Surfactant Emulsifier Research Articles

Preparation and characterization of vitamin E microcapsules stabilized by Zein with different polysaccharides

Vitamin E (VE) microencapsulation using a green surfactant emulsifier not only protects the active substance and is also environmentally friendly. In this study, we used alcohol ether glycoside as an emulsifier to prepare VE microcapsules using the biological macromolecule Zein and various polysaccharides. The resulting nano microcapsules exhibited a spherical structure, stable morphology, uniform size, and a >90% encapsulation efficiency. They also had good thermal stability and slow-release properties. Of these, xanthan gum/Zein-VE microcapsules were superior, with antioxidant properties up to 3.05-fold higher than untreated VE. We successfully developed VE nano microcapsules that meet eco-friendly and sustainable requirements, which may have applications in the food and pharmaceutical industries.

Fat crystallization and physical characteristics of mung bean protein-based frozen whipped emulsions: Effect of lipophilic surfactants and quinoa hydrolysate

Yogurt ice cream (acid frozen whipped emulsion) is a complex frozen emulsion-foam system. The study investigated the impact of three lipophilic surfactant emulsifiers [glyceryl monostearate (GMS), polyglycerol ester (PGE), and sucrose ester 970 (S970)] and quinoa hydrolysate (QH) on fat crystallization, physical properties, and morphology of frozen whipped emulsions containing fermented mung bean protein. QH serves as a sustainable and health-conscious alternative to traditional emulsifiers. pH12-shifting treatment was utilized to modulate fermentation performance of mung bean protein. Yogurt-like ice creams (10% coconut oil) were formulated using pre-whipped emulsions comprising fermented pH12-treated mung bean protein (FMP12) or native mung bean protein (NFMP), along with 0.5% (w/w) emulsifiers or QH. Pre-whipped FMP12 emulsions exhibited significantly higher emulsification stability (P < 0.05) compared to NFMP emulsions, owing to the better-balanced hydrophilic-lipophilic nature of FMP12. The individual addition of surfactants and QH promoted fat crystallization and improved the stability and viscous of FMP12 emulsion by competitively adsorbing with FMP12 at the O/W interface. Upon freezing, all three surfactants in whipped creams resulted in uniform and fine ice crystals with a moderate accumulation of oil droplets, showing a comparable effect to QH. Consequently, FMP12 frozen whipped emulsions with surfactants or QH both exhibited superior hardness and overrun, attributed to the presence of fine ice crystals and a stable fat crystal skeleton structure. These findings indicate the prospective utility of QH as a substitute for conventional small chemical emulsifiers, thereby enhancing the quality attributes of plant-based yogurt ice cream.

Synthesis and Performance Study of the Nanomaterial Used to Stabilize the Reversible Invert Emulsion Drilling Fluid

The reversible invert emulsion drilling fluids can achieve performance of oil based drilling fluid and solve the disadvantages associated by the oil based drilling fluid. This reversible invert emulsion drilling fluid can also focus the advantages of both oil based and water based drilling fluids. The surfactant emulsifier is the currently reported emulsifier used in the reversible invert emulsion. The stability of the reversible invert emulsion drilling fluid is very poor that can be known from the low emulsion breaking voltage. The dosage of the surfactant emulsifier is so much that it can increase the drilling cost and environmental pollution. In this paper, organic amine surfactant-modified nanoparticles are prepared and the modified nanoparticle which can be used to stabilize the reversible invert emulsion drilling fluid is chosen. The stability of the reversible invert emulsion drilling fluid stabilized by modified nanoparticles (emulsion breaking voltage&gt;1100V) is better than the reversible invert emulsion drilling fluid stabilized by surfactant (450V&lt;emulsion breaking voltage&lt;600V). The dosage of the organic amine surfactant-modified nanoparticle emulsifier (2.4 wt.%) is less than the dosage of the surfactant emulsifier (4 wt.%), hence, reducing the drilling cost and environmental threat. The reversible invert emulsion drilling fluid stabilized by modified nanoparticles perform similar to the reversible invert emulsion drilling fluid stabilized by surfactant in the aspect of oiliness cuttings treatment. The reversible invert emulsion drilling fluid stabilized by modified nanoparticles also perform well in the aspect of oiliness cuttings treatment.

Oxidative stability of oil-in-water emulsions stabilised with protein or surfactant emulsifiers in various oxidation conditions

Many studies have investigated the effect of emulsifiers on the oxidative stability of oil-in-water (O/W) emulsions. A better oxidative stability of surfactant-stabilised O/W emulsions as compared to protein-stabilised emulsions has been recently shown in conditions when the major part of the emulsifier is adsorbed at the oil–water interface and oxidation is induced by iron−ethylenediaminetetraacetic acid (EDTA) complex. In this work, the contribution of the interfacial layer to the oxidation of emulsified lipids is investigated under various incubation conditions, involving different oxidation mechanisms. O/W emulsions were formulated at pH6.7 with limited amounts of emulsifiers in the aqueous phase. Emulsions were incubated either at 33°C without initiator at 25°C in the presence of iron/ascorbate, metmyoglobin or 2,2′-azobis(2-amidinopropane)-dihydrochloride (AAPH). Oxygen uptake and volatile compound formation confirmed that protein-stabilised emulsions are less oxidatively stable than Tween 20-stabilised ones. This work also shows complex oxidative interrelationships between oxidation initiator and certain proteins, such as β-casein and bovine serum albumin.

Quantification of unadsorbed protein and surfactant emulsifiers in oil-in-water emulsions

Unadsorbed emulsifiers affect the physical and chemical behaviour of oil-in-water (O/W) emulsions. A simple methodology to quantify unadsorbed emulsifiers in the aqueous phase of O/W emulsions has been developed. Emulsions were centrifuged and filtered to separate the aqueous phase from the oil droplets and the concentration of unadsorbed emulsifiers in the aqueous phase determined. The quantification of unadsorbed surfactants based on the direct transesterification of their fatty acids was validated for Tween 20, Tween 80, citric acid ester (Citrem), Span 20 and monolauroyl glycerol. To determine unadsorbed proteins, results obtained with Folin–Ciocalteu reagent or UV-spectrophotometry were compared on emulsions stabilized by β-lactoglobulin (BLG), β-casein (BCN) or bovine serum albumin (BSA). The first method gave more accurate results especially during aging of emulsions in oxidative conditions. The whole methodology was applied to emulsions stabilized with single or mixed emulsifiers. This approach enables optimization of emulsion formulations and could be useful to follow changes in the levels of unadsorbed emulsifiers during physical or chemical aging processes.

Influence of pH on Stability and Dynamic Properties of Asphaltenes and Other Amphiphilic Molecules at the Oil−Water Interface

Oil-in-water emulsions are currently being investigated to facilitate the transport of viscous heavy oils. The behavior of these emulsions is largely controlled by the interfaces between oil drops and water. The surface-active components of crude oil, such as asphaltenes and naphthenic acids, compete among themselves at these interfaces and also with possibly added synthetic surfactant emulsifier. Here, we present a study of dynamic interfacial tension of interfaces between water and a model oil (toluene) in which variable amounts of asphaltenes are solubilized. We show that pH has a strong influence on interfacial properties of asphaltenes at the oil/water interface. At high or low pH, asphaltenes functional groups become charged, enhancing its surface activity. The influence of lower-molecular-weight surface-active species, such as the natural naphthenic acids contained in maltenes (crude oil without asphaltenes), has been investigated, and an interaction between asphaltenes and maltenes that facilitate...

The rheological and microstructural characterisation of the non-linear flow behaviour of concentrated oil-in-water emulsions

This paper reports experimental observations on the rheology and microstructure of concentrated oil-in-water emulsions stabilised by macromolecular and low-molecular-weight emulsifiers. From the four different samples that were tested, certain general trends were identified and the measured linear viscoelastic and non-linear viscoelastic properties were compared using a phenomenological factored integral constitutive equation with a continuous relaxation spectrum. The self-consistency of the model was quite good in two cases (vegetable protein and polyoxyethylene glycol non-ionic surfactant emulsifiers) with the general exception of low steady shear rate data where the model overpredicted experimental stress measurements. It is shown that the fitting of the experimental data is sensitive to a wide range of inter-relating factors. In addition, optical observations of the sheared materials consistently showed low shear rate surface slip and this observation was correlated with the rheology miss match. For some systems the optical microstructure studies reveal a range of behaviour for the emulsions dependent on emulsifier composition. Wall slip, microdomain movement, chaining and changes in droplet size distribution were all observed under different conditions and in some cases it has been possible to correlate these microstructure observations with the sample rheology.

Solids-Free Brine-in-Oil Emulsions for Well Completion

Summary An invert emulsion fluid composed of brine (e.g., NaCl, NaBr, CaCl2, CaBr2, and ZnBr2) emulsified into hydrocarbon oil (e.g., diesel, crude, or mineral) was formulated with a mixture of nonionic surfactant emulsifiers. Laboratory investigations were conducted to define the emulsion characteristics and to develop methods for controlling the fluid's rheological properties and emulsion stability at elevated temperatures. This system has oil as the external phase, and the stability of the emulsion in most cases is linked to the homogeneity and fineness of the brine-dispersed droplets. The emulsion stability is also related to its viscosity and to the strength of the interfacial film formed by the emulsifiers that coat the brine droplets. For packer-fluid applications, the solids-free invert emulsions offer several advantages over conventional oil- and water-based muds. For example, the fluid is virtually nonconductive, providing greater corrosion protection than conventional water-based muds and clear brines. It can also provide formation protection characteristics and can solve such problems as clay swelling and solids invasion. This new completion fluid is ideal for perforating, drilling in, under-reaming, and gravel packing. The emulsion can be filtered through a less-than-10-μm cartridge filter and can be reclaimed and used again. This new completion fluid was used successfully in the field as a packer fluid and as a perforating fluid for testing a reservoir that was drilled with conventional oil-based mud.

Spectrophotometric Study of the Antimony (lll) - 2 - (3,5 - dibromo - 2 - pyridylazo) - 5 - diethylaminophenol (3,5 - Br2-PADAP) Complex Formed in the Presence of Emulsifier OP

Abstract A sensitive and selective method for the spectrophotometric determination of micro amount of antimony in surface water with 3,5-Br2-PADAP and nonionic surfactant emulsifier OP is proposed. In 0.12∼0.25 MHC1 medium, Sb(III) forms blue-green trinary complexes with 3,5-Br2-PADAP and OP. The complex exhibits maximum absorption at 630 nm, and the apparent molar absorptivity at this wavelength is 5.2 × 104 Lmo mol−1 cm−1. Beer's law is obeyed for 0-25 μg of Sb(III) in 10ml of solution. The colour is stable for 7 days. Antimony can be determined directly in aqueous solution without separation. The proposed method has been used for the determination of micro amounts of Sb(III) in surface water with satisfactory results.