Liquid‐liquid extraction is performed in most cases at moderate temperatures to utilize its energy‐efficient advantages. A new concept of a process‐intensified extraction device for liquid‐liquid ...systems at increased temperature and pressure is presented. The design of the extraction device with its new subsystems, such as stirrer and pulsation, including a safety concept, is discussed within this work. Further, a mechanical stability analysis is shown to prove the usability of the extraction device for increased temperature and pressure.
Liquid‐liquid extraction has primarily been performed at ambient conditions to utilize its energy‐efficient advantages. An innovative concept of the process‐intensified liquid‐liquid extraction for increased temperature and pressure is presented which allows the performance of liquid‐liquid extraction under such conditions to gain higher separation efficiencies and throughputs.
•Leafy vegetables, fruits, and microalgae are the rich source of carotenoids.•The choice of solvent is the most critical for efficient extraction of carotenoids.•Soxhlet extraction is a conventional ...method delivers the highest yield of carotenoids.•Supercritical fluid extraction is the superior “green” method for the carotenoids.•Green extraction needs further methodological and technological advancements.
The versatile use of carotenoids in feed, food, cosmetic and pharmaceutical industries has emphasized the optimization of extraction methods to obtain the highest recovery. The choice of method for carotenoid extraction from food matrices is crucial, owing to the presence of diverse carotenoids with varied levels of polarity, and the presence of various physical and chemical barriers in the food matrices. This review highlights the theoretical aspects and recent developments of various conventional and nonconventional methods used for the extraction of carotenoids, including ultrasound-assisted extraction (UAE), pressurized liquid extraction (PLE), and supercritical fluid extraction (SFE). Recent applications of non-toxic and environmentally safe solvents (green solvents) and ionic liquids (IL) for carotenoid extraction are also described. Additionally, future research challenges in the context of carotenoids extractions are also identified.
Bletilla striata polysaccharides (BSPs) are effective for anti-inflammatory, detumescence, and radicals scavenging, with important applications in the area of food chain, pharmacy science, and health ...care. In this study, we comprehensively studied the interplay between the polysaccharides' formation, physicochemical properties, rheological properties, and associated antioxidant activities of BSPs from different extraction methods. The crude polysaccharides obtained from Bletilla striata by using the hot water extraction (BSPs-H), alkali-assisted extraction (BSPs-A), boiling water extraction (BSPs-B), and ultrasonic-assisted extraction (BSPs-U) methods showed different molecular weights, monosaccharide compositions, glycosidic bond compositions, and zeta potentials, but with the same IR spectra characteristic and thermal stability. By the above-mentioned four kinds of extraction methods, the resultant BSPs exhibited various degrees of reticular and lamellar structure. All the BSPs solutions exhibited shear-thinning behavior with the increase of the shear rate. Among these BSPs, BSPs-A exhibited better DPPH and ABTS radical scavenging activities and reducing power, whereas BSPs-H showed better hydroxyl radical scavenging activities.
•Extraction methods were compared for Bletilla striata polysaccharides (BSPs).•Preliminary structure characteristics were conducted for the BSPs.•Extraction methods impacted branched structure and crosslinked networks of BSPs.•BSPs-A showed good antioxidant activity and unique rheological properties.
Marine ecosystems cover more than 70% of the globe's surface. These habitats are occupied by a great diversity of marine organisms that produce highly structural diverse metabolites as a defense ...mechanism. In the last decades, these metabolites have been extracted and isolated in order to test them in different bioassays and assess their potential to fight human diseases. Since traditional extraction techniques are both solvent- and time-consuming, this review emphasizes alternative extraction techniques, such as supercritical fluid extraction, pressurized solvent extraction, microwave-assisted extraction, ultrasound-assisted extraction, pulsed electric field-assisted extraction, enzyme-assisted extraction, and extraction with switchable solvents and ionic liquids, applied in the search for marine compounds. Only studies published in the 21st century are considered.
Extraction of phenolic compounds: A review Alara, Oluwaseun Ruth; Abdurahman, Nour Hamid; Ukaegbu, Chinonso Ishamel
Current research in food science,
01/2021, Letnik:
4
Journal Article
Recenzirano
Odprti dostop
Phenolic compounds are parts of secondary metabolites mostly found in plant species with enormous structural diversities. They can exist as glycosides or aglycones; matrix or free-bound compounds; ...and comprising mostly polymerized or monomer structures. Additionally, these compounds are not universally dispensed within plants with varied stability. This has contributed to challenging extraction processes; implying that employing a single step or inappropriate extraction technique might change the recovery of phenolic components from the plant samples. Hence, it is important to select an appropriate extraction method so as to recover the targeted phenolic compounds. This is will helps to recover substantial yields from the sample matrix. Therefore, this review mainly focuses on the phenolic compounds and several methods of extraction that are used to obtaining them from plant materials. These extraction methods includes both conventional and unconventional techniques.
Display omitted
•Phenolic compounds from natural sources.•Methods of extracting phenolic compounds.•Selection of an appropriate extraction method to recover the targeted phenolic compounds from plant materials.
•Fundamentals of extraction and clean-up methods are given.•Application of extraction and clean-up methods for different alkaloids is provided.•Factors that influence each technique are ...discussed.•Advantages and limitations of each technique are addressed.
Alkaloids are a chemically diverse group of natural products known for their pharmacological and toxicological effects. Plants are the best known source of these compounds. Because of their high complexity, herbal matrices must be properly processed in order to access alkaloid content, overcoming different analytical steps, such as sampling, sample preparation, isolation, quantification and data analysis. Notably, sample preparation just recently is calling the attention, being considered a bottleneck of analytical processes. In this review, we provide the current state of the art in sample preparation for alkaloids analysis in herbal matrices, focusing on both extraction and clean-up steps. Both classic and modern techniques, such as Negative-Pressure Cavitation Extraction (NPCE), Microwave Assisted Extraction (MAE), as well as microfluidic chips are addressed, including the technique fundamentals, factors to be optimized, and their applications. A general discussion is also given, pointing out the advantages and limitations of each technique.
Pressurized liquid extraction (PLE) is a tool able to provide green extraction methods to further determine contaminants in food and the environment. The aim of this review is to offer a critical ...overview of the recent developments within this field and can be considered as an update of the previous that we published in 2015. Trends regarding sample treatment, solvents, in-cell clean-up approaches used in the extraction of organic contaminants are addressed. Special attention deserve those methods that include on-line clean up in the extraction cell. Comparison with other green techniques is also presented. The final objective of this review is to clearly define the role that this technique plays in the analysis of organic pollutants, their strengths and weaknesses, as well as the updated spectrum of applications for which PLE is an essential tool.
•Update review of the PLE to extract contaminants in food and the environment.•Establishment of the applications for which PLE is advantageous.•Main analytical parameters of the different PLE procedures are discussed.•Advantages and limitations in the analysis are considered and evaluated.•Future trends and prospects are envisaged.
Rice is one of the most important crops throughout the world, as it contributes toward satisfying the food demand of much of the global population. It is well known that rice production generates a ...considerable number of by-products, among which rice bran deserves particular attention. This by-product is exceptionally rich in nutrients, since it contains a wide spectrum of macronutrients (proteins, fats, carbohydrates) as well as dietary fibers and bioactive compounds. However, rice bran is usually wasted or just used for the production of low-cost products. The lipidic fraction of rice bran contains an unsaponifiable fraction that is rich in such functional components as tocopherols, γ-oryzanol, tocotrienols, and phytosterols. This lipidic fraction can be extracted to obtain rice bran oil (RBO), a high value-added product with unique health properties as a result of its high concentration in γ-oryzanol, a powerful antioxidant mixture of bioactive molecules. Conventional extraction methods employ hexane as the solvent, but these methods suffer from some drawbacks linked to the toxicity of hexane for humans and the environment. The aim of the review presented herein is to point out the new green technologies currently applied for the extraction of RBO, by highlighting reliable alternatives to conventional solvent extraction methods that are in line with the twelve principles of green chemistry and a circular economy.
Electromembrane extraction Huang, Chuixiu; Chen, Zhiliang; Gjelstad, Astrid ...
TrAC, Trends in analytical chemistry (Regular ed.),
October 2017, 2017-10-00, Letnik:
95
Journal Article
Recenzirano
Electromembrane extraction (EME) was inspired by solid-phase microextraction and developed from hollow fiber liquid-phase microextraction in 2006 by applying an electric field over the supported ...liquid membrane (SLM). EME provides rapid extraction, efficient sample clean-up and selectivity based on the nature of the SLM and the electrical field. EME has been applied for the separation of ionizable compounds from complex samples, and EME is currently considered as an active research topic in the area of sample preparation and analytical chemistry. We expect that EME will play important roles in future analytical laboratories. This review summarizes and highlights the advancements in EME from 2006 to 2016 with focuses on 1) fundamental aspects, 2) device and operation modes, 3) performance, and 4) hyphenation to other analytical sample preparation techniques. Meanwhile, this review indicates that the main objectives for future EME are to establish EME as tool for routine applications, and to stimulate for further research on sophisticated systems based on the EME principle.
Electromembrane extraction (EME) is a microextraction technique intended for extraction of cations and anions by applying an electric field over the supported liquid membrane (SLM). Display omitted
•Advances on the device and operation modes in electromembrane extraction are emphasized.•Selective, exhaustive and soft extractions using electromembrane extraction are summarized.•Hyphenation of electromembrane extraction to other sample preparation technique is reviewed.•Electrolysis, stability, and mass transfer in electromembrane extraction are discussed.•The main objectives for future electromembrane extraction are identified.
Template removal is a critical step in the preparation of most molecularly imprinted polymers (MIPs). The polymer network itself and the affinity of the imprinted cavities for the template make its ...removal hard. If there are remaining template molecules in the MIPs, less cavities will be available for rebinding, which decreases efficiency. Furthermore, if template bleeding occurs during analytical applications, errors will arise. Despite the relevance to the MIPs performance, template removal has received scarce attention and is currently the least cost-effective step of the MIP development. Attempts to reach complete template removal may involve the use of too drastic conditions in conventional extraction techniques, resulting in the damage or the collapse of the imprinted cavities. Advances in the extraction techniques in the last decade may provide optimized tools. The aim of this review is to analyze the available data on the efficiency of diverse extraction techniques for template removal, paying attention not only to the removal yield but also to MIPs performance. Such an analysis is expected to be useful for opening a way to rational approaches for template removal (minimizing the costs of solvents and time) instead of the current trial-and-error methods.
PDF
