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Production of submicron particles of the antioxidants of mango leaves/PVP by supercritical antisolvent extraction process
Abstract
Mango leaves contain bioactive compounds of interest, due to their beneficial activity for health as antioxidant among others. These compounds can easily degrade by light or oxygen, for this reason, the encapsulation of antioxidant natural extract from these leaves is suggested as an effective approach against the degradation of phenolic compounds and to achieve a sustained release of them. The antioxidants/PVP encapsulates were obtained by supercritical antisolvent extraction process (SAE) using pressurized liquid extract (PLE). Using different conditions of pressure (120–180bar), temperature (35–65°C) and mass ratio (1/3–1/9), spherical particles were obtained in a submicronic range between 0.11–0.59μm. Antioxidants/PVP ratio was the most significance variable on the particle size and on the time of release of the mangiferin, quercetin 3-D-galactoside and penta-O-galloyl glucose, what means as greater amount of polymer higher particle size and smaller percentage of release.
... Efficient extraction and utilization of various substances from mango parts have been explored, such as fat, phenolic and ethanolic extracts, and polymers (starch, lignin, hemicellulose, microcellulose, and cellulose nanocrystals) from the seed [40,58,[83][84][85][86][87]; polymers (pectin, hemicellulose, and RNA), polyphenols, and carbon quantum dots from fruits [88][89][90][91][92][93][94]; cellulose nanofibers from the stem [35]; and phenolic extracts from the leaves [95]. ...
... Within this category, studies explored the use of mango fruits to assess the effectiveness of polymer packaging [52,71,[96][97][98], as well as the extraction of compounds from fruits, seeds, or leaves for functionalizing polymeric packaging [26,63,89,91,95]. Additionally, the interaction between mango leaf and polymers was observed in applications such as the production of activated carbon for melanoidin removal from wastewater [76]. ...
... In Health and Wellness (HW), seven studies (9.46%) received special attention [25,37,61,87,89,95,123]. HW is closely associated with disease prevention and life satisfaction. ...
Mango (Mangifera indica L.) holds immense potential as a raw material in polymer science, influencing numerous applications. This systematic literature review, encompassing 74 studies published between 2018 and 2022, aims to elucidate the intrinsic relationship between polymers and mango. Polymers are extracted from mango plant tissues, and their substances are explored as reinforcing agents in polymeric materials. In turn, polymers are employed in the mango plant to extend shelf life. Mango by-products can serve as indicators of polymer presence. The diverse tissues and substances in mango offer considerable potential for extracting polymers, phenolic compounds, fats, and dietary fibers. Moreover, the substantial waste generated in mango production, including fruit peel, seed, stems, and leaves, can be utilized to extract economically valuable polymers. These polymers contribute to the adoption of sustainable practices in industries such as packaging, food processing, biomedical materials, wood manufacturing, and oil production.
Graphical abstract
... A detailed description of the SEDS technique can be found in numerous publications and reviews (see, for example, [18][19][20][21][22][23][24]). It is well-known that use of SCF media in the processing of polymers leads to new materials with enhanced properties [18][19][20][21][22][23][24][25][26][27][28]. ...
... A detailed description of the SEDS technique can be found in numerous publications and reviews (see, for example, [18][19][20][21][22][23][24]). It is well-known that use of SCF media in the processing of polymers leads to new materials with enhanced properties [18][19][20][21][22][23][24][25][26][27][28]. Supercritical fluids in various processes of production can be used as an anti-solvent or precipitant, for example, SEDS processes [19]. ...
... By varying the technological conditions (manipulating the process condition) in the supercritical reactor (pressure, temperature, concentration, vibration, etc.), it is possible to achieve rapid deposition of the initial product in the form of fine particles in the volume. There are a number of modifications of the SCF antisolvent method, such as SAS (Supercritical Anti-Solvent), GAS (Gas Anti-Solvent), SEDS (Solution Enhanced Dispersion by Supercritical Fluids), and ASES (Aerosol Solvent Extraction System); see for example, [11,13,19,22,[29][30][31][32]. The difference between these methods is the contact between solution and antisolvent. ...
The experimental solubility data of polyvinyl chloride (PVC) and high-pressure polyethylene (HPPE) in organic solvents (toluene, dichloromethane, and chloroform) at temperatures ranging from 308.15 to 373.15 K at atmospheric pressure are reported in the present paper. The solubility of the polymers (PVC and HPPE) in organic solvents (toluene, dichloromethane, and chloroform) was studied at temperatures between 298 and 373 K. The supercritical SEDS dispersion of PVC and HPPE polymer blends at pressures between 8.0 and 25 MPa and at temperatures from 313 to 333 K are reported in the present work. The kinetics of crystallization and phase transformation in polymer blends obtained by blending in a melt, and using the supercritical SEDS method, have been studied. The effect of the HPPE/PVC ratio on the thermal and mechanical characteristics of the polymer blends has been studied. For all studied polymer blends and pure polymers obtained using the SEDS method, the heat of fusion ΔfusH exceeds the values obtained by blending in the melt by 1.5 to 5) times. The heat of fusion of the obtained polymer blends is higher than the additive value; therefore, the degree of crystallinity is higher, and this effect persists after heat treatment. The relative elongation decreases for all polymer blends, but their tensile strength increases significantly.
... Other polymers, such as polyethylene glycol (average molecular weight 1000 g/mol, Merck, Darmstadt, Germany) and zein (Sigma-Aldrich Co., St. Louis, MO, USA), which are also characterized as biocompatible, biodegradable, GRAS, and which have good solubility in organic solvents, were tested (Supplementary Material); however, we have not had experimental success. In view of the results obtained with these tests and studies recently published by our research group [18,26], PVP polymer was selected for the development of this work. ...
... The spraying of the polymeric solution generates the formation of small droplets and a rapid mass transfer between the liquid and pressurized CO 2 phases. This causes supersaturation of the liquid solution (which is the anti-solvent effect) and, consequently, the precipitation of the grape residue extract particles together with the PVP polymer (co-precipitation) in the form of powder on the inner wall and filter of the precipitation vessel [26]. As soon as the predetermined amount (75 mL) of polymeric solution was introduced, its addition was stopped and the anti-solvent continued to flow for 50 min in order to remove residual ethanol present in the generated particles/co-precipitates This step is extremely important, since the amount of organic solvent remaining in the medium can cause the particles to coalesce and lose their original characteristics [13,16]. ...
... The simulated gastric fluid (SGF) was prepared by dissolving 2 g of sodium chloride with 1 L of water, while the simulated intestinal fluid (SIF) was prepared by mixing 6.8 g of monobasic phosphate in water (1 L). The gastric and intestinal solutions were adjusted to pH 1.2 ± 0.1 (0.2 N HCl) and pH 6.8 ± 0.1 (0.2 N NaOH), respectively [26]. ...
In this work, the co-precipitation of ethanol extract from grape residue with a biodegradable and biocompatible polymer, polyvinylpyrrolidone, was studied using sub- and supercritical carbon dioxide (CO2) technology, namely in the present work by pressurized anti-solvent (PAS). A full design was used to evaluate the effect of pressure (90, 130 and 170 bar) and temperature (20, 32 and 45 ºC) on the PAS process and the characteristics of the particles formed by it. The particles obtained from the best PAS conditions were submitted to in vitro release studies. Higher pressures and temperatures (CO2 in supercritical state) significantly resulted in operational conditions with better global precipitation yields and in the production of particles with a lower average diameter and residual ethanol content. The particles had a quasi-spherical shape connected to each other with sizes ranging from 1.3 to 4.1 µm. The interaction of low temperature with high pressure (CO2 in subcritical state) led to the production of dry powders more concentrated in anthocyanins and total phenolic compounds, and in processes with higher co-precipitation yields of these bioactives. From the in vitro release tests, it was observed that the microparticles released more slowly anthocyanins in simulated gastrointestinal fluids than the precipitated extract without polymer. In the end, it can be concluded that the PAS technique is a very promising process for co-precipitating and concentrating sensitive polar compounds present in crude plant extracts, and produce bioactive microparticles with interesting physicochemical characteristics. Furthermore, it leads to the production bioactive delivery systems with better dissolution rates in simulated gastrointestinal fluids, thus showing potential to be applied in areas that work in favor of health and human well-being.
... Some authors have even encapsulated natural extracts with polymers, such as Machado et al. [23], who generated submicron particle composites from grape residue extract and polyvinylpyrrolidone (PVP). In this way, Guaman-Balcazar et al. also formed an encapsulation of mango-leaf particles with PVP [24]. Visentin et al. achieved encapsulation of rosemary antioxidants [25] and Santana and Meireles achieved coprecipitation of turmeric extracts [26]. ...
The objective of this work was evaluation of the supercritical antisolvent extraction (SAE) process to generate microparticles with antioxidant activity from Moringa leaves. A biodegradable polymer was used as an inductor of particle precipitation. An ethanolic extract of 25 mg/mL was used in the SAE process, during which the influences of pressure (100–200 bar), temperature (35–55 °C) and extract–polymer ratio (0.11–0.33) on particle size and antioxidant activity were evaluated. An extract flow rate of 3 mL/min, a supercritical CO2 (scCO2) flow rate of 30 g CO2/min and a nozzle diameter of 100 µm were kept constant. The identification of several compounds of Moringa leaves, namely, coumaric acid and quercetin 3D glucoside, were determined with ultra-performance liquid chromatography coupled with mass spectrometry. The antioxidant activity of the extract and the precipitates was measured with 2,2-Diphenyl-1-picrylhydrazyl. Spherical microparticles with diameters in the range of 2–5 µm were obtained, with moderate antioxidant activity.
... Sub-and supercritical fluids are widely used in the processing of polymeric materials to tackle the problems of dispersion of polymeric materials [12][13][14][15][16][17][18][19]. There are many dispersion methods using supercritical fluid media such as RESS, SAS, GAS, SEDS, ASES, PGSS, etc. [20][21][22][23][24][25][26][27][28][29][30]. These methods make it possible to obtain homogeneous microparticles with specific physicochemical properties and sizes that are highly sensitive to the process conditions. ...
In this paper, we present the results of dispersion of thermodynamically immiscible polypropylene (PP) and ethylene-propylene triple synthetic rubber (EPTSR) polymer blends using the Solution-Enhanced Dispersion by Supercritical Fluid (SEDS) technique at operation conditions in the pressure range of (8 to 25) MPa and at temperatures t = 40 °C and 60 °C. The kinetics of crystallization and phase transformation in polymer blends obtained by conventional method (melt blending) and by mixing in the SEDS process have been studied using the DSC technique. The effects of the SEDS operation process on the physical—chemical (melting temperature, heat of fusion) and mechanical (microparticle size) characteristics of the SEDS-produced polymer blends were studied.
... Aloe vera (extract) [109] Astaxanthin [110] Caffeic acid [111] Carvacrol [112] Catechin [113] Chlorogenic acid [114] Cinnamon E.O. [115] Curcumin [116] Eugenol [112] Fenugreek (seed absolut) [117] Gallic acid [118] Hydrolyzed spent coffee grounds [119] Lemongrass E.O. [120] Mango (extract) [121,122] Melanin [123] Moringa oleifera (extract) [109] Quercetin [113,124,125] Rosmarinic acid [126] Rosemary (extract) [127] Tannic acid [128,129] Teucrium polium (extract) [130] Thyme (polyphenol extract) [131] Thymol [132] Vitamin C [133] Cellulose-PEG [120] CH [112,113,122,132] CH-derivates [118,131] CH-gum [115] HA [129] Halloyste [124] Magnesium alloy [128] P(3HB-co-3HV) [133] PDMS [125] PE [119] PEG-ALG [109] PEG-PCL [134] PLA -PEG [130] PLA [127] PVP [121] SF -collagen [117] SF [123] Silica [111,126] Silica-PEG [114] Indirect antioxidant effects (including cytoprotection) Citric acid [135] Curcumin [136,137] Cystamine [73] Gallic acid [138] Hydrolyzed spent coffee grounds [119] Lignin (alkali) [139] Quercetin [136] Rapeseed flower (pollen extract) [140] Vitamin C [141] Vitamin E [142] White tea (leaves extract) [143] CH [138] CH-derivates [116] Hyaluronic acid-β-cyclodextrin [142] Montmorillonite [143] PBAE [136] PCL [137,139] PE [119] PU [141] PVA [135] Biodegradation modulation ...
Although a large panel of natural antioxidants demonstrate a protective effect in preventing cellular oxidative stress, their low bioavailability limits therapeutic activity at the targeted injury site. The importance to deliver drug or cells into oxidative microenvironments can be realized with the development of biocompatible redox-modulating materials. The incorporation of antioxidant compounds within implanted biomaterials should be able to retain the antioxidant activity, while also allowing graft survival and tissue recovery. This review summarizes the recent literature reporting the combined role of natural antioxidants with biomaterials. Our review highlights how such functionalization is a promising strategy in tissue engineering to improve the engraftment and promote tissue healing or regeneration.
... However, the particles were not tested for drug delivery applications 2019) generated sub-micron particles of PVP with mango leaf extract, finding a relationship between the mango leaf extract/PVP ratio, temperature, and pressure of the supercritical antisolvent extraction process with the particle size (some of the particles were at the nanoscale). The in vitro desorption test showed a release profile of the extract components lasting up to 8 h under simulated intestinal fluids at pH 6.8 [187]. ...
Colorectal cancer (CRC) is the type with the second highest morbidity. Recently, a great number of bioactive compounds and encapsulation techniques have been developed. Thus, this paper aims to review the drug delivery strategies for chemotherapy adjuvant treatments for CRC, including an initial scientific-technological analysis of the papers and patents related to cancer, CRC, and adjuvant treatments. For 2018, a total of 167,366 cancer-related papers and 306,240 patents were found. Adjuvant treatments represented 39.3% of the total CRC patents, indicating the importance of adjuvants in the prognosis of patients. Chemotherapy adjuvants can be divided into two groups, natural and synthetic (5-fluorouracil and derivatives). Both groups can be encapsulated using polymers. Polymer-based drug delivery systems can be classified according to polymer nature. From those, anionic polymers have garnered the most attention, because they are pH responsive. The use of polymers tailors the desorption profile, improving drug bioavailability and enhancing the local treatment of CRC via oral administration. Finally, it can be concluded that antioxidants are emerging compounds that can complement today's chemotherapy treatments. In the long term, encapsulated antioxidants will replace synthetic drugs and will play an important role in curing CRC.
... The PVP method has now been accepted as one of the most used DNA extraction techniques, thereby indicating that the development of materials actually changes the technic in protecting biological resouces. [152][153][154][155] The protection of plant seeds is also a crucial biosafety issue. 156,157 Seed enhancement technologies play a pivotal role in supporting food security by enabling the germination of seeds in degraded environments. ...
The Corona Virus Disease 2019 (COVID-19) pandemic is a serious biosafety event that has a huge impact on the global society and economy. The importance of biosafety is once again being valued. After the outbreak of COVID-19, governments of most countries are encouraged to speed up the development of biosafety, which places higher requirements on researchers in biosafety and relevant fields. The outbreak of COVID-19 revealed many problems including no effective drugs and vaccines available, difficulty in disinfection especially for special places, insufficient protective equipment and shortage of transport equipment for infectious patients. To a large extent, those biosafety problems are largely due to the limited research on materials science. Currently, tremendous efforts on the research in materials science have provided a wide assortment of materials with peculiar properties to solve biosafety problems. Therefore, the integration of biosafety and materials science could be an effective way to overcome the challenges in biosafety field. Here we officially proposed the discipline definition and intension for biosafety materials, aiming to promote the development of biosafety materials, and call for active cooperation between materials scientists and the biosafety- related scientists in the worldwide.
... In SCCO 2 antisolvent system, increasing the operating temperature may reduce the solubility and increase the supersaturation where supersaturation is the most key factor to control the precipitation process during the formation of particles. 23,30,31 As shown in Figure 6, the different shapes of chitosan particle products were generated from chitosan feed solution after SCCO 2 (20 MPa) with various operating temperatures from 60 to 100 C. The morphologies of precipitated chitosan products were the spherical particles, the spherical with fiberlike particles, and the fiber-like free-spherical particles. Note that owing to the different morphologies of chitosan particle products, their diameter sizes were not observed. ...
The generation of chitosan particles through supercritical carbon dioxide (SCCO2) antisolvent process was studied. The experiments were carried out at temperatures of 60–100°C and pressures of 15–25 MPa with a 15 ml min⁻¹ CO2 flow rate. As a feed solution, chitosan powder was dissolved in acetic acid:water:ethanol. Scanning electron microscopy (SEM) observations described that the precipitated chitosan products have irregular morphologies with the spherical, the spherical with fiber‐like, and the fiber‐like free‐spherical particles. Interestingly, hollow‐core chitosan particles generated when SCCO2 antisolvent treatments were performed at a temperature of 60°C and pressures of 20–25 MPa. The Fourier transform infrared spectroscopy (FT‐IR) spectra indicated that the structural properties of chitosan did not shift after the SCCO2 antisolvent treatment. The results exhibited that this SCCO2 antisolvent technique is likely to be fruitful for the generation of biopolymer particles with hollow‐core structures.
... Numerous investigations in particle formation with supercritical fluids have been carried out to shed light the parameter to govern the crystallization mechanism using CO 2 as antisolvent (SAS) [2][3][4][5][6][7][8][9][10][11][12][13][14][15] or as solvent (RESS) [16][17][18][19][20][21][22][23][24][25][26][27][28]. ...
The results of an experimental study of the phase equilibrium (VLE) properties of CO2 in organic mixture of (0.564 toluene/0.436 chloroform) at three selected isotherms of 313.15 K, 333.15 K, and 353.15 K in the pressure range from (0.95 to 12.27) MPa, involved in the supercritical SEDS dispersion process of immiscible polymer blending, are reported in the present work. The compatibility of immiscible linear high-pressure polyethylene (HPPE)/polycarbonate (PC) polymer blends with organic toluene + chloroform solvent in the presence of supercritical carbon dioxide (SC CO2) was studied. The PC and LHPPE polymers blending have been carried out in the pressure range from (8 to 25) MPa at temperatures between (313.15 and 353.15) K using the supercritical SEDS method. The kinetics of crystallization and phase transformation in polymer blends obtained by the melt blending (mixed in the molten state) and the supercritical SEDS methods have been studied using DSC technique. The thermodynamic characteristics such as (temperature, tfus, and enthalpy of fusion, ΔfusH) of the produced LHPPE/PC polymer blends are presented. The influence of the supercritical SEDS dispersion process parameters on the heat of fusion of the obtained LHPPE/PC polymer blends has been studied. The compatibility of LHPPE/PC blends was confirmed by studying the DSC melting-crystallization curve properties and investigating the morphology. The morphology of the LHPPE/PC polymer blends was examined using a scanning electron microscope (SEM) and the particle sizes depending on the operating temperature and pressure were studied.
The low aqueous solubility and subsequently slow dissolution rate, as well as the poor bioavailability of several active pharmaceutical ingredients (APIs), are major challenges in the pharmaceutical industry. In this review, the particle engineering approaches using supercritical carbon dioxide (SC CO2) as an antisolvent are critically reviewed. The different SC CO2-based antisolvent processes, such as the gas antisolvent process (GAS), supercritical antisolvent process (SAS), and a solution-enhanced dispersion system (SEDS), are described. The effect of process parameters such as temperature, pressure, solute concentration, nozzle diameter, SC CO2 flow rate, solvent type, and solution flow rate on the average particle size, particle size distribution, and particle morphology is discussed from the fundamental perspective of the SAS process. The applications of the SAS process in different formulation approaches such as solid dispersion, polymorphs, cocrystallization, inclusion complexation, and encapsulation to enhance the dissolution rate, solubility, and bioavailability are critically reviewed. This review highlights some areas where the SAS process has not been adequately explored yet. This review will be helpful to researchers working in this area or planning to explore SAS process to particle engineering approaches to tackle the challenge of low solubility and subsequently slow dissolution rate and poor bioavailability.
Black beans (P. vulgaris) are highly consumed after different processing treatments, which generate by-products with high potential as functional ingredients with nutraceutical properties. This study assesses the supercritical CO2 extraction (SC-CO2) as selective, and green alternative to obtain non-polar phytochemicals from a black bean by-product. A Box-Behnken design was conducted to evaluate pressure (100-400 bars), temperature (40-70 °C), and 70% aqueous ethanol as co-solvent with flow rate (1-3 g/min) on total extraction yield, fatty acid (FA) composition, and phytochemical profile through GC-MS. Co-solvent and pressure-temperature interaction were found to significantly influence the yield. The maximum yield was 2.03 mg/g at 100 bar, 40°C and 2 g/min, like hexane extraction. Higher alkanes were mainly extracted with hexane while SC-CO2 selectively extracted compounds with potential biological activities. Solubility in CO2 of these phytochemicals, saturated and monounsaturated FAs showed a positive effect with temperature increase. This combination of findings provides insight into the effect of temperature and co-solvent on non-polar phytochemicals extraction.
The techniques of pressurized fluids using supercritical carbon dioxide for the development of bioactive release systems have been proposed as an alternative to conventional encapsulation/coprecipitation processes as they allow improving the performance of these in terms of particle size, particle-size distribution, and morphology control, without thermal and mechanical degradation and contamination of the final product. These techniques have garnered massive attention in recent years, and their feasibility and performance have been demonstrated experimentally for several substances. Although some of them are focused on the development of products for pharmaceutical applications, their uses for the production of plant-based products with benefits for human health are growing rapidly owing to their great potential. This chapter presents the main methods with supercritical fluids that can be used successfully for the formulation of natural substances together with a biocompatible or biodegradable carrier material to form delivery or encapsulated systems with potential biological activities. These are grouped into three groups according to the role of the pressurized fluid in the process: (1) as a solvent—rapid expansion of supercritical solutions; (2) as a solute—particles from gas-saturated solutions; and (3) as an antisolvent—supercritical antisolvent precipitation. Their origin, basic processing principles, specific characteristics, and main applications with focus on human health will be discussed in this chapter.
A critical analysis of the major steps involved in the cellulose acetate industrial process is performed, with the aim of proposing possible improvements using supercritical CO2 based sub-processes. Once highlighted the main weakness of the traditional process, related to the (i) fine modulation of the acetylation reaction to obtain 2.5 acetate, (ii) acetic acid removal from the acetic dope, and (iii) treatment of the diluted acetic acid–water solution, the most attractive alternative resulted the adoption of a supercritical antisolvent extraction (SAE) performed on the acetic dope. Operating in this way, the problems related to the use of large quantities of water to remove acetic acid from the acetic dope are resolved, since it will be directly extracted by supercritical CO2. Micro- and nanoparticles, or filaments, of cellulose acetate can be produced. Finally, an acetic acid residue of 23 ppm, in the supercritical CO2 treated cellulose acetate, confirmed the success of this alternative process configuration.
The VLE properties and the critical parameters of ternary mixture of CO2+toluene/dichloromethane involved in the SEDS precipitation process were studied. The derived VLE and the critical properties data were used to select most preferred thermodynamic conditions (optimal SEDS process parameters) for implementation of the process of supercritical dispersion of the polymer mixtures of EVCA-113/PC using Solution Enhanced Dispersion by Supercritical (SEDS) fluids method. SEDS process has been used to produce ethylene vinyl acetate copolymer (EVCA)/polycarbonate (PC) polymer mixture microparticles at operating parameters from (8 to 25) MPa in the temperature range from (313 to 323) K and at concentration of (0, 0.25, 0.50, 0.75, and 1.00) mass fraction of PC. The effect of SEDS process operating variables (temperature, pressure, and concentration) on EVCA/PC polymer mixtures microparticle sizes and their physical-mechanical properties was studied. We showed that it is possible to modify particle dimensions and physical - mechanical properties of SEDS produced EVCA/PC polymer mixtures by changing the operating parameters. SEM and DSC were used to characterize of the produced polymer mixture microparticles. The crystallization kinetics (degree of crystallinity) and phase -transformation characteristics (heat of fusion and melting temperature) of polymer mixtures obtained by melt mixing and using the SEDS method were studied. The mechanical characteristics such as tensile strength and elongation-at-break were studied as a function of process conditions (temperature, pressure, and concentration).
Development of hybrid materials with molecular structure of organic-inorganic co-network is a promising method to enhance the stability and mechanical properties of biopolymers. Chitosan-silica hybrid nanocomposite scaffolds loaded with mangiferin, a plant-derived active compound possessing several bioactivities, were fabricated using the sol-gel synthesis and the freeze-drying processes. Investigation on the physicochemical and mechanical properties of the fabricated scaffolds showed that their properties can be improved and tailored by the formation of 3-dimensional crosslinked network and the addition of ZnO nanoparticles. The scaffolds possessed porosity, fluid uptake, morphology, thermal properties and mechanical strength suitable for bone tissue engineering application. Investigation on the biomineralization and cell viability indicated that the inclusion of bioactive mangiferin further promote potential use of the hybrid nanocomposite scaffolds in guided bone regeneration application.
There are global trends for developing green and sustainable technologies in food processing, due to the growing awareness of the importance of environmental preservation and the consumer demand for natural high-value food products. Meeting these particular requirements, supercritical carbon dioxide (SC-CO2) has emerged as an innovative and promising technology for the processing of food ingredients and products. Over the last two decades, applications of SC-CO2 have attracted much attention and made great advancements at both laboratory and industrial level. These advances include the extraction of target bioactive compounds from various food matrices, microencapsulation, or extrusion to produce fine particles, and the inactivation of pathogenic and spoilage microorganisms and endogenous enzymes for food preservation. An example of successfully applying SC-CO2 at the commercial level is the decaffeination of coffee. In this article, an overview of the SC-CO2 applications in food processing including extraction, transformation, preservation, and drying are presented. For each application category, principles, processing parameters, characteristics, and latest applications are critically reviewed.
Supercritical anti-solvent precipitation (SAS) using carbon dioxide is a novel technique that can be used to produce powdered ingredients in small size particles, facilitating their incorporation into food matrices. In this work, the SAS precipitation of a licorice root ethanolic extract was studied. SAS assays were carried out at 15–20 MPa, 308.15 and 313.15 K, and two different concentrations (9.6 and 14.2 mg/ml) of the ethanolic licorice extract. In the range of conditions investigated, SAS pressure and temperature did not affect significantly the precipitation yield, but phytochemicals recovery was higher with the lower licorice extract concentration. Moreover, the fractionation of licorice bioactives (liquiritin, liquiritigenin, isoliquiritigenin, glabridin and glycyrrhizic acid) was assessed, together with the content of total phenolic compounds and antioxidant activity of the powders and oleoresin by-products obtained. In this respect, precipitates and oleoresins presented significant differences in the concentration of some licorice bioactives, and higher antioxidant activity was observed in precipitates. Additionally, significant effect of pressure, temperature and licorice extract concentration on the morphology and particle size of precipitates was observed, recovering smaller and more regular particles at 15–20 MPa, 313.15 K and 9.6 mg/ml licorice extract concentration, attaining satisfactory yield and antioxidant activity.
In this work, drug-loaded polymer microparticles were prepared by a supercritical solution impregnation (SSI) process with nitrendipine as the model drug and PLLA-PEG-PLLA as the drug carrier. The morphology, size, distribution and functional groups of the drug-loaded microparticles were characterized by scanning electron microscopy (SEM), laser particle size analyzer and fourier transform infrared analysis (FTIR). The effects of pressure, temperature and cosolvent concentration on the drug loading and release property of the microparticles prepared with and without cosolvent were investigated. The in vitro drug release kinetics of drug-loaded microparticles was studied with five models. The results indicated that the morphology of the drug-loaded polymer microparticles was not influenced by the SSI process. And the addition of ethanol cosolvent could significantly improve the drug loading of the microparticles. The most satisfied drug loading and the release properties of the microparticles were achieved under 55 °C, 13 MPa and cosolvent ethanol concentration of 3%. The drug could be released for more than 140 h. The analysis of the drug release kinetics showed that the experimental data fitted with Ritger-Peppas model were optimal. According to the release exponent value, the in vitro release process of the nitrendipine-loaded microparticles was controlled by Fickian diffusion, which can provides a theoretical basis for drug release of this type of experiment.
Batch supercritical antisolvent precipitation (SAS) process was used to coprecipitate Cefuroxime Axetil amorphous (CFA, antibiotic) and Polyvinylpyrrolidone (PVP-K30) for preparing drug–polymer composite particles. Solutions of CFA and PVP-K30 in methanol with overall concentrations of 50–150mg/ml and polymer/drug ratios of 1/1–4/1 were sprayed into the CO2 at 70–200bar and 35–50°C with drug+polymer solution injection rates of 0.85 and 2.5ml/min. Spherical particles having mean diameters of 1.88–3.97μm, distribution ranges of 0.82–9.7μm (the narrowest distribution) and 0.91–46.64μm (the broadest distribution) were obtained. Mean particle size was not affected significantly with the change of process parameters. It was only affected by pressure change. On the other hand particle size distribution was affected by pressure, temperature, drug+polymer solution injection rate and concentration. It was observed that temperature and polymer/drug ratio affected the particle morphology most. The drug release rate of SAS-coprecipitated CFA–PVP (1/1) particles was almost 10 times slower than the drug alone. As the ratio of the polymer increased drug release rate also increased due to the wetting effect of PVP.
Capsaicinoids, which are the responsible for the pungency of peppers, have strong pharmacological effects. The encapsulation of capsaicinoids can be an alternative for its industrial application. The aim of this work was to evaluate the effect of various ultrasound emulsification conditions, such as surfactant concentration, oil/water ratio, and ultrasound power on the emulsion droplet size. Emulsions formed by Hi-Cap 100 and oleoresin of Capsicum frutescens pepper were then applied in a SFEE process. Ultrasound emulsification resulted in high emulsification efficiency and stability. The selected time for emulsion injection into the SFEE system was 10 min after its preparation, based on the coalescence kinetics. The SFEE process resulted in a considerable loss of oleoresin by dissolution in the supercritical CO2 and promoted a droplet volume expansion, reflected by the increase in the diameter of the droplets in suspension. The formation of emulsions by ultrasound emulsification in the evaluated conditions showed promising results, but more studies are required to improve the SFEE process.
Natural polyphenols are valuable compounds possessing scavenging properties towards radical oxygen species, and complexing properties towards proteins. These abilities make polyphenols interesting for the treatment of various diseases like inflammation or cancer, but also for anti-ageing purposes in cosmetic formulations, or for nutraceutical applications. Unfortunately, these properties are also responsible for a lack in long-term stability, making these natural compounds very sensitive to light and heat. Moreover, polyphenols often present a poor biodisponibility mainly due to low water solubility. Lastly, many of these molecules possess a very astringent and bitter taste, which limits their use in food or in oral medications. To circumvent these drawbacks, delivery systems have been developed, and among them, encapsulation would appear to be a promising approach. Many encapsulation methods are described in the literature, among which some have been successfully applied to plant polyphenols. In this review, after a general presentation of the large chemical family of plant polyphenols and of their main chemical and biological properties, encapsulation processes applied to polyphenols are classified into physical, physico-chemical, chemical methods, and other connected stabilization methods. After a brief description of each encapsulation process, their applications to polyphenol encapsulation for pharmaceutical, food or cosmetological purposes are presented.
The thermal stability (60°C, 80°C, 100°C), antioxidant activity, and ultraviolet C light (UV-C) stability of standard polyphenols solutions (catechin, gallic acid, and vanillic acid) and of vegetal extracts from spruce bark and grape seeds were investigated. Exposure of the standard solutions and vegetal extracts to high temperatures revealed that phenolic compounds were also relatively stable (degradations ranged from 15 % to 30 % after 4 h of exposure). The highest antioxidant activity was obtained for ascorbic acid and gallic acid followed by catechin and caffeic acid and the grape seeds. The results show that, after 3 h of UV-C exposure, approximately 40 % of vanillic acid, 50 % of gallic acid, and 83 % of catechin were removed. Similar degradation rates were observed for vegetal extracts, with the exception of the degradation of catechin (40 %) from grape seeds. In addition, the photo-oxidation of polyphenols in the presence of food constituents such as citric acid, ascorbic acid, sodium chloride, and sodium nitrate was assessed.
Encapsulation may be defined as a process to entrap one substance within another substance, thereby producing particles with
diameters of a few nm to a few mm. The substance that is encapsulated may be called the core material, the active agent, fill,
internal phase, or payload phase. The substance that is encapsulating may be called the coating, membrane, shell, carrier
material, wall material, external phase, or matrix. The carrier material of encapsulates used in food products or processes
should be food grade and able to form a barrier for the active agent and its surroundings. Please see Chap. 3 for more information
on this.
Supercritical antisolvent precipitation (SAS) has been successfully used to produce microparticles and nanoparticles of controlled size and distribution either as a single precipitates or by coprecipitation of two or more compounds. SAS coprecipitation process has produced different particles morphologies and, differently from the single compound SAS precipitation, process mechanisms involved have never been elucidated and the effectiveness of the technique has been verified only in some cases. In this work, the mechanisms proposed in SAS coprecipitation are critically discussed and general indications about coprecipitation efficiency are given, based on several experimental evidences and on the possible underlying nucleation, growth and drying mechanisms. The most effective and reliable SAS coprecipitation resulted from the formation of microdroplets and their subsequent drying.
The objective of this work was the obtaining of nanoparticles with potent antioxidant activity by supercritical antisolvent extraction process (SAE) using different methods of antioxidants extraction: subcritical fluid extraction (SFE), pressurized liquid extraction (PLE) and enhanced solvent extraction (ESE) with different operating conditions. The employed conditions in SAE process were 20 mg/mL of the extract concentration, 150 bar of pressure and temperatures of 35 and 50 °C into the vessel, extract flow rate of 5 mL/min and supercritical CO2 (scCO2) flow rate of 30 g CO2/min. The quantification of polyphenols of mango leaves was determined by HPLC and the antioxidant activity was measured by DPPH. Spherical nano- and microparticles with diameters in the range of 0.01–1.34 μm were obtained with much stronger antioxidant activity than the extracts (SFE, PLE, ESE). The major compound found in the extracts and the SAE precipitates was iriflophenone 3-C-β-D-glucoside.
This study aims to develop a formulation of a turmeric-based dye extract using supercritical antisolvent (SAS) technology and different encapsulating polymers to improve the aqueous stability and solubility of curcumin. The dye formulation obtained by SAS consists of a mixture of Eudragit® L100 and Pluronic® 127 using tween 20 as a surfactant The characterization and quantification of curcumin extracts and the encapsulation product were conducted using high performance liquid chromatography (HPLC). The properties of the dye were determined using SEM, DSC, X-ray diffraction, particle size, zeta potential, and oxygen radical absorbance capacity (ORAC) to measure antioxidant capacity. The dye formulation contained a curcumin content of 4.45 µg/mL. The average diameter of the amorphous particles was 5667.4 nm, and the zeta potential was 11.21 mV. The largest aqueous stability and solubility was observed at pH 4. From color comparison with a solution of tartrazine 200 µg/mL solution of dye formulation based on curcuminoids is equivalent to an approximated 30 µg/mL tartrazine solution.
The effects of operating conditions and Z-isomer content of astaxanthin on coprecipitate formation of polyvinylpyrrolidone (PVP) and astaxanthin by solution-enhanced dispersion by supercritical fluids (SEDS) process were investigated. Using this process, nano-sized (100–200 nm) and water-soluble PVP/astaxanthin inclusion complex was successfully prepared. As the operating pressure increased from 8 to 15 MPa at a constant temperature, astaxanthin content in the coprecipitates decreased, and increasing the operating temperature from 40 to 60 °C at a constant pressure, the particle size and the astaxanthin content increased. Increasing the PVP ratio for astaxanthin in the range of 5:1 to 20:1, the particle size decreased and when 10:1 of the ratio, the astaxanthin content in the coprecipitates was the highest (60 °C, 10 MPa). Additionally, as the Z-isomer content of astaxanthin increased, the astaxanthin content decreased slightly. However, the coprecipitates rich in astaxanthin Z-isomers, which have higher bioavailability and antioxidant capacity, were obtained.
Polyphenols occurring in nature are sensible to light, heat and oxygen. For this reason, it is necessary to entrap them into drug carriers, such as liposomes. In this work, the Supercritical assisted Liposome formation process (SuperLip) was used for the encapsulation of a polyphenol-rich aqueous extract from olive pomace. The effect on liposome morphology and encapsulation efficiency of different operative parameters was studied. Liposomes were produced with mean diameters smaller than 265 nm at 130 bar and down to 168 nm for 170 bar. Narrower liposome distribution curves were obtained changing the nozzle diameter for the atomization of water. Encapsulation efficiencies up to 58% were obtained, that are about six times larger than using conventional methods.
This book reports on multidisciplinary research focusing on the analysis, synthesis and design of bionanomaterials. It merges the biophysicists’, the biochemists’ and bioengineers’ perspectives, covering the study of the basic properties of materials and their interaction with biological systems, the development of new devices for medical purposes such as implantable systems, and new algorithms and methods for modeling the mechanical, physical or biological properties of biomaterials. The different chapters, which are based on selected contributions presented at the second edition of BIONAM, held on October 4-7, 2016, in Salerno, Italy, cover both basic and applied research. This includes novel synthetic strategies for nanomaterials, as well as the implementation of bio- and smart materials for pharmacological and medical purposes (e.g. drug delivery, implantable systems), environmental applications, and many others. The book provides a broad audience of academic and professionals with a comprehensive, timely snapshot of the field of biomaterials. Besides offering a set of innovative theories together with the necessary practical tools for their implementation, it also highlights current challenges in the field, thus fostering new discussions and possible future collaborations between groups with different backgrounds.
Mangiferin, a common polyphenol present in mango plants, and cellulose acetate phthalate, a polymeric derivative of cellulose acetate, have been precipitated together by a supercritical antisolvent process (SAS) with two different nozzle devices. In the first approach (SAS1) the polymer and mangiferin were dissolved together in a solvent and the solution was sprayed into the vessel through a single nozzle. In a second approach (SAS2), separate solutions of the polymer and mangiferin were prepared and these were sprayed through different nozzles into the same vessel. Submicron and microparticles precipitated in the SAS1 and SAS2 processes, respectively. The percentage of mangiferin in the precipitates was higher in the first process than in the second one, which shows that mangiferin precipitation was favored when a single nozzle was used. The delivery profiles of mangiferin were obtained for simulated gastric and intestinal fluids. All of the co-precipitates were released more slowly than processed and commercial mangiferin. Moreover, the percentage of mangiferin released was lower in gastric than intestinal fluid. The presence of the polymer in the precipitate slowed down the delivery of the mangiferin both in the intestinal and the gastric fluids in the SAS1 process. However, in the SAS2 process the differences in solution flow rates led to a delayed release profile.
Curcumin is a hydrophobic polyphenol compound exhibiting a wide range of biological activities such as anti-inflammatory, anti-bacterial, anti-fungal, anti-carcinogenic, anti-human immunodeficiency virus, and antimicrobial activity. In this work, a swirl mixer was employed to produce the micronized curcumin with polyvinylpyrrolidone (PVP) by the supercritical anti-solvent process to improve the bioavailability of curcumin. The effects of operating parameters such as curcumin/PVP ratio, feed concentration, temperature, pressure, and CO2 flow rate were investigated. The characterization and solubility of particles were determined by using scanning electron microscopy, Fourier Transform Infrared spectroscopy, and ultra-violet-visible spectroscopy. The result shows that the optimal condition for the production of curcumin/PVP particles is at curcumin/PVP ratio of 1:30, feed concentration of 5 mg·mL−1, temperature of 40 °C, pressure of 15 MPa, and CO2 flow rate of 15 mL·min−1. Moreover, the dissolution of curcumin/PVP particles is faster than that of raw curcumin.
Mango leaf tea has been traditionally used by different cultures to reduce inflammation in the body. There is evidence that chronic inflammation increases the risk of cancer. This study investigates the antitumoural effects of pressurized mango leaf extracts on minimally (MCF7) and highly invasive (MDA-MB-231) breast cancer cells as well as on non-tumourigenic cells (MCF10). Extracts showed protective properties against oxidation and cytotoxic effects in breast cancer cell lines, causing minor damages in non-carcinogenic cells. Nontheless, some selective activity, depending on hormone receptor status, was observed. This was possibly related to the presence of minor compounds. Extracts with high levels of gallotannins showed cytotoxic action in MCF7 cells, while those who had methyl gallate and homomangiferin as common components were more effective against MDA-MB-231 cells. Therefore, the cytotoxic effect of mango leaf extracts might be attributed to the synergistic effects of different polyphenols and not just to mangiferin on its own, as the predominant compound in mango leaves.
Nimesulide (NIM) is an anti-inflammatory drug, widely used in the treatment of acute pain associated with different diseases. A major limitation in its usage is due to its reduced solubility in water; therefore, large doses are required to reach the therapeutic level, with consequent undesired effects on patient’s health. In order to improve NIM dissolution rate, a possible solution is represented by its micronization. Traditional micronization techniques show several drawbacks: lack of control over the particle morphology and particle size distribution, large solvent residues and use of high temperatures. An alternative to conventional techniques is represented by supercritical carbon dioxide (scCO2) based processes. In particular, nanoparticles and microparticles of different kind of materials were successfully obtained by supercritical antisolvent (SAS) precipitation. However, when processed using SAS, nimesulide precipitated in form of large crystals or it is completely extracted by the mixture solvent/antisolvent. A solution to this problem can be the production of drug-polymer composite microspheres, using a water soluble polymer in which the drug is entrapped. In this work, NIM coprecipitation with polyvinylpyrrolidone (PVP) is proposed on pilot scale. The effects of polymer/drug ratio, concentration, pressure and temperature were investigated to identify successful operating conditions for SAS coprecipitation. Microparticles with a mean diameter ranging between 1.6 and 4.1 µm were successfully produced. Drug release analyses revealed that NIM dissolution rate from PVP/NIM microparticles was 2.5 times faster with respect to unprocessed drug. The possible precipitation mechanisms involved in the process were discussed.
The aim of this study was to establish the effect of a 70% ethanol extract of Elaeocarpus sylvestris (ESE) on varicella-zoster virus (VZV) replication and identify the specific bioactive component(s) underlying its activity. ESE induced a significant reduction in replication of the clinical strain of VZV. Activity-guided fractionation indicated that the ethyl acetate (EtOAc) fraction of ESE contains the active compound(s) inhibiting VZV replication. High-Performance Liquid Chromatography coupled to Electrospray Ionization Quadrupole Time-of-Flight Mass Spectrometry (HPLC-Q-TOF-MS/MS) analysis of the EtOAc fraction of ESE facilitated the identification of 13 chemical components. Among these, 1,2,3,4,6-penta-O-galloyl-ß-D-glucose (PGG) markedly suppressed VZV-induced c-Jun N-terminal kinase (JNK) activation, expression of viral immediate-early 62 (IE62) protein and VZV replication. Our results collectively support the utility of PGG as a potential candidate anti-viral drug to treat VZV-associated diseases.
Extracts from mango leaves have been precipitated by a supercritical antisolvent (SAS) process and the phenolic content, size and size distribution of the resulting micro- and nanoparticles have been evaluated. The mango leaves were initially extracted by conventional ethanol extraction at 40 °C. The effects of different parameters on the outcome of the SAS process were evaluated using different concentrations (8 to 40 mg/mL), pressures (100 and 150 bar), temperatures (35 and 50 °C), extract flow rates (5 and 10 mL extract/min) and supercritical CO2 (scCO2) flow rates (30 and 40 g CO2/min). The antioxidant activity was evaluated by the radical scavenging activity method using 2,2-diphenyl-1-picrylhydrazyl radical (DPPH). Spherical nano- and submicron-particles with diameters in the range 0.04–0.39 μm were obtained with stronger antioxidant activity than the extract. The major compounds found in the extract and the SAS precipitates were mangiferin and benzophenone derivatives such as iriflophenone 3-C-β-D-glucoside and iriflophenone 3-C-(2-O-p-hydroxybenzoyl)-β −D-glucoside.
In this work, the incorporation of two liposoluble vitamins, α-tocopherol (TOC) and menadione (MEN), within polyvinylpyrrolidone (PVP) microparticles using Supercritical Antisolvent (SAS) coprecipitation is proposed. In order to control microspheres’ size and morphology, the effect of SAS main process parameters, such as polymer/vitamin ratio, operating pressure, temperature and overall concentration, was investigated. In the case of the system PVP/TOC, composite microparticles with mean diameters in the range 1.69-4.08μm were successfully produced; for the system PVP/MEN, composite microparticles with mean diameters in the range 2.64-5.09μm were obtained, depending on the operating conditions. Powders were characterized using UV-vis spectroscopy to calculate the vitamin entrapment efficiency and vitamin dissolution rate, FT-IR to identify possible interactions between the polymer and the vitamin, HPLC to verify the vitamin integrity, and GC to calculate the residual solvent. The analyses revealed that the drug entrapment efficiency was about 53% for TOC and 50% for MEN, and that the vitamin dissolution rate of the coprecipitates was between 3 and 3.5 times faster than the dissolution rate of unprocessed vitamins, respectively.
Supercritical antisolvent process (SAS) has been used to precipitate microparticles of quercetin, a plant pigment found in many foods and used for medical treatments, pharmaceutical and cosmetic industries, together with nanoparticles of cellulose acetate phthalate (CAP), a polymer quite frequently used in drug delivery. Previously, precipitation of nanoparticles of CAP by the same process was studied at different conditions of pressure, temperature, CO2 and solution flow rates, nozzle diameter and initial concentration of the solution. Morphologies of the precipitates were analyzed by scanning electron microscopy (SEM). A range between 84 and 145 nm of diameter in spherical particle were achievement in CAP precipitation. A same range of semi-spherical particles of CAP around 145 nm and needle-like particle of quercetin was obtained in the coprecipitation experiments. X-ray diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR) were carried out to find out the possible loss of crystallinity of the coprecipitates and the possible interactions between the polymer and quercetin, respectively. Release profiles of quercetin were carried out in simulated gastric and intestinal fluids. Higher quercetin:polymer ratios in the coprecipitates are recommended to achieve faster release and higher solubilities of quercetin in the assayed time. This fact would allow its use in pharmaceutical, cosmetic or nutraceutical applications.
Supercritical Assisted Atomization (SAA) has been applied to the formation of microspheres curcumin (CUR)-polyvinylpyrrolidone (PVP) to be used for biomedical applications. CUR has antioxidant, anti-inflammatory and antitumoral properties and is poorly water soluble; whereas, PVP is highly water soluble. The aim was to entrap CUR in form of nanoparticles in a polymeric hydrosoluble carrier, to protect the active principle and to enhance its bioavailability. Four CUR/PVP weight ratios were selected: 1/2, 1/4, 1/6 and 1/8 and processed by SAA at 80 °C and 99 bar in the saturator and 80 °C and 1.50 bar in the precipitator. Spherical particles of CUR/PVP were obtained in all cases, characterized by a mean size, calculated on particle number %, smaller than 400 nm and a D90 lower than 1 μm. X-ray, DSC, FTIR analyses showed that the microspheres were amorphous and that the drug was intimately mixed with the polymer. UV–vis spectrometric analyses confirmed an high loading efficiency of the active principles microspheres, ranging between 94 and 100%. Dissolution tests in aqueous environment at different pH values were performed to measure the improvement of the dissolution rate. It resulted up to 4.5 times faster with respect to the physical mixture for the most favorable 1/8 ratio, with a complete CUR dissolution time of 5.5 h at pH 6.5.
Many plants which are rich in phenolic compounds possess several health benefits, such as preventing urinary tract infections, stomach ulcers, and dental diseases. These phenolic compounds are generally stable and bioactive when present in plants. However, they are prone to degradation after extraction, which is a challenge when processing foods. Encapsulation is a process where the compounds of interest are enveloped by one or a mixture of polymers referred as matrix materials. It protects phenolic compounds from a relatively rapid degradation and helps to control the release of these compounds. Proteins are natural food grade polymers which are used as encapsulating matrices and do have a wide range of applications, especially in the food industry. In this review, the major phenolic compounds that are present in plants are outlined. The encapsulation methods and recent researches performed to encapsulate phenolic compounds present in plants using protein matrices are critically discussed.
Microparticles of ellagic acid were prepared by a supercritical antisolvent process. The main parameters that influence this process were identified in order to carry out a subsequent coprecipitation using eudragit as a coating agent. The initial concentration of the solution and temperature play a significant role in the powder precipitation of ellagic acid; powders did not precipitate at concentrations below 20 mg/mL and temperatures above 40 °C. Higher CO2 and liquid solution flow rates together with smaller nozzle diameters are recommended in order to obtain smaller particles of ellagic acid. Taking into account these results, coprecipitates of ellagic acid and eudragit in different ratios were obtained under the best operating conditions. The coprecipitates were formed as spherical microparticles of eudragit surrounding sticks and flowers of ellagic acid. Dissolution profiles for commercial ellagic acid and processed microparticles were obtained in simulated fluids together with the release profiles of the coprecipitates. Commercial ellagic acid had a poor dissolution profile in simulated fluids. In general, ellagic acid was dissolved or released to a greater extent in simulated gastric fluids than in simulated intestinal fluids. Coprecipitates had faster release than microparticles of ellagic acid alone. The crystallinity and stability of SAS-processed ellagic acid remained unchanged.
Eschweilera nana Miers has strong antioxidant activity owing to the presence of the flavonoids, such as rutin and hyperoside. However, their low solubility in water, bioavailability and stability to adverse environmental conditions limits their potential application in the therapeutics. In this paper, microparticles loaded with E. nana extract were produced by spray-drying technique using a mixture of arabic and xanthan gums, and characterized by morphology and particle size analyses, encapsulation efficiency, thermogravimetric analysis, differential scanning calorimetry, X-ray diffraction and Fourier transform Raman spectroscopy (FT-Raman). Results showed that, using the spray-drying technique, it was possible to obtain microparticulate systems containing E. nana extract with high encapsulation efficiency of rutin and hyperoside, which may be associated to a possible interaction between the polymers and the extract. All microparticle formulations were amorphous, hollow, and spherical with smooth surfaces. Thermal analysis revealed that the microencapsulation process conferred thermal protection to the extract. The release profile of rutin was carried out and showed that from the microparticles it was slower than the extract. The antioxidant activity also evaluated by the ability of the E. nana extract, and microparticles loaded with E. nana extract to decrease/scavenge reactive oxygen species (ROS) in the neutrophil respiratory burst.
Production of coprecipitated microparticles is an ambitious application of supercritical antisolvent precipitation (SAS). In this work, coprecipitates of beta-carotene (BC) and polyvinylpyrrolidone (PVP) have been successfully obtained using this technique. Nanostructured microparticles in the range 12.4 mu m were obtained, varying the polymer molecular weight (10 000 and 40 000 g/mol), the polymer/drug ratio (from 10/1 to 20/1), the operating pressure (from 85 to 100 bar), and the total concentration in the liquid solution (from 3 to 7 mg/mL). In particular, at 85 bar, 40 degrees C, 5 mg/mL, with a PVP/BC equal to 10/1, and using the polymer with the lower molecular weight, well-defined coprecipitated microparticles were obtained. Particles produced operating at these conditions showed a vitamin dissolution rate 10 times faster than the one of unprocessed BC, confirming the effective coprecipitation, and the increase of the beta-carotene dissolution rate. The precipitation process and the mechanisms involved are also discussed.
In this work, polyphenols from olive pomace were extracted with a high pressure-high temperature agitated reactor and for the first time encapsulated by spray drying, using maltodextrin as coating agent at different concentrations. In addition, effects of inlet temperature (130 °C and 160 °C) and feed flow (5 mL/min and 10 mL/min) were studied. Physicochemical, antioxidant properties and stability of microparticles were evaluated. High inlet temperature implied lower moisture and bulk density without affecting antioxidant properties. Increasing maltodextrin concentration caused lower bulk density and higher microparticles sizes, while higher feed flow lead to increased moisture content. Spray drying at inlet temperature of 130 °C, maltodextrin concentration of 100 g/L and feed flow of 10 mL/min, resulted in high microencapsulation yield (94%) and encapsulation efficiency (76%) with high polyphenols content (39.5 mgCAE/gDP) and antiradical power (33.8 mmolDPPH/Lextract). HPLC and thermogravimetric analysis revealed the thermal protection effect of maltodextrin for phenolic compounds. Microcapsules were stable at 5 °C in dark condition for 70 days, and only 21% were degraded increasing storage temperature up to 25 °C. UV light exposure resulted in a 66% loss in polyphenols after 48 h of exposure.
In this work chitosan microbeads were prepared by emulsion technique and loaded with thyme polyphenols by diffusion from an external aqueous solution of Thymus serpyllum L. The effects of concentrations of chitosan (1.5-3% (w/v)) and GA (glutaraldehyde) (0.1-0.4% (v/v)), as a crosslinking agent on the main properties of microbeads were assessed. The obtained microgel beads from ∼220 to ∼790μm in diameter were exposed to controlled drying process at air (at 37°C) after which they contracted to irregular shapes (∼70-230μm). The loading of dried microbeads with polyphenols was achieved by swelling in the acidic medium. The swelling rate of microbeads decreased with the increase in GA concentration. Upon this rehydration, thyme polyphenols were effectively encapsulated (active load of 66-114mgGAEgbeads(-1)) and the microbeads recovered a spherical shape. Both, the increase in the amount of the crosslinking agent and the presence of polyphenols, contributed to a more pronounced surface roughness of microbeads. The release of encapsulated polyphenols in simulated gastrointestinal fluids was prolonged to 3h.
Dissolution rate enhancement of the anti-inflammatory drug diflunisal was achieved using for the first time a supercritical fluid technology. The supercritical fluid antisolvent (SAS) method was applied to precipitate diflunisal alone and to coprecipitate the drug together with the biocompatible polymer polyvinylpyrrolidone (PVP K-30 and K-10). The untreated and SAS processed diflunisal, and the coprecipitates were characterized in terms of size, morphology, crystallinity, compositions, drug-polymer interactions, and drug release. SAS processed diflunisal exhibited a polymorphic form different from that of the untreated drug. Diflunisal crystallinity disappeared in the coprecipitates. Three different drug: polymer mass ratios were studied: 75:25, 50:50, and 25:75. Microparticle size decreased and aggregation disappeared as the relative amount of polymer increased. The 25:75 coprecipitate consisted of loose spherical particles exhibiting mean particle size of 410 nm while the 75:25 coprecipitate consisted of bigger aggregated particles. The SAS method was shown to be a suitable technology to form solid dispersions of a poorly soluble drug.
Polymer microspheres are becoming attractive drug delivery systems due to their biodegradability, nontoxicity and easy administration. In this study, a rosemary extract exhibiting anti-proliferative activity against various human cancer cell lines was encapsulated by polycaprolactone using gas anti-solvent process and solvent evaporation method. The particles were characterized by X-ray diffraction, differential scanning calorimeters analyses and scanning electron microscopy, whereas in vitro release kinetics was determined by the dialysis cell method. Although the fabrication methods seemed not to play an important role in the diffusion rate and release profiles of both loaded samples in aqueous medium, fabricated rosemary extract with gas antisolvent process at 300 bar, 40 °C and a flow rate of 20 g/min exhibited a narrow particle size distribution, a lower mean particle size and higher encapsulation efficiency (254.5 nm, 82.8%) compared to the traditional fabrication method (617.5 nm, 62.2%).
Supercritical Fluid Extraction (SFE) and Subcritical Water Extraction (SWE) from mango leaves were applied in order to obtain extracts with high phenolic content and potent antioxidant activity. The effects of extraction conditions on sub- and supercritical CO2 extraction were analyzed: temperature (35 and 55 °C), pressure (10 and 40 MPa), percentage of co-solvent (0 and 20%) and type of co-solvent (methanol/ethanol). The best condition (CO2 + 20% of ethanol at 10 MPa, 55 °C, 20 g/min and 3 h) was compared with SWE (4 MPa, 100 °C, 10 g/min, and 3 h) using seven mango cultivars. SWE was more efficient than subcritical CO2 + ethanol. The antioxidant activity was evaluated by DPPH assay, and the quantification of the main polyphenols of mango leaves by HPLC analysis. SWE showed global yields up to 35% for Kent variety, and extracts with antioxidant activities superior to (+)-α-tocopherol related with their high content on the polyphenols mangiferin and quercetin.
The purple Brazilian cherry (Eugenia uniflora L.) juice was encapsulated in xanthan, tara and xanthan-tara hydrogel matrixes. Encapsulation efficiency, Differential Scanning Calorimetry (DSC), X-ray diffractometry, release profile, stability of carotenoids, phenolic compounds and antioxidant activity of microparticles were evaluated. Encapsulation was confirmed. The highest encapsulation efficiency was obtained with xanthan gum and hydrogel was mostly indicated for the release of carotenoids in GFS and IFS medium. Phenolic compounds had the highest release rate but not in a gradually way, regardless of wall material and fluids under analysis. Stored microparticles at 4 and 25°C, showed carotenoid degradation. Xanthan and hydrogel wall material provided the greatest stability to these compounds. The microparticles' anti-oxidant activity decreased during storage due to the degradation of carotenoids.
The propolis has potential to be a natural food additive. However, its application is limited, because it is alcohol-soluble and has strong flavour. Microencapsulation may be an alternative for reducing these problems. The aim of this study was to encapsulate propolis extract by complex coacervation using isolated soy protein and pectin as encapsulant agents. The coacervation was studied as a function of pH (5.0, 4.5, 4.0 and 3.5) and the concentration of encapsulants and core (2.5 and 5.0 g/100 mL). Samples obtained at pH 4.0 in both concentrations were lyophilized and analyzed for hygroscopicity, encapsulation efficiency, particle size, morphology, thermal behavior, stability of phenolic and flavonoids during storage, as well as antioxidant and antimicrobial activities. It was possible to encapsulate propolis extract by complex coacervation and to obtain it in the form of powder, alcohol-free, stable, with antioxidant property, antimicrobial activity against Staphylococcus aureus and with the possibility of controlled release in foods.
In this work, green tea polyphenols were coprecipitated with a biodegradable polymer (poly-ɛ-caprolactone, MW: 25,000) by a semi continuous supercritical antisolvent process (SAS). Carbon dioxide was used as antisolvent in addition to be a dispersing agent. Green tea extracts were obtained by microwaved assisted extraction (MAE) technique with acetone. The influence of different process parameters, including the operating pressure (8–12 MPa) and temperature (283–307 K), the polymer to solutes concentration (w/w) ratio (4–58), and the CO2 to solution mass flow rate ratio (4–10) have been studied experimentally. Total content of polyphenols, quantified according to the Folin-Cicalteu method, showed concentrations from 60 to 100% of the maximum theoretical composition. Also HPLC analyses were performed to verify the presence of some of the major tea catechins. SEM images of the products show small particles (3–5 μm) with narrow particle size distribution with a high degree of agglomeration. Drug release profiles in phosphate buffer (pH = 6.8) reveal that the majority of catechins are encapsulated in the crystalline domains of the polymer.
The formulation of natural substances together with a biocompatible or biodegradable carrier material to form composites or encapsulates has a great relevance for pharmaceutical, cosmetic and food industries. Several precipitation methods with supercritical fluids can be successfully adapted to produce these materials. This article presents a review of the main aspects of supercritical encapsulation and co-precipitation processes, focused on a process mechanisms description as well as of the types of materials that can be formulated with them.
A screening design of experiments has been applied to the supercritical antisolvent precipitation of ampicillin (APC) using carbon dioxide (CO2) and N-methylpyrrolidone (NMP) as antisolvent and solvent, respectively. The proposed design of experiment (DOE) is useful for identifying the key factors involved in the SAS process in just a few runs at an early stage of experimentation. Seven factors were studied, and two levels were assigned to each. A fractional factorial design with 27-4 experiments plus two additional runs to calculate the accuracy of the estimates was used. The mean particle size (PS) and particle size distribution (PSD) of the processed ampicillin were chosen as responses to evaluate the process performance. Within the range of operating conditions investigated, concentration, temperature, and nozzle diameter proved to be the key factors having the greatest effect on both PS and PSD and, thus, the most important factors for controlling the formation of submicrometer particles of ampicillin by the SAS technique.
The encapsulation of antioxidants with biocompatible polymers is essential for their protection against degradation factors like light and oxygen, and facilitates its solubility in the target medium. This work presents the co-precipitation of an ethanolic extract of rosemary leaves by supercritical antisolvent (SAS) process in poloxamers in order to improve the aqueous solubility of the extract. In a first step, the precipitation of antioxidants by SAS was studied in the range of temperatures from 25 to 50 degrees C and pressures from 8 to 12 MPa. Total content of polyphenols was quantified according to the Folin-Cicalteu method. Also HPLC analyses were performed to verify the presence of some of the major rosemary antioxidants, carnosic and rosmarinic acid. The dissolution rate of rosemary polyphenols from particles was measured in isotonic phosphate buffer solution (pH = 6.8). The encapsulation of the extract was successfully achieved with a yield up to 100%. The total polyphenolic content was dissolved from the encapsulated product, in the aqueous medium, after 1 h, whereas only 15% of the antioxidants of the pure precipitate were dissolved after 8 h. (C) 2011 Elsevier Ltd. All rights reserved.
The polyphenolic extracts from bayberry were micro-encapsulated by a phase separation method using ethyl cellulose as a coating material. The microcapsules obtained were further characterized on polyphenols content, antioxidant capacity, particle size distribution, microstructures, in vitro study and storage stability. Results of antioxidant capacity assays showed that the antioxidant activity of bayberry polyphenols could be effectively protected by microencapsulation. The microcapsules were found to have a smooth surface shape with a particle size distribution of 10–97 μm by light microscope and SEM observation. Release rate of bayberry polyphenol from microcapsules was within the range of 2.56–15.14% under simulated gastric fluid with pH of 2–6. Comparatively, release rate of bayberry polyphenols increased significantly (up to 87.37%) under simulated intestinal fluid 24 with pH of 8. The storage stability of bayberry polyphenols against adverse environment was also remarkably improved by microencapsulation. This study would contribute to the guide of application of bayberry polyphenols on food processing.
Supercritical fluids (SCFs) are substances at pressures and temperatures above their critical values. It is characteristic that prop-erties of SCFs can be changed in a wide range. Their solvent power is the highest for non-polar or slightly polar components and decreases with increasing molecular weight. They can easily be removed from the solutes by mere expansion to ambient pressure. Carbon dioxide (CO 2) is particularly advantageous for processing food materials. SCFs are used for batch extractions of solids, for multi-stage counter-current separation (fractionation) of liquids, and for adsorptive and chromatographic separations. State of the art design for commercial plants is available, and a number of installed plants are working. Special applications to food processing include decaffeination of green coffee beans, production of hops extracts, recovery of aromas and flavours from herbs and spices, extraction and fractionation of edible oils, and removal of contaminants, among others. The application of SCFs is now extended to new areas like formulation or specific chemical reactions. Costs of SCF extraction (SCFE) processes are competitive. In certain cases SCFE processing is the only way to meet product specifications. Ó 2004 Published by Elsevier Ltd.
Active principles of a drug can be encapsulated through polymers in order to prevent adverse reac-tions and protect its properties. The aim of this work was the use of the supercritical anti-solvent (SAS) process to co-precipitate shrimp residue extract and polymer. The shrimp residue was pre-treated and macerated with acetone, producing the carotenoid extract. The effect of the operating parameters of the SAS precipitation was performed in small and large scale units, using Pluronic F127. The Supercritical Fluid Extraction of an Emulsion (SFEE) was also applied for the co-precipitation using modified starch. The encapsulation performance was evaluated by morphology and particle size, efficiency of astaxan-thin encapsulation and color stability. It was possible to micro-precipitate the carotenoid extract with Pluronic F127 by SAS, with an encapsulation efficiency of up to 74%. Nano-emulsion produced by SFEE presented the highest encapsulation performance and the lowest particle size. All particles produced by SAS and by SFEE obtained better color preservation compared to the crude extract.
The growing interest in the substitution of synthetic food antioxidants by natural ones has fostered research on vegetable sources and the screening of raw materials for identifying new antioxidants. Oxidation reactions are not an exclusive concern for the food industry, and antioxidants are widely needed to prevent deterioration of other oxidisable goods, such as cosmetics, pharmaceuticals and plastics. Polyphenols are the major plant compounds with antioxidant activity, although they are not the only ones. In addition, other biological properties such as anticarcinogenicity, antimutagenicity, antiallergenicity and antiaging activity have been reported for natural and synthetic antioxidants. Special attention is focussed on their extraction from inexpensive or residual sources from agricultural industries. The aim of this review, after presenting general aspects about natural antioxidants, is to focus on the extraction of antioxidant compounds (mainly polyphenols) from agricultural and industrial wastes, as well as to summarize available data on the factors affecting their antioxidant activity and stability, and, in some cases, the reported major active compounds identified.
A mathematical model for the supercritical antisolvent (SAS) process is presented and solved numerically. This model takes the main physical phenomena involved in this process into account, including jet hydrodynamics, mass transfer, phase equilibrium, as well as nucleation and crystal growth kinetics. The model allows to calculate the particle size distribution and the yield of the precipitation. The main innovation of this model concerns jet hydrodynamics, which is considered as the mixing of two completely miscible fluids forming a gaseous plume, and is modeled with a k–ε turbulence model. The model has been used to analyze the mechanism of particle formation in the SAS process, and to study the effects of the operating parameters on particle size and solid recovery. The comparison with experimental results shows good agreement in the trends. Particle size cannot be predicted accurately due to the lack of knowledge of some parameters of the model.
The antioxidant and antiproliferative properties of flesh and peel of mango (Mangifera indica L.) were investigated. The cytoprotective effect of mango flesh and peel extracts on oxidative damage induced by H2O2 in a human hepatoma cell line, HepG2, were determined, and the underlying mechanism was examined by a single-cell electrophoresis assay (comet assay). Treatment of HepG2 cell with mango peel extract prior to oxidative stress was found to inhibit DNA damage. The free radical scavenging activities of mango flesh and peel extracts were evaluated by electron spin resonance (ESR). The mango peel extract exhibited stronger free radical scavenging ability on 1,1-diphenyl-2-picrylhydrazyl (DPPH) and alkyl radicals than mango flesh extract, regardless of ripeness. Similarly, peel extract exhibited significant antiproliferative effect against all tested cancer cell lines, compared to that of flesh extract, in a dose-dependent manner. The result also showed that the antiproliferative activity of mango flesh and peel extracts correlated with their phenolic and flavonoid contents. Thus, mango peel, a major by-product obtained during the processing of mango product, exhibited good antioxidant activity and may serve as a potential source of phenolics with anticancer activity.