Solid-liquid Extraction Research Articles

Identification of Phytochemicals and Mineral Nutrients of Selected Malaysian Plant Extracts and its Effects on Seed Priming of Maize

Plants contain a variety of phytochemicals, which act as natural bioactive compounds to help plants enhance abiotic tolerance and promote growth. Therefore, plant extracts are considered to have great potential as environmentally friendly biostimulants in sustainable agriculture. This study aimed to identify the phytochemical compounds and quantify nutrients present in three plant extracts, namely Euphorbia hirta, Polygonum minus, and Eleusine indica, as well as to explore the effect on the growth of maize seedlings (Zea mays L.). The plant powder was extracted using methanol, followed by a solid-liquid extraction procedure. The phytocompounds were analyzed by liquid chromatography-mass spectrometry, while mineral nutrients were quantified using inductively coupled plasma. Five concentrations of plant extracts, i.e., 5, 15, 25, 50, and 100%, were designed to evaluate seed germination and priming. The result showed that 53, 45, and 39 phytocompounds were identified from E. hirta, P. minus, and E. indica, respectively, and classified into different chemical groups (such as flavonoids and amino acids) and rich nutrients (for example, N, P, and K). Besides, P. minus and E. hirta extracts with lower concentrations (5 and 15%) showed a positive effect on germination, shoot length and fresh weight, and the Highest concentration (100%) of E. hirta and E. indica extracts exhibited strong toxicity. This study emphasizes that weed extracts containing abundant secondary metabolites and nutrients can be used as natural biostimulants for maize seed priming.

Selective Extraction Process and Characterization of Antioxidant Phenolic Compounds from Pereskia aculeata Leaves Using UPLC-ESI-Q-TOF-MS/MS.

This study innovates in comparing biological activities and chemical composition obtained from extracts and fractions from Pereskia aculeate leaves. Seven extracts and five fractions were produced by conventional successive solid-liquid extraction coupled with simultaneous bioguided purification using solvents of distinct polarities. A comparative analysis was conducted between these purified fractions and the original extracts to elucidate potential improvements in the bioactivity. The extract and fractions were evaluated using the ABTS, DPPH, FRAP, and Folin-Ciocalteau methods and HPLC-DAD and UHPLC-ESI-Q-TOF-MS/MS evaluated chemical composition. The fractions obtained from the hydroalcoholic extract showed better results, with the acetone fraction (Fr-Ace) exhibiting enhanced bioactivity, especially in the FRAP (1095 μmol of FeSO4/g) antioxidant capacity method. The results demonstrated that medium to high polarity solvents were the most effective in extracting bioactive phenolic compounds, with rutin being the predominant compound. The sequential hydroalcoholic fractionation (SHF) method extracted a greater variety of compounds, including vanillic acid and cinnamic acid, which were reported for the first time in P. aculeate leaves. The identified compounds by UPLC-Q-TOF-MS/MS included flavonoids derived from quercetin, isorhamnetin, and kaempferol, phenolic acids, and their derivatives. Quercetin-3-O-xyloside, kaempferol-3-O-arabinoside, trehalose, feruloyltyramine, malyngic acid, pinellic acid, and 16-hydroxy-9-oxooctadeca-10,12,14-trienoic acid were identified for the first time in P. aculeata leaves.

Kinetic study of solid-liquid extraction of caffeine in Ilex guayusa Loes

Kinetic study of solid-liquid extraction of caffeine in Ilex guayusa Loes

From Waste to Wealth: Exploring the Bioactive Potential of Wine By-Products-A Review.

The present paper explores the biological potential of bioactive compounds present in wine industry wastes, highlighting their valorization to promote sustainability and circular economy. Wine by-products, such as grape pomace and vine shoots, contain a high concentration of polyphenols, flavonoids, anthocyanins and other phytochemicals with antioxidant, anti-inflammatory and anticarcinogenic properties. Both conventional extraction methods, such as solid-liquid extraction, and emerging technologies, including enzyme-assisted extraction, ultrasound-assisted extraction, supercritical fluid extraction, microwave-assisted extraction, pressurized liquid extraction, high-hydrostatic-pressure extraction, and deep natural solvent-assisted extraction (NaDES), are discussed. In addition, the preservation of polyphenolic extracts by microencapsulation, a key technique to improve the stability and bioavailability of bioactive compounds, is addressed. The combination of advanced extraction methods and innovative preservation techniques offers a promising perspective for the valorization of bioactive compounds from wine residues, driving sustainability and innovation in the industry.

Preliminary Studies about Valorization of Acmella oleracea Bioactive Content in Modern Dermato-Cosmetic Applications to Combat Skin Oxidative Stress.

The development of products with skin-protective effects has been driven by the increasing incidence of skin diseases that are exacerbated by increasing pollution, urbanization, poor living, working, fatigue, dietary habits, and general treatment. The ability of antioxidants to protect the skin from oxidative stress and its effects makes them one of the most important ingredients in today's cosmetics. This article aims first to characterize the plant extracts obtained from Acmella oleracea (A. oleracea) and then to evaluate the preliminary criteria for a new marketed product: the stability, antioxidant activity, and in vitro behavior of certain serums based on A. oleracea plant extract and hyaluronic acid. The extracts were obtained by liquid-solid extraction methods (maceration (M), ultrasound-assisted extraction (UEA), and a combined method between these two (UEA + M) using an aqueous solution of ethyl alcohol as the extraction solvent. The determination of the amounts of compounds with antioxidant activity highlighted the fact that the extract obtained from the whole plant of A. oleracea using maceration in conditions of S/L = 1:30, 20 days, and an extraction solvent percentage of 50% led to obtaining the highest amount of polyphenols (30.42 μg GAE/g), while using the combined UAE + M method under conditions of S/L = 1:30, 6 min + 20 days, and 50% extraction solvent led to obtaining the highest amount of flavonoids (32.88 mg QE/g). The tests performed on dermato-cosmetic serums based on the plant extract and multimolecular hyaluronic acid (HA) (1 HA with HMW-1.0 mDa-1.6 mDa; HA with LMW-10 kDa-200 kDa; and HA OLIGO, MW < 10 kDa) led to the conclusion that they exhibit structural stability, good shear behavior revealing a satisfactory texture, and high physical stability during storage. These results encourage the transition to in-depth testing, both microbiological and dermatological, as a final step in the consideration of a new commercial product.

Elemental analysis of valuable byproducts by TXRF spectrometry: coal fly ash and activated carbon

In order to ensure that byproducts are environmentally friendly and fit for purpose, their chemical composition must be determined, with special attention to elements at trace level. The large variability in the type of matrices demands a versatile analytical technique, compatible with sample preparation methods allowing both fast composition screenings and accurate quantitative analysis.In this work, byproducts derived from carbon-rich matrices, including coal fly ash and activated carbon from coconut and almond shells, were investigated by means of total reflection x-ray spectrometry and different sample preparations. Suspension, acid digestion, solid-liquid extraction and ashing were performed and assessed as to their complexity and detection capabilities, ranging from 0.01 mg/kg to 16 mg/kg, depending on the element and sample preparation. The internal standard quantification with gallium, aided by a variation of the standard additions method to take into account its possible presence in the samples, allowed to determine elements of environmental and technological interest, including K, Ca, Ti, V, Mn, Cr, Ni, Cu, Zn, Ga, As, Sr, Pb. Assets, limits and possible developments are presented and discussed.

Screening of Bioactive Compounds in Lettuce: Multivariate Optimization of an Ultrasound-Assisted Solid–Liquid Extraction Procedure

Screening of Bioactive Compounds in Lettuce: Multivariate Optimization of an Ultrasound-Assisted Solid–Liquid Extraction Procedure

Evaluation of Foliar Application of &lt;i&gt;Elusine indica&lt;/i&gt; Extract on Growth, Photosynthesis, and Osmoprotectant Contents in Maize under Drought Stress

To investigate the effects of foliar application of different concentrations of &lt;i&gt;Elusine indica&lt;/i&gt; extract (EIE) on growth, photosynthesis, and osmoprotectant contents in maize under drought stress. The weed powder was extracted using methanol, followed by a solid-liquid extraction procedure. Plants were sprayed with three different concentrations of EIE at 1, 3, and 5 g/L and morphological parameters, chlorophyll, relative water content (RWC), soluble sugar, proline, protein, glutathione (GSH), and malondialdehyde (MDA) contents were determined. The results showed that drought stress led to a decline in morphological characteristics, RWC and soluble sugar and increased proline, protein, GSH, and MDA contents. However, foliar application of EIE significantly improved plant height, fresh and dry weight, chlorophyll content, RWC, soluble sugar, and GSH, while the proline level was diminished compared to drought treatment. Soluble sugar showed a significant positive correlation with fresh and dry weight (&lt;i&gt;r&lt;/i&gt; = 0.742 and 0.783, &lt;i&gt;p&lt;/i&gt; &lt; 0.01) and a strong negative correlation with MDA (&lt;i&gt;r&lt;/i&gt; = -0.459, &lt;i&gt;p&lt;/i&gt; &lt; 0.05). Therefore, this result indicated that EIE can be used as an inexpensive and environmentally friendly biostimulant to help plants enhance tolerance to drought.

Phytochemical and Functional Diversity of Enzyme-Assisted Extracts from Hippophae rhamnoides L., Aralia cordata Thunb., and Cannabis sativa L.

Plant leaves are a source of essential phenolic compounds, which have numerous health benefits and can be used in multiple applications. While various techniques are available for recovering bioactive compounds from by-products, more data are needed on enzyme-assisted extraction (EAE). The aim of this study was to compare EAE and solid-liquid extraction (SLE), to evaluate the impact on bioactive compounds' extraction yield, phytochemical composition, and the antioxidant, antimicrobial, and antidiabetic properties of Aralia cordata leaves and roots, sea buckthorn Hippophae rhamnoides, and hemp Cannabis sativa leaves. The results indicate that EAE with Viscozyme L enzyme (EAE_Visc) extracts of the tested plant leaves possess the highest yield, antioxidant activity, and total phenolic content. Moreover, the EAE_Visc extract increased by 40% the total sugar content compared to the control extract of A. cordata root. Interestingly, the sea buckthorn leaf extracts exhibited α-glucosidase inhibitory activity, which reached an almost 99% inhibition in all extracts. Furthermore, the sea buckthorn leaves SLE and EAE_Visc extracts possess antibacterial activity against Staphylococcus aureus. Additionally, scanning electron microscopy was used to examine changes in cell wall morphology after EAE. Overall, this study shows that EAE can be a promising method for increasing the yield and improving the functional properties of the resulting extracts in a fast and sustainable way compared to SLE.

Determination of pesticide residues in five different corn-based products using a single and simple solid–liquid extraction without clean-up steps followed by comprehensive two-dimensional liquid chromatography coupled to tandem mass spectrometry

Pesticide residues in food products are a critical issue concerning food safety. Recent studies have increasingly focused on developing selective, rapid, innovative, and environmentally friendly analytical methods for detecting pesticides in foodstuffs. This study presents a novel analytical method utilizing comprehensive two-dimensional liquid chromatography-tandem mass spectrometry for the simultaneous determination of one hundred and thirteen multiclass pesticides in corn products. The method simplifies the process with a single-step solid–liquid extraction and benefits from two-dimensional separation to enhance resolution and minimize matrix effects. The methodology was validated according to European Commission DG-SANTE (SANTE/11312/2021) and European Committee for Standardization (EN 15662, 2018) guidelines, obtaining acceptable analytical parameters. Limits of detection ranged from 0.2 µg/L to 30.2 µg/L and limits of quantification from 0.3 to 91.6 μg/L, all bellow regulatory limits. Accuracy, ranged from 60 to 120 % and precision, estimated by relative standard deviation, was consistently below 15.1 % in all cases. The applicability of the method was demonstrated by analyzing pesticides in five representative corn products (tortilla, corn flakes, corn cake, starch, and polenta). Sixteen pesticides were detected, all within the regulatory residue limits. Three metric tools were applied to assess the analytical process. Environmental sustainability was evaluated using the AGREE metric, while analytical performance and method applicability were assessed with the Red-Green-Blue and Blue Applicability Grade Index models, respectively, yielding promising scores (0.5, ≥ 0.55, and 0.65). These findings and the comparison to previous methods indicated that this approach represents a promising, alternative and user-friendly strategy for pesticide determination, offering effective productivity and reliable analytical performance.

Decaffeination of yerba mate (Ilex paraguariensis) by pressurized liquid CO2 extraction: A feasible process?

This work introduces a pumpless high-pressure Soxhlet cross-current solid-liquid extraction method using liquid CO2 and hydrated ethanol for studying the decaffeination of yerba mate. By combining experimental results with thermodynamic modelling, a comprehensive evaluation of the impact of the co-solvent composition is achieved. It is observed that an ethanol/water mixture with a specific composition of 85 wt% is optimal under mild operating conditions (283 K and 4.5 MPa) for extracting caffeine from chopped yerba mate leaves with a negligible co-extraction of caffeoyl derivative antioxidants. The obtained selectivity, together with the phase equilibrium simulation, provide evidence of the significant potential of liquid CO2 extraction as a decaffeination alternative for yerba mate. Thus, high-pressure Soxhlet extraction serves as simple technique to access valuable experimental information with potential for the conceptual design of further scalable semi-continuous processes.

Recovery of nutrients from biofuel ash via organic acid-facilitated solid-liquid extraction

Solid-liquid extraction was investigated to obtain selected major plant nutrients (P, K, Ca, Mg) from biofuel ash using weak organic acids like salicylic acid, citric acid, and oxalic acid as sacrificial leaching agents. In this study, three organic acids were compared to determine the most effective leaching agent for maximizing the P, K, Ca, and Mg extraction from biofuel ash. The findings indicated that 0.1 M citric acid was the most efficient for plant nutrient recovery, with 81.9% of P recovered after 30 min, 82.4% of Ca, 76.8% of Mg, and 47.3% of K. after 120 min. The highest amount of K, with 59.3% was recovered after 180 min of extraction with 0.1 M oxalic acid. However, recovery of P–80.7% was lower, and much lower recovery of Ca–2.3%, and Mg–68.6% after 180 min of extraction with 0.1 M oxalic acid. The leachates were not contaminated with heavy metals, just 0.47 mg/L of Zn, 7.67 mg/L of Al, and 1.99 mg/L of Fe were detected after 180 min of extraction with 0.1 M oxalic acid. The formation of calcium oxalates after extraction with 0.1 M oxalic acid was seen by SEM-EDS. The findings indicated that to achieve the highest recovery of all beneficial nutrients (P, K, Ca, Mg) different extraction times and different extraction agents are required.

Optimization of Extraction Conditions from Gac Fruit and Utilization of Peel-Derived Biochar for Crystal Violet Dye Removal.

Gac fruit (Momordica cochinchinensis Spreng.) is a prominent source of carotenoids, renowned for its exceptional concentration of these compounds. This study focuses on optimizing the extraction of active components from the aril of gac fruit by evaluating the effects of extraction temperature, solid-liquid ratio, and extraction time. The primary objective is to maximize the yield of gac oil while assessing its antioxidant capacity. To analyze the kinetics of the solid-liquid extraction process, both first-order and second-order kinetic models were employed, with the second-order model providing the best fit for the experimental data. In addition, the potential of gac fruit peel as a precursor for biochar production was investigated through carbonization. The resultant biochars were evaluated for their efficacy in adsorbing crystal violet (CV) dye from aqueous solutions. The adsorption efficiency of the biochars was found to be dependent on the carbonization temperature, with the highest efficiency observed for BCMC550 (91.72%), followed by BCM450 (81.35%), BCMC350 (78.35%), and BCMC250 (54.43%). The adsorption isotherm data conformed well to the Langmuir isotherm model, indicating monolayer adsorption behavior. Moreover, the adsorption kinetics were best described by the pseudo-second-order model. These findings underscore the potential of gac fruit and its byproducts for diverse industrial and environmental applications, highlighting the dual benefits of optimizing gac oil extraction and utilizing the peel for effective dye removal.

Development of a greener and sustainable method to determine acrylamide in corn products by LC-MS/MS: Evaluation of levels in corn-based products

Acrylamide (AA) is produced through the reaction between sugars and amino acids present in starchy foods cooked at high temperature. It is classified as probably carcinogenic to humans. In 2019, the European Commission reported a list of foods for monitoring the presence of AA, which includes cereal snacks. This study presents the development and validation of an analytical approach for detecting AA in popcorn and corn-based snacks. It includes solid-liquid extraction and clean-up with dispersive solid phase extraction followed by analysis through liquid chromatography coupled with tandem mass spectrometry. The proposed method was characterized in terms of recoveries (84–105%), and precision (< 16.1%). Limits of quantification were 17 and 60 μg kg−1 for corn and popcorn, respectively. Sustainability of the methodology was evaluated using AGREEprep and BAGI, providing values of 0.43 and 65.0, respectively. Twenty-four corn-based products were analyzed, with AA levels from 219 to 418 μg kg−1.

Lipids from the purple and white açaí (Euterpe oleracea Mart) varieties: nutritional, functional, and physicochemical properties.

The Brazilian superfruit called Açaí or Assaí has gained interested from researcher and consumers worldwide, due to its health-related properties. In this context, this pioneering study aimed to compare the physicochemical, nutritional, and thermal properties of vegetable oils obtained from two varieties of açaí (Euterpe oleracea), purple and white. Both açaí oils from white (WAO) and purple (PAO) varieties were obtained by using the conventional solid-liquid extraction, which resulted in oil yields ranging from 52 to 61%. WAO and PAO were analyzed by their edibility quality parameters given the recommendations from Codex Alimentarius; their nutritional functionality indices and their composition of fatty acids and triglycerides content were estimated. Both oils showed low levels of acidity and peroxides, <1.8 mg KOH g-1 and < 1.7 mEq kg-1, respectively, which are good indicators of their preservation status, agreeing with the food regulations. PAO and WAO showed differences among the composition of fatty acids, mainly related to the content of monounsaturated fatty acids (MUFAs), which were 62.5 and 39.5%, respectively, mainly oleic acid. Regarding the polyunsaturated fatty acids (PUFAs), the WAO showed up to 23% of linoleic acid, whereas the PAO exhibited up to 11% of it. These differences reflect on the values of the nutritional functionality indices, atherogenic (AI), thrombogenic (IT), and hypocholesterolemic/hypercholesterolemic ratio (H/H). Both PAO and WAO showed low levels of AI and TI and superior values of H/H than other oilseeds from the literature. These results indicate the nutritional properties of açaí oils regarding a potential cardioprotective effect when included in a regular dietary intake. The thermogravimetric behavior and the evaluation of oxidation status by infrared spectroscopy (FTIR) were also studied. Both açaí oils demonstrated higher thermal stability (with an onset temperature ranging from 344 to 350 °C) and low indications of oxidation status, as no chemical groups related to it were noted in the FTIR spectrum, which agrees with the determined acidity and peroxide content. Moreover, the FTIR analysis unveiled characteristic chemical groups related to fatty acids and triglycerides, agreeing with the literature reports. These findings collectively contribute to a deeper comprehension of the nutritional and functional properties between white and purple açaí oils, offering valuable insights into their potential health, food, and industrial applications.

Efficient Capture and Release of the Rare-Earth Element Neodymium in Aqueous Solution by Recyclable Covalent Organic Frameworks.

Rare-earth elements (REEs) are present in a broad range of critical materials. The development of solid adsorbents for REE capture could enable the cost-effective recycling of REE-containing magnets and electronics. In this context, covalent organic frameworks (COFs) are promising candidates for REE adsorption due to their exceptionally high surface area. Despite having attractive physical properties, COFs are heavily underutilized for REE capture applications due to their limited lifecycle in aqueous acidic environments, as well as synthetic challenges associated with the incorporation of ligands suitable for REE capture. Here, we show how the Ugi multicomponent reaction can be leveraged to postsynthetically modify imine-based COFs for the introduction of a diglycolic acid (DGA) moiety, an efficient scaffold for REE capture. The adsorption capacity of the DGA-functionalized COF was found to be more than 40 times higher than that of the pristine imine COF precursor and more than four times higher than that of the next-best reported DGA-functionalized solid support. This rationally designed COF has appealing characteristics of high adsorption capacity, fast and efficient capture and release of the REE ions, and reliable recyclability, making it one of the most promising adsorbents for solid-liquid REE ion extractions reported to date.

Pressurized Hot Water Extraction as Green Technology for Natural Products as Key Technology with Regard to Hydrodistillation and Solid-Liquid Extraction.

Hydrodistillation and solid-liquid extraction with organic solvents or supercritical CO2 are standard technologies for natural product manufacturing. Within this technology, portfolio pressurized hot water technology is ranked as a green, sustainable, resilient, kosher and halal manufacturing process. Essential for sustainability is energy integration for heating and cooling the auxiliary water as well as product concentration without evaporation but with the aid of low energy consuming ultra- and nanofiltration membrane technology. The incorporation of modern unit operations, such as pressurized hot water extraction, along with inline measurement devices for Process Analytical Technology approaches, showcases a shift in traditional extraction processes. Traditional equipment and processes still dominate the manufacturing of plant extracts, yet leveraging innovative chemical process engineering methods offers promising avenues for the economic and ecological advancement of botanicals. Techniques such as modeling and process intensification with green technology hold potential in this regard. Digitalization and Industry 4.0 methodologies, including machine learning and artificial intelligence, play pivotal roles in sustaining natural product extraction manufacturing and can profoundly impact the future of human health.

Extraction of polyphenols and antioxidant compounds from SCOBY, as a by-product of Kombucha, using different types of extraction

Kombucha is obtained through a symbiosis fermentation of bacteria and yeast, generating a floating film called SCOBY (Symbiotic Culture of Bacteria and Yeast). After a period of use, SCOBY becomes a production waste. Thus, alternative uses of SCOBY can add value to Kombucha production. In this way, this work aimed to produce and evaluate antioxidant activity and total phenolic contents of SCOBY ethanolic extracts, which were obtained by two different solid–liquid extraction with three different waste weight/extractor solvent volume ratios. The SCOBY evaluated had a high concentration of cellulose (9.42 ± 1.00%) and low concentrations of proteins (0.84 ± 0.04%) and lipids (0.29 ± 0.05%). All evaluated extracts showed a high concentration of total phenolics (40.7–64.3 mg GAE/100 g of SCOBY) and high antioxidant activity (ABTS•+, FRAP and ORAC assays). The most efficient extraction of bioactive compounds was obtained by decoction using the highest solvent volume (ratio 1:20). The PCA showed clusters of the samples both by the type of extraction and by the different ratios of the weight of SCOBY to the solvent volume. Of our knowledge, our work is the first in the literature that describes such data. Therefore, the present work showed the possibility of using this industrial waste mainly to obtain active compounds and antioxidants.

Smart polymers and smartphones for Betalain measurement in cooked beetroots

Betalains in beetroots offer notable colouring properties and health benefits, including antioxidant, anti-inflammatory, hepatoprotective, and antitumorous activities. However, they degrade due to processing and storage conditions like temperature, pH, oxygen, and light-exposure. Traditional betalain determination methods are resource-intensive solid-liquid extractions. This study proposes a novel approach using a smart polymer to rapidly quantify betalains in processed beetroots. The polymer, containing N,N-dimethylaminoethyl methacrylate, selectively interacts with compounds like betalains. Characterization shows thermal stability over 250 °C and suitable mechanical properties. The film changes to colour upon interaction with betalains, allowing quantification via smartphone. The sensory polymer's efficacy was validated across 27 beetroot samples, showing no significant differences compared to traditional methods. Combining the smart polymer with a colour analysis app, “Colorimetric Titration,” provides a robust and efficient means of quantifying total betalains in beetroot puree, reducing the quantification time from 180 to 90 min, promising implications for routine food industry quality assessments.

Determination of the Nucleic Acid Constituents in Edible Mushrooms by High-Performance Liquid Chromatography with Diode Array Detection (HPLC-DAD)

Nucleosides and nucleobases in edible mushrooms collected from the Tekirdağ region of Turkey were determined by high performance liquid chromatography (HPLC). Separation of compounds was accomplished by gradient elution on a C18 column. A mixture of methanol (MeOH):50 mM sodium phosphate buffer (1:99, v/v) at pH 3.70 and methanol:50 mM sodium phosphate buffer (20:80) at pH 6.20 was used as the solvent. Two methods were used to treat the lyophilized mushrooms: ultrasound-assisted solid-liquid extraction (US-SLE) and pressurized (accelerated) solid-liquid extraction (PSLE). Deionized water was used as the extraction solvent. The extraction temperature and time were optimized. Fourteen nucleosides and nucleobases were simultaneously monitored at 254 nm within 25 min. Ultrasound-assisted solid-liquid was demonstrated to be more effective, perhaps because the pressurized liquid extraction system is a closed system and the matrix-solvent interaction may be insufficient. Adenosine, guanosine and uridine were the most abundant compounds in all studied mushrooms.