Emulsion Interface Research Articles

The role of lipid particle-laden interfaces in regulating the co-delivery of two hydrophobic actives from o/w emulsions

Co-delivery strategies have become an integral active delivery approach, although understanding of how the microstructural characteristics could be deployed to achieve independently regulated active co-delivery profiles, is still an area at its infancy. Herein, the capacity to provide such control was explored by utilizing Pickering emulsions stabilized by lipid particles, namely solid lipid nanoparticles (SLNs) and nanostructured lipid carriers (NLCs). These dual functional species, regarding their concurrent Pickering stabilization and active carrying/delivery capabilities, were formulated with different solid lipid and surfactant types, and the effect on the release and co-release modulation of two hydrophobic actives separately encapsulated within the lipid particles themselves and within the emulsion droplets was investigated. Disparities between the release profiles from the particles in aqueous dispersions or at an emulsion interface, were related to the specific lipid matrix composition. Particles composed of lipids with higher oil phase compatibility of the emulsion droplets were shown to exert less control over their release regulation ability, as were particles in the presence of surfactant micelles in the continuous phase. Irrespective of their formulation characteristics, all particles provided a level of active release control from within the emulsion droplets, which was dependant on the permeability of the formed interfacial layer. Specifically, use of a bulkier particle surfactant or particle sintering at the droplet interface resulted in more sustained droplet release rates. Compared to sole release, the co-release performance remained unaffected by the co-existence of the two hydrophobic actives with the co-release behavior persisting over a storage period of 1 month.

A metal–organic frameworks-imprinted emulsion interface with dynamic size- and site-selective recognition for significantly enhanced flavoniods extraction

The boronic acid suspended Cr based MIL-100 (MIL-100-B) sorbents have been widely used to separation of cis-diol containing molecules. However, it’s still challenging in fabrication of high performance metal organic frameworks (MOFs) due to its irregular size and low content of functional groups. For improving identification efficiency, the emulsion microreactor were firstly designed to purify MIL-100-B prior to their use. Herein, a highly ordered MOFs-imprinted polymer microsphere was synthesized by O/W Pickering emulsion template, which can highly selective separation of MIL-100-B via the synergistic effect of boronic acid sites and imprinted cavities. The obtained purified H-MIL-100-B exhibited the uniform size and abundant boronic acid groups (B elements ratio up to 27.37 %). The emulsion imprinted microsphere (EIMs) showed the good selectivity towards MIL-100-B. Additionally, the obtained MOF-imprinted microsphere exhibited green, convenient, sustainable separation process towards the purification and recycle of MIL-100-B. The purified MOFs (H-MIL-100-B) were used to specific bind with cis-diol flavoniods naringin (NRG). Satisfactorily, H-MIL-100-B show high adsorption amount (43.69μmol/g at 308 K), fast capture kinetics (160 min), high selectivity and excellent regenerability (up to seven cycles). Remarkably, the purified NRG solutions displayed lasting antibacterial activity against Staphylococcus aureus (S. aureus) with inhibition zone of 13.47 mm. More importantly, the H-MIL-100-B could effectively promote the specific recognition ability of NRG by reducing matrix interference and improving purification efficiency (93.93 %) from complex natural extracts. A high score (0.75) was predicted via analytical GREEnness (AGREE) approaches, demonstrating environmentally friendly and greenness of separation process. The MOFs-imprinted emulsion microspheres possessed dynamic recognition properties towards target MOFs, thus opening new direction for the development of convenient and efficient microreactor for the purification of other functional MOFs.

Phase-Specific Immobilization of Phospholipase D as an Efficient Pickering Emulsion Interfacial Catalyst for Converting Antarctic Krill Oil Phospholipid.

Phosphatidylserine (PS), a rare phospholipid in Antarctic krill oil (AKO) critical for brain development, can be produced from the abundant phosphatidylcholine (PC) using phospholipase D (PLD) in Pickering emulsion interfacial catalysis (PIC) systems. However, the exposure of PLD to organic solvent around the emulsion interface diminished PLD activity, limiting the conversion efficiency of PS. In this study, we proposed a strategy to fabricate a PIC system with high efficiency and stability by immobilizing PLD in a specific phase on the emulsion interface, based on investigating the effect of the interfacial microenvironment on PLD activity. Janus-poly(acrylic acid)/polystyrene (JPP) and Janus-polyethylenimine/octadecane (JPO) particles were fabricated as carriers to realize the specific-phase immobilization of PLD. The highest activity was observed when PLD was immobilized on the hydrophilic side of JPP (PLD@JPP(W)), 1.9-fold that of free PLD. The catalytic efficiency of PLD@JPP(W) was 1.7-fold that of free PLD, confirmed by the kcat/Km value enhancement. Immobilization on the hydrophilic side also enhanced the thermal stability of PLD. The half-lives of PLD were extended from 4 to 36 h at 40 °C and from 6 to 28 days at 4 °C. Importantly, PLD@JPP(W) showed excellent catalytic efficiency as a PIC system, achieving a PS productivity of 93% within a short time of 2 h at an enzyme dosage of 0.05 mg. PLD@JPP(W) exhibited a 3.6 times higher yield than free PLD in the production of PS from PC rich in Antarctic krill oil. The strategy in this work could also be applied to other lipases, providing a promising method for the efficient conversion of functional lipids.

Polyethylene Glycol-Enzyme Nanocomplexes as Carrier-free Biocatalyst for Pickering Interfacial Catalysis.

PEG-enzyme nanocomplexes are prepared and stabilized in an oil-in-water-type emulsion for Pickering interfacial biocatalysis, and these nanocomplexes function as catalysts and emulsifiers at the emulsion interface. The nanocomplexes are self-assembled by cross-linking mPEG-ALD with lipase, without complicated synthesis steps, toxic chemical reagents, and external carriers. Moreover, the mild cross-linking process preserves the original structure of the enzyme, the retention rate of enzyme activity is 82.1%, and the nanocomplexes are used to emulsify biphasic aqueous-organic solution into Pickering emulsion. The system exhibits excellent reusability, with enzyme activity remaining at 86.05% after five cycles, providing a desirable eco-friendly platform for carrier-free Pickering interfacial biocatalysis.

Improvement in the oxidative stability of microencapsulated linseed oil using carob protein hydrolysates and multilayer emulsions

The microencapsulation of linseed oil in multilayer emulsions stabilized by carob protein hydrolysates was evaluated in this study. Linseed oil was emulsified in both multilayer and single layer interfacial emulsions using either carob protein concentrate or carob protein hydrolysate. The protein hydrolysate was able to increase the encapsulation efficiency by up to 12 % compared to non-hydrolyzed concentrated protein. Larger particles containing the hydrolysates (mean diameter ∼3 µm) were observed; however, the size distribution and microstructure were similar for all samples, regardless of the use of protein concentrate or protein hydrolysate, in single or multilayer emulsion systems. Physical aspects of the particles, such as porosity and glass transition temperature (Tg), were also similar, showing low porosity (<7.5 %) and high Tg (>80 °C). The antioxidant capacity of the protein hydrolysates, combined with the protective effect provided by the multilayer systems, enhanced the oxidative stability of the microencapsulated oil during processing and storage. The use of both strategies seems to provide an improved alternative for the microencapsulation of linseed oil, resulting in particles with superior physicochemical and oxidative stability.

Titania-Cored Janus Multipods as UV-Protective Pickering Emulsifiers for Sunscreens.

Pickering emulsifiers have gained significant interest as alternatives for conventional surfactants in various applications that includes pharmaceutics, food, homecare products, and cosmetics. However, their function is primarily focused on enhancing emulsion stability of which still remains to be resolved. Herein, Janus multipods are presented that simultaneously shield UV while offering high emulsion stability. These particles are prepared by growing multiple silicon dioxide (SiO2) nanopods using sol-gel method on a spherical titanium dioxide (TiO2) core with a thin SiO2 shell. The incorporation of high refractive index TiO2 in the core is shown to effectively shield UV while the SiO2 shell suppresses the photocatalytic activity. Moreover, by utilizing wax colloidosomes as templates, these multipod nanoparticles are further modified to exhibit Janus characteristics. This leads to strong adsorption of the Janus multipods at the oil/water emulsion interface where the multipod feature additionally reinforces the interfacial stabilization by interdigitation and interlocking of the Janus multipods to suppress detachment of the highly dense particles from the interface. As these Janus multipods offer effective UV protection as well as excellent emulsion stability, it is envisioned that they have great potential in advanced cosmetic formulations which require both enhanced sunscreen performance and better feeling in skincare products.

Effect of ultrasonic pretreatment on the emulsion rheological properties and interface protein structure of epigallocatechin-3-gallate and rice bran protein complex

The effect of ultrasonic pretreatment on the emulsion rheological properties and the structural characteristics of interface-adsorbed protein (IAP) and interface-unabsorbed protein (IUP) of rice bran protein and epigallocatechin-3-gallate complex (RBP-EGCG) were studied. Compared to RBP-EGCG without ultrasonic pretreatment, appropriate ultrasonic pretreatment (ultrasonic power was 425 W) enhanced the IAP trypsin sensitivity (from 3.20 to 3.73), increased the IUP surface hydrophobicity (from 12.59 to 20.87), and decreased the ζ-potential (from −24.93 mV to −36.88 mV) and particle size (from 567.30 nm to 273.13 nm) of IUP, thereby increasing the viscosity and viscoelasticity of emulsion. Compared to appropriate ultrasonic pretreatment, high-power ultrasonic pretreatment (ultrasonic power was 500 W) attenuated the IAP trypsin sensitivity, and increased the ζ-potential and particle size of IUP, thereby decreasing the viscosity and viscoelasticity of emulsion. Overall, ultrasonic pretreatment changed the EGCG-RBP emulsion viscoelasticity by regulating spatial structural characteristics and flexibility of interface protein.

Colloidal nanoparticles of a β-cyclodextrin/L-Tryptophan inclusion complex for use as Pickering emulsion stabilizers

Inclusion complexes of β-cyclodextrin (β-CD) and tryptophan (Trp) were synthesized using an antisolvent approach, and fully characterized. Scanning electron microscope images proved the formation of the β-CD/Trp nanoparticles (NP) and the powder X-ray diffraction pattern indicated the formation of a crystalline channel-like structure for the β-CD/Trp NPs (NPs). The NPs of a β-CD/Trp inclusion complex were used as a natural stabilizer at the oil/water interface of a Pickering emulsion. Pickering emulsions with an oil to water ratio of 1:1 (v:v) were obtained under high-speed homogenization and different mass ratios of the β-CD to Trp (1:0, 1:0.1, 1:0.25, 1:0.5, 1:1), and at different pH levels (3, 5, 7, 9). At pH 9, when the β-CD:Trp mass ratio was 1:0.1, the β-CD/Trp NPs were hydrophilic, and the oil-in-water Pickering emulsions stabilized by those nanoparticles showed the highest storage stability: 180 days at room temperature. In contrast, when the emulsions were prepared at pH 5 with the weight ratios of either 1:0.1 or 1:1, β-CD:Trp, the nanoparticles were hydrophobic and could be used to stabilize water-in-oil Pickering emulsions.

Stereoselective Interactions of Chiral Polyurea Nanocapsules with Albumins.

Exploiting the chirality of nanometric structures to modulate biological systems is an emerging and compelling area of research. In this study, we reveal that chiral polyurea nanocapsules exhibit significant stereoselective interactions with albumins from various sources despite their nearly neutral surface potential. Moreover, these interactions can be modulated by altering the nanocapsule surface composition, offering new opportunities to impact their distribution and, if used as a drug delivery system, the pharmacokinetics of the drug. Notably, these interactions promote preferential cellular internalization of only one chiral configuration. We synthesized chiral polyurea nanocapsules with reproducible sizes via interfacial polymerization between toluene 2,4-diisocyanate and d- or l-lysine enantiomers on a volatile oil-in-water emulsion interface, followed by solvent evaporation. Further synthesis optimization reduced the capsule size to a range compatible with in vivo administration, and capsules with alternating chiral patterns were also produced. The stereoselective interactions with albumins were assessed through capsule size changes, fluorescence quenching, and surface charge measurements. Biocompatibility, stability, and cellular internalization were evaluated. Additionally, scanning transmission electron and atomic force microscopy were carried out to assess the capsule shape, surface composition, and morphology. We discovered that d-nanocapsules exhibited 2.1-2.6 times greater albumin adsorption compared with their l-counterparts. This difference is attributed to the distinct morphology of d-nanocapsules, characterized by a more concave shape, central depression, and rougher surface. The extent of adsorption could be finely tuned by adjusting the d- and l-lysine monomer ratios during synthesis. Both chiral configurations demonstrated biocompatibility and stability with d-nanocapsules showing a 2.5-fold increase in cellular internalization.

Encapsulation of octadecane through crosslinking of cellulose nanofibrils at the interface of Pickering emulsion: Effect of ionic strength on cellulose assembly and capsule shell properties

Emulsion interfacial polymerization is a versatile approach for the encapsulation of organic phase-change materials to improve their stability and prevent their elution and leakage. Herein, we report the successful octadecane encapsulation by the preparation of Pickering emulsions stabilized with carboxylated cellulose nanofibrils (CNF) at various ionic strengths of the dispersive medium. The stable capsule shells were obtained through the formation of amide bonds in the reaction with polymeric isocyanate dissolved in the oil phase. The addition of 5–200 mM NaCl resulted in different adsorption behaviors of carboxylated CNF, which led to an increase in capsule shell thickness (up to 530 nm), improved octadecane encapsulation efficiency (up to 78 %) and thermal stability, as well as reduced elution in organic medium with increasing ionic strength. The study presents a new strategy for the encapsulation of phase-change materials by surfactant-free emulsion interfacial polymerization into containers with defined and adjustable properties.

Design and engineering of 3D plasmonic superstructure based on Pickering emulsion templates for surface-enhanced Raman spectroscopy applications in chemical and biomedical sensing

The integration of Pickering emulsion as a versatile template facilitates the assembly of nanoscale and microscale NPs, leading to the formation of intricate 3D superstructures. These superstructures exhibit collective properties, including optical, electric, and catalytic functionalities, surpassing individual building block. This review comprehensively explores the design and engineering principles behind the creation of these multifaceted superstructures. The exploration begins with the fundamental aspects of surface chemistry governing nanoparticles, a crucial factor in directing their assembly behavior at the curved liquid–liquid emulsion interface. Emphasis is placed on understanding emulsion stability, a pivotal element guiding the formation of stable 3D architectures. The discussion extends to unraveling the underlying mechanisms promoting the formation of these 3D superstructures. The focus lies in elucidating the optical functionalities of these superstructures, particularly in the context of surface-enhanced Raman spectroscopy application. The surveyed literature showcases diverse Pickering emulsion-based strategies employed in the assembly of plasmonic nanoparticles into intricate superstructures, offering controlled architectures and unlocking unique potentials for chemical and biochemical sensing.

Impact of lipid droplet characteristics on the rheology of plant protein emulsion gels: Droplet size, concentration, and interfacial properties

Plant-based meat analogs are being developed to address environmental, sustainability, health, and animal welfare concerns associated with real meat products. However, it is challenging to mimic the desirable physicochemical, functional, and sensory properties of real meat products using plant-based ingredients. Emulsion gels consisting of lipid droplets embedded in biopolymer matrices are commonly used to create products with appearances, textures, and sensory attributes like meat products. In this study, the impact of soybean oil droplet characteristics (concentration, size, and charge) on the physicochemical properties of potato protein gels was studied. The oil droplets were either coated by a non-ionic surfactant (Tween 20) or a plant protein (patatin) to obtain different surface properties. The introduction of the oil droplets caused the protein gels to change from mauve to off-white, which was attributed to increased light scattering. Increasing the oil droplet concentration in the emulsion gels decreased their shear modulus and Young’s modulus, which was mainly attributed to the fact that the oil droplets were less rigid than the surrounding protein network. Moreover, increasing the oil droplet size made this effect more pronounced, which was attributed to their greater deformability. Competitive adsorption of proteins and surfactants at the oi-water interface in the Tween emulsion promoted emulsion instability. This research highlights the complexity of the interactions between oil droplets and protein networks in emulsion gels. These insights are important for the utilization of emulsion gels in the formulation of plant-based foods with improved quality attributes.

Addition of AlO(OH) nanoparticles to assist stabilizing emulsion for digital light processing lightweight but robust porous alumina ceramics

It is proposed here that introducing AlO(OH) nanoparticles to build a wide range of particle size distribution to assist stabilizing emulsion and regulate its properties is an important prerequisite for using Pickering emulsion as digital light processing (DLP) feedstock. Combined with DLP, porous alumina ceramics with hierarchical porosity composed of macro-pores from the designed model (based on body-centered cubic lattice) and micro-pores formed by emulsion droplet, can be prepared by adjusting the microstructure of framework via changing AlO(OH) content, oil-to-water ratio and dispersant content. The AlO(OH) addition facilitates the further filling of particles at the phase interface of emulsion, thus increasing the viscosity and reducing the pore size. Porous alumina ceramics exhibit an average pore size distribution of 4.71 μm–6.06 μm, porosity of 71.92%–78.60 %, and relatively high compressive strength ranging from 5.02 MPa to 10.36 MPa, demonstrating a combination of high porosity and excellent mechanical properties.

Stability and lipid oxidation of oil-in-water emulsion stabilized by Maillard conjugates of soybean phosphatidylethanolamine with different polysaccharides

Lipid oxidation and instability in oil-in-water (O/W) emulsion are the main challenges in emulsion-based foods. Polysaccharide-induced Maillard conjugation of soybean phosphatidylethanolamine (SP) holds great potential in improving physicochemical stability of emulsions. This work applied tamarind gum, pectin, inulin and maltodextrin to conjugate with SP to obtain the four Maillard conjugates (MCs), and investigated their difference in interface and anti-oxidant abilities in emulsions. Results showed that lower polymerization degree of polysaccharide moieties (tamarind gum＞pectin＞maltodextrin＞inulin) caused higher glycation degree in MC: inulin-SP-MC＞maltodextrin-SP-MC＞pectin-SP-MC ≈ tamarind gum-SP-MC, which corresponded their color changes. Compared with unconjugated mixtures, interface activity and anti-oxidant abilities of MCs were strengthened. Among the four MCs, tamarind gum-SP-MC (7.77 mN/m) and pectin-SP-MC (8.42 mN/m) could decrease interfacial tension more largely. It was due to the faster interface saturation benefited from broader steric network of tamarind gum and pectin moieties, and stable interfacial absorption facilitated by improved zeta potential and lipophilicity. Pectin-SP-MC also exhibited the highest anti-oxidant ability (DPPH scavenging ability of 97.81% and ferric-reducing antioxidant power of 2.742 A). It was attributed to the combined effects of grafting degree, interface activity and chain length of pectin moiety. As a result, emulsions stabilized by pectin-SP-MC had less water loss, smaller droplet sizes, and lower contents of oxidation products. Maillard reaction between SP and pectin was favorable to produce MCs with higher potential for the improvements of physical and oxidative stability of O/W emulsions.

Revealing the Existence of Long-Range Liquid-Liquid Interfacial Potential in Phase-Transfer Processes.

By employing fluorescence wide-field microscopy and a nanoparticle-based phase transfer catalyst (PTC), consisting of a fluorescent silica nanoparticle functionalized with trioctylpropylammonium bromide, we demonstrate that in the presence of NaOH, single nanoparticles display subdiffusive motion along the axis normal to an aqueous liquid-organic liquid interface. This is because of an extended interfacial potential with a shallow well (∼1 kBT) that stretches a few μm into the organic phase, in contrast to previous molecular dynamics studies that reported narrow interfaces on the order of ∼1 nm. Spontaneous interfacial emulsification induced by NaOH results in the propagation of water-in-oil nanoemulsions into the organic solvent that creates an equilibrium hybrid-solvent composition that solvates the PTC. A greater mobility and longer residence time of the PTC at the potential well enhance the interfacial phase transfer process and catalytic efficiency.

Optimizing shear-thickening fluid microencapsulation with high-temperature pickering emulsion for enhanced impact-resistant materials

Combining shear-thickening fluid (STF) with matrix material enables the creation of high-performance materials with enhanced impact resistance. However, effectively preventing STF leakage and avoiding potential reactions between the fluid and the matrix material remain notable challenges. Encapsulating STF through emulsion templating offers a viable solution to these issues. Traditional emulsion templating methods require adding extra solvents to STF to counteract the hindrance of shear-thickening on emulsification, accompanied with increased costs and environmental pollution, and difficulties in maintaining the integrity of core components. In this study, we developed STF microcapsules using a novel high-temperature Pickering double emulsion technique. Our investigation into the rheological properties of molecular sieve/diols suspensions demonstrates that the shear thickening effect could be controlled by particle concentration, surface charge of particles and solvent viscosity. Octadecyltrimethoxysilane-modified fumed silica and fumed silica were utilized as stabilizers for STF-in-paraffin primary emulsions and STF-in-paraffin-in-propylene glycol secondary emulsions, respectively. As temperature increased, droplet sizes of the primary emulsion were significantly reduced. The Pickering emulsion approach effectively preserves the STF composition by forming robust barriers at the emulsion interface with silica particles. Typical STF microcapsules were incorporated into a silicone rubber matrix, the composites exhibited a significant decrease in resilience and an enhanced impact resistance with a 20.9% reduction in maximum impact force. This study is the first to suggest the application of the high-temperature Pickering double emulsion technique for the microencapsulation of STF, offering a practical and scalable method without diluting the STF, thereby ensuring the controllability of the core components.

MIL-53(Al)–oil/water emulsion composite as an adjuvant promotes immune responses to an inactivated pseudorabies virus vaccine in mice and pigs

Although vaccination with inactivated vaccines is a popular preventive method against pseudorabies virus (PRV) infection, inactivated vaccines have poor protection efficiency because of their weak immunogenicity. The development of an effective adjuvant is urgently needed to improve the efficacy of inactivated PRV vaccines. In this study, a promising nanocomposite adjuvant named as MIL@A–SW01–C was developed by combining polyacrylic acid-coated metal–organic framework MIL-53(Al) (MIL@A) and squalene (oil)-in-water emulsion (SW01) and then mixing it with a carbomer solution. One part of the MIL@A was loaded onto the oil/water interface of SW01 emulsion via hydrophobic interaction and coordination, while another part was dispersed in the continuous water phase using carbomer. MIL@A–SW01–C showed good biocompatibility, high PRV (antigen)-loading capability, and sustained antigen release. Furthermore, the MIL@A–SW01–C adjuvanted PRV vaccine induced high specific serum antibody titers, increased splenocyte proliferation and cytokine secretion, and a more balanced Th1/Th2 immune response compared with commercial adjuvants, such as alum and biphasic 201. In the mouse challenge experiment, two- and one-shot vaccinations resulted in survival rates of 73.3 % and 86.7 %, respectively. After one-shot vaccination, the host animal pigs were also challenged with wild PRV. A protection rate of 100 % was achieved, which was much higher than that observed with commercial adjuvants. This study not only establishes the superiority of MIL@A–SW01–C composite nanoadjuvant for inactivated PRV vaccine in mice and pigs but also presents an effective method for developing promising nanoadjuvants. Statement of significanceWe have developed a nanocomposite of MIL-53(Al) and oil-in-water emulsion (MIL@A–SW01–C) as a promising adjuvant for the inactivated PRV vaccines. MIL@A–SW01–C has good biocompatibility, high PRV (antigen) loading capability, and prolonged antigen release. The developed nanoadjuvant induced much higher specific IgG antibody titers, increased splenocyte proliferation and cytokine secretion, and a more balanced Th1/Th2 immune response than commercial adjuvants alum and biphasic 201. In mouse challenge experiments, survival rates of 73.3 % and 86.7 % were achieved from two-shot and one-shot vaccinations, respectively. At the same time, a protection rate of 100 % was achieved with the host animal pigs challenged with wild PRV.

Milk fat globule membrane proteins are crucial in regulating lipid digestion during simulated in vitro infant gastrointestinal digestion

Products of lipolysis released during digestion positively affect the metabolism of newborns. In contrast to the 3-layer biological membranes covering human milk (HM) fat, the lipid droplets in infant milk formula (IMF) are covered by a single membrane composed of casein and whey proteins. To reduce the differences in lipid structure between IMF and HM, studies have used milk fat globule membrane (MFGM) components such as milk polar lipids (MPL) to prepare emulsions mimicking HM fat globules However, few studies have elucidated the effect of membrane proteins (MP) on lipid digestion in infants. In this study, 3 kinds of emulsions were prepared: One with MPL as the interfaced of lipid droplets (RE-1), one with membrane protein concentrate (MPC) (RE-2) as the interface of lipid droplets, and one with both MPL and MPC (1:2) as the co-interface of lipid droplets (RE-3). The interfacial coverage of the emulsions was confirmed by measuring the contents of MPL and MPC at the lipid droplet interface, and by confocal laser scanning microscopy analyzed. By controlling the homogenization intensity, the specific surface area of lipid droplets was controlled at the same level among the 3 emulsions. The stability constants of the emulsions varied, and RE-1 was the most stable. During simulated in vitro infant gastrointestinal digestion, the amount of free fatty acids (FFA) released from the lipid droplets was significantly higher from those with MPC at the interface (RE-2, RE-3) than from that with MPL at the interface (RE-1). The amount of FFA released at the end of intestinal digestion of RE-1, RE-2, and RE-3 was 255.00 ± 3.54 µmol,328.75 ± 5.30 µmol, 298.50 ± 9.19 µmol, respectively. Compared with the lipid droplets in RE-2, those with MPL at the interface (RE-1, RE-3) released more unsaturated fatty acids (USFAs) during digestion. The emulsifying activity index was highest in RE-3 (MPL and MPC co-interface). The presence of MPL at the emulsion interface increased the release of USFAs, while the presence of MPC increased the release of FFA. These results show that both MPL and MP are indispensable in the construction of MFGM. Understanding their effects on digestion can provide new strategies for the development of infant foods.

Nanoparticle Surfactants at Complex Emulsion Interfaces.

Using nanoparticle surfactants to stabilize the liquid-liquid interface has attracted significant attention for developing all-liquid constructs including emulsions and liquid devices. Here, an efficient strategy is demonstrated to stabilize complex emulsions that consist of multiphase droplets by using the co-assembly between the cellulose nanocrystal and amine-functionalized polystyrene. Cellulose nanocrystal surfactants (CNCSs) form and assembly in situ at the specified area of emulsion interface, showing a unique pH responsiveness due to their dynamic nature and allowing the reconfiguration of complex emulsion from encapsulated to Janus structures. Such complex emulsions can be further used as the templates to fabricate polymeric particles with hollow, semi-spherical, and spherical shapes on large scale. These findings establish a promising platform for designing intelligent soft matter that can be used in microreactors, sensors, and anisotropic materials.

Effect of heat treatment on the structural and emulsifying properties of copra meal protein: Improving interfacial properties to enhance performance of its Pickering emulsion

This study investigated the impact of different temperatures and durations on the structural and emulsifying properties of copra meal protein. Additionally, the stability of copra meal protein Pickering emulsions was assessed through rheological and interfacial characteristics. Findings revealed a positive correlation between emulsification properties and heating temperature and duration. Thermal aggregates, facilitated by hydrogen bonds, hydrophobic interactions, and disulfide bonds, significantly enhanced surface hydrophobicity. Heat-treated copra meal protein-based Pickering emulsions demonstrate enhanced adsorption at the oil-water interface and resistance to diffusion. The three-phase contact angle increases from 57.7° to 79.8° following heating at 95 °C for 30 min. The addition of NaCl and heating treatment did not affect emulsion particle size or interface adsorption ability. But it improved the rheological properties to varying degrees. These results offer valuable insights for optimizing the physicochemical and functional attributes of copra meal protein in the food industry.