Emulsion Formation Research Articles

Fabrication, characterization, and 3D printing of high-internal phase Pickering emulsion stabilized by heat-treated copra protein and calcium composite.

HCP-Ca nanoparticles were prepared by incorporating varying concentrations of CaCl2 into heated copra protein (HCP). The results showed a positive correlation between Ca2+ concentration and turbidity, indicating greater HCP aggregation with increasing Ca2+ levels. Microscopy analysis revealed that HCP-Ca nanoparticles had a rough surface morphology. Intermolecular forces such as disulfide bonds, hydrophobic interactions, and hydrogen bonds were key in the conformation of HCP aggregates, with calcium ions enhancing stability by forming salt bridges. HCP-Ca nanoparticle-based high internal phase Pickering emulsions (HIPPEs) were also fabricated using homogenization-centrifugation treatment. The nanoparticles showed contact angles of 87.8° to 98.3°, particle sizes between 80.42 and 80.95 nm, and the HIPPEs had zeta potentials ranging from -23 to -39 mV. The addition of Ca2+ enhanced stability by forming salt bridges, reducing particle size, and altering size distributions. Rheological and texture analysis showed that Ca2+ addition significantly improved the viscoelasticity of HCP-Ca nanoparticle-based HIPPEs, as well as increasing hardness and adhesiveness. Optical microscopy and magnetic imaging techniques revealed details about emulsion formation and oil-water distribution in HCP-Ca nanoparticle-based HIPPEs. The excellent printing stability and structural versatility of HCP-Ca nanoparticle-based HIPPEs allowed the formation of complex 3D structures, offering a valuable approach for fabricating processable and editable HIPPEs from waste materials. This paper aims to develop a food-grade copra protein-based Pickering HIPPE and explore differences in fabrication methods, providing new insights into the design of innovative Pickering stabilizers.

Designing invert emulsion drilling fluids for high temperature and high-pressure conditions.

Good and optimal rheology is a primary requisite for a drilling fluid to achieve better hole-cleaning and barite sag resistance. Conventional thickeners like organophilic clay that provide rheology to invert emulsion fluids degrade with time and thereby fail to maintain sufficient rheology of the drilling fluid. Generally, excess amount of organophilic clay or low gravity solids (LGS) is added to the drilling fluid to enhance rheology. However, addition of excess amount of organoclay or low gravity solids not only increases the cost of drilling but also may severely affect other drilling fluid properties, which will require further treatment. In addition, addition of organoclay or low gravity solids increases the plastic viscosity, decreases the rate of penetration thereby ultimately increasing the cost of drilling. Thus, there was a need to develop a drilling fluid with optimal rheology sufficient to give good hole cleaning and barite sag resistance. This paper describes the formulation of 70pcf, 90pcf and 120pcf organoclay-free invert emulsion drilling fluids formulated with a novel rheology modifier combination of RM1 and RM2. The paper describes the synergistic effect of RM1 and RM2 which is a combination of fatty acid and fatty amine respectively. The fluids were hot rolled at 250°F, 250°F and 350°F respectively and the temperature effect on the rheological and filtration properties were studied. The paper also describes the static aging and contamination studies of 90pcf and 120pcf fluids at 250°F and 350°F respectively. Rheology of the 90pcf invert emulsion fluid was measured across high temperature and high pressure (HTHP) conditions to observe their effects on the fluid properties. 70pcf, 90pcf and 120pcf organoclay-free invert emulsion drilling fluids formulated with the novel rheology modifier combination of RM1 and RM2 showed optimal rheology and low HTHP fluid loss. Static aging studies of 90pcf IEFs at 250°F respectively showed that the fluids are sag-resistant with low top-oil separation. Contamination studies of 90pcf fluid showed that the contaminants have minimal effect on the rheology and filtration properties of the invert emulsion fluid. HTHP rheology of the 90pcf invert emulsion fluid shows consistent rheology across high temperatures and pressures. The paper thus demonstrates the superior performance of the rheology modifier combination to achieve good rheological and filtration properties.

Development and stability evaluation of double emulsions enriched with Anthocyanins from Juçara

This study aimed to develop double emulsions enriched with anthocyanins extracted from juçara, a fruit rich in bioactive compounds with antioxidant properties. Anthocyanins are promising natural colorants but present instability to pH and temperature variations, limiting their application. Encapsulation in double emulsions (W/O/W) is an effective solution to increase the stability and retention of these compounds. The main objective was to develop and evaluate the stability of the double emulsions, aiming to protect the anthocyanins during processing. The methodology included the anthocyanins extraction from juçara and the formation of primary emulsions, followed by incorporation into external aqueous phases, testing different (W/O)/W proportions and concentrations of Arabic gum. The most stable double emulsion showed higher anthocyanin retention, with an encapsulation efficiency of 98.04%. The double emulsion system proved effective in protecting anthocyanins against different pHs, temperatures, and storage times, highlighting its potential for application as natural colorants in foods.

Simultaneous use of disulphide oil for chemical‐enhanced oil recovery by emulsion formation and stability with asphaltene deposition control

AbstractDisulphide oil (DSO) is a by‐product of oil and gas refining processes that is generated during the removal of mercaptans and the sweetening of light hydrocarbons. Asphalt deposition, especially asphaltene deposition during enhanced oil recovery methods, reduces oil recovery from the reservoir, so the use of a substance such as DSO, which has the ability to control and reduce asphaltene deposition, can be effective in increasing oil recovery from the reservoir. In this research, a micromodel with a fracture design and a matrix that represents fracture reservoirs was utilized. These tests were conducted in two groups. The first group of tests is related to adding DSO to crude oil and using 70 to 30 vol.% oil–water emulsion containing salt, surfactant, and nanoparticles. The second group involved adding DSO to both crude oil and emulsion. The first group aimed at stimulation and the second group aimed at chemical enhanced oil recovery (C‐EOR). The formation and stability of water‐in‐oil emulsion was done by analyzing the average droplet size. As a result, in the first group of tests with the presence of DSO in the oil, by measuring the average diameter before and after injection of AOS surfactant, it was observed that the average droplet size decreased from 6.89 to 4.01 μm, which indicates an increase in the emulsion stability. In the second group, where DSO was present in both oil and water emulsion in injected oil, it can be seen that the average diameter of the droplets in the surfactant decreased from 5.12 to 3.21 μm.

Fabrication of interfacial crystallized oleogel emulsion for quercetin delivery with enhanced environmental stability and bioaccessibility.

Quercetin is a flavonoid compound with numerous bioactivities. However, the low solubility, easy degradation and low bioaccessibility limit its application. In this study, a novel interfacial crystallized oleogel emulsion was fabricated, where beeswax was used as the oleogelator, for quercetin encapsulation with enhanced stability and bioaccessibility. The process of interfacial crystallization was investigated using interfacial rheology and polarized microscopy, with a positive correlation between crystal density and beeswax content in the oil phase. Emulsion stability was directly linked to beeswax concentration in the oil phase, with 100 mg g-1 showing enhanced stability under storage, UVB light exposure and ionic conditions. Beeswax addition significantly increased the quercetin loading capacity of the emulsion; particularly, at a 200 mg g-1 beeswax concentration, the loading capacity was improved by 285.55%, and the environmental stability was enhanced against UV light and Ca2+. Ultimately, in vitro simulated digestion experiment indicated improved bioaccessibility of quercetin. This strategy significantly enriched the formulation of oleogel emulsion and its potential applications in delivering bioactive ingredients with high environmental vulnerability. © 2024 Society of Chemical Industry.

Pickering Emulsion of Curcumin Stabilized by Cellulose Nanocrystals/Chitosan Oligosaccharide: Effect in Promoting Wound Healing

Background: The stabilization of droplets in Pickering emulsions using solid particles has garnered significant attention through various methods. Cellulose and chitin derivatives in nature offer a sustainable source of Pickering emulsion stabilizers. Methods: In this study, medium-chain triglycerides were used as the oil phase for the preparation of emulsion. This study explores the potential of cellulose nanocrystals (CNC) and shell oligosaccharides (COS) as effective stabilizers for achieving stable Pickering emulsions. Optical microscopy, CLSM, and Cyro-SEM were employed to analyze CNC/COS–Cur, revealing the formation of bright and uniform yellow spherical emulsions. Results: CLSM and SEM results confirmed that CNC/COS formed a continuous and compact shell at the oil–water interface layer, enabling a stable 2~3 microns Pickering emulsion with CNS/COS–Cur as an oil-in-water emulsion stabilizer. Based on FTIR, XRD, and SEM analyses of CNC/COS, along with zeta potential measurements of the emulsion, we found that CNC and COS complexed via electrostatic adsorption, forming irregular rods measuring approximately 200–300 nm in length. An evaluation of the DPPH radical-scavenging ability demonstrated that the CNC/ COS–Cur Pickering emulsion performed well in vitro. In vivo experiments involving full-thickness skin excision surgery in rats revealed that CNC/COS–Cur facilitated wound repair processes. Measurements of the MDA and SOD content in healing tissues indicated that the CNC/COS–Cur Pickering emulsion increased SOD levels and reduced MDA content, effectively countering oxidative stress-induced damage. An assessment based on wound-healing rates and histopathological examination showed that CNC/COS-Cur promoted granulation tissue formation, fibroblast proliferation, angiogenesis, and an accelerated re-epithelialization process within the wound tissue, leading to enhanced collagen deposition and facilitating rapid wound-healing capabilities. An antibacterial efficacy assessment conducted in vitro demonstrated antibacterial activity.

Structural characteristics determining starch digestibility in cooked rice complexed with an emulsion formulation

To evaluate the effects of structural characteristics on amylose-lipid complex (ALC) formation and the starch digestibility of cooked rice grains with the addition of 0, 5, 10, and 20 % emulsification formulation (EMF), both cooked rice (CR) grains with intact structural characteristics and CR slurry with their structural characteristics destroyed were examined. When EMF was added, the surface firmness, adhesiveness and adhesion of the CR grain changed. Depressions associated with ALC formation were observed on the surface of CR grains. The addition of more than 10 % EMF significantly suppressed starch hydrolysis in CR grains, while there was no significant difference in the starch digestibility of CR slurry, regardless of the amount of EMF. These results revealed that the structural characteristics of a layer like ALC on the CR grain suppressed starch digestibility and that once the structural characteristics were destroyed, the inhibitory effect of ALC on starch digestibility was lost.

Development of a demulsifier and technological process study for the preparation of highly viscous heavy oils for refinement

One of the challenges in the petroleum industry is the production of highly viscous heavy oils, often accompanied by undesirable emulsion formation with very high aggregate stability. To prepare the crude oils for refinement, the oils must be destroyed. The destruction of aqueous emulsions containing highly viscous heavy oils is an intricate task owing to the comparatively small disparity in water and oil densities, as well as the high viscosity of the dispersive medium and its high content of mechanical impurities. The problem of the destruction of petroleum emulsions arises desperately during the desalination and dehydration of crude oils with a high content of emulsifiers (resins, asphalts, paraffin, etc.) The creation of a highly efficient demulsifier and the development of an optimal technological process for the preparation of highly emulsifying oils that are distinguished by the composition and quantity of emulsifiers of West Siberian oils, which are widely refined in Russia, are the ways to resolve this challenging and timely issue. This study focuses on the viscous heavy oil of the Verbliouje deposit in the Astrakhan region. It also explains the creation of an effective demulsifier for the destruction of petroleum emulsions characterized by a very high emulsifying power and the fundamental principles of the development of deep dehydration technology and desalination of such high-viscosity heavy oils.

The Role of Eye Movements in the Process of Silicone Oil Emulsification After Vitreoretinal Surgery

Emulsification is a feared and common complication of the use of silicone oil (SO) as tamponade fluid after vitrectomy as it potentially associated with significant risks to ocular health, including elevated intraocular pressure (IOP), glaucoma, corneal and retinal changes. The aim of this study was to investigate the role and interplay of physical factors on the formation of SO emulsion. Experiments were performed in a model of the vitreous chamber with a realistic shape, filled with SO and an aqueous solution containing different concentrations of albumin, an endogenous protein known to modify the interfacial properties between SO and aqueous solutions. The model was subjected to harmonic and saccadic rotations and kept at body temperature. Results indicated that no emulsions were detected in the absence of albumin in the aqueous solution, while the presence of the protein facilitated emulsion formation, acting as a surfactant. Mechanical energy from eye movements was also found to be a key mechanism to produce emulsification, with higher mechanical energy provided to the system leading to smaller droplet sizes. The emulsions formed were stable over extended times. This study highlights the complex interplay of factors influencing SO emulsification in the vitreous chamber. A better understanding of the mechanisms underlying SO emulsification is crucial for developing strategies to mitigate SO emulsion and the related complications.

Waterborne cellulose acetate pickering emulsion generation mediated by cellulose nanocrystals for paper coating applications

There is a continually increasing demand for alternatives to single-use, non-degradable, and synthetic plastic packaging. Environmentally friendly paper products offer a potential solution, but typically do not meet stringent demands for barrier and other physical property performance unless coated with polymeric films, usually polyolefins. Replacing conventional plastic film coatings with bio-based polymer alternatives, such as cellulose acetate, can provide competitive barrier property performance while also providing sustainability benefits. Furthermore, water can be used as a coating medium for added environmental and coatability advantages. In this study, 10 wt% Pickering emulsions of cellulose acetate dispersed in water and stabilized via cellulose nanocrystals (CNC) were generated. Rheological behavior, particle size, stability, and particle morphology were analyzed, as was the effect of modifying the CNCs using (2-Dodecen-1-yl)succinic anhydride over several weeks. Unbleached kraft paper was coated and compared to polyolefin coated and uncoated paper. Water vapor permeability, grease resistance, water absorption, and wet mechanical properties were all investigated, displaying promising properties for barrier paper coating. The grease kit test yielded a result of 10/12 for the coated paper versus 0/12 for uncoated, and water Cobb value showed a 60 % improvement. Lastly, the performance of the coated paper as a food takeout container coating was explored, with convincing results demonstrating a strong avenue of applicability. Overall, the waterborne cellulose acetate Pickering emulsion formation and its paper coating application yielded promising results for sustainable packaging development.

Research and Application Progress of Crude Oil Demulsification Technology

The extraction and collection of crude oil will result in the formation of numerous complex emulsions, which will not only decrease crude oil production, raise the cost of extraction and storage, and worsen pipeline equipment loss, but also seriously pollute the environment because the oil in the emulsion can fill soil pores, lower the soil’s permeability to air and water, and create an oil film on the water’s surface to prevent air–water contact. At present, a variety of demulsification technologies have been developed, such as physical, chemical, biological and other new emulsion breaking techniques, but due to the large content of colloid and asphaltene in many crude oils, resulting in the increased stability of their emulsions and oil–water interfacial tension, interfacial film, interfacial charge, crude oil viscosity, dispersion, and natural surfactants have an impact on the stability of crude oil emulsions. Therefore, the development of efficient, widely applicable, and environmentally friendly demulsification technologies for crude oil emulsions remains an important research direction in the field of crude oil development and application. This paper will start from the formation, classification and hazards of crude oil emulsion, and comprehensively summarize the development and application of demulsification technologies of crude oil emulsion. The demulsification mechanism of crude oil emulsion is further analyzed, and the problems of crude oil demulsification are pointed out, so as to provide a theoretical basis and technical support for the development and application of crude oil demulsification technology in the future.

Emulsification in nearly Newtonian and non-Newtonian media of wormlike micelles

Emulsification experiments with four silicone oils, having viscosities ranging from 0.01 to 30 Pa.s, were conducted in two types of media: nearly Newtonian polyvinyl alcohol (PVA) solutions and non-Newtonian mixtures induced by worm-like micelles in solutions of sodium laureth sulfate and cocoamidopropyl betaine (BS) with NaCl. The increased viscosity of BS solutions upon the addition of NaCl did not significantly affect the drop size in the formed emulsions. In contrast, the increased viscosity of solutions with higher PVA concentrations significantly reduced the drop sizes for all silicone oils. A theoretical expression predicting the maximum drop size in both types of media (nearly Newtonian and non-Newtonian) was derived and validated against experimental data. The expression accounts for shear-thinning behavior in both the aqueous and oil phases. Interfacial stress dominates the breakage of less viscous oils, while viscous stress inside the breaking drop plays a leading role for more viscous oils. The formation of emulsions with similar sizes in non-Newtonian solutions of BS with different NaCl concentrations was explained by their strongly shear-thinning behavior, which leads to nearly similar viscosity at high shear rates, despite their zero-shear viscosities differing by more than two orders of magnitude.

The Impact of Homogenization Techniques and Conditions on Water‐In‐Oil Emulsions for Casein Hydrolysate–Loaded Double Emulsions: A Comparative Study

ABSTRACTThis study aims to evaluate homogenization techniques and conditions for producing stable, small droplet‐size water‐in‐oil (W/O) emulsions intended for incorporation into casein hydrolysate–loaded double emulsions. Three commonly used homogenization methods; rotor–stator, ultrasonic, and high‐pressure homogenization were individually optimized utilizing response surface methodology. Instances of over‐processing were observed, particularly with the rotor–stator and ultrasonic homogenizers under specific conditions. Nevertheless, optimal conditions were identified for each technique: 530 s at 17,800 rpm agitation speed for the rotor–stator homogenizer, 139 s at 39% amplitude for the ultrasonic homogenizer, and 520 s at 1475 bar for the high‐pressure homogenizer. Subsequently, the W/O emulsions produced under optimal conditions and their respective W1/O/W2 double emulsions were compared. The rotor–stator and high‐pressure homogenized W/O emulsions exhibited comparable narrow droplet‐size distributions, as indicated by similar Span values. However, high‐pressure homogenization failed to sufficiently minimize droplet size. Ultrasonic homogenization resulted in droplets at the 1‐μm scale but yielded more polydisperse droplet‐size distribution. According to TOPSIS analysis, an emulsion with a viscosity of 93.1 cP (centiPoise), a stability index of 93.8%, a D(90) of 0.67 μm (0th day), and a D(90) of 0.75 μm (30th day) produced using a rotor–stator was selected. Additionally, double emulsions containing primary emulsions prepared with the rotor–stator method demonstrated higher viscosity, narrower droplet‐size distribution, and lower creaming compared to other samples. This investigation sheds light on the influence of homogenization techniques on emulsion properties, providing valuable insights for optimizing double emulsion formulations.

New Biorefinery Approach for the Valorization of Fruit Processing Waste at a Local Scale: Pomegranate Pomace as Case Study

AbstractThe processing of fruit and vegetables generates globally high amount of organic waste, which is suitable to be valorized because of the chemistry it encloses. Conventional treatment methods for waste biomass generate low value products and cause climate altering emissions. Small biorefineries are valid alternatives for the sustainable waste biomass conversion, but their feasibility is strictly related to the use of low-energy process, and the market positioning of the final product. The present work provides an innovative approach for the green conversion of vegetable waste into high value product, with the aim to encourage the deployment of biorefinery at a local scale. It involves the enzymatic disassimilation of plant cell wall into chemicals with specific functions, and their recombination in form of emulsion, as a product prototype for food and cosmetic sector. To explain the biorefinery model, we applied it to pomegranate pomace, the residue from juicing, for the recovery of oil, pectin and antioxidant molecules via enzyme assisted extraction. The process left behind 30% of the initial solid waste. Finally, the dispersion of pomegranate oil into pomegranate pectin solution as emulsifier, brought to a novel emulsion, 98.9% waste-derived, further functionalizable with pomegranate exocarp hydrolysate with high antioxidant capacity. Graphical Abstract

Efficient recovery of organic phase from crud in solvent extraction unit of Sarcheshmeh copper complex in Iran by powerful water-absorbent reagents

The formation of stable multi-phase emulsions (crud) is a serious problem in almost all commercial solvent extraction (SX) plants. Crud is a mixture of organic and aqueous phases, air, and organic or inorganic solid particles, often found to distribute itself randomly throughout the separating phases of SX plants. Crud formation is encountered in almost all SX units in metal extraction plants. It causes the loss of solvent and thus increases the process costs. Therefore, the removal of crud and recovery of the expensive organic phase including diluent and extracting reagents from it is of great importance. In this research, the applicability of a range of powerful water absorbent reagents was studied for the recovery of organic phase from the crud formed in copper extraction/electrowining unit of Sarchashmeh copper complex (IRAN). The reagents included gypsum, carbomer, sodium polyacrylate, sodium sulfate, magnesium sulfate and calcium chloride. The results showed that gypsum, carbomer and sodium polyacrylate are effective additives which let the organic phase to be recovered with up to 95 % yield. To ensure that gypsum does not cause a negative effect on the copper loading and stripping of the recovered solvent, the extraction/stripping properties of the organic phase separated with gypsum was compared with the organic phase separated by centrifugation without additives. Surface tension analysis of the gypsum-recovered organic phase also confirmed its suitability for recovery of organic phase from crud. Finally, the calcium content of gypsum-recovered organic phase was measured and compared with that of the organic phase separated by centrifugation without any additive.

Enhancing dehydration/desalting efficiency of crude oil emulsions through experimental and computational insights

The formation of unwanted oil emulsions during producing, transporting, and processing crude oils is a major challenging issue, which causes serious technical problems, and subsequently huge financial losses. The present work delves into an optimization study focused on water separation from crude oil emulsions. The separation performance was initially assessed in static conditions through bottle tests, followed by a thorough investigation in dynamic conditions on an electrostatic desalting pilot plant under various conditions of the main operating parameters: temperature, oil space velocity, wash water ratio, and demulsifier concentration. The design of experiments and optimization of the process were performed by Central-Composite-Design of Response-Surface-Methodology (CCD-RSM). The effectiveness of the separation process has been analyzed by evaluating the Water-Removal-Efficiency (WRE) and Salt-Removal-Efficiency (SRE). The obtained results demonstrated that the used demulsifier was found to be extremely efficient and to have the greatest impact on the dehydration efficiency (F-value = 434.56). In addition, the sensitivity analysis indicated that the dehydration/desalting process is also very sensitive to the oil space velocity and wash water ratio while having less sensitivity to changes in the temperature. Furthermore, the process optimization indicated that the highest efficiency of simultaneous removal of water and salt from crude oil (WRE = 94.54 % and SRE = 97.23 %) was observed at optimal conditions of 19.5 ppm demulsifier concentration, 125 °C temperature, 1 1/h oil space velocity, and 6 vol% wash water ratio.

Production of Monodisperse Large Drop Emulsions by Means of High Internal Phase Pickering Emulsions-Processing and Formulation.

High internal phase Pickering emulsions (HIPPE) have received significant research attention in the last two decades due to their potential for a wide range of applications. The appropriate processing of such high-viscosity emulsions, hundreds of times more viscous than that of the continuous phase, and the control of the final droplet size remain challenges to be tackled. Our research targeted this knowledge gap by examining the influence of the emulsion formulation and the processing conditions on the final droplet size. The dispersed phase fraction (100 cSt silicon oil) ranged between 75 and 80%. The emulsions were produced in a regular mixing tank equipped with a helical ribbon impeller rotating at a low speed (100-150 rpm). The effective viscosity of the continuous phase was obtained from the experimental torque measurements. The droplet size distributions were measured after emulsification and dilution in the continuous phases. It is shown that the capillary number obtained from the observed emulsification performance can help predict the final droplet size. Our approach provides a straightforward methodology to generate concentrated Pickering emulsions with controlled and predictable droplet size.

Structure-property relationship of pea protein microgels as fat analogues in Pickering oil-in-water emulsions: effect of salt addition.

The design of plant-based microgels provides a platform for food ingredients to enhance palatability and functionality. This work aimed to explore the modifying effect of salt addition (KCl) on the structure of pea protein microgel particles (PPI MPs), on the interfacial adsorption and characteristics of formed emulsions as fat analogues. Salt addition (0-200 mmol L-1) promoted a structural transformation from α-helix to β-sheet, increased the surface hydrophobicity (from 1160.8 to 2280.7), and increased the contact angle (from 56.73° to 96.47°) of PPI MPs. The electrostatic shielding effect led to the tighter packing of MPs with irregular structures and lowered the adsorption energy barrier. Notably, salt-treated PPI MPs could adjust their adsorption state at the interface. The discernible adsorption of PPI MPs with 200 mmol L-1 salt addition that possessed enhanced anti-deformation ability dominated the interfacial stabilization, whereas a relatively rougher stretched continuous interfacial film formed after spreading and deformation of 0 mmol L-1 MPs. A tribological test suggested that emulsion stabilized by MPs at 0 (0.0053) and 80 mmol L-1 (0.0068) had similar friction coefficients to commercial mayonnaise (0.0058), whereas a higher salt concentration (200 mmol L-1) lowered its oral sensation due to the adsorption layer and enhanced the resistance to droplet coalescence during oral processing. Salt could be a modifier to tune the structure of microgels, and further promote the formation and attributes of emulsions. This study would improve application attributes of PPI MPs in the design of realistic fat analogues. © 2024 Society of Chemical Industry.

Comparison of Omega-3 polyunsaturated fatty acids bioavailability in fish oil and krill oil: Network Meta-analyses

Background and Aims: Fish oil and krill oil are primary sources of Omega-3 polyunsaturated fatty acids (PUFAs), differing in their molecular forms and bioavailability. Understanding these differences can optimize their therapeutic use. This study aims to compare the bioavailability of Omega-3 PUFAs in fish oil and krill oil using a network meta-analysis approach. By evaluating various molecular forms and dosages, the study seeks to identify the most effective Omega-3 sources and dosing regimens to maximize health benefits.Methods: The study adhered to the explanation of the PRISMA network meta-analysis 2015 (registered PROSPERO ID: CRD42024532536). The risk of bias was evaluated using the PEDro scale. This network meta-analysis incorporated data from studies published between 2003 and 2023, sourced from five databases: ClinicalTrials.gov, PubMed, Cochrane CENTRAL, the International Clinical Trials Registry Platform-World Health Organization, and Embase. Statistical analysis was conducted using advanced models in R software to ensure a rigorous evaluation of bioavailability.Results: Out of 26 high-quality studies, findings reveal superior bioavailability of krill oil compared to fish oil. Specifically, fish oil above 3000 mg, in re-esterified triacylglycerol or ethyl ester formulations (100–2900 mg), and krill oil (100–1900 mg) significantly enhanced the Omega-3 index. At lower dosages (under 2000 mg), krill oil shows superior Omega-3 absorption compared to fish oil. Using fish oil ethyl ester at doses between 2000 and 2900 mg may be the most effective for reducing Tmax. However, this finding should be interpreted with caution due to high heterogeneity and limited statistical significance. The highest AUC values were observed in krill oil phospholipid/free fatty acid formulation. Emulsion forms of fish oil are more effective in increasing Cmax than other formulations. These results were supported by robust statistical evidence (Egger's test, p > 0.05), highlighting the effectiveness of specific formulations and doses in optimizing Omega-3 absorption.Conclusion: The research highlights the importance of understanding the bioavailability of Omega-3 PUFAs from fish oil and krill oil. The findings suggest that low-dose krill oil and fish oil emulsions (under 2000 mg) are effective and potentially safer alternatives to high-dose fish oil, potentially minimizing the risk of adverse effects.

Emulsion formation and stability of surfactant–polymer flooding

Emulsification plays a pivotal role in the process of enhanced oil recovery, especially in chemical flooding. Surfactant–polymer flooding is a promising technique with significant potential for improving oil recovery in medium and high permeability oilfields in China. Emulsification has emerged as one of the key mechanisms facilitating oil recovery in surfactant–polymer flooding. This study aimed to assess the effects of surfactant structure and concentration, polymer, oil–water ratio, clay content, and injection rate on the formation of different emulsion types and their stabilities. The assessment was conducted based on the actual conditions of surfactant–polymer flooding in the Qizhong area of the Xinjiang oilfield. The findings revealed that KPS-1 (petroleum sulfonate) demonstrated superior emulsifying and solubilizing abilities for crude oil compared to BS-18 (betaine), whereas BS-18 exhibited better emulsifying stability. KPS, which was a combination system of KPS-1 and BS-18, displayed favorable emulsifying ability. However, the emulsifying stability of the three surfactants decreased in the presence of HPAM (hydrolyzed polyacrylamide). The oil–water ratio primarily influenced the morphology of the emulsion. When the oil–water ratio exceeded 6:4, a water-in-oil emulsion was formed, and the viscosity of the emulsion reached its maximum at an oil–water ratio of 7:3. Moreover, clay demonstrated a significantly high ability to emulsify, resulting in the formation of emulsions with increased viscosity and robust stability. Regarding the injection rate, effective emulsification occurred when the injection rate reached 1 m/d, while emulsions with high viscosity were observed at an injection rate of 7 m/d.