Effect of Homogenization Pressure and Supplementation with Sucrose Fatty Acid Ester on the Physical Properties of Dairy Cream-based Emulsions.

Cross-linking proteins by laccase: Effects on the droplet size and rheology of emulsions stabilized by sodium caseinate

Palm fatty acid distillate (PFAD) is a by-product of palm oil refining that contains valuable bioactive compounds such as phytosterols, tocopherol, tocotrienols, and squalene which acummulates in unsa-ponifiable fraction (USF). In the form of emulsion, USF will be convenient and easy to use as food supplements or fortificants. Microemulsion is a type of emulsion that has stable droplet sizes less than 10 mm. Hence, the best emulsifier for USF microemulsion is important to be determined. The USF micro-emulsion was prepared by homogenizing the sample mixtures at 12.000 rpm for 20 min at USF concentration of 10% (w/v) with lecithin and tween 80 as emulsifiers at concentration of 0.5,1.0, and 1.5% (w/v). The microemulsions were analyzed for their viscosity, stability, and particle size distributions, as well as microstructures. The results showed that characteristics of microemulsion were affected by emulsifier types and concentrations. Tween 80 produced better microemulsion than lecithin indicated by more stable emulsions, smaller droplet sizes, and narrower ranges of droplet size distributions. The increasing lectihin concentrations resulted in a narrower droplet size distribution but the average droplet size was not always smaller. Conversely, the increasing tween 80 concentrations increased average droplet sizes and ranges of particle size distributions. The most suitable emulsifier for USF microemulsion was tween 80 at concen-tration of 0.5%. This microemulsion contained bioactive compounds derived from USF, namely vitamin E (mainly tocotrienols), phytosterols, and squalene.

Emulsion refers to a mixture that includes two or more liquid phases. The uses of emulsions are found in several chemical, energy, and environmental industries such as the food, health care, chemical synthesis, and firefighting sectors. Water‐in‐oil emulsions are formed spontaneously during oil production when oil and water are mixed together and in the presence of asphaltene as a naturally occurring surfactant. For operational and economic reasons, oil emulsions need to be treated to recover both oil and water phases. To develop more efficient emulsion treatments, it is essential to have a better understanding of the factors that affect emulsion formation and stability. The droplet size variation is an important parameter that influences the stability and rheological characteristics of the emulsions. In addition, the available interfacial area for any possible chemical reactions might affect the behaviours and properties of the emulsions in various transport phenomena systems. The adequate knowledge of the factors and mechanisms affecting the droplet size and emulsion stability still needs further engineering and research activities. This study is aimed to provide a comprehensive literature review on the formation of water/oil emulsions and their stability in various physical systems (e.g., pipeline networks and porous media). In this review, fundamental aspects of emulsions, emulsion formation mechanisms, analytical models, and numerical solutions for the description and characterization of the behaviours of emulsions in porous media and/or separators are discussed. The effects of different fluid properties, physical model characteristics, and operational conditions on emulsion behaviours are studied. This paper also summarizes the previous experimental and modelling studies and methodologies with a focus on reliable laboratory equipment/tools and simulation and modelling packages/strategies for the investigation of emulsion stability and droplet size distribution where a systematic parametric sensitivity analysis to study various effects of important thermodynamic, process, and medium properties on the targeted variables is conducted. This review manuscript provides useful guidelines to characterize and model emulsions and their behaviours in different industrial sectors, which will considerably help to conduct better design and optimal operation of corresponding equipment.

The adsorption of proteins at oil/water interfaces can reduce interfacial tension and increase emulsion stability. However, emulsions stabilized by soy protein isolate (SPI) are not sufficiently stable. Using SPI as a control, a theoretical basis for the adsorption behavior of mixed SPI and whey protein isolate (WPI) at the oil/water interface was established and the effects of the protein ratio and content on the emulsion stability were studied. Compared to SPI solution, SPI-WPI mixed solutions were found to reduce the size distribution of emulsion droplets and significantly improve the emulsion stability. Among the studied protein contents and ratios, the protein content of 0.2 g kg-1 and SPI/WPI mass ratio of 1:9 offered the lowest creaming stability index (15%), the smallest droplet size (278 nm), and the largest absolute value ζ-potential (35 mV), i.e. the emulsion stability was excellent. The largest dilatational modulus (10.08 mN m-1 ), dilatational elasticity (10.01 mN m-1 ), and dilatational viscosity (1.18 mN m-1 ), were observed with a protein content of 0.15 g kg-1 (SPI/WPI ratio of 1:9), along with a high interfacial protein adsorption capacity (47.33%). SPI-WPI complexes form a thick adsorption layer around oil droplets, resulting in an increase of the expansion modulus of the interfacial layer. SPI-WPI complexes can form a thick adsorption layer around oil droplets, resulting in increased expansion modulus of the interfacial layer, which improves emulsion stability. © 2020 Society of Chemical Industry.

The effect of silanization assisted nanoparticle hydrophobicity on emulsion stability through droplet size distribution analysis

Formation of Nanoemulsions by Stirred Media Milling

Production of more sustainable emulsions formulated with eco-friendly materials

The droplet size distribution (DSD) of emulsions is the result of two competitive effects that take place during emulsification process, i.e., drop breakup and drop coalescence, and it is influenced by the formulation and composition variables, i.e., nature and amount of emulsifier, mixing characteristics, and emulsion preparation, all of which affect the emulsion stability. The aim of this study is to characterize oil-in-water (O/W) emulsions (droplet size and stability) in terms of surfactant concentration and surfactant composition (sodium dodecyl benzene sulphonate (SDBS)/Tween 80 mixture). Ultraviolet-visible (UV-vis) transmission spectroscopy has been applied to obtain droplet size and stability of the emulsions and the verification of emulsion stability with the relative cleared volume technique (time required for a certain amount of emulsion to separate as a cleared phase). It is demonstrated that the DSD of the emulsions is a function of the oil concentration and the surfactant composition with higher stability for emulsions prepared with higher SDBS ratio and lower relative cleared volume with the time. Results also show that smaller oil droplets are generated with increasing Tween 80 ratio and emulsifier concentration.

Chapter 62 - Effect of the viscosity ratio ηd/ηc on the droplet size distributions of emulsions generated in a colloid mill

In the process of waterflooding development of heavy oil, W/O emulsion has a strong ability to improve the mobility ratio and block the high-permeability layer, which can effectively improve the sweep coefficient and enhance oil recovery. In this paper, the stability and droplet size distribution of emulsions under different conditions were studied by taking heavy oil and formation water from Jimusar Oilfield in Xinjiang as samples. On this basis, double-pipe core flooding experiments were carried out to study the shut-off ability and oil displacement efficiency of W/O emulsion, and then a numerical simulation was carried out. The results show that oil and water can be completely emulsified when the stirring speed is higher than 4000 r/min. A stable emulsion can be formed when the experimental temperature is lower than 60 °C. A lower water cut results in a more stable emulsion. The emulsion is difficult to stabilize after the salinity exceeds 10,000 mg/L. When the pH value is about 7, the stability of the emulsion is the worst. With the increase in stirring speed, the increase in temperature, and the decrease in water content and salinity, the emulsion droplet size range is relatively concentrated, and the average particle size is smaller. In heterogeneous reservoirs, the permeability of different percolation channels is quite different, such that the displacement fluid only percolates along the high-permeability channel and cannot drive oil effectively. The results of displacement experiments show that the emulsion with a water cut of 60% has high viscosity and obvious sweep ability, but its stability is very poor; the effect is opposite when the water cut is less than 40%. The shut-off ability of W/O emulsion disappears gradually when the permeability contrast is more than 5.92. The research results are of great significance for improving oil recovery in heterogeneous heavy oil reservoirs.

Effects of regenerated cellulose on oil-in-water emulsions stabilized by sodium caseinate

Physical properties of emulsion-based hydroxypropyl methylcellulose films: Effect of their microstructure

Palm oil emulsion drink is one of the food diversification product, containing high provitamin-A. The dispersed phase of the emulsion is palm olein, while the rest was water as the dispersion medium (ratio 7:3). The low content of dispersion medium in the emulsion caused the rheological properties, droplet size and distribution, as well as its level of stability to be different from other commercial product of beverage emulsion. This research investigated the effect of storage time on the rheological properties, droplet size distributions and stability of the emulsion. The emulsion morphology was observed by polarized light microscopy, while its size and distribution were analyzed by dynamic light scattering technique using Zetasizer. The rheological analysis, including the determination of the flow behavior and consistency index, were measured using a rotational dial reading viscometer. The results showed that increasing of storage time led to increased droplet size and distribution (d4.3 value from 4.83 to 6.12 µm, value of flow behavior index from 0.9782 to 0.9873, and consistency index from 3.473 to5.047 Pa.sn). However, this condition also caused a decrease in emulsion stability (from 0.880 to 0.823). According to Pearson’s correlation coefficients, the droplet size was negatively correlated with emulsion stability (R = -0.907; α = 0.01). However, the droplet size were positively correlated with the flow behavior index (R = 0.778; α = 0.01) and consistency index (R = 0.939; α = 0.01). These results may help formulate palm oil emulsion drink with improved stability and shelf-life.

A water-in-water (W/W) emulsion consists of droplets formed by the spontaneous liquid–liquid separation of two immiscible aqueous phases. The inherent properties of the W/W interfaces, low or ultralow interfacial tension (γW/W = 1–1000 μN/m) and a large thickness of several nanometers, beget the poor inherent stability of emulsions. Herein, we report a nanofibril emulsifier having Schiff base reactivity to generate a W/W emulsion. The W/W emulsion has superior stability (stable > 6 months) because collagen nanofibrils, acting as a stabilizer of W/W emulsions, can simultaneously satisfy the requirements of size and overall coverage ratio of the phase interfaces. W/W emulsions having γW/W ∼10 μN/m were used as synthetic synovial fluids, showing superior lubrication performance with a coefficient of friction in the range of 0.003–0.011, which has been demonstrated to be suitable for joint lubrication. An intraarticular injection assessment further confirmed this protective effect on articular cartilage in vivo. Our study reveals the mechanism of emulsion stabilization and opens up the possibility of osteoarthritis (OA) treatment using the biolubrication effects of W/W emulsions for lubricated artificial implant surfaces.

Rheological approaches as a tool for the development and stability behaviour of protein-stabilized emulsions