Emulsion Size Research Articles

Rheological properties of water-oil emulsions of Archinskoe oil deposit

Relevance. The development of new methods for regulating the rheological properties of water-oil emulsion using thermal and chemical methods will allow reducing the viscosity of oil well products and energy consumption for pumping hydrocarbon mixtures. Aim. To determine the activation energy of viscous flow and particle sizes of the internal phase of the initial emulsion of the Archinskoe deposit and the emulsion with an introduced demulsifier. Methods. All experiments required to investigate the rheological properties of colloidal disperse systems were performed using HAAKE Viscotester iQ rotational viscometer. Results. Comparative experimental studies were carried out on the effect of the introduced demulsifier on the effective viscosity of the water-oil emulsion of the Archinskoe deposit. Laboratory-scale experiments were performed using the rotational viscometry, which allows one to evaluate the dependence of viscosity on shear rate and temperature. It was established that the studied samples are liquids with pronounced non-Newtonian properties, which are a consequence of the paraffinic nature of oil and its water-oil emulsion. The structure of nanoparticles of the dispersed phase of dehydrated oil and its emulsion is discussed and justified. Using the analytical Arrhenius–Frenkel–Eyring expression, which describes the dependence of viscosity on temperature and the physical and chemical nature of the liquid system, the results of viscometrical experiments were processed and the activation energies of viscous flow and the particle size of the inverse emulsion were calculated in the absence of a demulsifier and in its presence. Laboratory experiments have confirmed that for complete dehydration of oil well products, it is not enough to introduce only a demulsifier, but it also requires heating the emulsion to a temperature sufficient to melt and dissolve paraffin particles, which form a structural and mechanical barrier situated on the surface of the emulsion droplets.

The Characterization and Stability of Powdered Oil Loaded with β-Carotene Prepared from a Sodium Caseinate-Carrageenan Complex: The Effect of Vacuum Freeze-Drying and Spray-Drying.

β-carotene (BC) has various biological activities, such as anticancer properties, contributing to the prevention of cardiovascular diseases, etc., while the poor solubility and low bioavailability limit its further development in the food industry. Therefore, how to effectively encapsulate this unstable substance has become a hot topic. Here, different concentrations of sodium caseinate and ι-carrageenan (NaCas-CA) complex emulsions were used as wall materials, and the effect of spray-drying (SD) and vacuum freeze-drying (VFD) on the properties of BC powders loaded with NaCas-CA was investigated. The results showed that the characteristic peaks of BC disappeared in all powdered oils, indicating that BC could be effectively encapsulated. As the wall concentration increased, the surface oil of the powders decreased significantly. At the same concentration, the surface oil content of SD (minimum of 8.34%) was lower than that of VFD (minimum of 10.02%). However, the particle size of SD-reconstituted emulsions was larger than that of VFD. Furthermore, the SD-reconstituted emulsions were more stable than the VFD after storage at 25 °C for 3 h. This study reveals the effect of different drying methods on the structure and stability of powdered oils, providing valuable information for the research of functional active-loaded powdered oils and applications in the food industry.

Formation of whey protein, pectin, and chlorogenic acid ternary complexes and their application in emulsions

Physicochemical properties, stability, and digestive behavior of lycopene-loaded emulsions prepared by ternary complexes fabricated with different mixing sequences based on whey protein isolate (WPI), high methoxyl pectin (HMP), and chlorogenic acid (CA) were investigated. Spectroscopic and molecular docking analyses confirmed the non-covalent interactions among the compounds within the ternary complexes, as well as the conformational changes in the protein induced by the mixing sequence. The interfacial tension (6.92–9.44 mN/m) influenced by the different mixing sequences of WPI, HMP and CA was HMP-CA-WPI > WPI-CA-HMP > WPI-HMP-CA, and the size of emulsions stabilized by HMP-CA-WPI was approximately 10 nm larger than that of the other two. Complexes with mixing sequence of HMP, CA and WPI outperformed in antioxidant properties (Ferric reducing power absorbance 0.43, ABTS∙ radical scavenging activity 66.04 %), lycopene retention rate (after UV irradiation 85.11 %, after thermal treatment 83.15 %), and storage stability of emulsions than those prepared by WPI-HMP-CA and WPI-CA-HMP. Emulsions stabilized by different ternary complexes showed similar free fatty acid release profiles (39.62 %–41.59 %) and lycopene bio-accessibility (28.87 %–29.94 %) during digestion. This study mat offer novel insights for the rational utilization in emulsions of ternary complexes based on proteins, polysaccharides, and phenolic acids.

In-situ thermally induced formation of an ultra-glossy hydrophilic surface for oil fouling prevention in TiO2@MXene membranes

Oil droplets are inevitably deposited on the surface of membranes, resulting in membrane contamination during oily sewage separation. To effectively prevent oil fouling, a TiO2@MXene membrane with an ultra-glossy hydrophilic surface was designed via in-situ thermal induction to regulate the membrane surface structure and properties. Through high temperature-induced evolving the Ti valence and the functional groups of Ti3C2Tx, uniform TiO2 nanoparticles were generated in-situ on the Ti3C2Tx surface while altering the surface structure and properties, which considerably improved the hydrophilicity, underwater oleophobic properties, and surface finish of the membrane. Specifically, the TiO2@MXene membrane (MT600) exhibited a low water contact angle of 7.5° and a high underwater oil contact angle of 133.3°. Notably, the oil adhesion force of the membrane was as low as 0.0013 μN, outperforming most oil water separation membranes. Thus, the unique structure and surface properties endowed MT600 membrane with excellent oil retention (TOC removal efficiency of > 95 %) and antipollution ability (permeance decay rates of < 10 %) for oil-in-water emulsion separation. This is because the ultra-glossy hydrophilic and oleophobic surface prompted the formation of a continuous and stable hydration layer on the membrane surface and prevented oil droplets from falling into the membrane grooves. Benefiting from the robust, ultra-glossy surface, the MT600 membrane exhibited excellent long-term durability and reusability (emulsion permeance recovery of > 90 %) in high-salt, highly acidic, and highly alkaline environments. This study opens pathways to realize ultra-glossy membrane surface for the efficient demulsification of small size emulsions and long-lasting, stable oil water separation.

Characterization of liquid egg yolks hydrolyzed by phospholipase: Structure, thermal stability and emulsification properties

This study aims to clarify the difference between phospholipase A1 (PLA1) and phospholipase A2 (PLA2) in terms of hydrolyzing egg yolk (EY). The results indicated that the disintegration of the lipoprotein micelle structure after phospholipase hydrolysis induced an enhanced solubility of proteins. The solubility after PLA1 and PLA2 treatment (91.36 %/83.49 %) was significantly higher than that of the untreated egg yolk (27.89 %). Simultaneously, the disintegration of the lipoprotein micelle structure induced structural unfolding of proteins with hydrophobic chains buried inside the spatial structure, while charged amino acids and hydrophilic chains exposed on the surface. This structural deformation contributed to the increased thermal stability of EY, thereby increasing intermolecular electrostatic repulsion. In comparison, PLA1 hydrolyzed EY showed relatively better thermal stability than PLA2, due to the lower surface hydrophobicity. However, PLA2 hydrolyzed EY (up to 225 mL) had greatly higher emulsifying capacity than PLA1 (up to 159 mL), due to the better stability and emulsifying ability of the generated 1-lyso-phospholipase. Furthermore, we discovered that proteins and phospholipids jointly functioned at the interface to influence the particle size and stability of emulsions. Specifically, the emulsifying activity of phospholipids may play a more decisive role in determining the particle size, while the interfacial adsorption of proteins or protein particles may be more crucial in ensuring the stability of the emulsions. These findings had significant implications for the application and advancement of phospholipase-catalyzed egg yolk hydrolysis, providing practical guidance for the production of EY with high thermal stability or emulsifying capacity.

Combination of Milk Polar Lipids and Casein Hydrolysate as a Healthy Emulsifier for Ice Cream.

The demand for healthy ingredients in food products including ice cream, is continuously increasing. The potential of a combination of milk polar lipids (MPL) and casein hydrolysate (CH) to replace synthetic emulsifiers such as diacetyl tartaric acid esters of monoglycerides (DATEM), in ice cream production was investigated. Changes in particle size, emulsion stability, and interfacial tension of model emulsions (milk protein, casein:whey=8:2, w/v) were analyzed after the addition of MPL, CH, and their combination (MPL+CH). The use of MPL+CH reduced interfacial tension and increased αs- and β-casein displacement from the surface of cream layers compared to the addition of MPL alone. The addition of MPL+CH improved ice cream overrun to levels comparable to those of control ice cream containing DATEM (0.3%, w/v), without adversely affecting melt rate or microstructure. Confocal laser scanning microscopy revealed that ice cream prepared with MPL+CH formed a thick protein and coalesced fat layer on the surface of air cells that might help enhance overrun. These findings suggest that the combination of MPL (0.3%, w/v) and CH (0.03%, w/v) can be used as a potential emulsifier alternative to replace chemically synthesized emulsifiers such as DATEM.

High precision acoustofluidic synthesis of stable, biocompatible water-in-water emulsions

Water-in-water (w/w) emulsions, comprising aqueous droplets within another continuous aqueous phase, rely on a low interfacial tension for stability. Thus far, it has been challenging to control their size and stability without the use of stabilizers. In this study, we introduce a microfluidic technique that addresses these challenges, producing stable w/w emulsions with precisely controlled size and uniformity. Results shows that using an acoustically actuated microfluidic mixer, PEG, Dextran, and alginate solutions (84.66 mPa.s viscosity difference) were homogenized rapidly, forming uniformly distributed w/w emulsions stabilized in alginate gels.The emulsion size, uniformity, and shear sensitivity can be tuned by modifying the alginate concentration. Biocompatibility was evaluated by monitoring the viability of kidney cells in the presence of emulsions and gels. In conclusion, this study not only showed emulsion formation with a high mixing efficiency exceeding 90 % for all viscosities, actuated at an optimized frequency of 1.064 MHz, but also demonstrated that an aqueous, solvent, and emulsifier-free composition exhibited remarkable biocompatibility, holding promise for precise drug delivery, cosmetics, and food applications.

Fabrication of cellulose nanofibers/epigallocatechin gallate complexes: Insights into structure, antioxidant properties and enhanced emulsion performance

In this work, cellulose nanofiber/epigallocatechin gallate (CNF/EGCG) complexes at different ratio were fabricated and the effects on characteristics and stability of emulsions under different oil phase fraction (φ) were investigated. The results of functional groups indicated the formation of CNF/EGCG complexes via hydrogen bond interaction, leading to enhanced antioxidant activity as the proportion of EGCG increased. The complexes exhibited more fragments but pure CNF were more homogenously dispersed in the aqueous phase. Enhancing the EGCG content reduced the droplet size of emulsions firstly before increased, while the apparent viscosity and viscoelastic properties displayed a contrary trend. Emulsion gels with smaller droplet size, higher apparent viscosity, excellent viscoelastic properties and physical stability could be formed at φ = 0.5 while emulsions at φ = 0.3 exhibited slight creaming. The emulsions at lower CNF/EGCG ratio presented better oxidative stability, which was ascribed to the higher antioxidant activity of the complexes and the thicker interfacial film. Results suggest that EGCG could be combined with CNF to improve the emulsion performance and be applied in extending the shelf-life of the emulsion-based products.

Ionic Liquid-Based Grapeseed Oil Emulsion for Enhanced Anti-Wrinkle Treatment.

To address the poor efficacy and percutaneous penetration of grape seed oil, ionic liquids and nanotechnology were combined to prepare a grape seed oil emulsion. A novel Menthol-CoQ10 ionic liquid and ionic liquid based grapeseed oil emulsion were prepared and confirmed. The average size of the grapeseed oil emulsion was 218 nm, and its zeta potential was -33.5 mV. The ionic liquid-based grape seed oil emulsion exhibited a transdermal penetration effect 4.63-fold higher than that of ordinary grape seed oil emulsion. Ionic liquid also displayed enhanced efficiency both in vitro and in vivo. It significantly inhibited the production of DPPH free radicals and tyrosinase, inhibited melanin and matrix metalloproteinase-1 (MMP-1) produced by cells, and promoted type I collagen expression in fibroblasts. After 28 days of continuous use, the grapeseed oil emulsion improved the water content of the stratum corneum and the rate of transepidermal water loss, enhanced the firmness and elasticity of the skin, and significantly improved the total number and length of under-eye lines, tail lines, nasolabial folds, and marionette lines on the face. Menthol-CoQ10 ionic liquid is a promising functional excipient for both transdermal delivery increase and efficient enhancement. Ionic liquid and nanotechnology for grape seed oil facial mask displayed significantly enhanced efficacy and permeability.

Preparation and characterization of a new food-grade Pickering emulsion stabilized by mulberry-leaf protein nanoparticles.

Food-grade Pickering particles, particularly plant proteins, have attracted significant interest due to their bio-based nature, environmental friendliness, and edibility. Mulberry-leaf protein (MLP) is a high-quality protein with rich nutritional value and important functional properties. It has special amphoteric and emulsifying characteristics, making it valuable for use in Pickering emulsions. This study aimed to investigate the feasibility of using MLP nanoparticles as solid particles to stabilize Pickering emulsions. The particle size of MLP nanoparticles was less than 300 nm under neutral and alkaline conditions. At pH 9, the zeta potential value reached -34.3 mV, indicating the electrostatic stability of the particles. As ion concentration increased, the particle size of MLP nanoparticles increased, and the zeta potential decreased. Throughout the storage process, no obvious aggregation or precipitation was observed in the dispersion of MLP nanoparticles, indicating strong stability. The particle size of the Pickering emulsion decreased with the increase in protein concentration. When the protein concentration was low, the particles on the oil-water interface became sparse, resulting in poor stability of the prepared emulsion and making it susceptible to aggregation and thus larger particle sizes. Increasing the oil-phase ratio to 70% (v/v) promotes the formation of Pickering emulsions, which exhibit exceptional stability when MLP nanoparticles are fixed at a concentration of 20 mg mL-1. The overall findings indicated that MLP nanoparticles have potential as food-grade materials for Pickering emulsions, marking a novel application of these nanoparticles in the food industry. © 2024 Society of Chemical Industry.

Oil unsaturation degree dictates emulsion stability through tuning interfacial behaviour of proteins

The unsaturated vegetable oil is commonly incorporated as protein-stabilized emulsion into fat-substituted emulsified meat products (FSEMP), whose quality is closely related with the emulsion stability. Here, we systematically investigated the effects of oil unsaturation degree (UD) on the interfacial properties (structural changes, adsorption dynamics, interfacial rheology, adsorption layer thickness) of proteins and thus the emulsion stability. The oleic acid and linolenic acid were mixed with dodecane as model oils. Three types of proteins were selected as model emulsifiers (fibrous myofibrillar protein, MP; globular whey protein, WP; random-coiled sodium caseinate, SC). The proteins diffused slower to the higher UD interface, resulting in a lower interfacial pressure. This led to a larger droplet size of the higher UD oil emulsion upon emulsification. However, the proteins penetrated and rearranged faster at the higher UD interface ascribed to a more extensive structural unfolding, enabling the formation of stiffer and thicker adsorption layers. This contributed to a stronger short-term stability of MP- and WP-stabilized higher UD oil emulsion; while for the random-coiled SC, the higher UD oil emulsion was less short-term stable, which was primarily determined by the initial (larger) droplet size but not the interfacial layer properties. The stiffer layer at the higher UD interface was on the other hand less stretchable, which tended to yield when subjected to higher strain. This probably accounted for the weaker long-term stability of the higher UD oil emulsion, regardless of protein types. These results highlighted that the oil UD should be elaborately considered for the rational formulation of FSEMP.

Enhancement of oxidative stability of camelina oil via Alyssum homolocarpum seed gum/sodium alginate–based microcapsules loaded with Echinacea purpurea (L.) extract

Alyssum homolocarpum seed gum (AHSG) and sodium alginate (SA) were utilized as wall materials for the microencapsulation of Echinacea purpurea extract via spray drying. Furthermore, effect of microcapsules on the oxidative stability of camelina oil was assessed over a 30-day storage period. The results showed that with an increase in AHSG concentration, the particle size, polydispersity index, and zeta potential of emulsions decreased, while their viscosity, and stability increased. Microcapsules prepared with AHSG alone exhibited the highest encapsulation efficiency (90.70 %), loading efficiency (40.70 %), and water solubility (88.47 %), but the lowest moisture content (1.45 %), water activity (0.31), wettability (198 s), and hygroscopicity (13.50 g/100 g). Scanning electron microscopy analysis revealed a spherical and smooth surface for AHSG alone-based microcapsules. Fourier transform infrared spectroscopy analysis indicated that certain chemical interactions occurred between the E. purpurea extract and wall materials. By incorporating AHSG/SA-based microcapsules containing E. purpurea extract into camelina oil, the peroxide value (increasing from 1.79 to 5.12 meq∙O2/kg) and anisidine value (increasing from 1.63 to 7.09) were maintained during the 30-day storage period. In conclusion, the microcapsules prepared with AHSG alone showed significant potential for encapsulating E. purpurea extract and subsequently enhancing oxidative stability of camelina oil, comparable to TBHQ.

Effect of oil structure on adsorption behavior of emulsifier at the oil-polyol interface and the emulsion features

The aim of this study was to investigate the effect of oil structure on the dynamic adsorption behavior of emulsifier at the oil-polyol interface and the corresponding emulsion feature. Glycerol was used as the representative polyol, and the emulsifier was Polyglyceryl-2 Dipolyhydroxystearate (PGPH). Three kinds of alkanes and three kinds of ester oils were chosen for investigation. Firstly, the properties of each oil were studied by measuring surface tension (σ), interfacial tension with glycerol (γ0), and affinity between oils and PGPH. The results indicated that there was little difference in the fundamental characteristics of oils, with the exception of GTCC. Due to its triglyceride structure, GTCC exhibited similar polarity to glycerol, resulting in low interfacial tension and a strong affinity with PGPH. Secondly, the interfacial critical micelle concentration (CMCIFT), saturation adsorption amount (Γ∞), Langmuir constant (κ) and minimum molecular area (Amin) of PGPH were obtained by measuring the dynamic interfacial tension of PGPH adsorption at different oil-glycerol interfaces. The experimental results indicate that for alkanes, the longer the alkane chain length and the more the number of branch chains, the higher the emulsifier Γ∞ at the interface, leading to improved emulsion stability. In ester oils, the greater the affinity between the oil and glycerol, resulting in the lower the initial interfacial tension, a smaller Γ∞ and consequently smaller emulsion particle size. However, this also led to poor emulsion stability. Finally, Pearson correlation analysis was conducted between oil properties, adsorption parameters and emulsion size and stability. The results indicated that for alkanes, there was a negative correlation between particle size and emulsion stability with surface tension and Γ∞. In ester oils, there was a strong positive correlation between particle size and interfacial tension as well as κ. Additionally, the creaming of emulsions showed a strong negative correlation with interfacial tension and Γ∞.

Pectin from steam explosion-treated citrus peel exhibits good emulsion properties and bioavailability-promoting effect in vitro of nobiletin

Steam explosion (SE) is a potential method to modify pectin structure, which might be connected to its emulsifying characteristics and the bioavailability of encapsulated polymethoxyflavone like nobiletin. However, the relationship between SE-modified pectin and the bioavailability of encapsulated nobiletin is still unclear. In this study, nobiletin-loaded emulsion was fabricated using citrus pectin modified with SE (0.15–0.9 MPa, 3 min) as emulsifier for in vitro digestion study, and the transport and absorption of nobiletin in Caco-2 cells to investigate the bioavailability-promoting effect. The results showed that SE treatment lowered the droplet size of emulsion from 21.38 ± 2.30 μm to 2.14 ± 0.12 μm, enhanced the nobiletin encapsulation efficiency from 23.73 ± 0.78% to 86.27 ± 3.81%, improved the nobiletin bioaccessibility in vitro from 2.48 ± 0.10% to 25.42 ± 0.10% and increased the intracellular accumulation of nobiletin by over 10 times, even higher than that of Tween 80. In conclusion, pectin from SE-treated citrus peel exhibited good emulsion properties and bioavailability-promoting effect in vitro of nobiletin.

Sea Bass Fish Head Broth Treated by Thermo-Ultrasonication: Improving the Nutritional Properties and Emulsion Stability.

This work investigated the underlying mechanism of thermo-ultrasonic treatment to improve the nutritional properties and emulsion stability of sea bass fish head broth. The effects of ultrasonication on the processing of fish broth were compared with boiling water treatment. The nutritional properties of fish broth mainly include protein, fat, total sugar, 5'-nucleotide and free amino acid content. To achieve a similar effect of nutrient extraction, the thermo-ultrasonic treatment required a shorter time (30 min) than boiling water (120 min). The water-soluble protein, fat and total sugar contents were at their maximum at 120 min of the thermo-ultrasonic treatment. In particular, the fat content increased with the time of thermo-ultrasonic treatment from 0.58% to 2.70%. The emulsion structure of the fish soup was characterized by measuring its color and particle size, using optical microscopy and confocal laser scanning microscopy, and determining its storage stability. Thermo-ultrasonic treatment reduced the particle size of the fish broth emulsion and the fat globules became smaller and more homogeneous. Ultrasonication not only accelerated the nutritional and flavor content of the fish head broth, but also reduced the particle size and enhanced the stability of the emulsified system of the fish broth. The fish head tissue was more severely disrupted by the cavitation effect of an ultrasound, and nutrients migrated more and faster. This was mainly due to the cavitation and mechanical breaking force of the ultrasound on the fish head tissue and the fat globules of the fish broth. Altogether, these findings suggest that the thermo-ultrasonic treatment technique is useful for processing nutrient-rich, storage-stable and ready-to-eat fish head broth.

Fabrication of pea protein isolate-stabilized oil-in-water emulsions with high freeze-thaw stability: Effect of high intensity ultrasonic on emulsions and interfacial protein structure

The poor freeze-thaw stability of plant protein-based emulsions posed a major challenge for their application in the cold chain foods. The present study successfully prepared oil-in-water emulsions stabilized solely with pea protein isolate (PPI) with excellent freeze-thaw stability using a facile high intensity ultrasonic (HIU)-assisted method. The optimized emulsion can endure three freeze-thaw cycles without stratification or oil leakage, maintaining oil droplet sizes at the nanometer scale. Furthermore, changes of interfacial protein structure induced by HIU were systematically investigated to reveal the stabilizing mechanism. The freeze-thaw stability of emulsions treated under varying intensities was evaluated based on changes in the appearance and oil drop size distribution. The results showed that the oil drop size of emulsions decreased from micron to nanometer and the freeze-thaw stability was significantly enhanced with the increase of HIU intensity. The emulsion exhibited optimized freeze-thaw stability under 800W. Subsequently, the effect of HIU on the structure of interfacial protein was analyzed through SDS-PAGE, –SH/S–S contents, UV spectrum, surface hydrophobicity, protein adsorption percentage, emulsifying activity and interfacial dilatational rheology. It was found that HIU triggered crosslinking of disulfide bonds among interfacial PPI molecules and enhanced the strength of the interface layer. Additionally, HIU promoted the unfolding of interfacial PPI structure, resulting in the improvement of surface hydrophobicity, emulsifying activity, and interfacial adsorption percentage of PPI. The study demonstrated the feasibility of using HIU to improve the freeze-thaw stability of oil-in-water emulsions stabilized with PPI and provided references for the fabricating of plant protein-based frozen emulsion foods.

Effect of non-covalent binding of tannins to sodium caseinate on the stability of high-internal-phase fish oil emulsions

In this study, we designed the noncovalent binding of sodium caseinate (SC) to tannic acid (TA) to stabilize high internal phase emulsions (HIPEs) used as fish oil delivery systems. Hydrogen bonding was the dominant binding force, followed by weak hydrophobic interaction and weak van der Waals forces, as demonstrated by FTIR, fluorescence spectroscopy, and molecular docking experiments, with a binding constant of 3.25 × 106, a binding site of 1.2, and a static quenching of the binding. Increasing SC:TA from SC to 2:1 decreased the particle size from 107.37 ± 10.66 to 76.07 ± 2.77 nm and the zeta potential from −6.99 ± 2.71 to −22 ± 2.42 mV. TA increased the interfacial tension of SC, decreased the surface hydrophobicity from 1.3 × 104 to 1.6 × 103 and improved the oxidation resistance of SC. The particle size of high internal phase emulsions stabilized by complexes with different mass ratios (SC:TA from 1:0 to 2:1) increased from 4.9 ± 0.02 to 12.9 μm, the potential increased from −32.37 ± 2.7 to −35.07 ± 2.58 mV, and the instability index decreased from 0.75 to 0.02. Thicker interfacial layers could be observed by laser confocal microscopy, and an increase in the storage modulus indicated a formation of a stronger gel network. SC:TA of 1:0 showed emulsion breakage after 14 d of storage at room temperature. SC:TA of 2:1 showed the lowest degree of oil-water separation after freeze-thaw treatment. Especially, the most stable high endo-phase emulsion (at SC:TA of 2:1) prepared at each mass ratio was selected for further stability exploration. The emulsion particle size increased only from 15.63 ± 0.06 to 22.27 ± 0.35 μm at salt ion concentrations of 50–200 mM and to 249.33 ± 31.79 μm at 300 mM. The instability index and storage modulus of the high endo-phase emulsions increased gradually with increasing salt ion concentrations. At different heating temperatures (55–85 °C), the instability index of the high internal phase emulsion gradually decreased and the storage modulus gradually increased. Meanwhile, at 50 °C for 15 d of accelerated oxidation, the content of hydroperoxide decreased from 53.32 ± 0.18 to 37.48 ± 0.77 nmol/g, about 29.7 %, and the thiobarbituric acid value decreased from 1.06 × 103 to 0.8 × 103, about 24.5 %, in the high endo-phase emulsions prepared by 2:1 SC:TA compared to the fish oils, and the SC-stabilized high endo-phase only emulsion broke at the sixth day of oxidation. From the above findings, it was concluded that the high internal phase emulsion prepared with SC:TA of 2:1 can be used as a good delivery system for fish oil.

The conformational modification of myofibrillar protein by magnetic field improves its emulsification properties

This study investigated the effect of different magnetic field treatments (0, 3, 6, 9, 12 mT) on the structure and emulsification properties of myofibrillar protein (MP). The results showed that the emulsion stabilized by MP with 3, 6, 9 mT magnetic field treatments possessed higher emulsifying ability, storage stability and apparent viscosity, since magnetic field induced the structural unfolding of MP and exposed the hydrophobic groups (the surface hydrophobic increased from 30.10 to 43.73 μg). Meanwhile, the magnetic field treatments decreased the MP particle size from 1752.00 to 1278.67 nm, which was favorable for the diffusion and adsorption of proteins at the oil-water interface, thus improving the MP emulsification ability and stability. Furthermore, the 9 mT magnetic field-treated MP had the best ability to emulsify oil droplets with a more uniform and smaller emulsion size from 28.593 to 23.443 μm. However, high-intensity magnetic field treatment (12 mT) caused MP particles to aggregate and the hydrophobic binding sites to be buried, which was not conducive to encapsulating oil droplets.

Investigating the effects of oil type, emulsifier type, and emulsion particle size on textured fibril soy protein emulsion-filled gels and soybean protein isolate emulsion-filled gels.

The effects of oil type, emulsifier type, and emulsion particle size on the texture, gel strength, and rheological properties of SPI emulsion-filled gel (SPI-FG) and TFSP emulsion-filled gel (TFSP-FG) were investigated. Using soybean protein isolate or sodium caseinate as emulsifiers, emulsions with cocoa butter replacer (CBR), palm oil (PO), virgin coconut oil (VCO), and canola oil (CO) as oil phases were prepared. These emulsions were filled into SPI and TFSP gel substrates to prepare emulsion-filled gels. Results that the hardness and gel strength of both gels increased with increasing emulsion content when CBR was used as the emulsion oil phase. However, when the other three liquid oils were used as the oil phase, the hardness and gel strength of TFSP-FG decreased with the increasing of emulsion content, but those of SPI-FG increased when SPI was used as emulsifier. Additionally, the hardness and gel strength of both TFSP-FG and SPI-FG increased with the decreasing of mean particle size of emulsions. Rheological measurements were consistent with textural measurements and found that compared with SC, TFSP-FG, and SPI-FG showed higher G' values when SPI was used as emulsifier. Confocal laser scanning microscopy (CLSM) observation showed that the distribution and stability of emulsion droplets in TFSP-FG and SPI-FG were influenced by the oil type, emulsifier type and emulsion particle size. SPI-stabilized emulsion behaved as active fillers in SPI-FG reinforcing the gel matrix; however, the gel matrix of TFSP-FG still had many void pores when SPI-stabilized emulsion was involved. In conclusion, compared to SPI-FG, the emulsion filler effect that could reinforce gel networks became weaker in TFSP-FG.

The effect of functional lipids on the quality of walnut butter prepared from defatted walnut meal by ball mill grinding

AbstractIn this study, walnut butter was produced by mixing functional lipids with defatted walnut meal. Three kinds of functional lipids (FL), medium‐chain triglycerides (MCT), diacylglycerol (DG), and conjugated linoleic acid glycerides (CLA), were used to make functional lipids walnut butter (DG‐WB, CLA‐WB and MCT‐WB) and their physical properties as well as microscopic morphology were compared with commercial walnut butter. The functional lipids walnut butter (FLWB) was prepared by grinding FL and defatted walnut meal through the ball milling technique. The mixing ratios of FL to defatted walnut meal were 6:4, 6.5:3.5, and 7:3. The volumetric mean particle size of emulsion formed by DG‐WB and CLA‐WB decreased by 36.23% and 20.88%, respectively when the additional amounts of DG, and CLA increased from 60 wt% to 70 wt%. The rheological and microrheological results further indicated that FLWB showed similar gel‐like behavior to commercial walnut butter. Among the FLWB with three different kinds of FL, CLA‐WB appeared more similar apparent viscosity, thixotropy, and elasticity with those of commercial walnut butter. Finally, CLA‐WB with different CLA additive amount was analyzed for microstructure. The results showed that walnut butter prepared with 65 wt% CLA was closer to commercial walnut butter in terms of processed physical properties and micro‐morphology.