Behavior Of Emulsions Research Articles

Factors impacting lipid digestion and nutraceutical bioaccessibility assessed by standardized gastrointestinal model (INFOGEST): Emulsifier type

This paper is part of a series examining the impact of the main factors influencing lipid digestion and nutraceutical bioaccessibility in β-carotene-loaded oil-in-water emulsions using the harmonized INFOGEST simulated gastrointestinal model. Here, the impact of emulsifier type was examined since food emulsions and nutraceutical delivery systems are often stabilized by various types of emulsifier. The INFOGEST method was adopted to investigate the in vitro gastrointestinal fate of emulsions stabilized by five kinds of food-grade emulsifier representing different classes: synthetic surfactants (Tween 20); natural surfactants (quillaja saponin); proteins (caseinate); polysaccharides (gum arabic); and phospholipids (soy lysolecithin). Microfluidization produced emulsions with small droplet sizes for all emulsifiers, except soy lysolecithin. Within the gastrointestinal model, the caseinate-coated oil droplets had the worst gastric stability, with severe droplet flocculation and coalescence occurring in the stomach. The fraction of the lipid phase that had been digested by the end of the gastrointestinal model was considerably lower for the emulsions stabilized by soy lysolecithin (93%) or caseinate (93%), than those stabilized by gum arabic (99%), quillaja saponin (111%) or Tween 20 (117%). This effect was attributed to lower surface area of lipids available for lipase to attach to for the lysolecithin and caseinate emulsions. The overall bioaccessibility of the β-carotene increased in this order: lysolecithin (25%) < gum arabic (51%) < caseinate (55%) < quillaja saponin (56%) < Tween 20 (62%). The impact of emulsifier type on carotenoid bioaccessibility was ascribed to various factors: (i) some emulsifiers inhibited lipid digestion and so a fraction of the β-carotene remained inside the undigested droplets and the mixed micelle phase had less solubilization capacity, i.e., lysolecithin, and caseinate; (ii) some emulsifiers protected β-carotene from chemical degradation, i.e., lysolecithin and caseinate; and (iii) some emulsifiers promoted sedimentation of the β-carotene-loaded micelles, i.e., lysolecithin. These results suggest that food emulsion behavior in the human gut may be influenced by the nature of the emulsifier employed, which is important knowledge when creating functional food and beverage products.

Fabrication and characterization of starch/zein nanocomposites with pH-responsive emulsion behavior

Hydrophobic modified starch nanoparticles were fabricated through combined starch nanoprecipitation and complexation with zein, and their emulsifying behaviors were further evaluated as a Pickering emulsion stabilizer. Novel starch/zein nanocomposites with a unimodal particle distribution, mean diameter of 147.9 nm and contact angle of 83.0° were achieved. Fourier transform-infrared spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, differential scanning calorimetry, and confocal laser scanning microscopy demonstrated that the zein was successfully complexed with the starch molecules. Dissociation test confirmed that electrostatic interaction and hydrogen bonding were the main driving forces for the formation and maintenance of the starch/zein nanocomposites. Complexing with zein endowed the starch nanoparticles with emulsion pH-responsive behavior, which could provide a simple and green pathway to pH-responsive materials that afford controlled release of bioactive ingredients with emulsion delivery and recyclable catalysis of enzymatic reactions.

Interfacial Properties of Chitosan in Interfacial Shear and Capsule Compression.

The time-dependent behavior of surface-active adsorption layers at the oil/water interface can dictate emulsion behavior at both the micro- and macroscale. In addition, self-healing behavior of the adsorption layer may benefit emulsion stability subject to large deformation under processing or during final application. We explore the behavior of chitosan, a known hydrophilic emulsifier, which forms nanoparticle aggregates when the concentration of acetate buffer exceeds 0.3 M. We observe a Pickering adsorption layer building and strain-dependent behavior of the chitosan at the medium chain triglyceride oil/water interface. We compare this to the behavior of identical chitosan layers coated on oil droplets via atomic force microscopy colloidal probe compression in both linear and oscillatory compressions. In both interfacial shear rheometry and the capsule compression, a thick, elastic layer with strong time-dependent recovery behavior is observed, suggesting that the layer has some self-healing capabilities.

Polymer/particle/water intermolecular interaction regulated freeze-dried Pickering emulsion morphology

Colloidal particles self-assembled at oil-water interfaces of Pickering emulsion served as a desired template for functional materials fabrication, raising broad attention from pharmaceutical engineering. Linking interfacial colloidal particles in Pickering emulsion based on strong molecular bonding, such as covalent bonding and ionic bonding have been widely investigated for colloidosomes preparation. This study demonstrated that relatively weak intermolecular interactions such as chemical coordination bond and hydrogen bond can also regulate the distribution of inorganic particles at the oil-water interface of emulsion. Pickering emulsion stabilized by boron nitride (BN) particles has been systematically studied by tuning the dissolved polymer in water phase after lyophilization (freeze-drying). The morphology of as-formed polymer-BN composite exhibited hollow microcapsules, “sphere-strip” mixture and aerogel, respectively, depending on the polymer/BN and polymer/water interaction. The mechanism of polymer regulating Pickering emulsion morphology has been proposed, which will enrich the current understanding of Pickering emulsion behavior during lyophilization and provide new strategy for the fabrication of functional materials.

Nanodiamond-stabilized Pickering emulsions: Microstructure and rheology

HypothesisWe envisage the use of hydroxylated detonation nanodiamonds (ND-OH), a relatively novel carbonaceous filler with high adsorption activity, small size, and large surface area to create Pickering emulsions. The emulsion behavior under shear and the extent to which the microstructure can rebuild after breakdown is dependent on its yield stress. ExperimentsUsing a model system consisting of isopropyl palmitate and water stabilized by ND-OH particles, we investigate the stability of these emulsions, their microstructure and rheological behavior as a function of ND-OH concentration. FindingsConfocal microscopy reveals that increasing ND-OH concentration results in smaller droplet sizes in the emulsions. This behavior is consistent with our rheological results of higher elastic modulus G′ and yield stress of the emulsion with increased ND-OH, as the presence of smaller droplets facilitates the formation of a densely packed network. We find the rheological behavior of these emulsions to be a hybrid of colloidal gels and surfactant-stabilized emulsions, with interparticle interactions and droplets deformability dictating their elasticity and yield stress behavior. Structure recovery following large shear reveals the degree of microstructure recovery to depend on the applied stress, with the recovered modulus collapsing into a single master-curve when the applied stress is scaled by the yield stress.

Emulsification and application of a thymol loaded antibacterial fatliquor for leather industry

In this study, the antibacterial fatliquor emulsion was prepared from castor oil bearing thymol (1, 2, 4 and 8% w/w) to be used in the leather production. The average particle size and zeta potential of the fatliquors were determined by zeta sizer. The thermogravimetric behaviors of fatliquor emulsions under dry air were analyzed in order to determine the weight losses when they are exposed to constant heating rate. After the emulsification process, fatliquor emulsions were applied into chrome tanned cattle leathers. Antibacterial activities of the fatliquored leather were tested according to standard test method for determining the antimicrobial activity under dynamic contact conditions against Gram-positive and Gram-negative bacteria. Minimum inhibitory concentration (MIC) analysis of emulsion was also determined. The bacterial reduction was measured as 99.9% against S. aureus and 98.6% against E. coli bacteria. MIC values obtained from emulsions against bacteria were determined as 6.25 μL/mL and 12.5 μL/mL respectively. The results of antibacterial tests showed that thymol was very efficient in the fatliquor emulsion against both Gram-positive bacteria and Gram-negative bacteria. Physical characterization of leather was also carried out with optimum fatliquor emulsion (4% thymol w/w) and the results showed satisfactory physical properties on the fatliquored leathers compared to similar leather made with commercially available fatliquors. The results of the study indicated that thymol loaded fatliquor emulsions with small particle size could be a promising solo fatliquor to provide functional properties such as physical, strength, morphological and antibacterial properties to leather as an efficient fatliquor compared to conventional fatliquors.

Ultrasound-assisted formation of double emulsions stabilized by casein-whey protein mixtures

Double emulsions were designed using milk protein solutions with varying casein to whey protein (C:W) ratios of 60:40, 50:50, 40:60, milk protein isolate (MPI) and whey protein isolate (WPI) as internal (W1) and external (W2) aqueous phases with grape seed oil (O) using low-frequency ultrasound (20 kHz). The main aim of the present study was to investigate the effectiveness of different milk protein compositions on the encapsulation efficiency, storage stability and in vitro digestion behaviour of W1/O/W2 emulsions. Polyglycerol polyricinoleate (PGPR) was the most effective hydrophobic emulsifier to produce primary emulsions and milk protein composition decided the microstructure and droplet size of primary emulsions. Droplet size and the encapsulation efficiency of double emulsions were dependent on the C:W ratio and higher initial droplet size and encapsulation efficiencies were highly susceptible during storage as they tend to easily release entrapped material. Emulsions with higher whey protein fraction had greater encapsulation efficiencies than casein rich emulsions and they were more gastric stable during in vitro digestion. Milk protein composition and the properties (microstructure and droplet size) of the gastric digestion outcome play roles in the digestion behaviour of emulsions within the intestinal phase. Therefore, select combination of caseins and whey protein compositions can be used to design double emulsions with improved stability and nutritional properties in complex dairy-based food systems.

Controlled Movement of Complex Double Emulsions via Interfacially Confined Magnetic Nanoparticles.

Controlled, dynamic movement of materials through noncontacting forces provides interesting opportunities in systems design. Confinement of magnetic nanoparticles to the interfaces of double emulsions introduces exceptional control of double emulsion movement. We report the selective magnetic functionalization of emulsions by the in situ selective reactions of amine-functionalized magnetic nanoparticles and oil-soluble aldehydes at only one of the double emulsion’s interfaces. We demonstrate morphology-dependent macroscopic ferromagnetic behavior of emulsions induced by the interfacial confinement of the magnetic nanoparticles. The attraction and repulsion of the emulsions to applied magnetic fields results in controlled orientation changes and rotational movement. Furthermore, incorporation of liquid crystals into the double emulsions adds additional templating capabilities for precision assembly of magnetic nanoparticles, both along the interface and at point defects. Applying a magnetic field to liquid crystal complex emulsions can produce movement as well as reorganization of the director field in the droplets. The combination of interfacial chemistry and precise assembly of magnetic particles creates new systems with potentially useful field-responsive properties.

Multiple Stress Creep and Recovery Behavior of SBR-Modified Bitumen Emulsions

Abstract The effect of two grades of styrene-butadiene rubber (SBR) at 2, 4, 6, and 8 wt. % on the deformation behavior of cationic polymer-modified bitumen emulsion by a multiple stress creep and recovery test at three different temperatures (58°C, 68°C, and 78°C) was investigated. It was observed that increasing SBR latex content leads to a decrease in nonrecoverable creep compliance (Jnr) of the bituminous residue, whereas increasing temperature leads to an increase in Jnr. The results also revealed that reduction in Jnr is not remarkable for polymer content higher than 6 wt. %. Furthermore, comparing the effect of different SBRs revealed that at equal polymer content, the Jnr of SBR-modified bitumen emulsion residue was found to be twice that of a branched carboxylated styrene-butadiene rubber (X-SBR)–modified one. At the same polymer modification rate and temperature, X-SBR can be used for higher traffic levels compared to an SBR-modified bitumen emulsion.

The Digitalization of Bottle Tests Nuclear Magnetic Resonance Evaluation of Emulsion Stability

Bottle tests are the preferred meth-od to test petroleum emulsion stability in the industry today. A new technique using nuclear magnetic resonance (NMR) is available to evaluate both stability and demulsification behavior of emulsions. The NMR scans the water fraction throughout the entire length of the emulsion sample. These rapid measurements are designed to dynamically probe the emulsion, capturing its separation as a digital image. This case study presents the ways NMR has helped predict the effects of future well line-up changes. Introduction Emulsion stability negatively impacts oil processing operations and plant design. The assessment of emulsion stability is performed at wellheads and gas/oil separation plants (GOSPs). Bottle tests are largely used for emulsion assessment, due to their simplicity and low cost. These tests depend on the visual identification of the separated water layer as the only quantifiable parameter. NMR is one of the alternative methods for emulsion assessment that can pro-vide information for all emulsion components. These components include the water layer; the oil/water interface - including the rag layer (the dense-pack zone [DPZ] of droplets above the interface); the remaining water-in-oil emulsion; and the dry-oil continuous phase. The DPZ - or rag layer - is of particular importance for oil processing, as its occurrence in separation vessels can lead to process upsets, resulting in excessive concentration of oil at the vessel’s water outlets. This interfacial phenomenon is particularly critical in the production of heavy oils, oils with high solid content, and oils forming highly stable emulsions. NMR is not only capable of measuring the water fraction throughout the entire emulsion sample, but can also provide a digital image of the water separating in the sample. More advanced NMR analyses are able to determine the water droplet size distribution (DSD) in the emulsion, and how the distribution changes during separation. It is also possible to obtain information on the droplet sizes at each position in the sample, as they change in time. Bottle tests are limited to the visualization of the free-water layer. Measurement errors are common if the oil/water interface is not clear. Unlike the NMR, any water still emulsified in the oil cannot be measured as it is not visible. The formation of the rag layer cannot be identified either. In addition, the efficiency of separation calculated from bottle test results, or emulsion separation index (ESI), requires knowledge of the water cut of the sample. The production water cut can be provided by the oil-processing operations, but the value is hardly the same found at sampling points. If the water cut is not known, it needs to be accurately measured in the sample after the bottle test. Usually the total amount of water is measured after centrifugation. It is difficult to guarantee that the emulsion is fully separated, as some droplets could still be unresolved at the interface. Another test limitation is the determination of separation efficiency when the water quality is poor. The presence of an oil-in-water emulsion could be the cause of cloudiness, contributing to an inefficient separation. But most of all, no readings can be made if the emulsion does not separate spontaneously. With NMR it is possible to determine the sedimentation rate of water droplets, even if no coalescence takes place (and no free-water layer is formed).

Emulsification of Surfactant on Oil Droplets by Molecular Dynamics Simulation.

Heavy oil in crude oil flooding is extremely difficult to extract due to its high viscosity and poor fluidity. In this paper, molecular dynamics simulation was used to study the emulsification behavior of sodium dodecyl sulfonate (SDSn) micelles on heavy oil droplets composed of asphaltenes (ASP) at the molecular level. Some analyzed techniques were used including root mean square displacement, hydrophile-hydrophobic area of an oil droplet, potential of mean force, and the number of hydrogen bonds between oil droplet and water phase. The simulated results showed that the asphaltene with carboxylate groups significantly enhances the hydration layer on the surface of oil droplets, and SDSn molecules can change the strength of the hydration layer around the surface of the oil droplets. The water bridge structure between both polar heads of the surfactant was commonly formed around the hydration layer of the emulsified oil droplet. During the emulsification of heavy oil, the ratio of hydrophilic hydrophobic surface area around an oil droplet is essential. Molecular dynamics method can be considered as a helpful tool for experimental techniques at the molecular level.

Experimental Investigation on Separation Behavior of Heavy-Oil Emulsion for Polymer Flooding on Alaska North Slope

Summary The first-ever field pilot on Alaska North Slope (ANS) to validate using polymer floods for heavy-oil enhanced oil recovery is currently ongoing. One of the major concerns of the operator is the effect of polymer on oil/water-separation efficiency after polymer breakthrough. This work investigates the influence of polymer on the separation behavior of heavy-oil emulsions and evaluates the performance of emulsion breakers (EBs). In this study, two types of heavy-oil emulsions were prepared and tested at 20 and 50% water cut (WC), respectively. The bottle test method was used in the experiments, in which the separated water volume with time, the separated water quality, and the volume fraction of phases were recorded. Results showed that polymer accelerated the oil/water separation acting as an emulsion inhibitor at 20% WC but tended to impede the water separation at 50% WC. Regardless of WC, polymer resulted in poor water quality and the formation of a stable intermediate oil in water (o/w) emulsion, because of the increased viscosity of the water phase. The performance of EBs showed a complex dependency on the WC, the type of demulsifier and dosage, and the polymer concentration. Despite the varied conditions encountered in the heavy-oil/water/polymer/demulsifier system, a compound EB achieved satisfactory demulsification performance, showing the highest potential for deployment in the current ANS polymer flooding pilot. In this paper, we systematically studied the potential influence of polymer breakthrough on the separation behavior of heavy-oil emulsion on ANS for the first time. The findings of this study will provide practical guidance in advance for produced fluid treatment of the ongoing first-ever polymer flooding pilot on ANS.

Flow behaviors of emulsions in constricted capillaries: A lattice Boltzmann simulation study

We study the flow behaviors of emulsion droplets in constricted capillaries using a surfactant Lattice Boltzmann model. We first establish the model by introducing a surfactant component into the pseudopotential multiphase model and characterizing the amphiphilic structure using dipoles. Then we study the flow of emulsion droplets in single or parallel capillaries. The simulations show that single droplet can pass through single throat in three ways, i.e., passing directly, passing with deformation, and snap-off. Multiple droplets may flow through the capillary with coalescence, and can also block the throat by adsorption or bridging, which may induce upstream flow caused by buoyancy. There is a “trap effect” when emulsions flow through parallel throats, and the droplet could be pinched off by obstacles, while the surfactants can inhibit the droplet breakup due to Marangoni effect. The simulations present detailed flow behaviors at pore scale and provide new insights for emulsion flow modeling.

Impact of ultrasound processing parameters on physical characteristics of lycopene emulsion.

Using ultrasound technology for obtaining O/W lycopene emulsions needs analyzing the parameters for the enhanced application. To this end, O/W lycopene emulsions (30:70) were processed using ultrasound with powers of 240W and 360W in 5, 10, and 15min. Afterward, the poly dispersity index, droplet size, ζ-potential, turbidity, phase separation, lycopene concentration, rheological behavior, surface tension, and morphology of emulsions was investigated. The experimental results showed good emulsifying characteristics with respect to droplet size and ζ-potential. If the mean values of the droplet size were significantly reduced and the ζ-potential increased. The ultrasound application had a significant impact on emulsion stability with no phase separation and significantly high lycopene retention. Ultrasound reduced the apparent viscosity by reducing the particle size due to the energy supplied to the system. The final emulsion that was treated at 360W, and 2160J/cm3 in 10min, presented enhanced technological properties appropriate for food products.

Characterization of single cell protein from Saccharomyces cerevisiae for nutritional, functional and antioxidant properties

Malnutrition is a serious issue in the developing countries especially in Pakistan. It may be due to ever growing population, urbanization and industrialization along with decrease in agricultural lands. It ultimately is an alarming situation for food security, thus, there is a need to look for alternate sources for food and nutrition security. Therefore, the objective of this project was to produce single cell protein (SCP), as a non-conventional food source from Saccharomyces cerevisiae, a step toward sustainable production. In this study, effect of various temperature and nitrogen levels were investigated on SCP yield. Results indicated that maximum amount of SCP (9.18 g) was obtained at 30 °C for 6 days on sugar beet bagasse which was supplemented with ammonium sulfate as nitrogen source. It is rich in protein (47.78 ± 2.39%) contents with sufficient amount of fat (2.34 ± 0.11%), fiber (3.42 ± 0.17%) and ash (7.9 ± 0.4%). Furthermore, the ratio of unsaturated fatty acids (42.45% of total fats) to saturated fatty acids was 0.73. Similarly, SCP contained broad spectrum of essential amino acids like leucine (43.5 ± 0.21 g/kg), valine (38.3 ± 0.19 g/kg), lysine (31.4 ± 0.15 g/kg). Besides, SCP was suitable for utilization in food formulations considering the results for functional properties (bulk density, water and oil absorption capacities, foaming and emulsion behaviors). The scavenging activity (36.65%), β-carotene bleaching activity (38.16%) and FRAP (46.93 mmol trolox Eq/g) values exhibited the potential of SCP functional food. In short, SCP is good source of protein and may be in food products and supplements.

A mechanistic study of emulsion flooding for mobility control in the presence of fatty acids: Effect of chain length

Emulsion flooding is a promising method for enhanced oil recovery (EOR). The static and dynamic behavior of the emulsions is greatly influenced by the nature of the applied surfactant. In this work, the effect of fatty acids, as natural surface-active agents, and their chain length on the emulsion behavior was investigated in both bulk and porous media. A panel of the fatty acids with different chain lengths (6 < C < 18) was applied at constant concentration and pH. Upon the static stability tests, emulsion stability at the optimum value of chain length (C14) was increased by two orders of magnitude. Under the optimal condition, the hydrogen bonding between dissociated and undissociated fatty acids and the tail-to-tail adsorption of fatty acids enhanced the interface coverage. Moreover, interfacial tension was minimum in this case (35.8 mN/m). Additionally, a series of rheological measurements were conducted to examine the dynamic behavior of the emulsion. Two distinct regions were distinguished based on the shear rate. At the low shear rates, a linear relationship was observed between shear rate and shear stress, indicating a solid-like behavior of the emulsions. The effect of the fatty acid chain length on the hydrodynamic interactions was more evident at higher shear rates. Finally, the flooding experiments revealed that there is an excellent consistency between static and dynamic tests. Based on these results, a four-fold increment was recorded in the apparent viscosity of the emulsion in the optimum condition.

Generation of an O/W emulsion in a flow-focusing microchip: Importance of wetting conditions and of dynamic interfacial tension

To date, there is no information on the microfluidic emulsification of dibutyl adipate and n-butyl acetate in water. Since these solvents are very suitable for microencapsulation by interfacial polymerization, it is highly necessary to study the emulsification behavior of these solvents in microchannels. This work shows that the microfluidic emulsification of these solvents in water may fail to obtain stabilised flow regimes. This is due to droplet coalescence and wall wetting, even if a hydrophilic microchip is used. Hydrodynamic results show that squeezing and dripping regimes are especially affected because of the wall wetting by the dispersed phase. This difficulty can be circumvented by adding a surfactant (here Tween 80) into the aqueous phase. However, high surfactant concentrations (ten times the critical micelle concentration) should be used for the water-dibutyl adipate system. Indeed, comparison of flow maps for several surfactant concentrations seems to indicate that the dynamic interfacial tension is higher than the one expected (equilibrium), for surfactant concentrations lower than one hundred times the critical micelle concentration. The estimated diffusion time of Tween 80 is compared to the droplet formation time at different conditions. The choice of more appropriate dimensionless numbers to represent flow maps is also discussed.

Core-scale modelling and numerical simulation of zwitterionic surfactant flooding: Designing of chemical slug for enhanced oil recovery

Surfactant flooding is a proven enhanced oil recovery method for the recovery of trapped crude oil from the pores of the reservoir. In the present study, the applicability of a synthesized zwitterionic surfactant as an efficient EOR agent was tested, in terms of its interfacial tension reduction capability, emulsification behavior, and wettability modification behavior. Core flooding experiments conducted in sandstone core with the injection of 0.3 pore volume of chemical slug after water flooding showed 20% of additional oil recovery. The core flooding experiment was simulated using CMG-STARS simulator and history matching of relative permeability curve and its interpolation parameters were done. The validated model closely represented the experimental core flooding with very low error of 6%. The validated model helps in understanding the movement of crude oil and its interaction with the injected surfactant slug in the porous media. The validated model was further used for optimization of injected chemical slug by varying the parameters such as the surfactant concentration in the injected slug, the volume of injected chemical slug, and the injection rate of chemical slug. Each parameter had different effects on the oil recovery efficiency and cumulative oil recovery of more than 90% OOIP was obtained using model with injection of 1 PV of chemical slug containing 100 ppm of surfactant with the injection rate of 0.3 mL/min. The simulation of core flooding helped in optimization of crude oil production by zwitterionic surfactant and its implementation on field scale production by zwitterionic surfactant flooding.

Effect of protein and oil volume concentrations on emulsifying properties of acorn protein isolate

This study aims to extract acorn protein isolate (API) from locally abundant waste acorn fruit and investigate its emulsification behavior by mixing different protein (0.1–2% w/v) and oil volume concentrations (5–45% v/v). Significant decrease in emulsifying activity index (EAI) and an increase in emulsifying stability index (ESI) were observed with an increase in API concentrations (P < 0.05). Droplet sizes of emulsions and viscosity were observed to decrease significantly (P < 0.05) with increase in API concentration while the increase was observed in interfacial protein concentration (Г). In contrast, increase in oil volume concentration results in increase of droplet sizes, packing fractions and viscosity, while decrease in Г values was observed. The results reveal that main fractions of API (66.2–14.4 kDa) were migrated to oil-water interface for emulsion stabilization. These results demonstrate the potential application of API in food formulation and development.

In vitro digestion behavior of (W1/O/W2) double emulsions incorporated in alginate hydrogel beads: Microstructure, lipolysis, and release

The aim of the present study was to illuminate the digestion behavior of (W1/O/W2) double emulsions incorporated in alginate hydrogel beads using a simulated in vitro gastrointestinal tract model. Swelling study and fluorescence microscopy observation showed that compact beads gradually became swollen and heterogeneous during intestinal digestion, and the swelling extent was dependent on the alginate concentration. Laser diffractometry and flow cytometry were conducted to characterize the oil droplet population released from beads. The incorporated oil droplets were gradually released from the hydrogel matrix along with the swelling of beads, which might prevent the coalescence. The microstructure transformation from (W1/O/W2) double emulsion droplets to empty emulsion droplets could occur within beads without the requirement of the droplet release from beads, and oil droplets were mainly released from beads in the form of empty emulsion droplets at high alginate concentration. The release profiles of free fatty acids indicated that the lipolysis of incorporated double emulsions was gentler than that of double emulsions. Furthermore, the lipolysis was delayed at high alginate concentration. The incorporation had no influence on the cumulative release amount of encapsulated hydrophilic dye from double emulsions into digestive fluid. These results provided useful data for the design of (W1/O/W2) double emulsions-based delivery system with controlled lipolysis and adequate release of encapsulated hydrophilic active ingredients.