Emulsion Stability Research Articles

Pickering emulsions stabilized by cellulose nanofibers with tunable surface properties for thermal energy storage

Cellulose nanofibers (CNFs) have been widely used as a renewable emulsifier to stabilize two immiscible liquids due to their intrinsic amphiphilicity and excellent emulsifying ability. However, it remains challenging to fully understand the effects of carboxylate group content and surface charge density on the emulsifying ability of CNFs and the stability of Pickering emulsion. Herein, carboxymethylated CNFs were extracted from bleached kraft pulp using etherification reaction and high-pressure homogenization, allowing for easy surface charge density and size adjustment by changing sodium chloroacetate content and homogenization cycles. The optimizing CNFs possessed a high Zeta potential (−71.2 mV) and a suitable carboxylate group content (1.81 mmol/g), which enabled CNFs to irreversibly adsorb at the hydrophobic paraffin wax (PW) droplet surface and form interfacial steric barriers, providing large electrostatic repulsion between the PW droplets against coalescence. Thus, the CNF-stabilized PW emulsions could be stored for more than 6 months. Moreover, the phase change enthalpy of the freeze-dried emulsion is as high as 193.7 J/g, which provides the emulsion to reversibly store and release heat. This work provides a comprehensive insight into the interfacial stability mechanism of CNFs as stabilizers and facilitates the potential application in thermal energy storage.

Innovative Approach in Sustainable Agriculture: Harnessing Microalgae Potential via Subcritical Water Extraction

Microalgae can contribute to sustainable agriculture and wastewater treatment. This study investigated Tetradesmus obliquus, grown in piggery wastewater (To-PWW), as a biostimulant/biofertilizer compared to biomass grown in synthetic medium (To-B). Subcritical water extraction was tested for disruption/hydrolysis of wet biomass, at three temperatures (120, 170, and 220 ºC) and two biomass loads (1:10 and 1:80 (g dry biomass/mL water)). Extracts were evaluated for germination, and root formation/expansion. Residues were quantified for nutrient composition to assess their biofertilizer potential and tested for their affinity to oil compounds for bioremediation.The best germination was achieved by To-B extracts at 170 ºC (1:10: 148% at 0.2g/L, 1:80: 145% at 0.5g/L). Only To-PWW extracts at 0.2g/L had a significant germination effect (120 ºC: 120-123% for both loads; 170 ºC: 115% for 1:80). To-PWW extract at 120 ºC and 1:10 significantly affected cucumber and mung bean root formation (224 and 268%, respectively). Most extracts significantly enhanced root expansion, with all To-B extracts at 1:10 showing the best results (139-181%). The residues contained essential nutrients (NPK), indicating their biofertilizer potential, helping decrease synthetic fertilizers demands. To-B residues had high affinity to toluene and diesel but lower to used cooking and car oils. To-PWW showed very low affinity to all oil compounds. Finally, all residues were only able to form stable emulsions with the used car oil. This study fully exploits the use of microalgal biomass in sustainable agriculture, producing biostimulant extracts, and residues for biofertilizer and bioremediation, from a low-cost wastewater source.

Optimization of extraction for efficient recovery of kenaf seed protein isolates: evaluation of physicochemical and techno-functional characteristics.

Kenaf seeds are a rich source of protein; however, finding the best extraction method is crucial to obtaining high-quality protein from these underutilized seeds. This research devised an optimized extraction process for best recovery of kenaf seeds protein using response surface methodology. The key parameters affecting the yield and protein content were optimized, including extraction pH (2-11), seed:water ratio (5:1-50:1), temperature (30-90 °C), and duration (20-360 min). The physicochemical and techno-functional properties of kenaf seed protein isolates (KSPIs) were examined. A maximum protein yield of 12.05 g/100 g with purity level 91.94 g/100 g was obtained using an optimized extraction with pH 11.0, seed:water ratio 50:1, 360 min duration, and temperature 50 °C. The oil and water retention capacities of KSPI were 1.14 mL g-1 and 1.37 mL g-1 respectively. After 30 min at pH 7, KSPIs demonstrated remarkable emulsion capacity (83.12%) and stability (75.63%), along with high foaming capacity (106%) and stability (18.3%). As per high-performance liquid chromatography analysis, arginine, glutamic acid, leucine, phenylalanine, and lysine were the most abundant amino acids detected in KPSIs. The KSPIs' globular protein structure was successfully verified using analytical approaches, including Fourier transform infrared spectroscopy, protein fraction ratios, and differential scanning calorimetry. Sodium dodecyl sulfate polyacrylamide gel electrophoresis analysis revealed that KPSI has a molecular weight distribution ranging from 10 kDa to 50 kDa. The results of this study support the application of the proposed response-surface-methodology-optimized extraction method for efficient recovery of high-quality kenaf seed proteins that meet the necessary physicochemical and techno-functional requirements. © 2024 Society of Chemical Industry.

Role of the Polymer in the Emulsion Stability of an Amphoteric Polyacrylamide in Different Flooding Systems

Role of the Polymer in the Emulsion Stability of an Amphoteric Polyacrylamide in Different Flooding Systems

Impact of a Dual Treatment on Resistant Starch Level and Techno‐Functional Properties of Pea and Faba Bean Flours

AbstractStarch‐rich pulses’ flours, which are rich in fiber and resistant starch (RS), can be an interesting gluten‐free ingredient for the development of novel healthy foods. The study aims to increase the RS content of protein‐reduced fraction of legume flours (pea [P] and faba bean [FB]) by the application of thermal (autoclaving‐cooling) and dual (thermal plus high‐hydrostatic pressure) treatments. Both treatments enhance the RS contents, reaching 6.8% in P flour after dual treatment. The techno‐functional properties are dependent both on the type of flour and the treatment applied. A loss of water solubility (WS) and an increase in water binding capacity are observed. The WS index and emulsion activity remained unchanged or slightly changed, but emulsion stability decreased significantly. The viscosity of the samples is modified according mainly to the flour type. P flour is more affected by the dual treatment than FB flour, which is evidenced by the greater changes shown in RS, WS, and pasting properties.

Influence of Aqueous Phase Salt and Oil Phase Surfactants and Viscosity on the Dynamic Interfacial Tension and Coalescence Timescales.

Liquid-liquid separation is a critically important process in the treatment of emulsions that can occur in our environment, such as oily stormwater, shipboard bilgewater, or off-shore oil spill treatment. Effective filtration systems, including coalescing filters, are essential for mitigating these environmental pollutants. Achieving this requires a comprehensive understanding of liquid-liquid interface dynamics influenced by additives and surfactants. Furthermore, understanding the impact of surfactants on emulsion stability in saline environments is vital for optimizing filtration processes and ensuring the protection of marine and freshwater ecosystems. In this work, these effects are highlighted using measurements performed across a range of droplet size, surfactant concentration, viscosity ratios, and saline presence. Dynamic IFT measurements are conducted using the pendant drop method for water in light mineral oil, with and without salt in the water phase. The effect of salt addition is also highlighted by using microfluidic coalescence experiments, in which it was found that the addition of salt increases the dimensionless drainage time below the critical micelle concentration. The second focus of this work is to study the effect of bulk phase viscosity on the stability. Dynamic IFT measurements are performed at both millimeter and micrometer scales using pendant drop experiments and microfluidic tensiometry, respectively, involving light and heavy mineral oils with varying SPAN80 surfactant concentrations. The surfactant diffusivity and interfacial adsorption and desorption rates are then extracted by fitting a surfactant diffusion and equation of state equations to the dynamic IFT measurements. The results of the IFT decay, surfactant diffusivity, and adsorption rates are compared at two different viscosity ratios. This study also compares the times required for IFT relaxation with the film drainage times in water-in-oil systems. The comparison aids in comprehending the impact of competing timescales during film drainage. The findings presented in this paper offer valuable insights into the design and optimization of liquid-liquid filtration systems, especially when operating under challenging environmental conditions, such as in saline environments. The principles explored here can be applied to improving industrial water treatment and in the design of advanced filtration technologies for chemical and petrochemical industries, particularly those involving flow, contributing to more sustainable and efficient practices in handling emulsified waste streams.

Egg Yolk, a Multifunctional Emulsifier: New Insights on Factors Influencing and Mechanistic Pathways in Egg Yolk Emulsification

Egg yolk is a highly effective natural emulsifier used in various food products. Its emulsifying properties are influenced by food product chemical conditions, and processing methods. Nevertheless, to effectively utilize egg yolk in food products, a more comprehensive understanding of these factors is crucial. This review discusses recent developments regarding how factors like pH, ionic strength, thermal treatments, enzymatic treatments, and novel non-thermal treatments affect egg yolk emulsifying properties. It also explores the underlying mechanisms involved in egg yolk emulsification. Food products involve different ingredients leading to varying pH values and ionic strength, which affect egg yolk protein adsorption and emulsion stability. Processing steps like thermal treatment can damage egg yolk proteins, reducing their emulsifying capabilities and leading to unstable products. Incorporating sugar, salt, and amino acids can enhance egg yolk’s resistance to heat and preserve its ability to form stable emulsions. As an alternative to thermal treatment, non-thermal techniques such as high-pressure processing and high-intensity ultrasound can be employed to preserve egg yolk. Furthermore, forming egg yolk–polysaccharide complexes can enhance egg yolk emulsifying properties. These advancements have facilitated the creation of egg yolk-based products such as high internal phase Pickering emulsions (HIPEs), low-fat mayonnaise, and egg yolk gels. A comprehensive understanding of the emulsifying mechanisms and factors involved in egg yolk will be instrumental in improving food quality and creating novel egg yolk-based products.

Improved Antioxidant, Antihypertensive, and Antidiabetic Activities and Tailored Emulsion Stability and Foaming Properties of Mixture of Corn Gluten and Soy Protein Hydrolysates Via Enzymatic Processing and Fractionation

ABSTRACTBioactive peptides and protein hydrolysates have gained considerable attention in the food industry and functional food markets due to their diverse health effects, including antioxidant, antihypertensive, and antidiabetic properties. This study aimed to produce combined soy and corn protein hydrolysates using Alcalase (Al), modification of Al‐hydrolysates through sequential hydrolysis using Flavourzyme (Al‐FL), cross‐linking of Al‐hydrolysates using microbial transglutaminase (MTGase) (Al‐TG), and fractionation of Al‐hydrolysates by ultrafiltration (UF) with molecular weight (MW) cut‐off of 100 (Al‐F4), 30 (Al‐F3), 10 (Al‐F2), and 2 kDa (Al‐F1). Notably, the < 2 kDa fraction (Al‐F1) showcased exceptional biological activities, including antioxidant (81.54% DPPH, 98.02% ABTS), antihypertensive (95.45%), and antidiabetic effects (44.72% α‐glucosidase, 77.52% α‐amylase), linked to its high hydrophobic amino acid content and low molecular weights (111 and 263 Da). Conversely, the higher molecular weight fraction (Al‐TG) excelled in emulsion and foam stability, attributed to its balanced amino acid profile and larger peptides (1385–7057 Da). Our findings reveal that specific protein hydrolysate fractions, particularly Al‐F1 and Al‐TG, are promising for applications in food and pharmaceutical formulations due to their enhanced biological and functional properties.

Construction and characteristics of EGCG-porcine serum albumin pickering emulsion: Based on noncovalent interactions mechanism

Pickering emulsion prepared by the interaction between polyphenols and protein can improve the stability of protein-based emulsion. The purpose of this study was to explore the complex formation mechanism of epigallocatechin gallate (EGCG)-porcine serum albumin (PSA) complex and the preparation of food-grade Pickering emulsion. By the UV and fluorescence spectral analysis, it was found that EGCG has an obvious fluorescence quenching effect on PSA, mainly static quenching. The results of synchronous, three-dimensional fluorescence and FT-IR spectroscopy showed that the hydrophobic microenvironment of aromatic amino acids and the secondary structure of PSA changed after EGCG was added. The results of molecular docking examined that EGCG and PSA form more stable complexes due to hydrogen bonds, and the binding energy was −4.43 kcal /mol. Compared with the PSA emulsion, the successfully prepared EGCG-PSA Pickering emulsion had smaller droplets and no obvious color in CLMS. The Pickering emulsion of EGCG-PSA had strong emulsification and high viscosity, which belonged to pseudoplastic non-Newtonian fluid. In addition, the free fatty acids release rate of EGCG-PSA Pickering emulsion was decreased by 9.9 %. The antioxidant performance of the EGCG-PSA Pickering emulsion was improved, and the DPPH radical scavenging rate and the ABTS+ radical scavenging rate reached the highest, which were 93.72 % and 57.16 % respectively. This study provides important insights into the interaction between EGCG and PSA, and a reference for the development of polyphenol-protein complex Pickering emulsion in food, medicine, cosmetics, and other fields.

Characterization of Novel Exopolysaccharides from Weissella cibaria and Lactococcus lactis Strains and Their Potential Application as Bio-Hydrocolloid Agents in Emulsion Stability

The aim of the present study was the isolation of high exopolysaccharide (EPS) producers, Lactic Acid Bacteria (LAB) strains, from three types of milk: goat, sheep, and camel milk. Among 112 LAB isolates tested for their ability to produce EPS on MRS-sucrose agar, only 11 strains were able to produce EPS and only three higher producers’ strains were identified by 16S rRNA gene sequencing as two strains of Lactococcus lactis subsp. lactis (SP255, SP257) isolated from camel milk and one strain of Weissella cibaria (SP213) isolated from goat milk. The physicochemical characterization of the purified EPSs revealed a significant sugar yield, with concentrations ranging from 2.17 to 2.77 g/L, while the protein content remained relatively low (0.03 g/L). The UV-visible spectrum showed high Ultra Violet (UV) absorption at 240–280 nm and the Fourier-Transform Infrared (FTIR) spectra showed the presence of a large number of functional groups, including hydroxyl (-OH), carbonyl (-C=O), and methyl groups (-CH3). The EPS solubility indicated their hydrophilic properties and the investigation of interfacial properties indicated that these EPSs could be used as natural emulsifiers and stabilizers in both acidic and neutral emulsions. Moreover, a new type of emulsion system was developed by the utilization of EPSs in the formation of multilayer interfaces in oil-in-water (O/W) emulsions stabilized by sodium caseinate (CAS). Thus, the impact of an EPS addition on the particle size distribution and electrical charge has been studied. At pH 3, the studied EPSs adhered to the surfaces of caseinate-coated droplets and the stability of O/W emulsions was improved by adding certain concentrations of EPSs. The minimum concentration required to stabilize multilayer emulsions for EPSs SP255, EPS SP257, and EPS SP213 was 1.5, 1.5, and 1.7 g/L, respectively. These findings reveal a new EPS with significant potential for industrial use, particularly as an emulsion stabilizer.

The Potential Application of Mung Bean (Vigna radiata L.) Protein in Plant‐Based Food Analogs: A Review

ABSTRACTThe increasing demand for plant‐based food products by consumers along with the growing global population requires the discovery of novel and sustainable protein sources to address environmental challenges and meet nutritional requirements. Among various plant proteins, mung bean protein (MBP) exhibits several unique characteristics that make it a valuable ingredient in the field of plant‐based food analogs. This literature review aims to express the unique structure and composition of MBP, in addition to its physicochemical, functional, and nutritional properties. Furthermore, its potential applications in novel meat, dairy, and egg analogs are highlighted to meet the growing demand for sustainable, nutritious, and delicious plant‐based food alternatives. Structurally, MBP consists of a complex arrangement of amino acids, forming a globular protein with distinct functional properties. Its composition is also rich in essential amino acids, particularly leucine and lysine, making it a promising protein source for plant‐based diets. From a techno‐functional perspective, MBP exhibits remarkable gelling, emulsifying, foaming, and binding properties, which are necessary for the development of stable emulsions, airy foams, firm gels, and cohesive textures in various plant‐based food formulations. Moreover, MBP and its derivatives can possess notable bio‐functional properties, including antioxidant activity and anti‐inflammatory benefits, as well as cholesterol‐lowering, anti‐obesity, antidiabetic, antihypertensive, and anticancer effects. Consequently, the production of food analogs based on MBP not only improves the techno‐functional attributes of the final products but also can promote consumer health and well‐being.

Effect of pH-Shifting on Sunflower Meal Protein Isolate: Improved Stability and Interfacial Properties of Chitosan-stabilized Pickering Emulsion

Effect of pH-Shifting on Sunflower Meal Protein Isolate: Improved Stability and Interfacial Properties of Chitosan-stabilized Pickering Emulsion

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.

Functional characteristics and molecular structural modification of plant proteins. Review

Protein preparations from plant raw materials are widely used in the food industry as improvers, replacers or enrichers for products. However, their functional properties, as a rule, are less pronounced than those of proteins of animal origin. The aim of the review is to analyze and summarize the results of investigations dedicated to studying and characterizing the main functional properties of plant proteins (hydration, solubility, water binding capacity, fat binding capacity and gel-forming capacity, stability of emulsions, foams, rheological properties, texturization) and their modification. The objects of the research were scientific publications, most of which were published in 2017–2024. Functional properties of proteins were characterized; their dependence on the nature and variety of crop, methods of extraction, technological factors of processing and methods of modification was revealed. The search and selection of papers were carried out in the bibliographic databases eLIBRARY.RU, RSCI, Google Scholar, Scopus, Web of Science, Elsevier, and PubMed. Data analysis was performed with their systematization, generalization, intermediate conclusions and general conclusion. The special attention was paid to chemical, physical, physico-chemical and enzymatic methods for modification of protein properties, their advantages and disadvantages, as well as the interrelation of structural and physico-chemical features of proteins with their functional properties. The main regularities were revealed for an effect of modification methods on the secondary and tertiary structures of proteins, surface hydrophobicity, the ratio from fractions, aggregation, denaturation and biological activity obtained by the modern methods of investigations (IR‑spectroscopy, fluorescent microscopy, SDS-PAGE, circular dichroism, spectrophotometry and so on). It has been concluded that it is necessary to carry out further investigations aimed to studying interrelation of molecular structural features of proteins with indicators of functionality and regularities of their behavior in food systems due to an increase in the production of protein preparations from alternative raw materials (pea, chickpea, sunflower, kidney bean, rice and others). Based on the revealed and newly obtained theoretical information, the targeted modification and regulation of properties of protein ingredients for production of high-quality foods are possible.

Glycerol Carbonate as an Emulsifier for Light Crude Oil: Synthesis, Characterization, and Stability Analysis

This study focuses on the synthesis and application of glycerol carbonate (GC) as an emulsifier for light crude oil. GC was synthesized from glycerol and dimethyl carbonate via transesterification, achieving a 90% yield. Characterization through 1H-NMR, 13C-NMR, and FT-IR confirmed its structure. The emulsification properties of GC were tested by mixing it with light crude oil and water, demonstrating effective emulsification and forming stable emulsions. Stability tests with GC concentrations of 60/40, 70/30, and 80/20 revealed that emulsions remained stable for over 24 h. A particle size analysis indicated that higher GC concentrations produced smaller droplet sizes, enhancing the emulsification efficiency. This study highlights the potential applications of GC in oil spill remediation and enhanced oil recovery, emphasizing its biodegradability and low toxicity as environmental benefits. Overall, GC is presented as an effective and eco-friendly emulsifier for light crude oil, offering stable emulsions and promising industrial applications.

Influence of resins, asphaltenes and petroleum acid interactions on water/model oil interfacial properties and emulsion stability

The presence of natural lipophilic emulsifiers, such as asphaltenes (A), resin (R) and petroleum acids (PA) in crude oil, plays a crucial role in stabilizing the W/O emulsions. This study primarily focuses on elucidating the influence of their interactions on the interfacial properties of the water/model oil system, as well as its emulsion stability. First, equilibrium interfacial tension (IFT), interfacial dilational modulus (IDM) and phase angle are measured. Then, emulsion stability experiments are performed. Finally, microscopic images of the emulsions were captured to evaluate droplet size and dispersity. Results show that the addition of petroleum acid to both asphaltene-only and resin-only system reduces IFT and dilational modulus, weakening the strength of the interfacial film. The inhibitory effect of petroleum acid on resins’ adsorption at the interface is more pronounced compared to asphaltenes’. A low proportion of resin and petroleum acid (A/R ≥ 5, A/PA ≥ 7) enhances emulsion stability by co-adsorbing with asphaltenes at the oil–water interface. Conversely, a high proportion of resin and petroleum acid leads to a decrease in IDM and emulsion stability. For asphaltene/petroleum acid–water system, when A/PA ≤ 5, the presence of petroleum acid decreases the droplet size but enhances droplet dispersion while decreasing emulsion stability. It can be inferred that the presence of petroleum acids contributes more to the formation rather than stabilization of emulsions. This work deepens insights into the emulsion behavior of natural surfactants, providing theoretical guidance for the formation of stable emulsions underground and efficient demulsification above ground.

Application of reactive fatty alcohol ether sulfosuccinate emulsifier in surface sizing

AbstractIn this paper, a novel reactive fatty alcohol ether sulfosuccinate emulsifier (RAEOSS10‐9) was polymerized into macromolecular emulsifier RAFT‐PRS through reversible addition–fragmentation chain transfer (RAFT) polymerization, and then RAFT‐PRS was co‐polymerized with monomers to form anionic surface sizing agent. The structures of RAEOSS10‐9 and RAFT‐PRS were characterized by Fourier transfer infrared spectra, and the RAFT polymerization activity of RAFT‐PRS was verified by gel permeation chromatography. The effects of RAFT reagent and RAEOSS10‐9 content on the properties of sizing emulsion and sizing paper were investigated. The morphology of latex particles and sizing paper surface were observed by use of scanning electron microscope and atomic force microscope. The water resistance, bursting resistance and folding resistance of sizing paper were studied. The optimal formulation of sizing emulsion was built according to the above results. Besides, the investigation of the mechanical properties suggests that proper amount of reactive emulsifier is beneficial for enhancing the stability of emulsion and the performance of paper. The RAEOSS10‐9 displays better emulsifying properties than imported emulsifier SR‐10, and the emulsion produced by RAEOSS10‐9 display more excellent application properties.

Formation and Applications of Typical Basic Protein-Based Heteroprotein Complex Coacervations.

Lactoferrin, lysozyme, and gelatin are three common basic proteins known for their ability to interact with acidic proteins (lactoglobulin, ovalbumin, casein, etc.) and form various supramolecular structures. Their basic nature makes them highly promising for interaction with other acidic proteins to form heteroprotein complex coacervation (HPCC) with a wide range of applications. This review extensively examines the structure, properties, and preparation methods of these basic proteins and delves into the internal and external factors influencing the formation of HPCC, including pH, ionic strength, mixing ratio, total protein concentration, temperature, and inherent protein properties. The applications of different HPCCs based on these three basic proteins are discussed, including the encapsulation of bioactive molecules, emulsion stabilization, protein separation and extraction, nanogel formation, and the development of formulas for infants. Furthermore, the challenges and issues that are encountered in the formation of heteroprotein complexes are addressed and summarized, shedding light on the complexities and considerations involved in utilizing HPCC technology in practical applications. By harnessing the basic proteins to interact with other proteins and to form complex coacervates, new opportunities arise for the development of functional food products with enhanced nutritional profiles and functional attributes.

Rheological investigation of heavy oil-in-water pickering emulsions for potential applications of fracturing fluids

Pickering emulsions as a kind of emulsified fracturing fluids can enhance the efficacy of shale fracturing. Investigation of the rheological properties of Pickering emulsions yields valuable insights for their in-situ fracturing applications. In this work, nano-clay particles and heavy crude oil were employed to form oil-in-water (O/W) Pickering emulsions. The impact of salinity, pH, and temperature on the rheological properties, including viscosity property and viscoelastic property, of Pickering emulsions were tested and analyzed. The results showed that the viscosity of heavy O/W Pickering emulsions were significantly affected by the change of salinity and pH values, with higher salinity or lower pH resulting in increased viscosity. Under ultra-high salinities (>5 wt% NaCl), the coalescence stability of Pickering emulsion strengthens and creaming stability declines. The massive formation of clay clusters leads to a reduction in the number of nano-clay particles used to generate the network, causing instability in the emulsion creaming. The heavy O/W Pickering emulsions exhibited high stability and high viscosity characteristics, which were mainly caused by the change of surface charge of nano-clay particles and the corresponding change of particle adsorption on droplet surface and particle-particle interactions. At a salinity of 2.5% NaCl and a pH of 4.6, the emulsion system remained stable at a temperature up to 120 °C, holding a viscosity reaching 74.1 mPa s at a shear rate of 6.81 s−1. Besides, heavy O/W Pickering emulsions were viscoelastic fluids, with both noticeable viscous property and elastic property at the same time. Elastic modulus (G′) and viscous modulus (G″) of the emulsion increased with increasing salinity and decreasing pH, enhancing great deformation capacity. Remarkably, the Pickering emulsions could maintain its viscoelastic behavior at varying temperature conditions. For the first time, rheological study of Pickering emulsions formed by nano-clay nanoparticles as a single emulsifier to heavy oil. Our study underscores the emulsifying ability of nano-clay particles to heavy crude oils, under a wide range of salinity and pH, yielding Pickering emulsions with exceptional stability and rheological properties. This novel emulsion system, possessing high resistance to temperature and salinity, holds promise for a high-performance fracturing fluid design.

Encapsulation of resveratrol in nanosheet structured sodium caseinate dialdehyde β-cyclodextrin conjugate with enhanced physicochemical properties

The poor solubility and stability of resveratrol (Res) represent significant obstacles to its utilization and efficacy. Encapsulating in sodium caseinate (NaCas) has also faced issues concerning low encapsulation efficiency and stability. This study presented the synthesis of a novel NaCas and dialdehyde β-cyclodextrin (DA-β-CD) conjugate through the Schiff base reaction using a wet-heating method, which was then utilized to encapsulate resveratrol. Results showed the DA-β-CD was formed in the form of needle-like crystals, whereas the NaCas-DA-β-CD conjugate had a nanosheet structure. The NaCas-DA-β-CD exhibited a substantial increase in surface hydrophobicity, emulsifying activity index, and emulsion stability index. The incorporation of resveratrol into NaCas-DA-β-CD demonstrated a consistent and uniform dispersion at the nanoscale level. It achieved an encapsulation efficiency of 96.8% and exhibited excellent chemical stability, which surpasses those of the NaCas system. Furthermore, the water solubility and antioxidant capacity of resveratrol in NaCas-DA-β-CD exhibited characteristics similar to those in NaCas. The compacted nanosheet structure of the Res-NaCas-DA-β-CD complex, as observed in TEM and SEM, is likely responsible for those enhancements. Hence, the DA-β-CD can serve as an effective polysaccharide for protein modification, while the NaCas-DA-β-CD conjugate can function as an innovative delivery carrier for resveratrol and other hydrophobic bioactives.