Droplet Size Analysis Research Articles

Preparation of stable multiple emulsions using food-grade emulsifiers: evaluating the effects of emulsifier concentration, W/O phase ratio, and emulsification process

In this study, the effects of sodium caseinate (NaCN; emulsifier) concentration, a type of hydrophilic emulsifier, as well as concentration of primary W/O emulsion on the stability of water–oil-water (W/O/W) emulsions were investigated. Emulsions were made using two different emulsification techniques including ultrasonic liquid processing and high pressure homogenization (HPH). Microscopy images of W/O/W emulsions in combination with droplet size analysis and viscosity measurements showed that the sample with a higher percentage of primary W/O emulsion (50 wt% vs. 40 wt% and 25 wt%) was more resistant to coalescence (narrower droplet size distribution and lower creaming index). The higher stability of this emulsion at 50 wt% is due to the enhancement in the solution viscosity which slows down the coalescence and destabilization kinetics. The increase in the NaCN concentration from 0.3 wt% to 0.9 wt% (based on total weight of emulsion) led to formation of larger droplets possibly due to the destabilization of primary W/O emulsion through the disruption of polyglycerol polyricinoleate (PGPR) layer. Regarding the effect of emulsifier type, incorporation of Cremophor EL and Tween 60 in comparison with NaCN resulted in formation of smaller droplet size due to their enhanced surface activity at the interface. Finally, we found that using high pressure homogenizer (HPH) instead of ultrasonic processor was detrimental to the emulsion stability and size distribution. These findings further provide new pathways to design emulsion systems for food and drug delivery applications.

Dimensional analysis of droplet size and ligament length during high-speed rotary bell atomization

Modern spray-coating processes are based on high-volume, low-pressure, airless atomization or high-speed rotary bell atomization, often assisted by electrostatic charging to increase the transfer efficiency. The process from the liquid film flow beneath the bell, through ligament formation and consecutive disintegration to droplet deposition, has been constantly explored during the evolution of automotive spray coating. This work proposes a set of dimensionless groups that fully describe the process from film flow to ligament disintegration, including shear and elongational flow effects during atomization of particle laden, shear thinning, viscoelastic fluids.

Preparation and Characterization of Microemulsions Based on Antarctic Krill Oil.

Antarctic krill oil is high in nutritional value and has biological functions like anti-inflammation and hypolipidemic effects. But it has and unpleasant smell, and unsaturated fatty acids are prone to oxidative deterioration. Its high viscosity and low solubility in water make it difficult for processing. Microemulsion can be a new promising route for development of krill oil product. We determined a formula of krill oil-in-water microemulsion with krill oil: isopropyl myristate = 1:3 as oil phase, Tween 80:Span 80 = 8:2 as surfactant, ethanol as co-surfactant and the mass ratio of surfactant to co-surfactant of 3:1. After screening the formula, we researched several characteristics of the prepared oil-in-water microemulsion, including electrical conductivity, microstructure by transmission electron microscope and cryogenic transmission electron microscope, droplet size analysis, rheological properties, thermal behavior by differential scanning calorimeter and stability against pH, salinity, and storage time.

Investigation on the variation regularity of the characteristic droplet diameters in the swirling flow field

To investigate the variation regularity of the characteristic droplet diameters in the swirling flow field, experimental research and numerical simulations were conducted. In the experiments, the white oil–water and the hydraulic oil–water mixture in a 100-mm-diameter pipe swirling flow field were tested. A Malvern droplet size analyzer and an electrical resistance tomography were used to measure the droplet size distribution and local oil volume fraction, respectively. In the numerical simulations, the Eulerian multiphase model, the population balance model, and the RSM turbulent model were coupled to simulate the droplet behavior in the swirling fluid field. The results revealed bilinear relationship (corresponding to the developing section and swirling section) between the section average d32 and the turbulent energy dissipation rate in the logarithmic coordinate system. Subsequently, quadratic relationship between the section average d90 and the swirling number owing to the dual influence mechanism of the tangential momentum on droplet coalescence and stabilization was found. Finally, linear relationship was observed between the d5 and the swirling number in the swirling section. Furthermore, the results indicated that these characteristic droplet diameters were sensitive to the operating parameters of the entrance Reynolds number and entrance oil volume fraction, as well as the oil properties, including the density, viscosity, and surface tension coefficient. All these factors are important for understanding the droplet evolution in the swirling flow field and can provide guidance for the design and optimization of swirling vane type de-oiling separators.

Experimental study on correlation between adhesive penetration pattern and mechanical performances in oriented strand board

The aim of the experimental study presented here is to investigate the correlation between adhesive penetration and mechanical performances of wood-based composites. For this purpose, oriented strand boards were made with poplar uni-strands and PF resin. To make differences in resin penetration, strand moisture content (MC) and resin solid content (SC) were selected as variables of the experiment. The adhesive penetration pattern was studied by the elemental counting method (ECM) in two layers of the boards’ thickness. Mechanical properties including MOE, MOR, IB, tensile strength parallel to the grain, impact resistance, and creep bending were evaluated as well as resin droplets distribution. The results showed that strand MC and resin SC influence the mechanical performance and resin penetration parameters. The penetration parameters increased in the middle layer where the bondlines are close to heat and hydrodynamic pressure sources. The composites made with higher concentration resin and drier strands expressed weak penetration causing a reduction in mechanical properties except for tensile strength where the shear stress took place between bonded strands. Resin droplet size analysis proved that resin SC could change the droplet size distribution and influence the strengths. Strand MC could act as a modifying factor to develop the penetration and balance it between the layers. The results of the correlation analysis proved a significant relationship between mechanical properties and penetration parameters, in particular, those obtained from fiber quantity.

Cyclooxygenase 2 Regulates Isoprenaline Induced Adipolysis In Brown Adipocytes

PURPOSE: By converting fat into heat, brown adipocytes (BAC) play as an energy expenditure in mammalian. Cyclooxygenase 2 (COX2) is a key factor of Uncoupling protein 1 (UCP1) synthesis which is essential for dissipates energy into heat via adipolysis. Isoprenaline (ISO) can induce adipolysis in brown adipocytes (BAC); however, whether COX2 takes part in ISO induced adipolysis remains unclear. METHODS: C3H10T1/2 cells were differentiated into brown adipocytes. BACs were treated with 10μM ISO or 10μM ISO and 100μM NS-398 (COX2 inhibitor) for 0 (as control), 1, 3, 6, 12 or 24 hours. For lipid droplet (LP) size analysis, cells were fixed and stained with Oil Red O. Images were captured with a Leica CTR 4000 microscope with 10x objectives. All images were thresholded for LPs signal and watershed for individual LP size analysis using Image J. Data were loaded into GraphPad Prism 8 for LP size analysis and size frequency distribution. BACs were collected for UCP1 expression detection after 6-hour-incubation (beta tubulin as loading control). All results are presented as means ± std. error of mean. Statistics were performed in SPSS using Student's t test. RESULTS: Average LP size decreased as ISO incubation time prolonged (113.67 ± 2.40, 115.69 ± 2.21, 83.61 ± 1.69, 35.00 ± 0.88, 31.60 ± 0.69, 34.28 ± 0.77 μm2 after 0, 1, 3, 6, 12, 24 hours incubation, respectively). Incubation of ISO and NS-398 slowed down the rate of LP size reduction (95.08 ± 1.65, 107.73 ± 2.26, 85.22 ± 1.87, 56.97 ± 1.49, 41.32 ± 0.87, 37.43 ± 0.65 μm2 after 0, 1, 3, 6, 12, 24 hours incubation, respectively; slope (-53.04 ± 1.21 vs. -65.45 ± 1.33) LP size frequency distribution showed a shift of LP size towards smaller LPs following incubation with ISO. Inhibition of COX2 activity can delay the occurrence of left shift (became smaller) of LP size frequency distribution (12h vs. 3h). UCP1 expression were lower following ISO and NS-398 incubation than those treated with ISO only (0.74 ± 0.08 vs. 1.00 ± 0.00, p<0.05). CONCLUSION: COX2 inhibition can repress ISO induced adipolysis in BACs and may related to a decrease in UCP1 expression. Funded by FRF for the Central Universities of China (2018GJ017)

The stability and gastro-intestinal digestion of curcumin emulsion stabilized with soybean oil bodies

The study aimed at stabilizing the curcumin emulsions (CEs) using the soybean seed oil bodies (SSOBs) and investigated the gastrointestinal digestion of the CEs. The particle size decreased (P < 0.05) with the increasing concentration of SSOBs from 1.0 wt% to 5.0 wt%. The CEs stabilized with the SSOBs exhibited excellent stability at pH 2.0 and 6.0–10.0. The CEs were stable against the aggregation at 100–500 mmol/L NaCl concentration and elevated temperature. The droplet size analysis and confocal laser scanning microscope observation results indicated that the fat droplets aggregated in the CEs under the gastric conditions at 30 min and afterward it gradually dispersed. Under the simulated intestinal condition, the droplet size of the CEs significantly decreased compared to the simulated gastric conditions (P < 0.05). The release rate of curcumin continuously increased during 180 min digestion under the intestinal conditions. Therefore, SSOBs could be used as the natural emulsifiers and novel carriers in delivering the lipophilic bioactive compounds.

Ultrasound-assisted production and characterization of rice bran lecithin-based nanoemulsions

Rice bran lecithin (RBL) is a mixture of phospholipids which is obtained as a by-product during the refining of rice bran oil. The emulsifying properties of RBL help in the production of nanoemulsions. Ultrasonication is a high energy approach to produce nanoemulsions with small droplet size and high kinetic stability in comparison to the coarse emulsion. The current study aims to develop stable nanoemulsions using different concentrations of RBL as an emulsifier by ultrasonication (60% amplitude, 40 cycles). Xanthan gum is used as a stabilizing agent for the nanoemulsions. The stability of nanoemulsions under optimum conditions (pH 7, 25 °C) was determined. The nanoemulsions were characterized by determining creaming index, droplet size, polydispersity index (PDI), microstructure analysis, zeta potential, and shear viscosity. The emulsion with the highest concentration of RBL showed maximum kinetic stability against phase separation. The size of nanoemulsions vary in the range of (10–150 nm), the droplet size analysis showed the stability of nanoemulsions on the 14th day of preparation. Microstructure analysis of droplets on different days of storage showed uniform distribution of droplets in the nanoemulsion, thus leading to high kinetic stability. The zeta potential remained negative due to the adsorption of anionic lecithin on the droplet surface. The viscosity of the nanoemulsion formed after ultrasonication exhibited lower viscosity than the preemulsion due to the formation of small droplets.

Bioactive Self-Nanoemulsifying Drug Delivery Systems (Bio-SNEDDS) for Combined Oral Delivery of Curcumin and Piperine.

Background: Bioactive oils of natural origin have gained huge interests from health care professionals and patients. Objective: To design a bioactive self-nanoemulsifying drug delivery system (Bio-SNEDDS) comprising curcumin (CUR) and piperine (PP) by incorporating bioactive natural oils in the formulation. Methods: The self-emulsifying properties of apricot, avocado, black seed and Zanthoxylum rhetsa seed oils were screened within various SNEDDS formulations. Each liquid SNEDDS formulation was loaded with both CUR and PP. The optimal liquid SNEDDS were solidified using Aeroperl® and Neusilin® at 1:1 w/w ratio. Liquid and solid SNEDDS were characterized by droplet size analysis, equilibrium solubility, scanning electron microscopy, X-ray powder diffraction, differential scanning calorimetry, and Fourier transform infrared spectroscopy. In-vitro dissolution studies were performed to evaluate the efficiency of CUR and PP release from solid Bio-SNEDDS. Results: The liquid SNEDDS comprised of black seed oil exhibited excellent self-emulsification performance, low droplet size along with transparent appearance. The inclusion of the cosolvent Transcutol P improved the solubilization capacity of both CUR and PP. The liquid SNEDDS were efficiently solidified using the two adsorbents and presented the drugs within amorphous state. In particular, SNEDDS comprised of black seed oil/Imwitor988/Transcutol P/Cremophor RH40 (20/20/10/50) and when solidified with Neusilin showed enhanced CUR and PP release (up to 60% and 77%, respectively). In addition, this formulation efficiently delivers the highly bioactive black seed oil to the patient. Conclusions: The optimized Bio-SNEDDS comprising black seed oil showed outstanding self-emulsification characteristics along with enhanced CUR/PP dissolution upon solidification.

Micellar Catalysis Strategy of Cross-Condensation Reaction: The Effect of Polar Heads on the Catalytic Properties of Aminoalcohol-Based Surfactants

The effect of the polar head and the concentration of quaternary ammonium surfactants (C14EtOH, C14iPrOH, C14PrOH, where, 14 = carbon number iPrOH = iso-propanol, EtOH = ethanol, PrOH = propanol) in micellar catalysis for the cross-condensation reaction (Claisen–Schmidt) was investigated. The reaction in the Micellar-NaOH system with different concentrations of surfactants above the critical micelle concentration from 15 to 30 mmol between benzaldehyde and acetophenone was used as a model of reaction for this study. The examination of the effectiveness of the catalytic activity reveals that the compound C14EtOH has the best yield (80% of the desired product), followed by C14iPrOH and C14PrOH. The results were interpreted according to the solubilization capacity, droplet size analysis of reagents (benzaldehyde and acetophenone) in the micellar medium and stability of reaction intermediate (enolate) by the electrostatic interactions generated by positive charge of N+ quaternary ammonium atom. Therefore, the quantum calculations carried out by DFT method for surfactants in the aqueous medium, show that electrophilicity degree and the reaction yield% for three cationic surfactants varies in the same following order: C14PrOH < C14iPrOH < C14EtOH.

The stability and in vitro digestion of curcumin emulsions containing Konjac glucomannan

Konjac glucomannan (KGM) was used to characterize the structure of the curcumin emulsions stabilized with whey protein isolate (WPI). With an increasing concentration of KGM from 0.1% to 0.3%, the fat droplet size decreased significantly (p < 0.05) with increasing KGM content. The retention of curcumin in emulsions with KGM was significantly higher (p < 0.05) than the emulsions without KGM, after heating at 85 °C for 90 min. These two emulsions showed good stability in the pH range of 2–8 in addition to pH 5. Both emulsions with/without KGM were stable at 0–80 mM salt concentration, however the curcumin emulsion with KGM was unstable at 100 mM NaCl concentration. The droplet size analysis and microscopic observations indicated that the aggregation of fat droplets in these two emulsions occurred under simulated gastric fluid (SGF) conditions with a digestion time of 10 min. There were more undigested fat droplets in the curcumin emulsion with KGM than the emulsion without KGM under simulated intestinal fluid conditions after 120 min of digestion. The addition of KGM in WPI-stabilized curcumin emulsions slowed down the release rate of free fatty acids and curcumin from the emulsion droplets. These findings indicated that KGM could be used to achieve a controlled and sustainable release of bioactive compounds from emulsions.

Investigation into atomization spray blending property in heavy crude oil extraction under laboratory conditions

Abstracts In this study, the atomization blending property for heavy crude oil extraction was systematically investigated both numerically and experimentally. In the experiment conducted, the blending behavior was simulated using hydraulic oil and spray with 1:10 light phase-gas atomize volume flow rate ratio in an equipment sharing the same scale as the on-site production. A Malvern Insitec droplet size analyzer was applied for the droplet size measurement, and a quick closing valve method was applied for the phase fraction measurement. A numerical simulation combined with a population balance model and the RNG k-e model was performed under both the corresponding operating conditions and a high-pressure drop environment to further investigate the blending procedure. The results show that the atomization spray blending performs better than the equivalent pure gas lifting method with more crude oil carried at the exit. Under 0.6 m3/h light phase inlet conditions, spray blending brings 8% more heavy crude than gas lifting, and the improvement rises as inlet flow rate increases. Both a droplet and liquid film are present in the casing space before blending for the spray liquid phase. In addition, the light phase droplet diameter decreases with an increase in the inlet flow rates in the lifting pipe after blending. Moreover, the blending behavior differs under various light phase inlet flow rates, while the mixture viscosity is reduced by 50% for the atomization spray method. Each of these factors was shown to be beneficial for refining the blending used in a heavy crude oil extraction technique.

A REVIEW ON FORMULATION AND CHARACTERIZATION OF NANOEMULSION

Nanoemulsions are clear, thermodynamically stable mixtures of oil, water, surfactant and co-surfactant. These are the oil-in-water type of emulsions with the average droplet size ranging from 5 nm to 100 nm. Nanoemulsions are thermodynamically stable transparent or translucent dispersions of oil and water stabilized by an interfacial film of surfactant and co-surfactant molecules having a droplet size of less than 100 nm. This review provides brief information about the method of preparation and evaluation of nanoemulsion as drug carriers for improving the delivery of therapeutic agents. There are several techniques are to be used for preparation of nanoemulsions like high pressure homogenization, microfluidization, low energy emulsification and solvent evaporation method and parameter that are to be used for its characterization like droplet size analysis, viscosity determination, drug content, refractive index, pH, zeta potential, Transmission electron microscopy, thermal stability, release and in vitro skin permeation study.Nanoemulsion

ENHANCING THE SUNSCREEN EFFICACY OF BEMOTRIZINOL MICROPIGMENT BY USING O/W NANOEMULSION TOPICAL PREPARATIONS

Objective: Bemotrizinol (BEMT) is the most efficient broad-spectrum UV-absorber having a dual mechanism of action in absorbing and reflecting photons. The main objective of this work was to develop successful oil in water (o/w) nanoemulsion for improving the solubility of BEMT and its protective characteristics.&#x0D; Methods: Pseudo-ternary phase diagrams were constructed using labrafac PG and isopropyl myristate as oil phase, tween 80 as surfactant (S) and cremophor EL as cosurfactant (CoS) the ratio of S/CoS was determined according to highest percent of water incorporation to the system. Full factorial study design (24) using Design-Expert® software was adopted to study the effect of four independent variables namely: oil type, oil concentration, S/CoSmix (3:1) concentrations and BEMT concentration on the particle size and the in vitro release at 2 h (Q2h) of the prepared nanoemulsion formulae. Two systems each of eight formulae were developed and evaluated through droplet size analysis, zeta potential measurement, refractive index, in vitro drug release and according to the desirability value two formulae (F6 and F14) were used for further evaluations including in vitro sun protection factor (SPF), ex-vivo deposition by tape stripping technique, permeation test and photostability study.&#x0D; Results: Formula (F14) was chosen as the optimum formula having an in vitro SPF of 16.08±0.39, lowest permeation of 140±0.06 μg/cm2after six h and highest photostability (t90% = 168.02) after 120 min.&#x0D; Conclusion: Despite the poor solubility of bemotrizinol, it could be enhanced by novel drug delivery systems with good SPF value while maintaining its photostability.

EMULSION INVERSION OF CRUDE OIL BY SOLID PARTICLE AND SURFACTANT ADDITION

Crude oil produced as water-in-oil (W/O) emulsion can show high viscosity, causing difficulties during pipeline transportation. The production of O/W emulsion by adding an aqueous phase containing solid particles and surfactant is an alternative to decrease oil viscosity. Thus, the objective of this work is to study the synergistic effect of a surfactant (Triton X-100) and a solid particle (sodium bentonite) addition on emulsion inversion. Emulsions were characterized in conductivity, rheology, kinetic stability, and droplet size analyses. W/O to O/W emulsions inversion occurred when aqueous solutions were between 30 and 40% (m/m), according to conductivity and rheology analyses. The increment of water content from 30 to 50 % (w/w) increased mean droplet size from 2.6 to 10.6 µm, increased phase separation from 9.5 to 68.0 (v/v), and decreased emulsion viscosity from 183 to 1.07 mPa.s. Aqueous solution containing solid particle and surfactant affected emulsions’ properties, producing systems with lower viscosity than crude oil, making it easier for oil pumping and pipeline transportation.

Atomization behaviour of juice-fibre suspensions in a two-fluid nozzle

Atomization of non-Newtonian viscoelastic liquids was carried out using a two-fluid nozzle. Juice-fibre suspension is a shear thinning liquid that exhibits significant extensional resistance when forced through an extensional flow-field. Two types of fibres were used with aspect ratios of 2–3 and 8–10. The atomization behaviour of the suspensions discharging in the air was photographed using a backlit setup to visualise the atomization pattern of viscoelastic fibre suspensions. The effect of the extensional resistance is to delay the droplet formation by forming filamentary structures that link successive droplets together. As a consequence, droplets of viscoelastic fibre suspensions are usually bigger than Newtonian droplets. Using a two-fluid nozzle, at an atomizing air velocity of 150 m/s, the average droplet size of fibre suspension with aspect ratio 2–3 was 450 μm while the average droplet size of fibre suspension with aspect ratio 8–10 was 530 μm. Increasing the atomizing air velocity in the two-fluid nozzle yielded better atomization by forming smaller droplets as proved by the droplet size analysis. At the highest tested atomizing air velocity of 240 m/s, both average droplet sizes were reduced to approximately 200–250 μm.

Ultrasonic/sonochemical synthesis and evaluation of nanostructured oil in water emulsions for topical delivery of protein drugs

Delivery of drugs and active agents to human skin by formulation containing nanosystems have shown remarkable advance in recent nanotechnology research. The aim of current investigation is to study protein drug, extracted from medicinal leech tissue and evaluate an isotropic and kinetically stable nanoemulsion formulation, with least surfactant and co-surfactant concentrations also with optimal solubility and stability, for topical delivery. It is a fact that physical properties of oil phase has an impact on nanoemulsion formation and stabilization. In this research, various factors, such as oil types (olive oil and sesame oil) and oil content for their effects on particle size and stability of protein nanoemulsion were first investigated. Secondly, optimized formulation of protein nanoemulsion was characterized by droplet size and zeta potential analysis, Transmission electron microscopy (TEM), viscosity, pH, and refractive index. Thirdly, stability studies were done to select the best formulation. The results of our experiments showed that an increase in the concentration of olive oil and sesame oil led to a nanoemulsion with smaller size of droplets and with higher stability, respectively. However; slight variations in droplet size were observed in case of nanoemulsion with olive oil. As a result of various experiments, a Nanoemulsion with 25% olive oil was selected as optimized formulation owing to its much smaller droplet size (143.1 nm), lower polydispersity index, higher zeta potential (−33.3 mV). No considerable changes in droplet size, viscosity and pH occurred during a 30-day storage period at 4 °C. This procedure also suggested that our selected nanoemulsion was physically stable. Additionally, TEM revealed that particles were morphologically spherical. In conclusion, our analyses of the experiments proved the fact that nanoemulsions are promising novel formulations for protein drugs and can greatly enhance stability of protein drugs.

Pore-level visual analysis of heavy oil recovery using chemical-assisted waterflooding process – Use of a new chemical agent

Chemical-assisted waterflooding enhances the ultimate recovery of a conventional waterflooding process through several mechanisms such as reducing interfacial tension between water and oil, formation of in-situ emulsions, treatment of adverse mobility ratio, and wettability modification. Application of chemical-assisted waterflooding for recovery of heavy oil is still an active research topic. A new chemical technology (i.e. IPC Technology as referred to in this paper) has been developed. A proprietary mixture of surfactants is used in several techniques associated with surface extraction as well as in-situ recovery of heavy oil and bitumen. This formulation of solvents and surfactants is reusable, low foaming, non-flammable, not acutely toxic, and non-carcinogenic. The efficacy of using IPC as an additive for waterflooding was presented earlier through a systematic coreflooding study, which showed increased ultimate recovery of different types of oils when compared with commercial surfactant and alkali flooding. In order to investigate the mechanisms behind the enhanced macro-scale oil recovery, a series of pore-scale tests were designed and conducted in this study. Glass micromodel type of porous media was used in the presence of brines with different ion compositions. The pore-scale chemical-assisted waterflooding tests were carried out in four consecutive stages: brine flooding, chemical flooding, soaking period, and extended brine flooding. High quality pore-scale images were captured for qualitative and quantitative analysis of the IPC-assisted waterflooding at the pore-level. IPC intensified water wettability of grain particles in the presence of NaCl; however in the presence of MgCl2, use of IPC makes solid surfaces oil-wet. The phenomenon of water-in-oil and oil-in-water emulsification was observed when IPC was used along with different brine compositions. This phenomenon is weakened for lighter oils. When the acid number of the oil was low, extension of soaking period intensified wettability alteration and emulsification mechanisms. Other pore-scale phenomena were also observed during visualization tests such as coalescence of microdroplets during the extended waterflooding stage, snap-off mechanism creating daughter droplets during the extended waterflooding stage, occasional flow of bulk oil films toward the production end, and wettability reversal during various flooding stages. Attempts were also made to conduct statistical analysis of emulsion droplet sizes under different test conditions. Several parameters, including chemical concentration as well as ion concentration in brines, were found to significantly affect the emulsion droplet size distribution.

Effect of Shear and Water Cut on Phase Inversion and Droplet Size Distribution in Oil–Water Flow

Oil–water dispersed flow occurs commonly in the petroleum industry during the production and transportation of crudes. Phase inversion occurs when the dispersed phase grows into the continuous phase and the continuous phase becomes the dispersed phase caused by changes in the composition, interfacial properties, and other factors. Production equipment, such as pumps and chokes, generates shear in oil–water mixture flow, which has a strong effect on phase inversion phenomena. The objective of this paper is to investigate the effects of shear intensity and water cut (WC) on the phase inversion region and also the droplet size distribution. A state-of-the-art closed-loop two phase (oil–water) flow facility including a multipass gear pump and a differential dielectric sensor (DDS) is used to identify the phase inversion region. Also, the facility utilizes an in-line droplet size analyzer (a high speed camera), to record real-time videos of oil–water emulsion to determine the droplet size distribution. The experimental data for phase inversion confirm that as shear intensity increases, the phase inversion occurs at relatively higher dispersed phase fractions. Also the data show that oil-in-water emulsion requires larger dispersed phase volumetric fraction for phase inversion as compared with that of water-in-oil emulsion under the same shear intensity conditions. Experiments for droplet size distribution confirm that larger droplets are obtained for the water continuous phase, and increasing the dispersed phase volume fraction leads to the creation of larger droplets.

Pickering stabilization of thymol through green emulsification using soluble fraction of almond gum – Whey protein isolate nano-complexes

In this study, the soluble fraction of almond gum (SFAG) as a sustainable biopolymer source and whey protein isolate (WPI) were used for self-assembly preparation of SFAG-WPI nano-complexes through electrostatic interaction. The SFAG was characterized using 1H and 13C NMR. The influence of total biopolymer concentration (0.2–0.4 %w/v) and ratios (1:3–3:1) as well as of the pH (2–6) on the formation of complexes was established by visual, light scattering, surface charge, and spectrometric observations. The outcomes proved the formation of negatively charged soluble complexes in the range of pH 4–5 and insoluble complexes at pH values 3 to 4. The soluble coacervate particles at pH 4.5 and total concentration of 0.4 %w/v were selected to induce Pickering stabilization of thymol. The static light scattering with microscopy studies (CLSM and Cryo-SEM) showed the formation of thymol oil-in-water emulsions by adsorption of nano-complexes on the surface of the droplets. Thymol emulsions stabilized using complexes had no size variation under storage (40 days) with an opaque and homogenous appearance. On the other hand, the emulsions containing solely WPI at pH 4.5 showed a substantial droplet size increase with severe creaming. Droplet size analysis together with coalescence and flocculation indices presented that coalescence was mainly responsible for droplet size coarsening of the emulsions stabilized by native WPI at pH 4.5. Overall, our outcomes indicated the improvement of WPI in the stabilization of emulsions through complexation.