Emulsion Viscosity Research Articles

Tremella fuciform Polysaccharides: Extraction, Physicochemical, and Emulsion Properties at Different pHs.

The chemical composition, macromolecular characteristics, and structure of four types of Tremella fuciform polysaccharides (TPS) were analyzed, including one TPS that was extracted in the laboratory (L-TPS) and three commercial TPS. The effects of pH on the properties of TPS emulsions were investigated by analyzing their zeta potential, particle size, apparent viscosity, and stability. The results showed that L-TPS presented a higher percentage content of protein (2.33%) than commercial TPS (0.73-0.87%), and a lower molecular mass (17.54 × 106 g/mol). Thus, L-TPS exhibited the best emulsifying activity but gave poor emulsion stability. The droplet sizes and apparent viscosity of commercial TPS-stabilized emulsions were larger or higher in acidic environments. At pH 2, the apparent viscosity was the lowest for L-TPS. Commercial TPS emulsions were most stable at pH 6, while the L-TPS-stabilized emulsion was most stable at pH 2. The obtained results revealed that the emulsifying properties of TPS varied and the effects of pH on emulsion characteristics differed, as determined from the molecular mass, macromolecular characteristics, and structure. This research is useful for expanding the application of TPS as a novel food ingredient in emulsions.

Investigating the impact of processing conditions on the emulsion stability, viscosity, and foaming capacity of concentrated infant formula emulsions

Factors (degree of protein denaturation, order of lactose addition, pH, and lecithin concentration) affecting emulsion stability, viscosity and foaming capacity of concentrated infant formula systems were investigated through the application of Design of Experiments (DOE) methodology. Fat globule size (D50) varied from 0.63 μm to 4.92 μm depending on the processing conditions. The degree of fat droplets flocculation, ranging from 1.2 to 9.1, was observed to be driven mainly by the interaction term of pH and lecithin concentration. The viscosity of the concentrated infant formula emulsions varied widely from 28 mPa·s to 191 mPa·s, and was found to be not only a function the flocculation state of the emulsion systems, but also was likely impacted by other contributing factors. The interaction term of pH and lecithin concentration modified also significantly the foaming capacity of the studied samples (p = 0.019). Data suggested that the foaming capacity of the concentrated infant formula emulsions was affected by the presence of flocculated oil drops (p = 0.032). The findings of the present study may be considered in the formulation design of concentrated dairy-based emulsions to mitigate the adverse effects of viscosity development and foam generation during processing of such complex systems.

Dissolved gas amount influence on oil viscosity

The article presents the results of a study of oil gas saturation influence on its viscosity. Studies of the dissolved gas effect on the oil viscosity in a wide range of gas and water content changes in reservoir products are presented. According to some studies, the dissolved gas presence in oil can significantly reduce its viscosity. Based on a comparative analysis of the oil viscosity under standard conditions, a statistical relationship between the viscosity of gas-saturated oil and its standard value, depending on the gas saturation, was obtained. A method for gas-saturated water-oil emulsion viscosity calculating is proposed on the example of reservoir oils of the Arlan oil field based on preliminary measurement of the viscosity of degassed liquid and gas-saturated oil at 20° C, the residual amount of dissolved gas in oil determination by the degassing curve of this oil. Keywords: dissolved gas; degassed oil viscosity; water content; oil-water emulsion.

Formulation and Evaluation of Tea tree/ Rosemary Essential oil-based Microemulsion for Antimicrobial Activity

ABSTRACT: This research aims to prepare microemulsion from Tea Tree and Rosemary essential oil to treat gram-positive and gram-negative bacterial infections. A phase titration has been used to make the proposed microemulsion, which contained 71% water, 23% of a 1:1 mixture of propylene glycol (surfactant), tween 80 (co-surfactant), and 6% of tea tree/rosemary essential oil. In Rosemary essential oil pale yellowish transparent microemulsion, droplet size, zeta potential, and polydispersity index (PDI) of 58.9, 883.6, and 0.678, respectively, showed a stable microemulsion. Tea tree oil loaded in a light, clear microemulsion with zeta potential, droplet size, and polydispersity index (PDI) values of 265.9, 746.8, and 0.987, respectively, indicated a stable microemulsion. The RMO/TTO micro emulsion's viscosity was 1.844/1.933 cps, and its pH ranged from 4.69 to 5.59. The formulation was determined to be a safe, reliable, and effective one in light and good in stability experiments. Escherichia coli, Staphylococcus aureus, and Candida albicans can all be treated using a microemulsion that contains 6% tea tree oil and rosemary oil by agar well diffusion method. Both the EOs-based microemulsion showed more zone of inhibition against Escherichia coli and Candida albicans while Staphylococcus aureus is the less susceptible zone of inhibition. The microemulsion formulation's minimum inhibitory concentration was effective against Staphylococcus aureus, Candida albicans, and E. coli on all physiological parameters. It can be concluded that TTO/RMO essential oil-loaded microemulsion is considered a promising substitute for the current gram-positive and gram-negative regimens.

Starch-based Janus particle: Fabrication, characterization and interfacial properties in stabilizing Pickering emulsion

Janus particles (J-OSPs) based on the composite of chitosan nanoparticles (CSNPs) and octadecenyl succinic anhydride starch (OSPs) were tailor-made by Pickering emulsion method and electrostatic interaction. With different positions of OSPs embedded in the oil phase of Pickering emulsion template and the diversified shapes of starch particles, J-OSPs exhibited various asymmetric structures, which was verified by scanning electron microscope (SEM) and confocal laser microscope (CLSM). By characterizing the interfacial characteristics of J-OSPs, directional distribution of CSNPs was found to enhance the hydrophobicity of J-OSPs and changed its surface charges from positive to negative as pH increased. When J-OSPs were taken as stabilizers, the formed Pickering emulsion had the highest emulsion index and viscosity compared with OSPs and OSPs fully covered by CSNPs (F-OSPs), which was attributed to the self-assembly property of Janus particles that enabled them to form larger aggregates to hinder the collapse of droplets. This study provides a new idea for the construction of plant-derived Janus particles, and its superiority in stabilizing the Pickering emulsion will broaden the application of Janus particles in the field of storage and delivery of active substances.

Performance of ultrathin K2O·nSiO2 based laminated anti-fire glass: Influence of viscosity and morphology

The ultrathin K2O·nSiO2 based laminated anti-fire glass with super-multilayer morphology is prepared by a gradient heating method using a high SiO2 content (55 wt%) and low viscosity (684.5mPa.s ± 43.8mPa.s, 48 rpm) SiO2 core-shell emulsion. Meanwhile, K2O·nSiO2 with uniform morphology as a comparison sample is prepared by a thermostatic method using the same SiO2 emulsion. This article systemically characterized and analyzed the viscosity, morphology, hardness, ultraviolet (UV), and fire-resistant performance. The mechanism of shear-thinning characteristics is obtained by monitoring the viscosities of these SiO2 core-shell emulsions. The super-multilayer and uniform morphology are shown in SEM micrographs, and the UV-resistant capacity is more than 3000 h for outdoor use. Still, the hardness of the former is more than the latter. The foaming expansion layer has ensured window integrity under the fire. This work has provided a new simple routine for preparing ultrathin K2O·nSiO2 based laminated anti-fire glass for architectural safety applications.

Characteristics of Malaysian Crude Oils and Measurement of ASP Flooded Water in Oil Emulsion Stability and Viscosity in Primary Separator

With the application of chemical enhanced oil recovery methods, water separation is a major issue in a production facility. Oil/water separation is suppressed with a stable emulsion. The present study evaluated the impact of different emulsifiers in enhanced oil recovery. The effectiveness of each additive such as an alkali, surfactant, or polymer on the stability of the emulsion was anticipated using laser scattering to measure the emulsion’s stability. An artificial neural network was applied to predict the effectiveness of the additives on stabilization/destabilization and to assess how alkali/surfactants, surfactant/polymers, and polymer/surfactants affect the separation profiles. Measurements of the viscosity and zeta potential of residual emulsion clarify that the increase in surfactant makes the emulsion stable and became unstable with the increase in the alkali and polymer. The droplet zeta potential was within −i9~−i5 mV. The absolute value of the zeta potential decreased at a high polymer concentration with a low surfactant concentration resulting in fast flocculence phenomena. With an increase in the surfactant concentration and the presence of high alkali, the droplet’s absolute zeta potential demonstrated an increase in the repulsion force in the emulsions. The study also focuses on the carbon number distribution, wax appearance temperature (WAT) and wax content of four crude oil samples from different field locations (Miri, Angsi, Penara and Dulang). Findings show that crude oil samples with higher mol percent of carbon distribution from C20 to C40 (paraffinic composition) contains higher wax content, wt% and subsequently results in higher wax appearance temperature (WAT). This is obviously shown by the crude oil sample from Penara field. Further similar investigation on other field locations will assist in characterizing the paraffinic composition in Malaysian oil basins.

The role of β-subunit in emulsifying performance of β-conglycinin

The most crucial protein that affects the ability of soybean protein to emulsify is β-conglycinin. The subunit composition of β-conglycinin is one of the important factors affecting its emulsification performance. In order to investigate the effect of β-subunit of β-conglycinin on its emulsifying property, the separated and purified β-subunit was added to β-conglycinin in different proportions, and the properties of the β-conglycinin before and after emulsification were measured. The β-subunit appeared to improve the stability of the β-conglycinin in the aqueous dispersion as evidenced by the average particle size significantly decreasing, the surface hydrophobicity significantly increasing, and the Emulsification activity index and Emulsion stability index further improving. The secondary structure of β-conglycinin was altered by the addition of β-subunit, which caused more conversion of β-sheet and β-turn to α-helix, increasing the flexibility of protein molecules. Additionally, the particle size distribution, ζ-potential and creaming index of the stable emulsion formed by β-conglycinin were also measured. The results showed that the increase of β-subunit content improved the stability of the emulsion to some extent. The stability of emulsion mainly relies on their internal structure to maintain. It could be concluded from rheological analysis that the viscosity of emulsion increases due to the presence of β-subunits and the existence of weak gel structure inside them, which is corroborated by the results of confocal laser scanning electron microscopy. The elucidation of the influence of subunits on the emulsification characteristics of soyabean protein is beneficial to the development of soybean protein industry.

Impact of surface-modified silica nanoparticle and surfactant on the stability and rheology of oil-in-water Pickering and surfactant-stabilized emulsions under high-pressure and high-temperature

Emulsions have a wide range of applications, and with the advancement in the use of nanoparticles to form stable Pickering emulsions, it is important to understand their rheological properties to infer their stability under high-pressure and high-temperature (HPHT) compared to the emulsion formed using conventional surfactants. In oil and gas production strategies, oil often forms an emulsion with brine either within reservoirs or at surface facilities in the presence of natural or artificial surfactants. Nanoparticles are also being explored to increase oil recovery from matured reservoirs. In various instances, stable emulsions are either formed in-situ (within the reservoir) or at surface facilities or injected into the reservoir to mobilize the trapped oil. It is also essential to understand their rheology for efficient oilfield application. This study investigates the impact of surface-modified silica nanoparticles (Ludox CL), NaCl salt, and surfactant on the stability of oil-in-water Pickering and surfactant-stabilized emulsions under high-pressure (0.1–10) MPa and high-temperature (303–363) K conditions. The viscosity of emulsion samples was measured at varying shear rates (0.1–1000) s−1. The viscoelastic behavior (G′, G″, η*, and δ) of the Pickering emulsion and surfactant-stabilized emulsion were also measured. The stability of the emulsions was measured in terms of changes in emulsion viscosity and droplet diameter. Both emulsions showed non-Newtonian shear thinning behavior and an increase in droplet diameter under HPHT conditions. However, the surfactant-stabilized emulsion exhibits a greater degree of change in emulsion viscosity and droplet diameter than the Pickering emulsion. It indicates that the Pickering emulsion showed better stability than the surfactant-stabilized emulsion under HPHT conditions. Hence, Pickering emulsions are an incredibly promising tool that might be employed in HPHT applications, especially for enhanced oil recovery applications, due to their better rheological stability.

Enhanced freeze-thawing stability of water-in-oil Pickering emulsions stabilized by ethylcellulose nanoparticles and oleogels

This study developed water-in-oil (W/O) Pickering emulsions stabilized by ethylcellulose (EC) nanoparticles and EC oleogels, which presented significantly improved freeze-thawing (F/T) stability. Microstructural observation suggested EC nanoparticles were distributed at the interface and within the water droplets, and the EC oleogel trapped oil in the continuous phase. Freezing and melting temperatures of water in the emulsions with more EC nanoparticles were lowered and the corresponding enthalpy values were reduced. F/T led to lower water binding capacity but higher oil binding capacity of the emulsions, compared to the initial emulsions. Low field-nuclear magnetic resonance confirmed the increased mobility of water but decreased mobility of oil in the emulsions after F/T. Both linear and nonlinear rheological properties proved that emulsions exhibited higher strength and higher viscosity after F/T. The widened area of the elastic and viscous Lissajous plots with more nanoparticles suggested the viscosity and elasticity of emulsions were increased.

Effect of chemicals on the phase and viscosity behavior of water in oil emulsions

Due to population growth, the need for energy, especially fossil fuels, is increased every year. Since the costs of exploring new reservoirs and drilling new wells are very high, most reservoirs have passed their first and second periods of life, and it is necessary to use EOR methods. Water-based enhanced oil recovery (EOR) methods are one of the popular methods in this field. In this method, due to the possibility of emulsion formation is high, and by creating a stable emulsion, viscosity and mobility improved. In this study, the parameters affecting the stability and viscosity of the emulsion have been investigated step by step. In the first step, 50% (v/v) of water has been selected as the best water cut. The type of salt and its best concentration was evaluated in the second step by measuring the average droplets size. The third step investigated the effect of SiO2 nanoparticles and surfactant (span80) on emulsion stability and viscosity. According to the results, the best amount of water cut was 50% due to the maximum viscosity. In salts the yield was as follows: MgCl2 > CaCl2 > MgSO4 > Na2SO4 > NaCl. The best yield was related to MgCl2 at a concentration of 10,000 ppm. Finally, it was shown that the synergy of nanoparticles and surfactants resulted in higher stability and viscosity than in the case where each was used alone. It should be noted that the optimal concentration of nanoparticles is equal to 0.1% (w/w), and the optimal concentration of surfactant is equal to 200 ppm. In general, a stable state was obtained in 50% water-cut with MgCl2 salt at a concentration of 10,000 ppm and in the presence of SiO2 nanoparticles at a concentration of 0.1% and span 80 surfactants at a concentration of 200 ppm. The results obtained from this study provide important insights for optimal selection of the water-based EOR operation parameters. Viscosity showed a similar trend with stability and droplet size. As the average particle size decreased (or stability increased), the emulsion viscosity increased.

Modulating hydrophilic properties of β-cyclodextrin/carboxymethyl cellulose colloid particles to stabilize Pickering emulsions for food 3D printing

This research investigated edible Pickering emulsions stabilized by polysaccharide complexes as inks for food 3D printing. The interface membrane structure in the Pickering emulsion system was formed using complexes consisting of β-cyclodextrin (β-CD) and carboxymethyl cellulose (CMC). Except for provide sufficient steric barrier and electrostatic repulsion to increase the stability of the Pickering emulsions, the interface membrane constructs also can demonstrate good biphasic wettability and lower oil/water interfacial tension. The hydrophilicity of complexes (β-CD/CMC) was mainly adjusted by the ratio of β-CD/CMC (Rβ/C) and the substitution degree (DS) of CMC, which further adjusted the physical and chemical properties of Pickering emulsion to make it correspond to the rheological behavior applied to 3D printing. The stable Pickering emulsion (Rβ/C = 2:2, DS = 1.2, weight ratio of oil phase (φ) = 65 %) displayed excellent printing potential by characterizations analysis of Pickering emulsions. The smoothness, viscosity, and self-supporting ability of the Pickering emulsion under the optimized conditions were further analyzed using a filling density printing experiment of a cuboid model. The emulsifying properties of β-CD were adjusted by hydrophilic CMC to achieve the required amphipathic properties of the complexes to develop Pickering emulsions for food 3D printing.

Effect of γ-polyglutamic acid on the physicochemical properties of soybean protein isolate-stabilized O/W emulsion.

An increased interest has been observed in the application of soybean protein isolate (SPI) into O/W emulsion because of the amphipathic characteristics of SPI. However, at pH around 4.5, SPI was almost lost its hydrophilic characteristic, thus greatly limiting its application in emulsion under an acidic environment. Therefore, this drawback of SPI needs to be urgently solved. This study aims to investigate the effect of γ-polyglutamic acid (γ-PGA) on physicochemical properties of SPI-stabilized O/W emulsion. The results suggested that the interaction between γ-PGA and SPI improved the SPI solubility in solution, and increased emulsifying properties of SPI in the pH range of 4.0-5.0 via electrostatic interaction. Meanwhile, the charge neutralisation between SPI emulsions with γ-PGA was confirmed via ζ-potentiometry. With the presence of γ-PGA in emulsion at pH 4.0 and 5.0, the electrostatic complexation between SPI and anionic γ-PGA exhibited decreased the viscosity of SPI emulsion, which might be related to the phenomenon as indicated by the confocal laser scanning microscope measurements. Therefore, the electrostatic complexation between SPI and γ-PGA suggested that the promising potential of γ-PGA to be used in SPI-stabilized O/W emulsion under an acidic environment.

Whey Protein Isolate-Mesona chinensis Polysaccharide Conjugate: Characterization and Its Applications in O/W Emulsions.

Mesona chinensis polysaccharide (MCP), a common thickener, stabilizer and gelling agent in food and pharmaceuticals, also has antioxidant, immunomodulatory and hypoglycemic properties. Whey protein isolate (WPI)-MCP conjugate was prepared and used as a stabilizer for O/W emulsion in this study. FT-IR and surface hydrophobicity results showed there could exist interactions between -COO- in MCP and -NH3+ in WPI, and hydrogen bonding may be involved in the covalent binding process. The red-shifted peaks in the FT-IR spectra suggested the formation of WPI-MCP conjugate, and MCP may be bound to the hydrophobic area of WPI with decreasing surface hydrophobicity. According to chemical bond measurement, hydrophobic interaction, hydrogen bond and disulfide bond played the main role in the formation process of WPI-MCP conjugate. According to morphological analysis, the O/W emulsion formed by WPI-MCP had a larger size than the emulsion formed by WPI. The conjugation of MCP with WPI improved the apparent viscosity and gel structure of emulsions, which was concentration-dependent. The oxidative stability of the WPI-MCP emulsion was higher than that of the WPI emulsion. However, the protection effect of WPI-MCP emulsion on β-carotene still needs to be further improved.

Preparation of hydrophobic nano calcium carbonate and its application in EOR

W/O emulsification flooding is a new type of oil displacement method, which can effectively improve oil recovery, but there are few materials used for W/O emulsification at present. Therefore, we prepared a hydrophobic nano calcium carbonate (WS-Ca) and compounded it with Span80 to form a nano oil displacement system. The contact angle experiment demonstrates that WS-Ca is lipophilic material. After testing the emulsification performance, viscosity, interfacial tension and oil displacement performance of the oil displacement system, it is found that the nano oil displacement system with the best performance is WS-Ca (800ppm) +Span80 (1%), and the displacement system and oil are emulsified into W/O emulsion, and the viscosity of emulsion is 25 times that of crude oil. Furthermore, the oil displacement system can successfully lower the oil-water interfacial tension and increase the oil recovery of injection water to 62.63%.

Emulsified Silica Gel for Deep Reservoir Water Conformance Control

Large volumes of water are produced with the production of oil, posing challenges of corrosion, scaling, and an increased water–oil ratio. Silica-based gels have previously been used as water sealants; however, reservoirs with high temperature and/or salinity cause early gelation, thereby preventing deep penetration into the reservoir. This work discusses factors affecting gel formation from colloidal silica and mixing methods for the preparation of a thermally stable Pickering emulsion and the effect of various parameters on its rheology. Sensitivities include salinities ranging from 5 to 20 wt % for seven different salts, silica gel concentrations from 20 to 28 wt %, pH values from 4 to 9, and temperatures from 80 to 150 °C. The effect of each parameter on the gelation time and gel strength was studied at a constant shear rate and pressure of 100 s–1 and 1100 psi, respectively. A commercial phyllosilicate (organoclay) has been used with diesel to form an invert emulsion of 28% silica gel, with diesel as a continuous phase and colloidal silica as a dispersed phase. Dynamic gel tests were performed to study the effect of the emulsion mixing method, temperature, and organoclay concentrations on the emulsion stability, strength, and viscosity. A lower concentration of salt has a longer gelation time with a lower gel strength. Increasing pH increases the gel strength but reduces the gelation time. The Pickering emulsion formed is stable to high shear, high temperatures, and high salinities. The bulk mixing method produces a direct emulsion, whereas drop-by-drop mixing results in an invert emulsion. A comparison of the gelation time and viscosity has also been provided with non-emulsified silica gel to highlight the benefit of encapsulation in terms of increased gelation time. This work will help academia and industry in designing a cost-effective system for water conformance control in harsh reservoir conditions.

Experimental study on self–emulsification of shale crude oil by natural emulsifiers

Self–emulsification can be accomplished by enhanced oil recovery (EOR), the realization of the exploration of natural emulsifiers, which is a crucial task to understand the mechanism of crude oil self–emulsification, albeit it is, of course, accompanied by difficulties, during the development of shale crude oil. In this study, we separated the active components of crude oil, and with the help of modern characterization and laboratory tests, coupled with nuclear magnetic resonance of core flooding method, we fully explored the independent and synergistic effects of crude oil active components, and deepened the understanding of the mechanism of crude oil self–emulsification. Among the active components of crude oil, asphaltene and resin have vital effects on its self–emulsification, which is shown in the amphiphilic structure of asphaltene and the effect of resin solvent. Asphaltene can reduce oil–water interfacial tension to 19 mN/m, and the resin significantly increase the viscosity of emulsion. Meanwhile, resin and asphaltene stabilize the viscoelasticity of oil–water interface films and affect the phase transition of emulsions in different water oil ratio environment. As a result, the active components of crude oil are closely related to formation and stabilization of the emulsion, which together endue the inherent conditions of its self–emulsification. Core flooding test confirmed that some emulsions in nanoscale size are produced in shale porous media, and the average emulsion diameter size is 181 nm. This study explored the effects of natural emulsifiers on the self–emulsification of crude oil, thereby promising new potential opportunities for EOR of shale oil.

High internal phase emulsions and edible films with high methoxyl pectin and pea protein isolate or sodium caseinate

Structuring of sunflower oil by forming HIPEs in the presence of high methoxyl pectin (HMP) and pea protein isolate (PPI) or sodium caseinate (SC) was evaluated first. Initially, emulsions with protein: polysaccharide ratios of 2:1 and 6:1 and two different pectin concentrations (0.5 and 1% wt) were formed and compared with emulsions with just protein, with the former exhibiting greater viscosity and stability. All emulsions exhibited pseudoplastic behaviour with the higher biopolymer concentrations leading to increased emulsion viscosity. The type of protein was significant for stability only for the initial pectin concentration of 0.5% wt. Then, SC and PPI emulsions with a protein: polysaccharide ratio of 6:1 for both pectin concentrations were selected for HIPE formation. The formed HIPE for both proteins had a great oil loss (83–95%), showing that the used combination of biopolymers did not lead to the formation of a structured system. Subsequently, edible films formed by drying the aqueous dispersions of the previously selected protein-polysaccharide binary systems were studied. All films had the same density. The greater total biopolymer concentration led to thicker, heavier, stronger and stiffer films with greater water vapour permeability and opacity. SC films were thicker, heavier, stronger, stiffer and brighter than PPI films, with lower moisture content and opacity. Overall, the used protein affected the studied properties of the films, indicating differences in the formed network.

Amphiphilic O(Phe-r-Glu) oligopeptides randomly polymerized via papain exhibiting a pH-insensitive emulsification property

Natural amino acid polymers have been wide-used as bio-compatible emulsion stabilizers. In this study, Amphiphilic O(Phe-r-Glu)s were synthesized through the papain-catalyzed random polymerization of L-phenylalanine and L-glutamate with the major degree of polymerization value of 6–7. The polymerization yield was increased by more than 35 % using choline to reduce the energy barrier for the amino substrates to form the tetrahedral intermediate with the catalytic triad. The squalene/water emulsions stabilized by O(Phe-r-Glu) nanoparticles were pH-insensitive at pH 1–12. The investigation of mechanism found the combined effects of steric hindrance, electrostatic repulsion and the viscosity of the emulsion contributed to the stability of the emulsion droplets. Under acidic condition, the layers of O(Pho-r-Glu)s particle aggregates formed around the emulsion droplets and the higher viscosity of emulsion mainly contributed to the stability of emulsions. At basic condition, the strong electrostatic repulsion between emulsion droplets covered by the negatively charged O(Pho-r-Glu) particles and the steric hindrance contributed mainly to the prevention of the coalescence of emulsion droplets. The application of enzymatically synthesized amphiphilic peptides in emulsion, along with tunable performance through the polymerization of amino substrates, is in line with the sustainable development requirements in fields such as pharmaceuticals, food and cosmetics.

High-intensity ultrasound assisted-emulsification using ionic liquids as novel naturally-derived emulsifiers for food industry applications

Over the last decade, conscious food consumption has been revolutionizing the food industry. The search for additives that meet concepts of naturalness, healthiness and sustainability represents one of the major challenges in food industry. The development of emulsifiers in the ionic liquid (IL) form using compounds that can be obtained from natural sources to replace conventional ones is a promising approach. In this work, we have reported the application of bio-based ILs derived from fatty acids (FAs) and choline (Ch) as novel emulsifiers to produce potential food-grade oil-in-water emulsions by pre-mixing (PM) or PM followed by high-intensity ultrasound (HIUS)-assisted process (PM + U). The effects of the type of IL, considering molecular structures of FAs (C18OOH or C18:1OOH) and vegetable oil concentration (30:70 or 70:30, oil:water ratio) to form and stabilize emulsions were evaluated. The study was focused on the following aspects: synthesis and characterization of ILs, and kinetic stability, droplet size and size distribution, optical microscopy, viscosity profile and rheological behavior of the emulsions. ILs presented high emulsifier ability, since some emulsions were stable after storage time of at least 30 days, being such stability related to the type of IL, oil concentration and emulsifying process. The observed behavior was associated to lower droplet size and/or emulsion viscosity. [Ch][C18OO] presented higher emulsifier ability than [Ch][C18:1OO], and this behavior was more evident at higher oil concentration. Emulsions obtained by PM presented phase separation after their preparation, whereas most of those prepared by PM + U were visually stable, being those containing higher oil concentration the formulations that presented higher viscoelasticity, with a gel like behavior. Therefore, bio-based ILs have promising application potential as emulsifiers, and their use to obtain high stable emulsions can be enhanced by using the HIUS technique.