Liquid-liquid Dispersions Research Articles

Avocado seed extract encapsulated in zein nanoparticles as a functional ingredient

Nano-delivery of natural compounds has gained increasing attention in the food and pharmaceutical ingredients industry. Avocado seed was extracted by a total lipid extraction and the presence of two acetogenin compounds was confirmed by the high-performance liquid chromatography (LC-MS) technique. Then, the avocado seed extract (Avo) was encapsulated into zein nanoparticles by liquid-liquid dispersion and the formation of zein nanoparticles loaded with avocado seed extract (Avo-ZNPs) was confirmed by FTIR analysis. The Avo-ZNPs with various Avo contents showed an average size ranging from 166.9 ± 14.1 to 305.2 ± 16.2 nm with 0.19–0.26 of polydispersity index (PDI), and a surface charge range was −59.5 ± 8.1 to −32.9 ± 0.4 mV, as measured by dynamic light scattering (DLS). The entrapment efficiency (EE) values were up to 82 % and the highest loading capacity (LoC) was 14.8 %. The Avo-ZNPs were found to have significantly higher antioxidant potency compared to the control, as measured by DPPH and FRAP assays. Moreover, the zein nanoparticles were also biocompatible with the acute myeloid leukemia (AML) cell lines, and encapsulated avocado extract induced leukemia cell death. Thus, zein nanoparticles could be a promising delivery system for natural avocado seed extract to be used in the medical and food industries.

Factors influencing the properties of zein nanoparticles encapsulated with fragrances prepared by liquid-liquid dispersion

Factors influencing the properties of zein nanoparticles encapsulated with fragrances prepared by liquid-liquid dispersion

Rational Design of Liquid-Liquid Microdispersion Droplet Microreactors for the Controllable Synthesis of Highly Uniform and Monodispersed Dextran Microspheres.

Hydrogel microspheres are biocompatible materials widely used in biological and medical fields. Emulsification and stirring are the commonly used methods to prepare hydrogels. However, the size distribution is considerably wide, the monodispersity and the mechanical intensity are poor, and the stable operation conditions are comparatively narrow to meet some sophisticated applications. In this paper, a T-shaped stepwise microchannel combined with a simple side microchannel structure is developed to explore the liquid-liquid dispersion mechanism, interfacial evolution behavior, satellite droplet formation mechanism and separation, and the eventual successful synthesis of dextran hydrogel microspheres. The effect of the operation parameters on droplet and microsphere size is comprehensively studied. The flow pattern and the stable operation condition range are given, and mathematical prediction models are developed under three different flow regimes for droplet size prediction. Based on the stable operating conditions, a microdroplet-based method combined with UV light curing is developed to synthesize the dextran hydrogel microsphere. The highly uniform and monodispersed dextran microspheres with good mechanical intensity are synthesized in the developed microfluidic platform. The size of the microsphere could be tuned from 50 to 300 μm with a capillary number in the range of 0.006-0.742. This work not only provides a facile method for functional polymeric microsphere preparation but also offers important design guidelines for the development of a robust microreactor.

CFD-PBM coupled modeling of the liquid-liquid dispersion characteristics and structure optimization for Kenics static mixer

Kenics static mixers (KSM) are extensively used in industrial mixing–reaction processes by virtue of high mixing efficiency, low power homogenization and easy continuous production. Resolving liquid droplet size and its distribution and thus revealing the dispersion characteristics are of great significance for structural optimization and process intensification in the KSM. In this work, a computational fluid dynamics–population balance model (CFD–PBM) coupled method is employed to systematically investigate the effects of operating conditions and structural parameters of KSM on droplet size and its distribution, to further reveal the liquid–liquid dispersion characteristics. Results indicate that higher Reynolds numbers or higher dispersed phase volume fractions increase energy dissipation, reducing Sauter mean diameter (SMD) of dispersed phase droplets and with a shift in droplet size distribution (DSD) towards smaller size. Smaller aspect ratios, greater blade twist and assembly angles amplify shear rate, leading to smaller droplet size and a narrower DSD in the smaller range. The degree of impact exerted by the aspect ratio is notably greater. Notably, mixing elements with different spin enhance shear and stretching efficiency. Compared to the same spin, SMD becomes 3.7–5.8 times smaller in the smaller size range with a significantly narrower distribution. Taking into account the pressure drop and efficiency in a comprehensive manner, optimized structural parameters for the mixing element encompass an aspect ratio of 1–1.5, a blade twist angle of 180°, an assembly angle of 90°, and interlaced assembly of adjacent elements with different spin. This work provides vital theoretical underpinning and future reference for enhancing KSM performance.

Liquid-Liquid Dispersion Performance Prediction and Uncertainty Quantification Using Recurrent Neural Networks.

We demonstrate the application of a recurrent neural network (RNN) to perform multistep and multivariate time-series performance predictions for stirred and static mixers as exemplars of complex multiphase systems. We employ two network architectures in this study, fitted with either long short-term memory and gated recurrent unit cells, which are trained on high-fidelity, three-dimensional, computational fluid dynamics simulations of the mixer performance, in the presence and absence of surfactants, in terms of drop size distributions and interfacial areas as a function of system parameters; these include physicochemical properties, mixer geometry, and operating conditions. Our results demonstrate that while it is possible to train RNNs with a single fully connected layer more efficiently than with an encoder-decoder structure, the latter is shown to be more capable of learning long-term dynamics underlying dispersion metrics. Details of the methodology are presented, which include data preprocessing, RNN model exploration, and methods for model performance visualization; an ensemble-based procedure is also introduced to provide a measure of the model uncertainty. The workflow is designed to be generic and can be deployed to make predictions in other industrial applications with similar time-series data.

CFD-aided contraction-expansion static mixer design for oil-in-water emulsification

Abstract Contraction-expansion (CE) static mixers can enable solid-liquid and liquid-liquid dispersion with low energy dissipation, low risk of obstruction, and without moving parts. In this work, the influence of CE elements of different geometries on the imposed turbulence of a flowing liquid has been assessed by a two-dimensional computational fluid dynamic (2D-CFD) simulation. The effect of CE on the dispersion of droplets of an immiscible liquid has also been analysed from simulations, using the volume of fluid (VOF) approach. Direct numerical simulation (DNS) performed by the open-source Gerris Flow Solver software was used to get the velocity fields and turbulence characteristics. Different ratios of CE diameters and lengths were analysed for liquid Reynolds numbers from 500 to 20,000. From simulations, the CE geometry that maximised the average root mean square velocity, as an indicator of turbulence, was determined for different liquid flow rates. It was found that the average RMS had a maximum for a wide range of liquid flow rates when the CE diameter ratio was between 0.55 and 0.59 and the length ratio was between 0.2 and 0.3. Then, a device with seven CE elements with geometrical features within this range was built and used for preparing an oil-in-water emulsion. The test system contained water and sunflower oil (5 % v/v) with the further addition of TritonX100 (0.5 % in volume of the solution) as surfactant. The stability of the emulsions was assessed by measuring the time evolution of turbidity (absorbance at 860 nm), to get the initial separation velocities. The emulsions prepared using the CE device showed initial phase separation rates lower than the one obtained in a stirred flask, evidencing the feasibility of using CE static mixers for preparing emulsions with relatively low energy consumption. Moreover, the emulsions obtained with the CE device, although dependent on the flow rate, showed similar features when obtained with 10, 100 and 250 passes through the CE static mixer.

Liquid-liquid and gas-liquid dispersions in electrochemistry: concepts, applications and perspectives.

Electrochemistry plays a pivotal role in a vast number of domains spanning from sensing and manufacturing to energy storage, environmental conservation, and healthcare. Electrochemical applications encompassing gaseous or organic substrates encounter shortcomings ascribed to high mass transfer/internal resistances and low solubility in aqueous electrolytes, resulting in high overpotentials. In practice, strong acids and expensive organic electrolytes are required to promote charge transfer in electrochemical cells, resulting in a high carbon footprint. Liquid-liquid (L-L) and gas-liquid (G-L) dispersions involve the dispersion of a nano/micro gas or liquid into a continuous liquid phase such as micelles, (macro)emulsions, microemulsions, and microfoams stabilised by surface-active agents such as surfactants and colloidal particles. These dispersions hold promise in addressing the drawbacks of electrochemical reactions by fostering the interfacial surface area between immiscible reagents and mass transfer of electroactive organic and gas reactants and products from/to the bulk to/from the electrode surface. This tutorial review provides a taxonomy of liquid-liquid and gas-liquid dispersions for applications in electrochemistry, with emphasis on their assets and challenges in industrially relevant reactions for fine chemistry and depollution.

GC-MS analysis and cytotoxic activity of the n-hexane fraction from Curcuma sahuynhensis Škornick. & N.S.Lý leaves collected in Vietnam

Curcuma sahuynhensis Škornick. & N.S.Lý is an endemic plant in Vietnam that has been used by the Sa Huynh people as a spice and medicine to cure illnesses linked to digestive disorders. Very little information is available so far about the chemical composition and biological effects of C. sahuynhensis. To find new pharmaceutical ingredients, the in vitro cytotoxic effect and the chemical profile of C. sahuynhensis leaf extract were investigated. In this study, the percolation method and liquid-liquid dispersion technique were used to extract dry sample powder. The chemical composition was detected by gas chromatography-mass spectrometry (GC-MS). The Sulforhodamine B and MTT methods were used to determine the cytotoxic activity. The chemical composition analysis showed that the leaf extract contained 14 components. The major components in the n-hexane extract were 6,10,14-trimethylpentadecan-2-one, phytol, 1-ethylbutyl hydroperoxide, isoborneol, 1-methylpentyl hydroperoxide, and neophytadiene. On human cancer cell lines, namely MFC-7, SK-LU-1, Hela, MKN-7, and HL-60, the leaf extract showed dose-dependent cytotoxic activity, with IC50 values ranging from 221.70±10.24 to 369.42±10.60 ?g/mL. The present study provides significant information on the chemical components and cytotoxic effects of the n-hexane extract from C. sahuynhensis leaves. The findings will continue to be crucial in future research on the evaluation of secondary metabolite compound analysis for cancer therapeutic effects.

Effect of surfactants and interfacial rheology on equilibrium drop size in turbulent liquid-liquid dispersions

Surfactants are often required to stabilize liquid-liquid dispersions produced by high shear mixers. Due to the high power input, drops are deformed rapidly in the dispersion zone so the dynamic interfacial properties governed by the surfactant adsorption rate can have a significant impact on the resulting drop size. The objective of this work is to develop a fundamental link between surfactant adsorption dynamics, interfacial properties, and turbulent emulsification processes. To ensure constant bulk surfactant concentration during dispersion, equilibrium drop size for dilute dispersions produced by a batch rotor-stator mixer were studied. Silicone oils of various viscosity were dispersed in aqueous nonionic surfactant solutions. Drop size distributions (DSD) were measured via a video microscopy/automated image analysis technique. Equilibrium interfacial tension was measured via a pendant drop technique, as a function of surfactant concentration. The dynamic surface tension was similarly measured. The data were fit to the Langmuir adsorption isotherm and the long-times approximation to the Ward – Tordai equation and the adsorption parameters and surfactant diffusivities so obtained were employed, with an estimate of the drop deformation timescale, to estimate the surface dilational modulus (Esd) or Marangoni stress acting on the drop’ surface due to interfacial tension gradients. Trends observed in the measured equilibrium mean drop size and DSD are explained in terms of the interfacial and rheological properties. Below the CMC, Esd peaks and the drop size increases with bulk surfactant concentration, despite a decrease in equilibrium interfacial tension. Above the CMC, Marangoni stresses are small but the presence of the surfactant still modifies the rheology of the interface, increasing the effective viscosity of the drops. A comprehensive set of mechanistic models for drop size in turbulent flows, based on Kolmogorov-Hinze theory, was developed and modified to partially account for the effect of surfactants via an appropriately defined effective viscosity. The approach allows integration of surfactant phenomena into widely accepted correlations for drop size in surfactant free systems.

Liquid–liquid dispersion system in a moving baffle OBC: a numerical and theoretical study

Liquid-liquid dispersion is prevalent in the chemical industries to create a larger interface between the phases that can intensify the chemical processes, such as liquid extractions and heterogeneous reactions. Oscillatory baffled columns (OBCs) have emerged as alternatives to conventional commercial columns in which external components apply an oscillating flow. A computational fluid dynamics (CFD) approach coupled with the factorial design of the experiment method was employed to study the effect of main geometrical and operational factors, including free baffle area (known as amplitude, and frequency along with their interactions on minimum droplet diameter (), maximum droplet diameter (), and Sauter mean diameter (). The ANOVA p-values showed that the interaction between frequency and all the other main factors was insignificant for all responses. In addition, did not have a significant impact on the in the system, and amplitude had the most substantial impact on all the responses (i.e., and ) among all the factors. It was found that the higher amplitude, higher frequency, and smaller resulted in smaller which can provide higher interfacial area, higher mass transfer, and higher reaction rate for the processes such as suspension polymerization and liquid-liquid extractions. In addition, the larger provided a narrower range of droplets ( which is of significance for polymerization processes. Mathematical models were also developed for and using regression analysis with a reasonable level of accuracy. For the first time, semi-theoretical models were proposed for and in an OBC by combining the models existing in the literature for and and a quasi-steady-state model for energy dissipation rate in an OBC. The proposed models can be used to predict the parameters mentioned above by having geometrical and operational parameters, which help design suitable OBCs for a desired liquid-liquid dispersion system. A visual assessment of the and the dispersed phase volume fraction was also accomplished, showing larger droplets tended to be closer to the wall. Besides, a very uniform dispersed phase volume fraction throughout the OBC indicated the suitability of the column for such processes.

Development of coating material by incorporating curcumin-loaded zein nanoparticles to maintain the quality of mango (Mangifera indica L. cv. Nam Dokmai)

Anthracnose caused by Colletotrichum gloeosporioides is a major postharvest disease that reduces the shelf life of mango ( Mangifera indica L. cv. Nam Dokmai), an indigenous crop of Thailand. Curcumin, a substance in turmeric, has antimicrobial activity, which is hypothesized to be enhanced in the form of nanoparticles. In this research, curcumin-loaded zein nanoparticles (CZNP) were synthesized using a liquid-liquid dispersion method and were incorporated into zein coating material. The effect against C. gloeosporioides was evaluated relative to curcumin and zein mixture solution (CZ) as a control. The results showed that the solution of free curcumin at 100 μg/ml (CZ100) was less effective compared to when curcumin was entrapped in zein nanoparticles at the same amount (CZNP100), which was more effective at inhibiting the mycelial growth of C. gloeosporioides . It was consistent with the study of disease severity when the curcumin in both forms was mixed in zein coating materials and applied to mangoes. The disease severities of inoculated mangoes treated with CZNP and CZ were significantly retarded (25.93% and 39.79%) compared to the uncoated mangoes (64.13%) after 9 days of storage. Subsequently, their effect also prolonged the postharvest quality of mangoes after 9-day storage in terms of delayed color change and loss of weight and firmness. These results indicated that functionalized curcumin-loaded zein nanoparticles added in a biodegradable zein coating significantly suppressed anthracnose disease severity in mango fruit, providing a promising strategy for disease control in mango fruit. • Zein nanoparticles enhanced the effectiveness of entrapped curcumin. • Zein coating added curcumin nanoforms inhibited C. gloeosporioides mycelia growth. • Zein coating resulted in alleviating the anthracnose disease in mangoes. • Curcumin nanoforms added in the coating prolonged mangoes from deterioration. • Both curcumin forms delayed color change, loss of weight and firmness of mangoes.

Liquid-liquid dispersion and flow characteristics in a miniaturized annular rotating device

Liquid-liquid microchemical processes suffer from the problems of small handling capacity and large pressure drops. In particular, process intensification is highly required for high phase ratios of the dispersion phase to the continuous phase and high- viscosity conditions. In this study, we reported a novel microdispersion device named miniaturized annular rotating device (m-ARD), which is a novel microdispersion device with a large handling capacity, small pressure drop, and relatively narrow droplet distribution, even at a low phase ratio of the continuous phase to the dispersion phase and under high-viscosity conditions. Various parameters were studied to determine the dispersion of the generated droplets and the flow pattern, average droplet diameter, pressure drop, and hold-up of the dispersion phase. Two typical droplet generation routes, namely, dripping and jetting, and typical flow patterns, i.e., helical and annular flows were also obtained. Transition maps of the droplet generation route and flow pattern were constructed. The average droplet diameter and handling capacity were up to 380 μm and 30 mL/min, respectively. A small pressure drop was observed in the m-ARD. Furthermore, two dimensionless equations were developed to calculate the average droplet diameter and hold-up of the dispersion phase. This work provides a promising dispersion technology for the process intensification of liquid–liquid mass transfer and reactions.

Investigation of Drop Size in Liquid-Liquid Dispersion Agitated by Sawtooth Impeller: Effect of Optical Measuring Device

Investigation of Drop Size in Liquid-Liquid Dispersion Agitated by Sawtooth Impeller: Effect of Optical Measuring Device

A new mathematical model of continuous gravitational separation with coalescence of liquid-liquid emulsions

A model for a continuous gravitational separation process of a liquid-liquid dispersion is presented, which is formulated as a population balance equation (PBE) that describes the coalescence and the hindered polydisperse sedimentation of droplets. This is important because this separation process is critical in the operation of many industries as discussed later. This study is based on previous findings by Garcia and Betancourt (2019) where a formulation for a batch process was presented. This analysis shows the improvements and differences between the model presented in this study and the formulation by Garcia and Betancourt (2019). The modeling framework comes from the Kynch’s theory that has been employed to model solid particle sedimentation processes; however, in this case the principles are applied to an organic phase-aqueous phase liquid mixture. For the numerical solution of the model, the PBE is discretized in terms of droplet volume. Since the population balance model is subject to mass loss due to droplet coalescence, we propose a formula to compute the source term of the largest droplet class. Model validation used experimental data from literature for a continuous process. Numerical results explored the variation of parameters such as feed flowrate, feed oil volume fraction and the standard deviation of the initial and feed droplet volumes.

Polyethylene Glycol-Stabilized Zein Nanoparticles Containing Gallic Acid

SUMMARYResearch backgroundGallic acid is a polyphenol with antioxidant and antitumor activities; however, its use as a nutraceutical or drug is hindered by its low bioavailability. Zein is a natural protein found in corn and has been applied as nanoparticle drug carrier. In this study, zein nanoparticles were obtained and stabilized with polyethylene glycol (PEG) as gallic acid carriers.Experimental approachNanoparticles were obtained by the liquid-liquid method and characterized in terms of mean size, polydispersity index, zeta potential, morphology, solid-state interactions and encapsulation efficiency/drug loading. The stability of nanoparticles was evaluated in simulated gastrointestinal fluids and food simulants, and the antioxidant activity was determined by the scavenging of the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical.Results and conclusionsZein nanoparticles containing gallic acid were obtained and stabilized only in the presence of PEG. Under optimal conditions, nanoparticles with mean size <200 nm, low polydispersity index (<0.25) and negative zeta potential (−20 mV) were obtained. The gallic acid encapsulation efficiency was about 40%, loading about 5%, and it was encapsulated in an amorphous state. Fourier transform infrared spectroscopy (FTIR) did not identify chemical interactions after gallic acid nanoencapsulation. Zein nanoparticles were more prone to release the gallic acid in gastric than intestinal simulated medium; however, more than 50% of drug content was protected from premature release. In food simulants, the gallic acid release from nanoparticles was prolonged and sustained. Moreover, the nanoencapsulation did not reduce the antioxidant activity of gallic acid.Novelty and scientific contributionThe results show the importance of PEG in the formation and its effect on the properties of zein nanoparticles obtained by the liquid-liquid dispersion method. This study indicates that PEG-stabilized zein nanoparticles are potential carriers for oral intake of gallic acid, preserving its antioxidant properties and enabling its use in the pharmaceutical and food industries.

Multiphase Microreactors Based on Liquid-Liquid and Gas-Liquid Dispersions Stabilized by Colloidal Catalytic Particles.

Pickering emulsions, foams, bubbles, and marbles are dispersions of two immiscible liquids or of a liquid and a gas stabilized by surface‐active colloidal particles. These systems can be used for engineering liquid–liquid–solid and gas–liquid–solid microreactors for multiphase reactions. They constitute original platforms for reengineering multiphase reactors towards a higher degree of sustainability. This Review provides a systematic overview on the recent progress of liquid–liquid and gas–liquid dispersions stabilized by solid particles as microreactors for engineering eco‐efficient reactions, with emphasis on biobased reagents. Physicochemical driving parameters, challenges, and strategies to (de)stabilize dispersions for product recovery/catalyst recycling are discussed. Advanced concepts such as cascade and continuous flow reactions, compartmentalization of incompatible reagents, and multiscale computational methods for accelerating particle discovery are also addressed.

Enhancement of turbulent liquid-liquid dispersions in a round-bottom stirred tank equipped by a flexible impeller

Stirred tanks have been widely used for liquid-liquid mixing in the chemical industry. In the present work, the influences of flexible impeller on the hydrodynamic characteristics and droplet size distribution of oil in water dispersions were investigated using experimental and numerical approaches. The one-way Fluid Structural Interaction (FSI) analysis was carried out to model the geometry of the flexible impeller used in CFD simulations. Computational fluid dynamics (CFD) was coupled with the population balance model (PBM) to simulate the liquid-liquid dispersion process in the stirred tank. The numerical model was validated by the experimental results. Compared with the rigid impeller, the flexible impeller generates a more uniform distribution of turbulent kinetic energy and turbulent dissipate rate in the stirred tank. Compared with the case of rigid impeller, the region indicating the trailing vortices behind the impeller blades was significantly reduced by the flexible impeller. It was found the flexible impeller with a smaller elastic modulus can result in narrower droplet size distributions in turbulent dispersion process. Its peak value of the number fraction frequency was in the range of 244-308μm while that was 308-388μm for the case of rigid impeller. It was found that most of the dispersed phase droplets occur in the turbulent inertial subrange regime. Related correlations between the Sauter mean diameter and local turbulent field were also obtained. The shape factor accounting for the effects of the impeller shape on the Sauter mean diameter was found to be dependent on the material property of the impeller blades, such as the Poisson's ratio and elastic modulus.

Development of extraction-surface enhanced Raman spectroscopy and its application in detection of hazardous materials

<p indent="0mm">Surface enhanced Raman spectroscopy (SERS), which is known for its high sensitivity and molecular characteristics of the fingerprint spectrum, has been used in many fields. SERS might be interfered by the sample matrix and the impurity especially when trace analyte is being analyzed, which limits its application in actual samples analysis. Therefore, extraction-surface enhanced Raman spectroscopy (Ex-SERS) hyphenated technique is proposed to solve this problem. Several extraction technologies including solid phase extraction, solid phase microextraction, micro magnetic dispersive solid-phase microextraction, thin layer chromatography extraction, liquid-liquid dispersion microextraction have been used to construct Ex-SERS hyphenated technique. A variety of Ex-SERS methods were developed for rapid <italic>in</italic>-<italic>situ</italic> separation and detection of trace analytes from complex sample, which could promote the application of SERS technology in actual sample analysis.

Acute oral toxicity of zein nanoparticles with encapsulated gamma oryzanol in Sprague Dawley rats

Gamma oryzanol (GO) is well known for its antioxidant activity and health-promoting benefits. The gamma oryzanol-loaded zein nanoparticles (GOZNs) were successfully prepared in our previous study. In the present work, the acute oral toxicity of GOZNs was evaluated based on OECD guideline 420. GOZNs were fabricated by the liquid-liquid dispersion and lyophilized. The samples displayed a mean diameter of 311.20±3.01 nm and high loading capacity of 311.22±7.97 to 322.69±5.67 mg-GO/g-powder after 42-day storage at -18oC. Healthy female Sprague Dawley rats (8 weeks of age) were used for the experiments. Five female rats were administered a single dose of 2,000 mg GO/kg body weight via the oral route. Observations of toxicity signs were recorded for the first 24 hours, and the changes in the general physical conditions were monitored for 14 days before the gross necropsy on day 15. The results show that Sprague Dawley rats exhibited normal growth, and neither mortality nor acute toxicity signs were observed throughout the study period. The findings revealed that GOZNs did not have acute toxicity and were safe when administered orally in Sprague Dawley rats for short periods with LD50 &gt; 2,000 mg/kg.

The Effects of the Solvent Choice of the Continuous Phase on the Poly(Urea-Urethane) Microcapsules Properties

Xylitol, a natural crystalline polyol, presents a cooling effect due to its negative heat of solution at 35 °C supported by humidity absorption, contributing to a fresh sensation when it dissolves. Since this material is sometimes in a liquid state, it cannot be incorporated in or onto a substrate without being protected. One of the strategies to protect the active substance may be forming a barrier layer at its surface, i.e., microencapsulation. The present work is devoted to studying the effect of continuous phase parameters affecting on encapsulation of xylitol with a poly (urea-urethane) shell through a two-step microencapsulation process. The first step is liquid-liquid dispersion either in toluene or Miglyol 812N, and the second step is microencapsulation by interfacial polymerization. The process can be used to control the size distribution of the microparticles, the thickness, and the chemical nature of the shell, which influences the release rate of the active substance. The choice of the continuous phase solvent (toluene or Miglyol 812N) required some changes in the formulation of the system, especially the HLB of the surfactant mixture, to obtain a stable emulsion with a narrow particle size distribution. The thermo-chemical and morphological characteristics of microparticles were studied by Fourier transform-infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC), enthalpy of dilution, and scanning electron microscope (SEM). The microparticle size is governed by the emulsion step and the chemical composition of the organic phase. Most of the thermal properties are related to their porous structure and their chemical shell formation during the interfacial polymerization step.