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1.
EMBO J ; 40(12): e107270, 2021 06 15.
Artigo em Inglês | MEDLINE | ID: mdl-33885174

RESUMO

Paraspeckles are constructed by NEAT1_2 architectural long noncoding RNAs. Their characteristic cylindrical shapes, with highly ordered internal organization, distinguish them from typical liquid-liquid phase-separated condensates. We experimentally and theoretically investigated how the shape and organization of paraspeckles are determined. We identified the NEAT1_2 RNA domains responsible for shell localization of the NEAT1_2 ends, which determine the characteristic internal organization. Using the soft matter physics, we then applied a theoretical framework to understand the principles that determine NEAT1_2 organization as well as shape, number, and size of paraspeckles. By treating paraspeckles as amphipathic block copolymer micelles, we could explain and predict the experimentally observed behaviors of paraspeckles upon NEAT1_2 domain deletions or transcriptional modulation. Thus, we propose that paraspeckles are block copolymer micelles assembled through a type of microphase separation, micellization. This work provides an experiment-based theoretical framework for the concept that ribonucleoprotein complexes (RNPs) can act as block copolymers to form RNA-scaffolding biomolecular condensates with optimal sizes and structures in cells.


Assuntos
Micelas , Polímeros , RNA Longo não Codificante , Ribonucleoproteínas , Linhagem Celular , Humanos
2.
Eur J Nutr ; 63(6): 2261-2270, 2024 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-38753174

RESUMO

PURPOSE: The original aim of the study was to determine, in a double-blind 3-arm crossover human trial (n = 7), the effect of supplemental levels of iron (25 mg) and zinc (30 mg) on ß-carotene (synthetic) bioavailability (10 h postprandial). However, despite the high dose of supplemental ß-carotene (15 mg) consumed with the high fat (18 g), dairy-based breakfast test meal, there was a negligible postprandial response in plasma and triglyceride rich fraction ß-carotene concentrations. We then systematically investigated the possible reasons for this low bioavailability of ß-carotene. METHODS: We determined (1) if the supplemental ß-carotene could be micellised and absorbed by epithelial cells, using a Caco-2 cell model, (2) if the fat from the test meal was sufficiently bioavailable to facilitate ß-carotene bioavailability, (3) the extent to which the ß-carotene could have been metabolised and converted to retinoic acid/retinol and (4) the effect of the test meal matrix on the ß-carotene bioaccessibility (in vitro digestion) and Caco-2 cellular uptake. RESULTS: We found that (1) The supplemental ß-carotene could be micellised and absorbed by epithelial cells, (2) the postprandial plasma triacylglycerol response was substantial (approximately 75-100 mg dL-1 over 10 h), indicating sufficient lipid bioavailability to ensure ß-carotene absorption, (3) the high fat content of the meal (approximately 18 g) could have resulted in increased ß-carotene metabolism, (4) ß-carotene bioaccessibility from the dairy-based test meal was sixfold lower (p < 0.05) than when digested with olive oil. CONCLUSION: The low ß-carotene bioavailability is probably due to a combination of the metabolism of ß-carotene to retinol by BCMO1 and interactions of ß-carotene with the food matrix, decreasing the bioaccessibility. TRAIL REGISTRATION: The human trail was retrospectively registered (ClinicalTrail.gov ID: NCT05840848).


Assuntos
Disponibilidade Biológica , Estudos Cross-Over , Laticínios , Período Pós-Prandial , beta Caroteno , Humanos , beta Caroteno/farmacocinética , beta Caroteno/sangue , beta Caroteno/administração & dosagem , Células CACO-2 , Método Duplo-Cego , Período Pós-Prandial/fisiologia , Masculino , Feminino , Adulto , Triglicerídeos/sangue , Suplementos Nutricionais , Refeições , Gorduras na Dieta/administração & dosagem , Gorduras na Dieta/farmacocinética , Zinco/farmacocinética , Zinco/administração & dosagem , Vitamina A/farmacocinética , Vitamina A/sangue , Vitamina A/administração & dosagem , Vitamina A/metabolismo , Dieta Hiperlipídica , Absorção Intestinal/fisiologia , Ferro/farmacocinética , Ferro/metabolismo , Ferro/sangue , Digestão/fisiologia , Pessoa de Meia-Idade
3.
Molecules ; 29(3)2024 Feb 02.
Artigo em Inglês | MEDLINE | ID: mdl-38338434

RESUMO

2-ethylhexanol, an oxo alcohol competitively priced on the global market, has not been explored intensively as a raw material for surfactants, due to its weak hydrophobic character. However, its sequenced propoxylation and ethoxylation yield an innovative amphiphilic structure, which exhibits unique interfacial activity. The paper presents the differences in the fractional composition of innovative surfactants derived from 2-EH alcohol prepared using alkali and dimetalcyanide catalysts, as well as examples of excellent adsorption and interfacial properties of the latter. The adsorption behavior of the synthesized compounds was explored using equilibrium surface tension (the du Noüy ring method), dynamic surface tension (the maximum gas bubble pressure method) and static/dynamic contact angle (the sessile drop method). The results from the adsorption tests conducted at the air/aqueous surfactant solution interface underwent comprehensive qualitative and quantitative analyses. Moreover, based on the experimentally obtained dynamic surface tension isotherms and the developed algorithm, the diffusion coefficients for these preparations were estimated, and it was shown that the diffusivity of these surfactants is higher compared to the commercial formulations. The study's outcomes in the testing of wettability indicate that new synthesized nonionic and anionic surfactants constitute an interesting group of amphiphiles with a wide application potential as effective wetting agents, especially in relation to the polymer surface. It should therefore be emphasized that the innovative surfactants described in this article, derived from 2-EH alcohol and prepared using dimetalcyanide catalysts, can successfully compete with conventional preparations such as ABS (Dodecylbenzenesulfonic Acid) or AES (Alcohol Ethoxysulphate) acid salts.

4.
BMC Genomics ; 24(1): 579, 2023 Sep 28.
Artigo em Inglês | MEDLINE | ID: mdl-37770878

RESUMO

BACKGROUND: The characteristic pink-reddish color in the salmonids fillet is an important, appealing quality trait for consumers and producers. The color results from diet supplementation with carotenoids, which accounts for up to 20-30% of the feed cost. Pigment retention in the muscle is a highly variable phenotype. In this study, we aimed to understand the molecular basis for the variation in fillet color when rainbow trout (Oncorhynchus mykiss) fish families were fed an Astaxanthin-supplemented diet. We used RNA-Seq to study the transcriptome profile in the pyloric caecum, liver, and muscle from fish families with pink-reddish fillet coloration (red) versus those with lighter pale coloration (white). RESULTS: More DEGs were identified in the muscle (5,148) and liver (3,180) than in the pyloric caecum (272). Genes involved in lipid/carotenoid metabolism and transport, ribosomal activities, mitochondrial functions, and stress homeostasis were uniquely enriched in the muscle and liver. For instance, the two beta carotene genes (BCO1 and BCO2) were significantly under-represented in the muscle of the red fillet group favoring more carotenoid retention. Enriched genes in the pyloric caecum were involved in intestinal absorption and transport of carotenoids and lipids. In addition, the analysis revealed the modulation of several genes with immune functions in the pyloric caecum, liver, and muscle. CONCLUSION: The results from this study deepen our understanding of carotenoid dynamics in rainbow trout and can guide us on strategies to improve Astaxanthin retention in the rainbow trout fillet.


Assuntos
Oncorhynchus mykiss , Humanos , Animais , Oncorhynchus mykiss/metabolismo , RNA-Seq , Carotenoides/metabolismo , Músculos/metabolismo , Fígado/metabolismo
5.
Proc Natl Acad Sci U S A ; 117(9): 4518-4526, 2020 03 03.
Artigo em Inglês | MEDLINE | ID: mdl-32071209

RESUMO

The inception and development of supramolecular chemistry have provided a vast library of supramolecular structures and materials for improved practice of medicine. In the context of therapeutic delivery, while supramolecular nanostructures offer a wide variety of morphologies as drug carriers for optimized targeting and controlled release, concerns are often raised as to how their morphological stability and structural integrity impact their in vivo performance. After intravenous (i.v.) administration, the intrinsic reversible and dynamic feature of supramolecular assemblies may lead them to dissociate upon plasma dilution to a concentration below their critical micellization concentration (CMC). As such, CMC represents an important characteristic for supramolecular biomaterials design, but its pharmaceutical role remains elusive. Here, we report the design of a series of self-assembling prodrugs (SAPDs) that spontaneously associate in aqueous solution into supramolecular polymers (SPs) with varying CMCs. Two hydrophobic camptothecin (CPT) molecules were conjugated onto oligoethylene-glycol (OEG)-decorated segments with various OEG repeat numbers (2, 4, 6, 8). Our studies show that the lower the CMC, the lower the maximum tolerated dose (MTD) in rodents. When administrated at the same dosage of 10 mg/kg (CPT equivalent), SAPD 1, the one with the lowest CMC, shows the best efficacy in tumor suppression. These observations can be explained by the circulation and dissociation of SAPD SPs and the difference in molecular and supramolecular distribution between excretion and organ uptake. We believe these findings offer important insight into the role of supramolecular stability in determining their therapeutic index and in vivo efficacy.


Assuntos
Portadores de Fármacos/química , Micelas , Pró-Fármacos/administração & dosagem , Animais , Antineoplásicos/administração & dosagem , Antineoplásicos/farmacocinética , Antineoplásicos/uso terapêutico , Camptotecina/administração & dosagem , Camptotecina/farmacocinética , Camptotecina/uso terapêutico , Portadores de Fármacos/toxicidade , Feminino , Células HT29 , Humanos , Dose Máxima Tolerável , Camundongos , Camundongos Nus , Polietilenoglicóis/química , Polimerização , Pró-Fármacos/farmacocinética , Pró-Fármacos/uso terapêutico , Ratos , Ratos Sprague-Dawley
6.
Int J Mol Sci ; 24(6)2023 Mar 11.
Artigo em Inglês | MEDLINE | ID: mdl-36982468

RESUMO

The need to protect human and environmental health and avoid the widespread use of substances obtained from nonrenewable sources is steering research toward the discovery and development of new molecules characterized by high biocompatibility and biodegradability. Due to their very widespread use, a class of substances for which this need is particularly urgent is that of surfactants. In this respect, an attractive and promising alternative to commonly used synthetic surfactants is represented by so-called biosurfactants, amphiphiles naturally derived from microorganisms. One of the best-known families of biosurfactants is that of rhamnolipids, which are glycolipids with a headgroup formed by one or two rhamnose units. Great scientific and technological effort has been devoted to optimization of their production processes, as well as their physicochemical characterization. However, a conclusive structure-function relationship is far from being defined. In this review, we aim to move a step forward in this direction, by presenting a comprehensive and unified discussion of physicochemical properties of rhamnolipids as a function of solution conditions and rhamnolipid structure. We also discuss still unresolved issues that deserve further investigation in the future, to allow the replacement of conventional surfactants with rhamnolipids.


Assuntos
Glicolipídeos , Tensoativos , Humanos , Glicolipídeos/química , Tensoativos/química , Tecnologia , Água
7.
Molecules ; 28(7)2023 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-37049878

RESUMO

The poor solubility of berberine (Ber) in water limits its practical use. Its solubility can be increased, among other ways, by the addition of surfactants. Of the surfactants, Kolliphor® ELP (ELP) and Kolliphor® RH 40 (RH40) can be very useful in this respect. The increase of Ber's solubility in water in the presence of ELP and RH40 should be reflected in the composition of the surface layers at the water-air interface and the micelles. The determined composition is reflected in the Gibbs energy of interactions of berberine with ELP and RH40 through the water phase and the standard Gibbs free energy, enthalpy, and entropy of adsorption and micellization. These energies were determined from the equations proposed by us, based on the Gibbs surface excess concentration of the Ber mixture with ELP and RH40, the activity of these compounds in the surface layer at the water-air interface and in the micelles obtained by the Hua and Rosen method, and the contributions of Ber, ELP, and RH40 to the reduction in the water surface tension. For this determination, the measurements of the surface tension of the aqueous solution of the Ber mixture with ELP or RH40 and that of the Ber mixture with these two surfactants, as well as the density and conductivity were performed. Moreover, the fluorescence emission spectra for the Ber + surfactant mixtures were recorded.

8.
J Fluoresc ; 32(4): 1557-1563, 2022 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-35553318

RESUMO

The present work describes the synthesis and characterization of pyrene derivatives, N-(1-Pyrenoylmethyl) pyridinium bromide (PM-PB) and N-(1-Pyrenoylmethyl)-N,N,N-triethylammonium bromide (PM-TAB). The photophysical behavior of these molecules has been studied in various protic and aprotic solvents. Using steady state fluorescence intensity, fluorescence anisotropy and dynamic fluorescence lifetime studies, the sensitivity of these molecules towards the micellization process of bile salts has been monitored. These derivatives have been effectively used in estimating critical micellar concentration (CMC) of bile salt, sodium deoxycholate (NaDC).


Assuntos
Ácidos e Sais Biliares , Sais , Brometos , Ácido Desoxicólico , Micelas
9.
Molecules ; 27(21)2022 Nov 04.
Artigo em Inglês | MEDLINE | ID: mdl-36364390

RESUMO

The present work deals with the micellar state study of sodium cholate and sodium deoxycholate in the aqueous solution of a bioactive peptide, namely glycyl dipeptide, having different concentrations through conductivity and fluorescence methods at different temperatures. The data obtained from conductivity is plotted against the concentration of Bile salts, and CMC (critical micelle concentration) values are calculated. The results realized have been elucidated with reference to Glycyl dipeptide-bile salts hydrophobic/hydrophilic interactions existing in solution. In addition, the CMC values converted to mole fraction (Xcmc) values have been used to evaluate the standard thermodynamic factors of micellization viz., enthalpy H, free energy ΔGm0, and entropy (ΔSm0) which extract information regarding thermodynamic feasibility of micellar state, energy alteration, and the assorted interactions established in the existing (bile salts-water-glycyl dipeptide) system. Furthermore, the pyrene fluorescence spectrum has also been utilized to study the change in micro polarity induced by the interactions of bile salts with glycyl dipeptide and the aggregation action of bile salts. The decrease in modification in the ratio of intensities of first and third peaks i.e., (I1/I3) for the pyrene molecules in aqueous bile salts solution by the addition of dipeptide, demonstrates that the micelle polarity is affected by glycyl dipeptide. This ratio has also been utilized to determine CMC values for the studied system, and the results have been found to be in good correlation with observations made in conductivity studies.


Assuntos
Ácidos e Sais Biliares , Micelas , Corantes Fluorescentes , Água/química , Peptídeos , Pirenos , Dipeptídeos
10.
Molecules ; 27(23)2022 Dec 02.
Artigo em Inglês | MEDLINE | ID: mdl-36500588

RESUMO

The studies on the behavior of Auramine O (AuO) at the water-air interface and in the bulk phase of the aqueous solution of Kolliphor® ELP (ELP) and Kolliphor® RH 40 (RH40) and their mixture were based on the results obtained from the measurements of the contact angle of water, formamide and diiodomethane on the polytetrafluoroethylene covered by the AuO layer, the surface tension of the aqueous solution of AuO, AuO + ELP, AuO + RH40, AuO + ELP + RH40, density and fluorescence intensity. Based on the obtained results, it was possible to determine components and parameters of the AuO surface tension, concentration and composition of the mixed monolayer, including AuO, ELP and RH40, as well as that of the mixed micelles, and to determine the Gibbs standard free energy of adsorption, micellization and AuO solubilization. The obtained results also showed that surface tension isotherms of the studied solutions can be described by the Szyszkowski equation and the exponential function of the second order and predicted by the Fainerman and Miller equation. In addition, the mixed surface layer composition can be predicted based on the contribution of the components of this layer to the water surface tension reduction.


Assuntos
Benzofenoneídio , Água , Soluções , Tensão Superficial , Micelas
11.
Molecules ; 27(11)2022 Jun 03.
Artigo em Inglês | MEDLINE | ID: mdl-35684536

RESUMO

The surface tension of aqueous solutions of Triton X-165 with rhamnolipid or surfactin mixtures was measured. The obtained results were applied for the determination of the concentration and composition of the Triton X-165 and biosurfactants mixture at the water-air interface as well as the contribution of the particular component of the mixtures to water surface tension reduction and the mutual influence of these components on the critical micelle concentration. The determination of these quantities was based on both the commonly used concepts and a new one proposed by us, which assumes that the composition of the mixed monolayer at the water-air interface depends directly on the pressure of the monolayer of the single mixture component and allows us to determine the surface concentration of each mixture component independently of surface tension isotherms shape. Taking into account the composition of the mixed monolayer at the water-air interface, the standard Gibbs adsorption free energy was considered. The obtained results allow us to state that the concentration of both mixture components corresponding to their saturated monolayer and the surface tension of their aqueous solution can be predicted using the surfactants' single monolayer pressure and their mole fraction in the mixed monolayer determined in the proposed way.


Assuntos
Água , Adsorção , Derivados de Benzeno , Glicolipídeos/química , Polietilenoglicóis/química , Tensão Superficial , Termodinâmica
12.
Molecules ; 27(9)2022 Apr 29.
Artigo em Inglês | MEDLINE | ID: mdl-35566192

RESUMO

Due to the increasing practical use of mixtures of flavonoids with nonionic surfactants the presented studies were based on the measurements of surface tension and conductivity of aqueous solution of the quercetin (Q) and rutin (Ru) in the mixtures with Triton X-114 (TX114) and Tween 80 (T80) as well as the contact angle of model liquids on the PTFE surface covered by the quercetin and rutin layers. Based on the obtained results components and parameters of the quercetin and rutin surface tension were determined and the mutual influence of Q and Ru in the mixtures with TX114 and T80 on their adsorption and volumetric properties were considered. It was found, among others, that based on the surface tension isotherms of the aqueous solution of the single flavonoid and nonionic surfactant, the surface tension isotherms of the aqueous solution of their mixture, the composition of the mixed monolayer at the water-air interface as well as the CMC of flavonoid + nonionic surfactant mixture can be predicted. The standard Gibbs energy, enthalpy and entropy of the adsorption and aggregation of the studied mixtures were also found, showing the mechanism of the adsorption and aggregation processes of the flavonoid + nonionic surfactant mixture.


Assuntos
Flavonoides , Tensoativos , Adsorção , Polissorbatos , Quercetina , Rutina , Temperatura , Água
13.
Compr Rev Food Sci Food Saf ; 21(5): 3963-4001, 2022 09.
Artigo em Inglês | MEDLINE | ID: mdl-35912644

RESUMO

Increasing awareness of the health benefits of specific constituents in fruits, vegetables, cereals, and other whole foods has sparked a broader interest in the potential health benefits of nutraceuticals. Many nutraceuticals are hydrophobic substances, which means they must be encapsulated in colloidal delivery systems. Oil-in-water emulsions are one of the most widely used delivery systems for improving the bioavailability and bioactivity of these nutraceuticals. The composition and structure of emulsions can be designed to improve the water dispersibility, physicochemical stability, and bioavailability of the encapsulated nutraceuticals. The nature of the emulsion used influences the interfacial area and properties of the nutraceutical-loaded oil droplets in the gastrointestinal tract, which influences their digestion, as well as the bioaccessibility, metabolism, and absorption of the nutraceuticals. In this article, we review recent in vitro and in vivo studies on the utilization of emulsions to improve the bioavailability of nutraceuticals. The findings from this review should facilitate the design of more efficacious nutraceutical-loaded emulsions with increased bioactivity.


Assuntos
Suplementos Nutricionais , Trato Gastrointestinal , Disponibilidade Biológica , Emulsões/química , Trato Gastrointestinal/metabolismo , Água
14.
J Comput Chem ; 42(31): 2221-2232, 2021 12 05.
Artigo em Inglês | MEDLINE | ID: mdl-34561897

RESUMO

A new method to extract the free energy of aggregation versus aggregate size from molecular simulation data is proposed and applied to a united atom model of the zwitterionic surfactant dodecyl phosphocholine in water. This system's slow dissociation rate and low critical micelle concentration (CMC of approximately 1-2 mM) make extraction of cluster free energies directly from simulation results using the "partition-enabled analysis of cluster histogram" (PEACH) method impractical. The new approach applies PEACH to a model with weakened attractions between aggregants, which allows sampling of a continuous range of cluster sizes, then recovers the free energy of aggregation under the original fully-attractive force field using the BAR free energy difference method. PEACH-BAR results are compared with free energy differences calculated via umbrella sampling, and are used to make predictions of CMC, average cluster size, and SAXS scattering profiles that are in fair agreement with experiment.

15.
Int J Vitam Nutr Res ; 91(5-6): 439-450, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34134516

RESUMO

Vegetables rich in vitamin K consumption could prevent bleeding and maintain bone status. The aims of the present work were to investigate i) the effect of household cooking (i.e., boiling for 5 min at 100 °C in distilled water and stir-frying for 3 min at 180 °C in hot canola oil) on phylloquinone bioaccessibility of five rich phylloquinone leafy vegetables, namely Water spinach (Ipomoea aquatic Forssk), Amaranth (Amaranthus blitum subsp. oleraceus L.), Chinese broccoli (Brassica alboglabra), Pak choi (Brassica rapa L.) and Drumstick (Moringa oleifera Lam.), and ii) the structural changes of these leaves before and after in vitro gastro-intestinal digestion. All the experiments were realized in triplicate for each vegetable. The amounts of phylloquinone in leafy vegetables were noticeable in almost all species and ranged from 94 to 182 µg/100 g DM. Their cell wall polysaccharide contents greatly varied from 4.3 to 8.4 g for 100 g. The content in bioaccessible phylloquinone was low in raw leaves (<25 µg/100 g DM) as well as its bioaccessibility (<15%). Leaf pectin content impaired phylloquinone bioaccessibility using principal component analysis. Boiling and stir-frying significantly improved the bioaccessibility of phylloquinone in leaves by a factor of three to twelve and two to seven respectively (p<0.05). These variations were associated with changes in leaf structure. Palisade and spongy cells appeared ruptured and disorganized after stir-frying. Given the estimated bioaccessibility of phylloquinones, the consumption of 500 g of cooked wet leaves per day would cover phylloquinone needs of an individual adult average body weight.


Assuntos
Verduras , Vitamina K 1 , Disponibilidade Biológica , Parede Celular , Culinária , Digestão
16.
Entropy (Basel) ; 23(2)2021 02 18.
Artigo em Inglês | MEDLINE | ID: mdl-33670582

RESUMO

Isothermal titration calorimetry is frequently employed to determine the critical micelle concentration and the micellization enthalpy of surfactants in terms of geometrical characteristics of the titration curves. Previously we have shown theoretically that even for an infinitesimal injection, the heat per titrant mol depends on the stock solution concentration. In this work, we explore experimentally the influence of the stock solution concentration on the geometrical characteristics of the titration curve and its effect in determining the critical micelle concentration and the micellization enthalpy of surfactants. The systematic study of this phenomenology involves a great number of measurements at different temperatures with several repetitions carried out using a robotic calorimeter. As surfactant hexadecyltrimethylamonium bromide was used. The magnitude and shape of the heat titration depend on the stock solution concentration. As a consequence, the inflexion-point, break-point, and step-height decrease until a limiting value. A qualitative analysis suggests that the limiting value depends only on substance. This work shows that graphical methods could not be suitable for the calculation of the critical micelle concentration and micellization enthalpy because the magnitude and shape of the titration curve depend on the stock solution concentration. Micellar properties should be calculated by the application of theoretical models as in the ligand-binding studies.

17.
Molecules ; 25(23)2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-33271846

RESUMO

The trisiloxane polyether surfactant (3-[3-(hydroxy)(polyethoxy)propyl]-1,1,1,3,5,5,5 -heptamethyltrisiloxane) (TS-EO12) was successfully synthesized by a hydrosilylation reaction in the presence of Karstedt catalyst. The structural analysis of the surfactant was done by 1H-NMR, 13C-NMR, 29Si-NMR and FT-IR analysis. In addition the thermal stability of TS-EO12 was studied by the thermogravimetric measurements. On the one hand the surface properties of TS-EO12 at the water-air interface were investigated by surfactant aqueous solutions surface tension measurements carried out at 293 K, 303 K and 313 K, and on the other the aggregation properties were analyzed based on the solubilization properties of TS-EO12 aggregates at different temperatures. On the basis of the obtained thermodynamic parameters of adsorption and micellization of studied surfactant the temperature impact on its surface and volume properties were deduced. It was proved that the tendency of the studied surfactant molecules to adsorb at the water-air interface and to form micelles weakens with decreasing temperature. It was also concluded that the structure of the adsorption layer changes with temperature. Optical microscopy measurements were used for the TS-EO12 micelle morphology determination.


Assuntos
Siloxanas/química , Siloxanas/metabolismo , Tensoativos/química , Tensoativos/metabolismo , Temperatura , Termodinâmica , Adsorção , Propriedades de Superfície , Tensão Superficial
18.
Vopr Pitan ; 89(5): 101-109, 2020.
Artigo em Russo | MEDLINE | ID: mdl-33211922

RESUMO

Emulsion fat products due to the presence of the aqueous phase are more prone to oxidative damage than pure oils and fats, which requires the use of antioxidants. Based on a social request for the use of natural antioxidants in the food industry, tocopherols, their mixtures, as well as ascorbic acid are widespread. However, most natural antioxidants (vitamins, plant extracts) have lower antioxidant activity in fats than synthetic ones and require more incorporation into the product, which can negatively affect its organoleptic properties and the cost of the finished emulsion fat product. One way to solve this problem is to use new micellized forms of antioxidants. The micellization of various types of waterand fat-soluble antioxidants can increase their specific activity, which is apparently associated with an increase in the relative interaction surface in the product. The development of emulsion fat products using new technological forms of natural antioxidants in order to increase their shelf life is relevant and practically significant for the food industry. The aim of the study was a comparative assessment of the effectiveness of natural antioxidants in native and micellized forms in the margarine formulation. Material and methods. Antioxidants (tocopherols, rosemary extract and ascorbic acid) in the native and micellized forms were selected as objects of the study for their introduction into margarine with a mass fraction of fat of 82%. Peroxide Value and p-anizidin Value were determined in dynamics during storage of margarine in its fatty phase. Results. Experimental data have been obtained on the action of the studied antioxidants in various technological forms on the formation of primary and secondary oxidation products in margarine during storage at the temperature 23±3 °Ð¡. It was determined that the introduction of micellized forms of various antioxidants into margarine at a concentration of 0.015-0.03% most effectively slows down the formation of oxidation products compared to using their native forms in an amount equivalent to the active substances. Conclusion. It has been experimentally established that the use of micellized forms of tocopherols, ascorbic acid and rosemary extract allows more efficient creation of emulsion fat products with an extended shelf life.


Assuntos
Antioxidantes/química , Gorduras na Dieta , Conservação de Alimentos , Extratos Vegetais/química , Óleos de Plantas/química , Tocoferóis/química , Emulsões , Micelas
19.
Ecotoxicol Environ Saf ; 186: 109784, 2019 Dec 30.
Artigo em Inglês | MEDLINE | ID: mdl-31634657

RESUMO

Surface-active ionic liquids (SAILs) belonging to the series of N-alkylmethylimidazolium halides [C8mimX] (X = Br, Cl, and BF4) and [CnmimBr] (n = 10, 12, 14, and 16) were employed to understand the influence of hydrophobicity of alkyl chain length and the chaotropicity of counter-ions of SAILs on the micellization, antimicrobial action and cytotoxicity properties. The micellization phenomenon of SAILs in an aqueous environment was examined employing tensiometry and steady-state fluorescence spectrophotometry. The corresponding interfacial parameters viz., critical micelle concentration (CMC), effectiveness (γCMC), surface pressure (ПCMC), maximum surface excess concentration (Гmax), and the minimum area engaged per molecule (Amin) at the air-water interface were evaluated at 303.15 K. These experimental findings were monitored and geometrically optimized theoretically using Gaussian software to highlight the recent advances in this field of theoretical calculations for putative structure. The simulation descriptors correlated the micellization behavior as a function of hydrophobicity which may contribute to obtaining awareness on their ecological behavior and fate. In addition, the biological screening of all the examined SAILs was undertaken with a combined experimental and theoretical (optimized) method against bacteria and fungus. Results revealed that SAILs with the alkyl chain-length greater than C8- act as a fair antimicrobial agent against the selected microbial strain which is attributed to the enhanced degree of SAILs hydrophobicity. The cytotoxicity of these imidazolium-based SAILs was also assessed on the cervical human cell line (HeLa) using the MTT cell viability assay and the data thus obtained were subjected to statistical analysis.


Assuntos
Líquidos Iônicos/química , Tensoativos/química , Anti-Infecciosos/química , Anti-Infecciosos/farmacologia , Sobrevivência Celular/efeitos dos fármacos , Células HeLa , Humanos , Interações Hidrofóbicas e Hidrofílicas , Imidazóis/química , Líquidos Iônicos/farmacologia , Micelas , Tensoativos/farmacologia , Água/química
20.
Molecules ; 24(7)2019 Mar 27.
Artigo em Inglês | MEDLINE | ID: mdl-30934775

RESUMO

Micellar systems consisting of a surfactant and an additive such as an organic salt or an acid usually self-organize as a series of worm-like micelles that ultimately form a micellar network. The nature of the additive influences micellar structure and properties such as aggregate lifetime. For ionic surfactants such as sodium dodecyl sulfate (SDS), CMC decreases with increasing temperature to a minimum in the low-temperature region beyond which it exhibits the opposite trend. The presence of additives in a surfactant micellar system also modifies monomer interactions in aggregates, thereby altering CMC and conductance. Because the standard deviation of ß was always lower than 10%, its slight decrease with increasing temperature was not significant. However, the absolute value of Gibbs free enthalpy, a thermodynamic potential that can be used to calculate the maximum of reversible work, increased with increasing temperature and caffeic acid concentration. Micellization in the presence of caffeic acid was an endothermic process, which was entropically controlled. The enthalpy and enthropy positive values resulted from melting of "icebergs" or "flickering clusters" around the surfactant, leading to increased packing of hydrocarbon chains within the micellar core in a non-random manner. This can be possibly explained by caffeic acid governing the 3D matrix structure of water around the micellar aggregates. The fact that both enthalpy and entropy were positive testifies to the importance of hydrophobic interactions as a major driving force for micellization. Micellar systems allow the service life of some products to be extended without the need to increase the amounts of post-harvest storage preservatives used. If a surfactant is not an allowed ingredient or food additive, carefully washing it off before the product is consumed can avoid any associated risks. In this work, we examined the influence of temperature and SDS concentration on the properties of SDS⁻caffeic acid micellar systems. Micellar properties can be modified with various additives to develop new uses for micelles. This allows smaller amounts of additives to be used without detracting from their benefits.


Assuntos
Ácidos Cafeicos/química , Micelas , Dodecilsulfato de Sódio/química , Coloides/química , Aditivos Alimentares/química , Interações Hidrofóbicas e Hidrofílicas , Estrutura Molecular , Tensoativos/química , Temperatura , Termodinâmica
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