Highest Extraction Yield Research Articles

Optimization of microwave-assisted extraction of phenolic compounds from Inula britannica L. using the Box-Behnken design

A closed-vessel microwave-assisted extraction (MAE) of phenolic compounds from the aerial parts of Inula britannica L. using single-factor experiments and the Box-Behnken design with four independent variables (liquid-to-solid ratio, ethanol concentration, extraction time, and temperature) was investigated. The ANOVA results showed that the obtained model was significant at a 95 % confidence level. The extraction parameters for the maximal total phenolic content (46.19 mg GAE/g DM) were determined to be 15.13 ml/g liquid-to-solid ratio, 55.95 % EtOH, 73.74 ºC, and 5.73 min. Compared with classical maceration, the proposed MAE of phenolic compounds from I. britannica saves a lot of time and gives a high extraction yield.

Response surface modeling and optimization of the extraction conditions using lactic acid-based deep eutectic solvents as green alternative extraction media for Mentha pulegium.

Most recurrently available organic solvents are toxic and inflammable and pose high risks to human health. Natural deep eutectic solvents (NADESs) have been developed as promising green alternatives. We aimed to extract polyphenolic compounds from Mentha pulegium using lactic acid-based deep eutectic solvents. Extraction parameters were optimized by response surface methodology. Combined with ultrasound-assisted extraction, three different lactic acid-based deep eutectic solvents were investigated for the extraction of polyphenols. Methanol (80%, v/v) was used for comparison. The optimized influencing factors were: water content in solvent, extraction time, and temperature. The design was adopted including 17 experiments with three center points. All NADESs tested showed an excellent extraction efficacy compared to 80% methanol. Under the optimized conditions, with 45% of water, at 30°C, and for extraction 90 min, the highest extraction yields were recorded using lactic acid:sodium acetate (3:1), achieving 173.35 ± 0.02 mg gallic acid equivalents (GAE)/g dry weight (dw) of polyphenols and 95 ± 0.09% antioxidant activity. After extraction for 90 min at 80°C with 18% of water, we obtained 164.06 ± 0.01mg GAE/g dw and 94 ± 0.02% antioxidant activity using lactic acid:glucose (5:1). Efficient recovery (64.92 ± 0.01 mg GAE/g dw and 97 ± 0.1% antioxidant activity) was achieved using lactic acid:glycine (3:1) with 31% of water, at 35°C, and extraction for 30 min. Our results indicate that with optimized parameters, the proposed natural solvents are excellent alternatives to chemical ones for the extraction of phenolic compounds.

Red and brown seaweeds extracts: A source of biologically active compounds

The biological activities of Porphyra sp., Gracilaria gracilis, Alaria esculenta and Saccharina latissima extracts prepared by enzymatic and ball milling-assisted methods and hot water were evaluated. Enzyme-assisted methods allowed the highest extraction yields. Alcalase-assisted extraction (EAA) was the most effective in the recovery of polyphenolic compounds and Porphyra sp. had the highest content. The efficiency of flavonoids extraction was highly dependent on the used method. Globally, Porphyra sp. and EAA extracts exhibited the highest antioxidant and chelating activities. The highest α-amylase inhibitory activity was determined in HW Porphyra sp. extract while EAA A. esculenta extract had the highest α-glucosidase inhibitory activity. The highest ACE inhibitory activity was obtained in EAA from S. latissima. None of the extracts showed antimicrobial activity against the tested bacteria. The results showed that Porphyra sp. and S. latissima are potentially useful as ingredient in functional foods and nutraceuticals.

Cupressus arizonica fruit essential oil: A novel green inhibitor for acid corrosion of carbon steel

Natural-based corrosion inhibitors have gained great research interest thanks to their low cost and higher performance. The Cupressus arizonica fruit essential oil (CAFEO) has a higher extraction yield than leaves; however, it has less antibacterial and antifungal activities. The three main components in the CAFEO were α-pinene (51.07%), myrcene (17.92%), and limonene (9.66%). Essential oils with a higher percentage of α-pinene were found to have outstanding corrosion inhibition properties. Therefore, herein, the CAFEO was investigated as a green corrosion inhibitor for carbon steel (CS) in 1.0 mol/L HCl using electrochemical, i.e., potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS), and scanning electron microscope (SEM) techniques. The experimental results revealed that CAFEO successfully inhibited the carbon steel corrosion in 1.0 mol/L HCl solution. Results from PDP indicated that the inhibitor had a mixed-type effect with a predominance cathodic character. EIS data showed that the charge transfer resistance of the CS electrode increased from 20.9 Ω cm2 in blank solution to 294.5 Ω cm2 in HCl solution inhibited with 0.5 g/L of CAFEO at 298 K, leading to a significant decrease in the double layer capacitance values and an inhibition efficiency (η%) of 93%. The high temperatures showed a negative effect on the corrosion inhibition efficiency of the tested inhibitor. At 323 K, the η% of CAFEO decreased to 77%. Besides, SEM images showed that the inhibitor formed a protective barrier against acid attack, preventing carbon steel from corrosion. Theoretical calculations by Density Functional Theory (DFT) were performed to investigate the reactivity of the three main components of CAFEO.

Study on South African Indigenous Teas-Antioxidant Potential, Nutritional Content, and Hypoxia-Induced Cyclooxygenase Inhibition on U87 MG Cell Line.

Background: This study comparatively assessed seven indigenous traditional tea plants on several attributes that included antioxidant, nutritional, caffeine contents, and cyclooxygenase activity. Methodology: Nutritional content of all tea plants were determined for energy, fat, carbohydrates, total sugars, dietary fiber and amino acids. Antioxidant potential and the antioxidant potentiating secondary metabolites were also measured and compared. Further, we investigated the tea plants for any role they would have on cyclooxygenase (COX) activity on cobalt chloride (CoCl2) induced human glioma cell lines (U87MG). Results: The tea plants were found non-cytotoxic at concentrations tested against the human Chang liver and HeK 293 kidney cells and were found to be naturally caffeine free. The lowest and highest extraction yield among the tea plants was 7.1% for B. saligna and 15.48% for L. scaberrimma respectively. On average, the flavonol content was 12 to 8 QE/g, ORAC 800 µmol TE/g, TEAC 150 µmol TE/g, FRAP 155 µmol AAE/g, polyphenols 40 mg GAE/g, flavanols 0.35 mg CE/g, flavonols 12 mg QE/g and total flavonoid content (TFC) 180 µg QE/mg. The COX activity has been found to be inhibited by a dose-dependent manner by L. scaberrimma, B. saligna and L. javanica. Conclusion: The results further support competitive value of tea plants and need for improved and further development.

Supercritical CO2 extraction of bioactive compounds from local Peganum Harmala plant seeds and optimization of the extraction yield and the antioxidant activities

A great variety of natural plants provide an important source of bioactive compounds having interesting applications in sensitive fields like food, pharmaceutical and cosmetic industries, particularly with the development of the supercritical carbon dioxide extraction. Therefore the present study focused on the study of this technique to extract valuable bioactive substances from seeds of a local natural plant known as Peganum harmala. The properties of the extracts were also considered, particularly insisting on the antioxidant activity potential. The extraction yield was optimized and the corresponding operating conditions were determined. A Box-Behnken statistical design was used to investigate the effect of operating parameters like pressure, temperature and particle size at a fixed supercritical CO2 flow rate of 50 g min−1 for an extraction time of 180 min. Furthermore, the total antioxidant activity of the plant extracts was assessed using the 2, 2-diphényl-1-picrylhydrazyl (DPPH) method whereas the Response surface methodology (RSM) combined with Box-Behnken design was used for the optimization of process key parameters. The highest extraction yield was achieved at a pressure of 300 bar, a temperature of 55 °C and a particle size of 0.3 mm. A maximum total phenolic content (TPC) and a 50% inhibition concentration (IC50) of 79.04 mg GAE/g E and 172.199 μg/mL, respectively were obtained at 100 bar and 35 °C for a particle size of 0.9 mm, whereas a total flavonoid content of 7.10 mg QE/g E was obtained still at 35 °C and for a particle size of 0.9 mm but at a pressure of 170.7 bar. Finally supercritical CO2 extraction showed to be an efficient technology, creating an added value through bioactive compounds with targeted properties like the antioxidant activity.

The Oral Wound Healing Potential of Thai Propolis Based on Its Antioxidant Activity and Stimulation of Oral Fibroblast Migration and Proliferation.

Introduction Propolis has demonstrated wound healing effects. Propolis' effects vary based on its composition and geographical origin. However, there are few reports on the effects of propolis on oral wound healing. The aim of this study was to evaluate the antioxidant and in vitro gingival wound healing effects of the n-hexane extract of propolis (HEP), ethyl acetate extract of propolis (EEP), and aqueous extract of propolis (AEP) fractions of the ethanol extract of Thai propolis. Materials and Methods The crude ethanol extract of propolis was obtained by maceration with 95% ethanol that was sequentially fractionated with hexane, ethyl acetate, and distilled water. The chemical profiles of the samples were assessed by thin-layer chromatography (TLC) and gas chromatography-mass spectrometry (GC-MS). Antioxidant activity was determined using DPPH and FRAP assays. The effects of the propolis fractions on human gingival fibroblast (HGF) proliferation, migration, and in vitro wound healing were determined by MTT, modified Boyden chamber, and scratch assay, respectively. Results We found that solvent polarity greatly affected the extract yield and TLC profiles. The highest extract yield was found in HEP (38.88%), followed by EEP (19.8%) and AEP (1.42%). TLC revealed 7 spots in the crude ethanol extract (Rf 0.36–0.80), 6 spots in HEP (Rf 0.42–0.80) and EEP (Rf 0.36–0.72), and 4 spots in AEP (Rf 0.17–0.79). GC-MS analysis revealed a high amount of triterpenoids in HEP (82.97%) compared with EEP (28.96%). However, no triterpenoid was found in AEP. The highest antioxidant activity and stimulation of HGF proliferation were observed in HEP, followed by EEP and AEP. HEP and EEP, but not AEP, enhanced HGF migration. However, all propolis fractions induced wound closure. Conclusions HEP contained a large amount of triterpenoids. Antioxidant and in vitro wound closure effects were found in HEP, EEP, and AEP fractions.

Effects of ionic liquids and pulsed electric fields on the extraction of antioxidants from green asparagus roots

SummaryAsparagus officinalis root (AR) contains valuable bioactive compounds that have beneficial health properties. The aim of this study was to optimize the extraction of polyphenols and flavonoids in green AR using two novel technologies; pulsed electric field (PEF) and ionic liquids (IL). Further, the antioxidant activity of the obtained extracts was determined. The total polyphenol content, total flavonoid content (TFC), and antioxidant activity (2,2‐diphenyl‐1‐picrylhydrazyl, oxygen radical absorbance capacity and Ferric reducing/antioxidant power assays) were determined. The PEF conditions (PEF strength of 1.6 kV/cm, frequency of 200 Hz and pulse width of 20 µs) resulted in a higher extraction yield as compared to conventional solvent extraction, but had lower antioxidant activities. The optimal conditions for IL extraction were by using 0.5% 1‐butyl‐3‐methylimidazolium chloride at a solid: liquid (S:L) ratio of 1:10 for four min. The IL extraction resulted in a total of 122 mg RE/ mL TFC which was 70 to 80 folds more than the TFC obtained by PEF. The IL extracts had higher TFC and antioxidant activity than PEF, but the safety of the ILs need further research.

The Effect of Standardised Leaf Extracts of Gaultheria procumbens on Multiple Oxidants, Inflammation-Related Enzymes, and Pro-Oxidant and Pro-Inflammatory Functions of Human Neutrophils.

The leaves of Gaultheria procumbens are polyphenol-rich traditional medicines used to treat inflammation-related diseases. The present study aimed to optimise the solvent for the effective recovery of active leaf components through simple direct extraction and verify the biological effects of the selected extract in a model of human neutrophils ex vivo. The extracts were comprehensively standardised, and forty-one individual polyphenols, representing salicylates, catechins, procyanidins, phenolic acids, and flavonoids, were identified by UHPLC–PDA–ESI–MS3. The chosen methanol–water (75:25, v/v) extract (ME) was obtained with the highest extraction yield and total phenolic levels (397.9 mg/g extract’s dw), including 98.9 mg/g salicylates and 299.0 mg/g non-salicylate polyphenols. In biological tests, ME revealed a significant and dose-dependent ability to modulate pro-oxidant and pro-inflammatory functions of human neutrophils: it strongly reduced the ROS level and downregulated the release of pro-inflammatory cytokines and tissue remodelling enzymes, especially IL-1β and elastase 2, in cells stimulated by fMLP, LPS, or fMLP + cytochalasin B. The extracts were also potent direct scavengers of in vivo relevant oxidants (O2•−, •OH, and H2O2) and inhibitors of pro-inflammatory enzymes (cyclooxygenase-2, hyaluronidase, and lipoxygenase). The statistically significant correlations between the tested variables revealed the synergic contribution of individual polyphenols to the observed effects and indicated them as useful active markers for the standardisation of the extract/plant material. Moreover, the safety of ME was confirmed in cytotoxicity tests. The obtained results might partially explain the ethnomedicinal application of G. procumbens leaves and support the usage of the standardised leaf extract in the adjuvant treatment of oxidative stress and inflammation-related chronic diseases.

Roasting treatments affect physicochemical, aroma and nutritional quality of strong fragrant rapeseed oil

The strong fragrant rapeseed oil (SFRO) attracts the growing interest in China due to its fragrant flavor, attractive color, and physical and oxidative stability. It is usually produced with simple processes including rapeseed roasting, mechanical pressing, and degumming with hot water (80–90 °C). To produce SFROs with high quality and nutritional contents, the seed roasting parameters including temperature up to 220 °C and time ranging from 10 min to 30 min were investigated. Results showed that 20-min roasting at temperature 160 °C resulted in the highest oil extraction yield of 33.20% with the lowest water content of 0.121%. The produced SFRO had the roasted, nutty and soft tastes with the maximum overall score, the highest total tocopherol and sterol contents of 789.73 mg/kg and 4582.80 mg/kg, respectively, and high CoQ10 content of 65.57 mg/kg. Over-roasting at roasting temperature of over 180 °C and time of over 30 min led to the high Lovibond red readings, off-flavors, and increased concentrations of high saturated fatty acids and Benzo[a]pyrene (BaP). Our findings would provide a reference to produce SFROs with the highest extraction yield and nutrient contents, acceptable physicochemical properties, optimal profile of the fatty acids and the key aroma compounds, and relatively-low BaP concentration.

Arnica Montana L. Supercritical Extraction Optimization for Antibiotic and Anticancer Activity.

Arnica montana L. flower heads are known for their antioxidant, antimicrobial, and anticancer activity. The aim of this work was to optimize the process of supercritical CO2 extraction, to achieve high extraction yield and high content of biologically active components, and to confirm the antimicrobial and anticancer activity of the extract. The influence of pressure and temperature on the total phenolic content, antioxidant activity, and proanthocyanidin content was evaluated. The pressure and temperature were found to be interdependent. A temperature of 60°C and a pressure of 30 MPa resulted in a high extraction yield, antioxidant activity and phenolic content. The content of proanthocyanidins was highest at a pressure between 18 and 24 MPa. The extracts inhibited three different microorganisms successfully; Staphylococcus aureus, Escherichia coli and Candida albicans, at concentrations ranging from 0.1 to 5.16 mg/ml and showed anticancer activity decrease up to 85% at a concentration of 0.5 mg/ml.

Supramolecular solvent-based sample treatment workflow for determination of multi-class drugs of abuse in hair by liquid chromatography-tandem mass spectrometry

Hair is becoming a main matrix for forensic drug analyses due to its large detection window compared to traditional matrices (i.e. urine & blood) and the possibility of establishing the temporal pattern of drug consumption. However, the extremely time- and solvent-consuming nature of conventional sample treatments render it difficult for routine use of hair analysis in forensics. In this paper, this drawback was intended to be addressed by the use of hexanol-based supramolecular solvents (SUPRAS) with restricted-access properties. The aim was to develop a fast and interference-free sample treatment workflow for the determination of opioids, cocaine, amphetamines and their metabolites in human hair. The main variables affecting the extraction were optimized and the method was validated following the European Medical Agency guideline. Major advantages of the proposed method were the straightforward sample preparation, which combines a high extraction yield (93–107%) and matrix effect removal (93–102%SSE) in a single step, the high sample throughput, and the reduced volume of organic solvent required (100 µL of SUPRAS per sample), which makes sample treatment cost-effective and eco-friendly. Method quantification limits were lower enough for all the target drugs (0.5–1.1 pg mg−1) to allow their quantitation in human hair routine analyses. The method was successfully applied to the determination of drugs of abuse in a human hair control sample.

해조류 바이오매스로부터 Lactic acid를 제조하는 방법에 관한 연구

With the spread of COVID-19 worldwide, non-face-to-face services have grown rapidly, but at the same time, the problem of plastic waste is getting worse. Accordingly, eco-friendly policies such as carbon neutrality and sustainable circular economy are being promoted worldwide. Due to the high demand for eco-friendly products, the packaging industry is trying to develop eco-friendly packaging materials using PLA and PBAT and create new business models. On the other hand, Ulva australis occurs in large quantities in the southern seas of Korea and off the coast of Jeju Island, causing marine environmental problems. In this study, lactic acid was produced through dilute acid pretreatment, enzymatic saccharification, and fermentation processes to utilize Ulva australis as a new alternative energy raw material. In general, seaweeds vary in carbohydrate content and sugar composition depending on the species, harvest location, and time. Seaweed is mainly composed of polysaccharides such as cellulose, alginate, mannan, and xylan, but does not contain lignin. It is difficult to expect high extraction yield of the complex polysaccharide constituting Ulva australis with only one process. However, the fusion process of dilute acid and enzymatic saccharification presented in this study can extract most of the sugars contained in Ulva australis. Therefore, the fusion process is considered to be able to expect high lactic acid production yield when a commercial-scale production process is established.

Volatile Constituent Analysis of Wintergreen Essential Oil and Comparison with Synthetic Methyl Salicylate for Authentication.

A comparative analysis of Gaultheria fragrantissima (Ericaceae) essential oils based on geographical location, distillation time, and varying distillation conditions was carried out, and their compositions were evaluated by gas chromatography–mass spectrometry (GC–MS), chiral GC–MS, and gas chromatography–flame ionization detection (GC–FID). In addition, each of seven commercial wintergreen essential oil samples from Nepal and China were analyzed. The highest extraction yield was 1.48% and the maximum number of compounds identified in natural wintergreen oil was twenty-two. Based on distillation time, the maximum numbers of identified compounds are present in 120 min. Linalool, phenol, vetispirane, and ethyl salicylate were present in commercial wintergreen oils both from Nepal and China. The presence of compounds such as elsholtzia ketone and β-dehydroelsholtzia ketone in the China samples represented a significant difference in wintergreen oil between the two geographical sources. Dimethyl 2-hydroxyterephthalate is a well-known synthetic marker for wintergreen oil when synthesis is carried out using salicylic acid, but the synthetic marker was absent while using acetylsalicylic acid as a precursor during synthesis. Adulteration analysis of wintergreen oil showed an increase in the concentration of dimethyl 2-hydroxyterephthalate, whereas the concentrations of minor components decreased and methyl salicylate remained unchanged. To the best of our knowledge, this is the first report of the enantioselective analysis of wintergreen essential oil. Furthermore, three samples showed notable antibacterial activity against Staphylococcus epidermidis, with an MIC value of 156.3 μg/mL. Similarly, one sample showed effectiveness against Aspergillus niger (MIC = 78.1 μg/mL).

Caustic potash assisted roasting of the Nigerian ferro-columbite concentrate and guanidine carbonate-induced precipitation: A novel technique for extraction of Nb–Ta mixed-oxides

The current study focuses on alkali-assisted roasting, dissolution, and recovery of mixed oxides of niobium (Nb) and tantalum (Ta) from a ferro-columbite concentrate collected from Jos Plateau in Nigeria. Alkali-assisted roasting and water-based leaching to extract Nb and Ta using guanidine carbonate salt were adopted for sustainable extraction. The concentrate was roasted with caustic potash (KOH) as flux at optimized conditions (250 °C, 100% mass flux-to-concentrate ratio, 1 h) and leached with water. This resulted in dissolution of 97-96% Nb, 80-96% Ta, 92-91% W and 64-65% Mn for −250 and + 250 μm size fractions respectively while leaving behind in the residue most of Sn (94-83%) and Fe (79-81%). The amount of Nb and Ta dissolved were selectively recovered with novel application of guanidine carbonate salt as precipitating agent. High extraction yield (∼100%) was achieved. The final recovery of approximately 96% Nb and 85% Ta contained in the +250 μm concentrate feed sample was obtained under optimum conditions of 50 mg/mL guanidine. The (Nb,Ta)-guanidine precipitate obtained was then calcined at 900 °C for 1 h and converted into mixed (Nb,Ta)2O5 (97%) and removed the guanidine. Based on material balance, it was found that approximately 734.5 kg of (Nb,Ta)-guanidine precipitate with purity higher than 84% could be obtained from one tonne of ferro-columbite feed concentrate. The current technique of alkali-assisted roasting, dissolution, and recovery of mixed oxides of Nb and Ta is a novel process and presents an environmentally benign, and it is an efficient technique to replace the traditional method which uses an environmentally harmful hydrofluoric acid to extract Nb and Ta.

Effect of agitation on extraction of phenolic compounds from ripe pericarp of Wodyetia bifurcata

In this study, the ripe pericarp extracts of Wodyetia bifurcata were prepared by solvent extraction techniques with and without agitation. The influence of agitation was examined on the extraction yield, total phenolic content (TPC), total flavonoid content (TFC) and antioxidant activity of the ripe pericarp extracts of Wodyetia bifurcata. Antioxidant capacity of extracts was evaluated by measuring the scavenging effect on 2, 2’-azinobis (3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) and 2, 2’-diphenyl-1-picrylhydrazyl (DPPH) radicals. Compared to solvent extraction without agitation, solvent extraction with agitation significantly (p < 0.05) increased the extraction yield, TPC, TFC and antioxidant capacities (ABTS and DPPH) of the ripe pericarp extracts of Wodyetia bifurcata. In addition, higher agitation speed resulted in higher extraction yield, TPC, TFC and antioxidant activities (ABTS and DPPH) of the ripe pericarp extracts of Wodyetia bifurcata.

Application of Citrus By-Products in the Production of Active Food Packaging.

Some citrus by-products such as orange peel contains valuable compounds that could be recovered and restored into the food chain. In this study, an efficient valorization of orange peel has been investigated using green extraction, fractionation, and impregnation techniques. The first step included its extraction using CO2 and ethanol under different pressure (200–400 bar) and temperature (35–55 °C) conditions. The extracts obtained at 300 bar and 45 °C showed strong antioxidant with moderate antimicrobial activity. Then, the extract was subjected to a sequential fractionation process. The fraction obtained at 300 bar, 45 °C, and using 32% ethanol showed the strongest antioxidant and antimicrobial activity with a high extraction yield. Finally, the potential of the two best extracts (obtained at 400 bar and 45 °C before any fractionation and the fractions obtained at 300 bar, 45 °C using 32% ethanol) was determined by conducting an impregnation process to obtain an antioxidant food-grade rigid plastic that would preserve fresh food. The percentage of cosolvent (1 and 2% ethanol), the impregnation time (1 and 3 h), the pressure (200 and 400 bar), and the temperature (35 and 55 °C) were evaluated as variables of this process. The impregnated plastic showed good antioxidant and antimicrobial activities.

Optimisation of patchoulol in the lipid-soluble concentrates of Pogostemon cablin using response surface methodology (RSM) coupled with genetic algorithms (GA)

Pogostemon cablin Benth. contains abundance of patchoulol as one of the bioactive components. The present study demonstrated comprehensive optimizations of ultrasonic assisted extraction (UAE) and microwave assisted extraction (MAE) to achieve maximum lipid-soluble extract comprising highest patchoulol content by response surface methodology (RSM) followed by genetic algorithms (GA) approach. The extraction variables such as solute to solvent ratio (UAE, 10–30 g mL−1; MAE, 40–60 g mL−1), time (UAE, 10–20 min; MAE, 30–120 s) and sono-frequency (30–50 kHz) or microwave power (300–900 W) exerted significant influence on the yield and patchoulol content. RSM based optimizations for UAE resulted maximum yield of 182.24 mg/g of plant material consisting 48.84% patchoulol, while, yield 227.46 mg/g of plant material comprising 30.60% patchoulol were recorded under MAE. With the use of GA, the optimized values were further refined to obtain maximum yield of 207.87 mg/g of plant material comprising of 53.45% patchoulol under UAE, whereas, maximum 230.03 mg/g of plant material yield consisting of 31.71% patchoulol was achieved using MAE. UAE and MAE based kinetic modeling studies revealed involvement of more than one extraction mechanisms to achieve maximum yield and patchoulol (%). Further, higher extraction yield using MAE and UAE were also explained from the scanning electron microscopic (SEM) images, showing disintegration of matrix cell wall with numerous fractures leading to better dissolution of phytoconstituents in the extracting medium. Additionally, patchoulol content in the extract was significantly enhanced to 92.70% using silica gel. Patchoulol 92.70% and 53.45% containing extracts displayed excellent fungal mycelial inhibition against virulent strains of Aspergillus flavus (EC50 27.0–29.2 μg mL−1) and A. fumigatus (EC50 41.5–57.2 μg mL−1), respectively.

Trace‐level analysis of polychlorinated biphenyls, organochlorine pesticides and polycyclic aromatic hydrocarbons in human plasma or serum by dispersive liquid–liquid microextraction and gas chromatography–tandem mass spectrometry

A method to determine 8 polychlorinated biphenyls (PCBs), 23 organochlorine pesticides (OCPs) and 16 polycyclic aromatic hydrocarbons (PAHs) was described using dispersive liquid-liquid microextraction (DLLME) of a small amount of plasma or serum sample and gas chromatography-tandem mass spectrometry (GC-MS/MS). The appropriate selection of the extraction solvent and dispersing solvent contributes to a high extraction yield and a clean extract. To verify the developed method, the interference, linearity of the calibration curve, detection limit, precision and accuracy were evaluated. The calibration curves were linear by 2-3 orders of magnitude with correlation coefficients above 0.997 in all cases. The LODs of PCBs, OCPs and PAHs were measured in the ranges of 0.0006-0.0029, 0.001-0.029 and 0.0002-0.012 ng/mL. The intraday precision achieved by this method was 2.19-10.3% (PCBs), 1.65-14.3% (OCPs) and 0.91-12.8% (PAHs), and the intraday accuracy 1.56-7.37% (PCBs), 2.34-19.6% (OCPs) and 1.49-15.7% (PAHs). The advantage of this method is that the analysis of PCBs, OCPs, and PAHs can be performed in a single chromatographic run, and the low detection limit enables monitoring of target substances in low exposure general public samples, and the analysis procedure is relatively simple and fast.

Pressurized hot water-assisted recovery of crude residual agar from a never-dried algae industry waste stream: A Box-Behnken design approach

The potential of using pressurized hot water extraction to valorize the remaining crude agar in Gelidium sesquipedale waste stream after an initial industrial extraction was investigated. In this process, a four-factor Box-Behnken design was coupled with a response surface methodology. The impact of the operating temperature (°C), the internal pressure (bar), the extraction time (min), and the algae concentration (% w: v), as well as their quadratic effects and two-way interactions, on the physicochemical properties of the residual agar, was analyzed. The yield (%), gel strength (g/cm2), gelling temperature (°C), melting temperature (°C), 3,6-anhydrogalactose content (%), and the sulfate content (%) were all considered in the evaluation. A multiple regression statistical model was used to fit all the experimental responses to a second-order polynomial equation that confirmed the suitability of the approach. Temperature of 120 °C, low pressure of 3.28 bar, and an extended extraction time of 150 min along with a 3% (w: v) algae concentration were projected to be optimum conditions for a high extraction yield of 17.03%. The strength of the recovered agar hydrogel oscillated between a minimum of 25 g/cm2 and a maximum of 350 g/cm2. The key parameters impacting the fluctuation of the sulfate content in the recovered agar (2% ≤ sulfate content ≤10%, with R2 = 79.8%) appeared to be the temperature and the algae concentration, in addition to the quadratic effect of the solid concentration. By adjusting the parameters, the process can accommodate the physicochemical properties of agar for wider range of applications.