC) and their interdependencies were studied using information analysis. A mathematical model was developed on cubic spline functions. The analysis of individual compounds showed the presence of a wide range of flavonoids (procyanidin B2, procyanidin B1, hyperoside and quercetin), flavones (catechin), hydroxybenzoic acid derivatives (gallic, protocatechuic, p-hydroxybenzoic acids, m-hydroxybenzoic acid, syringic acid), hydroxycinic acid derivatives and ferulic acid methyl ester. The malvidol-3-glucoside was the main anthocyanin identified in the extract. A high amount of tartaric acid was also found. GME showed significant antimicrobial activity against Gram-positive bacteria and lower activity against Gram-negative bacteria.

Microwave-assisted extraction of antioxidant compounds from Russian olive leaves and flowers: Optimization, HPLC characterization and comparison with other methods

Russian olive is a medicinal plant containing phytochemicals with antioxidant activities, which are of great interest due to their beneficial health effects. Our preliminary studies produced extracts from Russian olive leaves and flowers and determined their potential antioxidant activity and their most abundant phenolic compounds were detected. However, the maximum retention of these antioxidant compounds during microwave-assisted extraction (MAE) requires optimized process conditions. Therefore, two-level fractional factorial designs in preliminary tests were used for assessing the magnitude of microwave extraction factors' effects on the extraction of bioactive compounds from Russian olive samples and the experimental domains were determined. Subsequently, Response surface methodology (RSM) was conducted to determine the optimized MAE process variables including citric acid’s molarity (X1: 1–5 M), extraction temperature (X2: 60–110 °C), ethanol concentration (X3: 0–100%) and solid to solvent ratio (X4: 5–15) for maximum recovery of total phenolic content, total flavonoid content and total antioxidant compounds in the extracts. Based on the results, the optimal extraction conditions were as follows: solid to solvent ratio of 7.5 (w/v), citric acid molarity of 2 M, ethanol concentration of 59.8% and 66.4%, and temperature of 97.4 °C and 97.5 °C for Russian olive leaves and flowers, respectively. In addition, the influence of extraction parameters on the responses was modeled using a second-order regression equation and a good agreement between the predicted values and the experimentally obtained values was indicated. Finally, among phenolic compounds which were previously identified through Quadrupole Time of Flight Mass Spectrometer (QTOF-MS) analysis, three abundant flavonoids of the extracts with therapeutic properties including isorhamnetin, luteolin and rutin contained in the optimized extract from MAE were compared with that of ultrasonic extraction and conventional extraction using high-performance liquid chromatography (HPLC) analysis. Results confirmed MAE as an efficient method for extraction of bioactive phytochemicals from Russian olive.

Application of an eco-friendly sodium acetate/urea deep eutectic solvent in the valorization of melon by-products

An eco-friendly sodium acetate/urea (NaOAc:urea:water) deep eutectic solvent (DES) was evaluated for the extraction of bioactive compounds from melon peels. Melon peels were first extracted with water to separate the water-insoluble solids (WIS) from free sugars, and the WIS were subsequently extracted with the DES. The extracts were analyzed for oligosaccharides and protein as well as total phenolic content and antioxidant activities. The influence of extraction parameters (time, temperature, DES molar ratio, water content and solid consistency) on the composition of the extracts was evaluated. At the selected conditions (NaOAc:urea:water with molar ratio 1:3:1.6 (10% (w/w) water), with a consistency of 2% (w/w), at 90 °C for 10 min), the total oligosaccharide yield was 8.84 g oligosaccharides/100 g WIS, of which 90% were oligogalacturonides, and the total phenolic content and protein content were 4.35 mg GAE/g WIS and 2.87 g/100 g WIS, respectively. Pectin enriched in branched rhamnose units with a low degree of methyl esterification was recovered by precipitation, with a yield of 7.95 g/100 g WIS and a galacturonic acid content of 49.44%.

Selected Aspects Related to Medicinal and Aromatic Plants as Alternative Sources of Bioactive Compounds.

Natural compounds obtained from different medicinal and aromatic plants have gained respect as alternative treatments to synthetic drugs, as well as raw materials for different applications (cosmetic, food and feed industries, environment protection, and many others). Based on a literature survey on dedicated databases, the aim of the present work is to be a critical discussion of aspects regarding classical extraction versus modern extraction techniques; possibilities to scale up (advantages and disadvantages of different extraction methods usually applied and the influence of extraction parameters); and different medicinal and aromatic plants’ different applications (medical and industrial applications, as well as the potential use in nanotechnology). As nowadays, research studies are directed toward the development of modern, innovative applications of the medicinal and aromatic plants, aspects regarding future perspectives are also discussed.

Green Extraction of Antioxidant Polyphenols from Green Tea (Camellia sinensis).

In this study, the feasibility of improving the extraction yield of green tea antioxidant polyphenols by the combination of ultrasound-assisted extraction (UAE) and deep eutectic solvents (DESs) was investigated. Choline chloride (ChCl)-glycerol was selected as the best DES among 12 ChCl-based DESs to extract tea antioxidant polyphenols. Subsequently, the influences of extraction parameters on total phenolic content (TPC) values were investigated, and liquid/solid ratio, ultrasonic power, and ultrasonic time were optimized based on the response surface methodology. The optimal extraction conditions were a liquid to solid ratio of 36:1 (mL/g), ultrasonic power of 461.5 W, and ultrasonic time of 21 min, with the highest TPC value of 243 ± 7 mg gallic acid equivalent (mg GAE)/g dry weight (DW), which was 13% higher than that before optimization. In addition, under the optimal extraction conditions, tea polyphenolic extract exhibited higher antioxidant activity compared with conventional extraction methods. Four major catechins in the green tea extracts, including (−)-epicatechin (EC), (−)-epigallocatechin (EGC), (−)-epicatechin gallate (ECG) and (−)-epigallocatechin gallate (EGCG) were identified and quantified by high-performance liquid chromatography. In addition, scanning electron microscopy (SEM) analysis revealed that UAE-DES effectively disrupted the green tea leaf cells, thereby improving tea polyphenol yield. In summary, UAE-DES is an ideal green extraction method for the extraction of tea antioxidant polyphenols.

Influence of extraction parameters and stability of betacyanins extracted from red amaranth during storage.

Natural colorants are important alternatives to synthetic colorants. They are considered harmless and positively affect biological activities owing to their antioxidant potential. The present study deals with the assessment of the extraction processes and the effects of pH (1.0, 3.0, and 5.0), extraction media (water and 50% ethanol) and storage condition (ambient and refrigeration) on betacyanin content, color values, as well as degradation kinetics of total betacyanins in red amaranth. Betacyanin content was more stable at higher than at lower pH. The degradation rate constant (K) was higher and the half-life (t1/2) was lower at ambient temperature compared to refrigeration temperature. Betacyanin degradation was higher at ambient temperature (30 ± 2°C) than at refrigeration temperature (4°C). The pH, storage time, and temperature affected the stability of the color attributes. Therefore, this work suggests that water and lower temperature (4°C) could be applied to extract more betacyanins from red amaranth and betacyanins might be used as an alternative to synthetic color.

Influence of Extraction Parameters on the Yield, Phytochemical, TLC-Densitometric Quantification of Quercetin, and LC-MS Profile, and how to Standardize Different Batches for Long Term from Ageratum conyoides L. Leaves

Influence of Extraction Parameters on the Yield, Phytochemical, TLC-Densitometric Quantification of Quercetin, and LC-MS Profile, and how to Standardize Different Batches for Long Term from Ageratum conyoides L. Leaves

Pilot‐scale supercritical CO2 extraction of edible insect oil from Tenebrio molitor L. larvae – Influence of extraction conditions on kinetics, defatting performance and compositional properties

In view of industrial fractionation processes for edible insects, supercritical CO2 extraction of Tenebrio molitor larval oil was studied. The influence of extraction parameters on defatting of larvae was investigated using a full factorial design. Furthermore, the effect of operating conditions on extraction kinetics, fatty acid composition, and acidity of mealworm oil was evaluated. Pressure, time, and their interaction showed the most significant effects on defatting. Maximal defatting (95%) was achieved at 400/250 bar, 45°C, and 105 min. Extraction kinetics revealed that incrementing pressure increased the solubility of mealworm oil in SC–CO2 enabling faster extraction. Extracted oils contained 72% unsaturated fatty acids, and oleic acid accounted for 42% of total FAME. Oil composition and acidity were found to be affected by extraction parameters showing the highest amount of low molecular and free fatty acids after slow extraction at 250 bar and 65°C. Use of selective extraction conditions enabled simple time‐dependent fractionation and deacidification yielding fractions with tailored fatty acid profiles or facilitating subsequent refining processes, respectively. Defatting performance and oil composition were not substantially different when using hexane as a solvent in comparison to SC–CO2. Mealworm larvae can be effectively defatted using SC–CO2 at high pressure and moderate temperature, yielding two valuable fractions: oil‐ and protein‐rich residue.Practical applications: Mealworm larvae are promising candidates for the inclusion of edible insects in the western food and feed industry due to modest breeding demands, existing rearing knowledge, and high contents of protein and fat. The development of fractionation processes for the production of standardized insect bulk materials and incorporation in feed or food in analogy to soy and other plant raw materials rich in fat and protein will help gain industrial applicability and enhance consumer acceptance. Depending on the processing approach, a defatting step is crucial prior to protein extraction. The results of this study indicate that SC–CO2 extraction is suitable for achieving a high yield of solvent‐free oil and a protein‐enriched, solvent‐free residue at low extraction temperatures. Both fractions can be further refined and purified in order to achieve valuable intermediates for food and feed applications.The SC–CO2 extraction of mealworms yielded highly unsaturated oil and a defatted residue containing protein and chitin. The operating parameters clearly affected the defatting performance and the extraction rate.

The influence of extraction parameters on spent coffee grounds as a renewable tannin resource

Spent coffee grounds that are left behind during the coffee brewing process consist of valuable tannin compounds which makes them ideal material as a renewable tannin resource. For this reason, the concept of cleaner production had been applied in practice and a tannin extraction process with spent coffee grounds as raw material was investigated in the present study. Among the extraction key factors, namely sodium hydroxide concentration, extraction temperature, liquid to solid ratio, and extraction time, the former three factors had exerted a considerable effect on spent coffee ground tannin extraction yield and its reactivity. However, extraction time had only marginal effects which could be simply neglected in the tannin extraction process. These observations imply that spent coffee grounds can be reused as a renewable tannin resource by properly selecting the extraction parameters in order to produce the spent coffee ground tannin with desirable extraction yield and reactivity. By taking both the spent coffee ground tannin extraction yield and reactivity into consideration, the optimum extraction conditions are; 5% sodium hydroxide concentration, 100 °C extraction temperature, 30 min extraction time, and 8.23 liquid to solid ratio, so that tannin with a high extraction yield (21.02%) and high reactivity (29.69%) could be recovered. The present study provides an understanding on the impact of the extraction parameters on isolated spent coffee ground tannin as well as to fill up academic deficiencies in spent coffee grounds, which, in turn, could serve as a reliable guideline for the development of a full-scale, sustainable spent coffee ground tannin extraction process in coffee industries.

Influence of Extraction Parameters on Hydroalcohol Extracts of the Stem Bark of &lt;i&gt;Rapanea ferruginea&lt;/i&gt; Mez Using Myrsinoic Acid B as Marker

Purpose: To evaluate the influence of extraction parameters on standardization of hydroalcoholic extract of Rapanea ferruginea Mez. Methods: A 3 3 factorial design was used to evaluate the influence of alcohol concentration (50, 70 and 90 % v/v), extraction time (2, 6 and 10 h), and particle size of the herbal drug (0.25, 0.5 and 1.0 mm) on the pH, dry residue and myrsinoic acid B (MAB) content of hydroalcoholic extracts by high performance liquid chromatography (HPLC) method. Results: For the extracts, there was inverse correlation between dry residue and MAB content (p < 0.8046). The parameter that had the greatest influence on extraction process was alcohol concentration (p < 0.007) followed by particle size (p < 0.046). However, extraction time did not influence the process in terms of MAB (p < 0.675). Although, the highest MAB content was obtained with 70 % v/v alcohol and extraction time of 6 h, the best methodology for extractive preparation was the use of 90 % v/v alcohol and extraction time of 2 h because it resulted in a higher yield of MAB per solution volume, i.e,, with regard to MAB content and mass yield. Conclusion : The results indicate that 90 % v/v alcohol and extraction time of 2 h have optimum influence on extraction process and were the best conditions for obtaining a standardized extract of R. ferruginea , using the method employed in this study. Thus, the findings of this study are a contribution to the development of a new phytopharmaceutical intermediate product. Keywords : Rapanea ferruginea, Hydroalcoholic extract, Myrsinoic acid B, Phytopharmaceutical, Factorial desing, Standardization

Semi-automated solid-phase extraction method for studying the biodegradation of ochratoxin A by human intestinal microbiota

A simple and rapid semi-automated solid-phase (SPE) extraction method has been developed for the analysis of ochratoxin A in aqueous matrices related to biodegradation experiments (namely digestive contents and faecal excreta), with a view of using this method to follow OTA biodegradation by human intestinal microbiota. Influence of extraction parameters that could affect semi-automated SPE efficiency was studied, using C18-silica as the sorbent and water as the simplest matrix, being further applied to the matrices of interest. Conditions finally retained were as follows: 5-mL aqueous samples (pH 3) containing an organic modifier (20% ACN) were applied on 100-mg cartridges. After drying (9mL of air), the cartridge was rinsed with 5-mL H2O/ACN (80:20, v/v), before eluting the compounds with 3× 1mL of MeOH/THF (10:90, v/v). Acceptable recoveries and limits of quantification could be obtained considering the complexity of the investigated matrices and the low volumes sampled; this method was also suitable for the analysis of ochratoxin B in faecal extracts. Applicability of the method is illustrated by preliminary results of ochratoxin A biodegradation studies by human intestinal microbiota under simple in vitro conditions. Interestingly, partial degradation of ochratoxin A was observed, with efficiencies ranging from 14% to 47% after 72h incubation. In addition, three phase I metabolites could be identified using high resolution mass spectrometry, namely ochratoxin α, open ochratoxin A and ochratoxin B.

Application of SPME Based on a Stainless Steel Wire for the Determination of Pyrethroid Insecticide Residues in Water and Soil

In this study, a solid-phase microextraction (SPME) method based on a bare stainless steel wire as the fiber has been developed for extraction and determination of five pyrethroid insecticides (fenpropathrin, cyhalothrin, cypermethrin, fenvalerate and deltamethrin) in water and soil samples. The influences of extraction parameters (extraction time, stirring rate and salt addition) on the SPME extraction efficiency were investigated, and the optimum conditions were applied for the extraction of the target analytes from water samples. The method showed linear behavior ranging from 0.05 to 2 µg L−1 with detection limits of 0.6–1.9 ng L−1 for water analysis. Recoveries were from 71 to 112% for all the target insecticides in water and soil sample, with RSDs from 6.8 to 19.4% (n = 3). The study demonstrated the feasibility of the proposed SPME fiber based on stainless steel wire for the extraction of pyrethroid insecticides in water and soil.

Characteristics and Composition of Watermelon Seed Oil and Solvent Extraction Parameters Effects

AbstractWatermelon seed oil characteristics were evaluated to determine whether this oil could be exploited as an edible oil. Hexane extraction of watermelon seeds produced yields of 50% (w/w) oil. The refractive index, saponification and iodine value were 1.4712 (at 25 °C), 200 mg KOH/g and 156 g I/100 g, respectively. The acid and peroxide values were 2.4 mg KOH/g and 3.24 mequiv/kg, respectively. The induction time of the oil was also 5.14 h at 110 °C, which was measured for the first time. Total unsaturation contents of the oil was 81.6%, with linoleic acid (18:2) being the dominant fatty acid (68.3%). Considering that the watermelon seed oil was highly unsaturated, the relatively high induction time might indicate the presence of natural antioxidants. In addition, the influence of extraction parameters on extraction of oil from watermelon seed with hexane as a solvent was studied at several temperatures (40, 50, and 60 °C), times (1, 2, and 3 h) and solvent/kernel ratios (1:1, 2:1, and 3:1). The oil yield was primarily affected by the solvent/kernel ratio and then time and temperature, respectively. The protein content of the oil‐free residue was 47%.