Pressurized Liquid Extraction Method Research Articles

Improving pressurized liquid extraction of passion fruit (P. edulis) bagasse: Exploring the effects of high-temperature, particle size, and extraction bed dimensions

Extraction techniques to obtain bioactive molecules from passion fruit bagasse have emerged recently. The driving force behind this effort lies in the array of biological properties related to its compounds, including anti-carcinogenic, antioxidant, anti-inflammatory, and vasorelaxant properties. Given this background, this work proposes improvements to the extraction process from defatted passion fruit bagasse (DPFB). The effect of pressurized liquid extraction (PLE) temperature was examined at 70, 90, and 110 °C, revealing an increase in global yield and total reducing content (TRC) with rising temperature. However, the yield of piceatannol was statistically equal between 70 and 90 °C and decreased at 110 °C, suggesting thermal degradation. These findings were corroborated by thermal stability analysis and oxygen radical absorbance capacity assessment. The impact of raw material particle size was investigated and showed that granulometric classification led to an increase in the TRC and piceatannol yields by 35% and 84%, respectively, and allowed identifying the piceatannol's location within the outer layer of the passion fruit seed (FR1). Mathematical modelling was applied to the kinetic extraction of DPFB-FR1 to assess the effect of bed height to diameter ratio (H/D). The two-site desorption model has properly fitted experimental data and indicated an enhancement in piceatannol mass transfer rate when increasing H/D. In summary, the present work presents findings and conclusions not previously documented in the literature, contributing to the improvement of PLE and pre-treatment methods for passion fruit bagasse.

Hass Avocado (Persea americana Mill.) residues as a new potential source of neuroprotective compounds using pressurized liquid extraction

Epicarp and seed of Hass avocado (Persea americana Mill.) are agro-industrial residues rich in bioactive compounds. In this study, a pressurized liquid extraction (PLE) method was optimized to obtain phenolic compound-rich extracts with neuroprotective potential. The optimal extracts, obtained from 100% epicarp with pure water (0% ethanol) at 40 °C and 100 bar, demonstrated high extraction yield (26.8 ± 0.9%) and total phenol content (TPC = 505 ± 25 mg gallic acid equivalent/g dry extract), good antioxidant capacity (ABTS = 3350 ± 179 µmol Trolox equivalent/g dry extract, ORAC = 0.14 ± 0.01 µg/mL), and moderate acetylcholinesterase inhibition (33.6 ± 2.9 µg/mL). UHPLC-ESI-QTOF-MS analysis of the optimal extracts tentatively identified phenolic acids, phenolic alcohol derivatives, and various flavonoids; namely flavonols. The results reveal the potential of avocado processing by-products, particularly the epicarp, as source of potential neuroprotective agents. The proposed PLE methodology was demonstrated to be a sustainable and efficient strategy for avocado residues valorization.

Effects of dietary Scutellaria baicalensis extract on growth performance, immune-related genes expression, and resistance against Vibrio parahaemolyticus in white shrimp (Litopenaeus vannamei)

In this study dietary Scutellaria baicalensis extract (SBE) was used to improve the shrimps' immune response and its resistance to Vibrio parahaemolyticus. SBE obtained by solid-liquid extraction (SLE) has shown stronger antibacterial activity against V. parahaemolyticus compared to extracts obtained through the pressurized liquid extraction (PLE) method. A stronger immune response, such as the production of reactive oxygen species and the induction of expression of immune genes in hemocytes was seen in the SBE (SLE) treated group in vitro.SBE (SLE) had better immune stimulation effects and bactericidal activity than SBE (PLE) and therefore was chosen for in vivo feeding trial. The group fed with 1% SBE showed a better growth performance after 2 weeks of the feeding trial, but the growth-promoting effects did not last until the end of the trial at week four.Higher SBE intake reduced shrimp resistance to V. parahaemolyticus on week two but showed better resistance than the control group on the fourth week. Gene expression assays were used to investigate contradictory responses of the SBE-fed groups to V. parahaemolyticus at different times. Most of the genes examined in the selected tissues were not significantly changed, suggesting that the higher mortality of shrimp fed with high dose of SBE was not due to suppression of immune-related genes at earlier time point.Collectively, the bioactivity of SBE is influenced by the extraction conditions. Higher dietary doses of SBE (1% and 5%) improved the resistance of the white shrimp to V. parahaemolyticus after a longer feeding period (week four), but caution should be taken when applying SBE in the feed since a vulnerable status (week two) was seen during the feeding trial.

Multiresidue extraction of current-use pesticides from complex solid matrices using energized dispersive guided extraction with analysis by gas and liquid chromatography tandem mass spectroscopy

The development of sample processing techniques that recover a broad suite of pesticides from solid matrices, while mitigating coextracted matrix interferences, and reducing processing time is beneficial for high throughput analyses. The objective of this study was to evaluate the effectiveness of an automated extraction system for pesticide analyses in solid environmental samples. An Energized Dispersive Guided Extraction (EDGE) system was used to evaluate two different extraction solvents in optimizing the extraction of 210 pesticides and pesticide transformation products. A graphitized carbon cleanup step was implemented, and three elution solvents were evaluated separately for analyte recoveries. Recoveries between 70 and 130% were achieved for 167 compounds in a test soil using acetonitrile as an extraction solvent and carbon cleanup with acetonitrile and dichloromethane elutions. Nine field samples (soil, sediment, and biosolids) were extracted using the newly developed method and were compared with a previously validated pressurized liquid extraction (PLE) method using an Accelerated Solvent Extraction (ASE) system. Concentrations obtained from the two methods were comparable (linear R2 > 0.999), suggesting similar performance between the EDGE and PLE extractions in complex matrices. The new method provided slightly better sensitivities in comparison to the PLE method, ranging from 0.09 to 2.56 ng g−1. The method presented here significantly reduces extraction setup and runtimes while also minimizing the volume of carcinogenic solvents (e.g., dichloromethane) used in the laboratory and presents a sensitive multiresidue method for a wide range of pesticides in solid matrices.

Effects of Ultrasound Assisted Extraction on Efficiency and Quality of Rice Bran Oil

Effects of ultrasound-assisted extraction (UAE) conditions viz., ultrasound power and treatment time on extraction efficiency and quality of oil from rice bran were studied. The sonication power and irradiation time varied between 6.11, 12.23, and 18.35 W/cm2; and 5, 15, and 25 min, respectively. The recovery, physicochemical and phytochemical properties of UAE oil were measured and compared with conventional soxhlet extraction (SE) and pressurized liquid extraction methods (PLE). The results showed that increasing the ultrasonic irradiation time and power led to greater oil extractability. However, the oil quality and ultrasonic intensity were inversely correlated. Specifically, higher power intensity (18.35 W/cm2) and longer irradiation time (15-25 min) impaired the unsaturated fatty acids (UFAs) and phytochemical compositions of the extracted oil. The maximum oil extractability obtained by PLE and UAE (12.23 W/cm2 and 15 min) were 16.77 mg/g rice bran and 16.59 mg/g rice bran, respectively, and higher than the SE process (14.96 mg/g rice bran). No significant differences were shown among PLE and UAE (12.23 W/cm2 and 15 min) oils for the physiochemical and phytochemical properties. Similar to the PLE and SE oils, oleic acid was the dominant fatty acid in the UAEs oils, followed by linolenic and palmitic acids. Scanning electron microscopy (SEM) results showed that the UAE process effectively damaged the cell walls of rice bran, resulting in improved oil yield. Thus, UAE is a promising method for extracting oil from rice bran.

Comparison of Green Technologies for Valorizing Sugar Beet Leaves (Beta vulgaris L.)

This study is focused on the valorization of sugar beet leaves (Beta vulgaris L.), a prominent by-product wasted during the process of sugar. For doing so, Ultrasound-Assisted Extraction (UAE), Pressurized Liquid Extraction (PLE), and Maceration Extraction (ME) methods were compared by evaluating the extraction yield, Total Phenolic Compounds (TPC), Total Flavonoid Content (TFC), individual phenolic profile, and antioxidant activity (e.g., DPPH, FRAP, and ABTS). Ethanol and water (70% V/V) were employed as extracting solvents. The TPC for UAE and PLE methods was 4.90±0.083 and 6.46±0.33 (mg GAE/mL), respectively, differing significantly (P<0.05) from each other. Moreover, the TFC in the PLE method was the highest with 1.45±0.06 mg QE/mL (P<0.05). The antioxidant activity of extracts was significantly different as the PLE method yielded the highest quantities. Benzoic acid was present only in the PLE extracts, while PLE and ME methods recovered the highest quantity of syringic acid (0.35±0.00 mg/L) and pyrogallol (74.80±0.01 mg/L), respectively. However, the extraction yield obtained by the UAE method (19.58±0.33%) had a significant statistical difference from other methods. Therefore, despite the higher TPC and antioxidant activity reached by the PLE method, it was proved that UAE yields higher polyphenolic compounds with a lower quantity of beet leaves.

Supercritical fluids in analysis of cannabinoids in various Cannabis products

We developed a fast, selective, and sensitive method for the determination of various neutral and acidic phytocannabinoids with an emphasis on the separation of structurally related compounds. Optimized ultra-high performance supercritical fluid chromatography (UHPSFC) allowed the separation of 2 groups of structural isomers, including isomers of m/z 357: cannabidiolic and Δ9-tetrahydrocannabinolic acid, and isomers of m/z 315: cannabichromene, Δ9-tetrahydrocannabinol, Δ8-tetrahydrocannabinol, cannabicyclol, and cannabidiol only in mere 3.5 min followed by 1.5 min equlibration. The 2-ethylpyridine functionalized stationary phase and gradient elution using mobile phase comprising carbon dioxide and methanol: acetonitrile (25:75) + 5% water mixture were selected after the optimization. Tandem mass spectrometry (MS/MS) with electrospray ionization in positive and negative modes with methanol + 5% water as a make-up solvent provided adequate selectivity and sensitivity needed for analysis of phytocannabinoids in complex matrices. The limits of quantification were in the range 0.01–0.5 ng/mL for most of the monitored cannabinoids. The optimized UHPSFC-MS/MS method was then used for the determination of cannabinoids in various products, such as dietary supplements, nutraceuticals, and cosmetics. Solvent extraction methods were optimized for the cosmetic and nutraceutical products with the accuracy in the range 80.4–120.6% and precision 0.5–18.9%. To extract cannabinoids from the herbal infusion matrix, supercritical fluid extraction (SFE) and pressurized liquid extraction (PLE) methods were developed using environmentally friendly solvents water, ethanol, and carbon dioxide. The detailed optimization of extraction solvent composition, temperature, and pressure was carried out with the emphasis on avoiding the thermal degradation of cannabinoids. Optimized SFE and PLE methods were compared and applied to different herbal infusions to confirm declared cannabinoids content.

Neuroprotective Potential of Thinned Peaches Extracts Obtained by Pressurized Liquid Extraction after Different Drying Processes.

Genetic, environmental and nutritional factors are suggested as primary factors of Alzheimer’s disease (AD), and secondary metabolites such as polyphenols present in thinned peaches are considered as good candidates for AD prevention. Thinned peaches are usually dried to avoid putrefaction, but the effects of the drying method and the extraction process on the polyphenol composition and the neuroprotective potential have never been addressed. In this work, a pressurized liquid extraction (PLE) method was optimized and applied to thinned peaches dried under different conditions, and their neuroprotective potential was evaluated in vitro. In addition, the PLE extracts were characterized via HPLC-Q-TOF-MS/MS, and a permeability assay was performed to evaluate the ability of the identified metabolites to cross the blood–brain barrier (BBB). The PLE extracts obtained from freeze-dried (FD) samples with 50% ethanol in water at 180 °C showed the best neuroprotective potential. Finally, among the 81 metabolites identified, isoferulic acid, 4-methyldaphnetin, coniferyl aldehyde and 3,4-dihydroxyacetophenone were found at higher concentrations in FD extracts. These metabolites are able to cross the BBB and are positively correlated with the neuroprotective potential, suggesting FD together with PLE extraction as the best combination to exploit the neuroprotective capacity of thinned peaches.

Pressurized liquid extraction coupled in-line with SPE and on-line with HPLC (PLE-SPExHPLC) for the recovery and purification of anthocyanins from SC-CO2 semi-defatted Açaí (Euterpe oleracea)

This study aimed to extract anthocyanins from dried and semi-defatted açaí pulp using green technologies based on the coupling of pressurized liquid extraction (PLE) with in-line purification through solid-phase extraction (SPE) and on-line analysis by high-performance liquid chromatography (HPLC). Critical parameters that affect the extraction efficiency and purification were investigated and optimized by response surface methodology (RSM). PLE was performed with acidified water at different pH (2.0, 4.5, and 7.0) and temperatures (40, 80, and 120 °C) at 15 MPa, 2 mL/min, and solvent-to-feed mass ratio equal to 40. SPE was optimized in a column packed with the adsorbent PoraPak™ Rxn. Different ethanol concentrations (50, 75, and 100 %) and temperatures (30, 40, and 50 °C) were evaluated for the anthocyanin’s elution. The optimal conditions of the two experimental designs were determined by the RSM, firstly for PLE: 71 °C and pH 2; then using this PLE condition, the optimization of the SPE was obtained: 30 °C and 50 % ethanol. The developed PLE method provided similar anthocyanin yield to other techniques, and the coupling with SPE in-line produced an extract 5-fold more concentrated than PLE alone. Therefore, the system (PLE-SPE × HPLC-PDA) proved to be a powerful tool for monitoring the extraction process in real-time.

Development and validation of a simultaneous method for the analysis of benzothiazoles and organic ultraviolet filters in various environmental matrices by GC-MS/MS.

The presence of benzothiazoles (BTHs) and organic ultraviolet filters (UV filters) in aquatic ecosystems has emerged as a significant environmental issue, requiring urgent and efficient determination methods. A new, rapid, and sensitive determination method using gas chromatography triple quadrupole mass spectrometer (GC-MS/MS) was developed for the simultaneous extraction and analysis of 10 commonly used BTHs and 10 organic UV filters in surface water, wastewater, sediment, and sludge. For aqueous samples, solid-phase extraction (SPE) method was employed with optimizing of SPE cartridge type, pH, and elution solvent. For solid samples, ultrasonic extraction-solid-phase extraction purification (UE-SPE) and pressurized liquid extraction (PLE) methods were compared. And extraction conditions for ultrasonic extraction method (extraction solvents and extraction times) and PLE method (extraction temperatures and extraction cycles) were optimized. The limits of quantification for the 20 target compounds in surface water and wastewater were 0.01-2.12ng/L and 0.05-6.14ng/L, while those for sediment and sludge with UE-SPE method were 0.04-5.88ng/g and 0.22-6.61ng/g, respectively. Among the 20 target compounds, the recoveries ranged from 70 to 130% were obtained for 16, 15, 15, and 15 analytes in the matrix-spiked samples of surface water, wastewater, sediment, and sludge with three levels, respectively. And the precision was also acceptable with relative standard deviation (RSD) below 20% for all analytes. The developed methods were applied for the determination and quantification of target compounds in surface water, sediment, wastewater, and sludge samples collected from two wastewater treatment plants (WWTPs) and the Pearl River in Guangzhou, China. BTHs were frequently detected in surface water and wastewater, while UV filters were mainly found in sediment and sludge. Benzotriazole (BT) and 2-hydroxybenzothiazole (2-OH-BTH) were the two major BTHs in influent wastewater and surface water, respectively, with concentrations up to 966 and 189ng/L. As for sediment and sludge, 2-(2'-hydroxy-5'-octylphenyl)-benzotriazole (UV-329) was a predominant chemical, detected at concentrations of 111 and 151ng/g, respectively.

Application of Pressurized Liquid Extractions to Obtain Bioactive Compounds from Tuber aestivum and Terfezia claveryi

A PLE (pressurized liquid extraction) method was adjusted following a full-factorial experimental design to obtain bioactive-enriched fractions from Tuber aestivum and Terfezia claveryi. Temperature, time and solvent (water, ethanol and ethanol–water 1:1) parameters were investigated. The response variables investigated were: obtained yield and the levels of total carbohydrate (compounds, β-glucans, chitin, proteins, phenolic compounds and sterols). Principal component analysis indicated water solvent and high temperatures as more adequate parameters to extract polysaccharide-rich fractions (up to 68% of content), whereas ethanol was more suitable to extract fungal sterols (up to 12.5% of content). The fractions obtained at optimal conditions (16.7 MPa, 180 °C, 30 min) were able to protect Caco2 cells from free radical exposure, acting as antioxidants, and were able to reduce secretion of pro-inflammatory cytokines in vitro: IL-6 (50%), and TNFα (80% only T. claveryi ethanol extract), as well as reduce high inhibitory activity (T. aestivum IC50: 9.44 mG/mL).

Protein valorization from ora-pro-nobis leaves by compressed fluids biorefinery extractions

Ora-pro-nobis (Pereskia aculeata) leaves were selected as raw material for biorefinery application based on compressed fluid extractions with green solvents. The fractionation followed the sequential processes: (1) Supercritical fluid extraction (SFE) with CO2, (2) Gas expanded liquid extraction (GXL), using CO2:Ethanol, and pressurized liquid extraction (PLE) with ethanol, and (3) Subcritical water extraction (SWE). In vitro analysis of total phenolic and total carotenoid contents and antioxidant activity (DPPH and ORAC) were assessed, stipulating PLE method as the second step of the sequential extractions. Total protein and carbohydrate contents were evaluated from SWE samples. Phenolics profile from PLE and SWE samples was assessed by LC-DAD-ESI-MS/MS, identifying 8 phenolic compounds, with quercetin, isorhamnetin and kaempferol as the main detected flavonoids. SWE at 150 and 185 °C provided the highest protein recovery, as the third step in a sequential process.

Antioxidant activity of extracts obtained by high-pressure extraction procedures from Asparagus stipularis Forssk

Roots and rhizomes of Asparagus stipularis Forssk were separately extracted using supercritical CO2 extraction (SCCO2) and pressurized liquid extraction (PLE) and their Total Phenols Content and antioxidant potential was investigated. The results indicated that the roots and rhizomes are a potential source of natural antioxidants. The PLE method gave better extraction yields than SFE and its fractions present the highest antioxidant activity. Direct evaluation of antioxidant capacity using the QUENCHER procedure showed that also the solid residue of the plant material remaining after the SCCO2 and PLE may be of interest as a source of valuable phytochemicals.

Quantification and Ecological Risk Assessment of Colloidal Fullerenes Nanoparticles in Sediments by Ultrasonic-Assisted Pressurized Liquid Extraction and High Performance Liquid Chromatography.

Fullerenes engineered nanomaterials are regarded as emerging environmental contaminants. This is as their widespread application in many consumer products, as well as natural release, increases their environmental concentration. In this work, an ultrasonic-assisted pressurized liquid extraction (UAPLE) method followed by high performance liquid chromatography with ultraviolet-visible detector (HPLC-UV-vis) was developed for extraction and determination of fullerene in sediments. The method was validated and found to be suitable for environmental risk assessment. Thereafter, the method was used for the determination of fullerene (C61-PCBM) in sediment samples collected from Umgeni River, South Africa. The current method allows for adequate sensitivity within the linear range of 0.01–4 µg g−1, method limit detection of 0.0094 µg g−1 and recoveries ranged between 67–84%. All the parameters were determined from fortified sediments samples. The measured environmental concentration (MEC) of fullerene in the sediment samples ranged from not detected to 30.55 µg g−1. To the best of our knowledge, this is the first report on the occurrence and ecological risk assessment of carbonaceous fullerene nanoparticles in African sediments and biosolids.

Optimization of Pressurized Liquid Extraction and In Vitro Neuroprotective Evaluation of Ammodaucus leucotrichus. Untargeted Metabolomics Analysis by UHPLC-MS/MS.

Ammodaucus leucotrichus is a spontaneous plant endemic of the North African region. An efficient selective pressurized liquid extraction (PLE) method was optimized to concentrate neuroprotective extracts from A. leucotrichus fruits. Green solvents were tested, namely ethanol and water, within a range of temperatures between 40 to 180 °C. Total carbohydrates and total phenolics were measured in extracts, as well as in vitro antioxidant capacity (DPPH radical scavenging), anticholinesterase (AChE) and anti-inflammatory (LOX) activities. Metabolite profiling was carried out by ultra-high-performance liquid chromatography coupled to quadrupole time-of-flight tandem mass spectrometry (UHPLC-ESI-q-TOF-MS/MS), identifying 94 compounds. Multivariate analysis was performed to correlate composition with bioactivity. A remarkable effect of the temperature using water was observed: the higher temperature, the higher extraction yield, the higher total phenolic content, as well as the higher total carbohydrates content. The water extract obtained at 180 °C, 10.34 MPa and 10 min showed meaningful anti-inflammatory (IC50LOX = 39.4 µg/mL) and neuroprotective activities (IC50AChE = 55.6 µg/mL). The Principal Components Analysis (PCA) and the cluster analysis correlated these activities with the presence of carbohydrates and phenolic compounds.

Obtaining phytotherapeutic chlorophyll extracts using pressurized liquid technology

The use of natural extracts in medical treatments has grown in recent years. However, conventional extraction methodologies generate large amounts of toxic residues, which cause severe problems for human health and the environment. For this reason, in this study, the pressurized liquid extraction method was used to obtain chlorophyll-rich spinach extracts applicable for Antimicrobial Photodynamic Therapy, a medical modality aimed at pathological conditions caused by microorganisms. Several conditions were evaluated, with variations in temperature, pressure, and percentage of ethanol in water as solvent. The highest yield was achieved by the combination of 8 MPa pressure, 75 °C, and 80% (v/v) ethanol/water, for which we obtained a yield of 25.3% (w/w). The extraction of kinetic curves fitted Sovová's model. The clean methodology belongs to the green chemistry and has proven to be fast and efficient. The extract obtained has a high potential for the development of phytotherapeutic medicines.

Thermo-chemical conversion of cannabis biomass and extraction by pressurized liquid extraction for the isolation of cannabidiol

Cannabis plants produce acidic cannabinoids, however the neutral form is required to effectively bind to the human cannabinoid receptor. This research aimed to develop and validate methodology for thermo-chemical conversion of acidic cannabinoids during pressurized liquid extraction for the isolation of cannabidiol.Cannabinoid decarboxylation is typically performed by heating plant material or extract, however cannabinoids are thermolabile and can readily degrade or convert to undesired metabolites. Consequently, decarboxylation during the extraction process would minimize additional steps and potential for degradation and metabolite formation thereby proving beneficial in the isolation of neutral cannabinoids.A thermo-chemical conversion process was established to convert acidic cannabinoids to their neutral forms. Subsequent extraction with ethanol yielded a cannabidiol extract of 75.8 % purity. Purification with flash chromatography resulted in cannabidiol rich fractions being collected for liquid-liquid extraction and crystallization. The end product was 91.8 % pure. The loss over the extraction and purification process was analyzed and found to be 22 %, which can be reduced by reprocessing select fractions.The optimized pressurized liquid extraction method using water for thermo-chemical conversion of acidic cannabinoids prior to an ethanol extraction step is proposed. The extraction process combined with purification by flash chromatography and liquid-liquid extraction yields cannabidiol crystals of greater than 90 % purity.

Optimization of pressurized liquid extraction and ultrasound methods for recovery of anthocyanins present in jambolan fruit (Syzygium cumini L.)

This work aimed to evaluate and optimize the experimental conditions for the extraction of anthocyanins from jambolan (Syzygium cumini L) applying pressurized liquid extraction (PLE), bath ultrasound extraction (BUE), and probe ultrasound extraction (PUE). This work applied a non-factorial design to evaluate the extraction parameters and response surface methodology to optimize the extraction parameters regarding anthocyanin content. The experiments carried out using aqueous acidified ethanol solution (80% v/v) extracted more anthocyanins (14.4 mg c3g.g−1 DF) than using acidified methanol, acetone, or water. Among the methods, PUE resulted in the highest anthocyanins recovery. The optimal conditions obtained by RSM for PUE anthocyanin extraction from jambolan were: ultrasound power density of 5000 W/L, extraction time of 7.5 min, and 79.6% of ethanol. At optimal conditions, the concentration of anthocyanins was 60.5 mg c3g.g−1 DF. No statistical difference was found between the experimental value and the value predicted by the model (p > 0.05). Identification of the jambolan anthocyanins was carried out using UPLC-ESI-QTOF-MS. Delphinidin-3,5-diglucoside, petunidin-3,5-diglucoside, and malvidin-3,5-diglucoside were identified as the main anthocyanins in the ethanolic extracts, obtained by all three methods (PLE, BUE, and PUE).

An eco-friendly pressure liquid extraction method to recover anthocyanins from broken black bean hulls

This study aimed to recover the anthocyanin-rich extract from broken black bean hulls by pressurized liquid extraction (PLE) and to study their chemical stability, inhibition capacity toward carbohydrate-enzymes and application in gelatin. A Box-Behnken design (BBD) coupled to response surface methodology (RSM) was applied in order to maximize the anthocyanin extraction conditions. Optimum PLE conditions obtained were ethanol:citric acid solution 0.1 mol L−1 (30:70, v/v), a flow rate of 4 mL min−1, and 60 °C. Delphinidin-3-glucoside was the main anthocyanin quantified. The PLE crude and purified anthocyanin-rich extracts inhibited α-amylase (IC50: 0.52 and 2.85 mg mL−1) and α-glucosidase (0.03 and 0.15 mg mL−1) enzymes, respectively. The PLE anthocyanin-rich extracts showed higher stability in low temperatures and in the absence of light. Besides, the application in gelatin provided a natural color and supplementation with antioxidant compounds. Overall, anthocyanin-rich extract obtained from black bean by-product using an eco-friendly PLE method shows potential as natural colorant and supplement. Industrial relevancePLE method is an emerging technique that performs fast and efficient extractions under high temperature and pressure conditions. The association of green technologies with green solvents makes PLE an eco-friendly technology. This article provides information about the extraction of anthocyanin-rich extracts from the broken black bean hulls by green PLE process under optimized conditions. The process allowed to obtain antioxidant-rich extracts with high application potential in food, supplements, and pharmaceutical industries.

Characteristics of a novel on-line micro pressurized liquid extraction method

A novel on-line micro pressurized liquid extraction (μPLE) method is introduced, which directly interfaces miniaturized solid sample preparation with HPLC for fast analysis. The technique employs rapid heating to remove analytes from 5–10 mg samples in typically 20–40 s using only about 300 μL of solvent. The resulting extract is then internally transferred to an HPLC injector for chromatographic analysis. Results show that good analyte recoveries can be achieved, similar to conventional PLE and off-line μPLE approaches, without manual sample handling. For example, 103% ± 3% (n = 4) of the acetylsalicylic acid present in pharmaceutical tablets was extracted into methanol after 20 s at 180 °C. Further, 105% ± 9% (n = 4) of the caffeine present in a green tea sample was extracted into methanol after 40 s at 275 °C. Typical time to analysis was about 95 s total for most samples, and solvents could also be easily alternated during trials to increase extract selectivity. The on-line μPLE system was applied to the extraction of model PAHs from a biochar matrix and was found to extract 97% ± 5% (n = 4) of anthracene present in the sample after a 30 s static and 60 s dynamic extraction at 220 °C. This yield is much better than results obtained by previous approaches and is attributed to the small size, high temperature, low thermal mass, and dynamic flow of the system. Findings indicate that the on-line μPLE system can greatly assist in such extractions and provide a useful method for rapidly preparing solid samples for analysis using little solvent.