Novel Bilayer Emulsions Costabilized by Zein Colloidal Particles and Propylene Glycol Alginate, Part 1: Fabrication and Characterization

Fabrication of soy protein-polyphenol covalent complex nanoparticles with improved wettability to stabilize high-oil-phase curcumin emulsions

BACKGROUND

Recent studies have shown that the wettability of protein-based emulsifiers is critical for emulsion stability. However, few studies have been conducted to investigate the effects of varying epigallocatechin gallate (EGCG) concentrations on the wettability of protein-based emulsifiers. Additionally, limited studies have examined the effectiveness of soy protein-EGCG covalent complex nanoparticles with improved wettability as emulsifiers for stabilizing high-oil-phase (≥ 30%) curcumin emulsions.

RESULTS

Soy protein isolate (SPI)-EGCG complex nanoparticles (SPIEn) with improved wettability were fabricated to stabilize high-oil-phase curcumin emulsions. The results showed that EGCG forms covalent bonds with SPI, which changes its secondary structure, enhances its surface charge, and improves its wettability. Moreover, SPIEn with 2.0 g L -1 EGCG (SPIEn-2.0) exhibited a better three-phase contact angle (56.8 ± 0.3o) and zeta potential (-27 mV) than SPI. SPIEn-2.0 also facilitated the development of curcumin emulsion gels at an oil volume fraction of 0.5. Specifically, the enhanced network between droplets as a result of the packing effects and SPIEn-2.0 with inherent antioxidant function was more effective at inhibiting curcumin degradation during long-term storage and ultraviolet light exposure.

CONCLUSION

The results of the present study indicate that SPIEn with 2.0 g L -1 EGCG (SPIEn-2.0) comprises the optimum conditions for fabricating emulsifiers with improved wettability. Additionally, SPIEn-0.2 can improve the physicochemical stability of high-oil-phase curcumin emulsions, suggesting a novel strategy to design and fabricate high-oil-phase emulsion for encapsulating bioactive compounds. © 2024 Society of Chemical Industry.

Starch-lauric acid complex-stabilised Pickering emulsion gels enhance the thermo-oxidative resistance of flaxseed oil

Hydrophobic-modified starch complexes have the potential to form Pickering emulsions and improve the oxidative stability of flaxseed oil. Here, V-type starch-lauric acid complexes (SLACs) were fabricated via solid encapsulation within 0.5-12 h and applied in flaxseed oil Pickering emulsions. Complexing index, X-ray diffraction and differential scanning calorimetry analyses confirmed that the degree of complexation increased with the reaction time. Pickering emulsion gels stabilised by SLACs generated with reaction times of 6 h and 12 h exhibited good storage stability and high yield stress, G' values and apparent viscosity. Confocal laser scanning microscopy and cryo-scanning electron microscopy revealed a gelation mechanism involving increased interface roughness and enhanced droplet-droplet interaction. In comparison to pure flaxseed oil, higher thermo-oxidative resistance was observed at 130 °C, with a markedly longer oxidation induction for emulsions and emulsion gels stabilised by SLACs. Our findings could assist in the design of hydrophobic-modified starch and provide a new paradigm for delaying oil oxidation.

The presence of propylene glycol alginate increased the stability and intestine-targeted delivery potential of carboxymethyl starch-stabilized emulsions

Propylene glycol alginate (PGA) was added to improve the stability and delivery performance of carboxymethyl starch (CMS)-stabilized emulsion. In the first instance, the CMS/PGA complexes were characterized, which proved that the formation of CMS/PGA complexes mainly depended on hydrogen bonding, and the CMS/PGA complexes showed porous networks. The CMS/PGA complexes were more hydrophobic than CMS, and the interaction of CMS with PGA enhanced the thermal stability of CMS. Next, the effects of CMS/PGA complexes on the properties of emulsions were investigated, and the intestine-targeted delivery potential of emulsions was evaluated through the in vitro release study as well. The droplet size of CMS/PGA complex-stabilized emulsions gradually decreased and the encapsulation efficiency (EE) improved with increasing the PGA content in CMS/PGA complexes. The addition of PGA also greatly improved the physical stability of emulsions, including anti-flocculation and anti-coalescence stabilities. All emulsions exhibited non-Newtonian pseudoplastic properties. Furthermore, the emulsions stabilized by CMS/PGA complexes showed reduced curcumin (Cur) release in the simulated gastric fluid (SGF), whereas exhibited sustained release in the α-amylase-containing simulated intestinal fluid (SIF). These results demonstrated that the emulsion stabilized by CMS/PGA complex was able to control and modulate the release of Cur in the gastrointestinal tract, and was therefore a promising intestine-targeted delivery system for Cur.

Demulsification of Bacteria-Stabilized Pickering Emulsions Using Modified Silica Nanoparticles

Pickering emulsions stabilized by bacteria acting as particle emulsifiers are new platforms for microbial transformations of hydrophobic chemicals. However, their high stability often hampers demulsification during downstream processing. Since the existing methods (like addition of surfactants) to demulsify bacteria-stabilized Pickering emulsions have negative effects, new practical methods need to be developed. Here, using chemically modified fumed silica particles with different hydrophobicity, the demulsification of W/O Pickering emulsions stabilized by Mycobacterium neoaurum whole cells was first studied. The binary particle-stabilized emulsions exhibited phase inversion and dewatering induced by the coalescence of W/O emulsions or creaming of O/W emulsions. The silica particle hydrophobicity and concentration were the important parameters influencing the emulsion type, droplet morphology, and dewatering rate. The highest dewatering rate and largest droplet size were obtained at the inversion point from W/O to O/W. Confocal microscopy showed that no interaction between the bacteria and silica particles existed and the silica particle adsorption at the interface induced the detachment of bacteria from the interface, revealing that there was competitive adsorption between the binary particles at the interface. Based on these results, we suggested that the average hydrophobicity of the binary particles at the interface would determine the emulsion type and stability. Finally, this strategy was successfully applied to the demulsification of the Pickering emulsion formed during microbial transformation of sterols. Overall, this study provides a new strategy to demulsify Pickering emulsions by addition of another particle emulsifier. This is also the first example of separation of products as well as organic phases after microbial transformation in Pickering emulsions.

Emulsions co-stabilized by soy protein nanoparticles and tea saponin: Physical stability, rheological properties, oxidative stability, and lipid digestion

Herein, the effects of the concentration (0.1%-1.0%, w/v) and addition sequence of tea saponin (TS) on the physical stability, oxidative stability, rheological properties, and in vitro digestion of the emulsions stabilized by heat-induced soy protein isolate nanoparticles (SPs) were investigated. The results revealed that the concentration and addition sequence of TS have significant impact on the microstructure, stability, rheological properties, and in vitro digestion of the emulsions. TS was shown to not only fill the interfacial gaps but also adsorb on the particle surfaces, contributing to interfacial wettability. With increasing TS concentration, interfacial tension decay is clearly observed. Further, TS endows the droplets with electrostatic repulsion and steric resistance, preventing their flocculation, coalescence, and oxidation. Finally, in vitro digestion experiments demonstrated that the presence of TS delayed the lipid digestion of the emulsions.

A novel propylene glycol alginate gel based colorimetric tube for rapid detection of nitrite in pickled vegetables

The detection of nitrite is of great significance because it is closely related to food safety. In this work, a rapid colorimetric method was developed for nitrite detection based on the reaction of propylene glycol alginate (PGA) gel interface. In the reaction of nitrite and 4-Aminoacetophenone, diazo compound formed, which could be further transformed to purplish red compound by reacting with N-(1-Naphthyl)ethylenediamine (NED). Nitrite exhibited a linear relationship with the grayscale of the gel interface in the range of 0.3-9 μg mL^-1 with a detection limit of 0.3 μg mL^-1. The method was applied to detect nitrite in four types of pickled vegetables with recovery of 80.9-119.02% and relative standard deviation of 0.11-6.73%. Notably, the detection process can be accomplished within 5 min. The proposed colorimetric method exhibited advantages of simplicity, quickness and sensitivity, showing potential application prospects for the real-time and on-site detection of nitrite in pickled vegetables.

Fabrication and characterization of superior stable Pickering emulsions stabilized by propylene glycol alginate gliadin nanoparticles

Gliadin, a kind of amphiphilic protein from wheat, has been widely used for stabilizing Pickering emulsions, which is easy to form colloidal particles. Herein, gliadin/propylene glycol alginate (PGA) colloidal particles (GPPs) with different gliadin/PGA ratios were developed and used as emulsifiers to prepare Pickering emulsions with an internal phase of 80% (v/v). The addition of PGA made the GPPs a tree-fruit-like morphology, increasing the particle size and changing the zeta-potential. Hydrogen bond and electrostatic interaction are the major forces between gliadin and PGA. The wettability of GPPs was improved significantly in the presence of PGA. The oil-water contact angle reached 89.5° when the gliadin/PGA ratio was 1 : 1. The emulsion could be maintained at room temperature for 6 months when the oil phase ratio (Φ) was 70%. The high stability of the Pickering emulsion could be attributed to the thin film formed by GPPs on the surface of oil droplets. The improved resistance of algal oil in emulsions against oxidation was proved as the induction time increased six times. In addition, the porous material prepared using GPPs-stabilized emulsion as the template displayed an oil absorption ability of 106.41 g g^-1 and heavy metal adsorption ability of 202.71 mg g^-1. Such performance implies that GPPs are highly efficient food-grade Pickering emulsifiers that may be applied in various fields.

Protection of menhaden oil from oxidation in Pickering emulsion-based delivery systems with α-lactalbumin-chitosan colloidal nanoparticle

In this study, α-lactalbumin-chitosan (ALA-CHI) colloidal nanoparticles were spontaneously formed mainly through electrostatic interactions for stabilizing Pickering emulsion loaded with health-beneficial but unstable menhaden oil. The oxidative stability of menhaden oil was supposed to be significantly enhanced with Pickering emulsion-based delivery systems with ALA-CHI colloidal particles. The film of ALA-CHI colloidal nanoparticles had higher surface hydrophobicity than ALA at pH 5.0, and 6.5. A near-neutral wettability (89.6°) of ALA-CHI nanoparticles was observed at pH 5.0. Stable Pickering emulsions (60% menhaden oil fraction, w/w) were successfully fabricated with only 0.12% (w/w) of ALA-CHI nanoparticles. Pickering emulsions exhibited superior storage, heat, and centrifugation stability. The formation of gel-like structures was confirmed by rheological results. The viscosity and storage modulus in the frequency range of 0.1 to 10 Hz with a 1.0% strain exhibited remarkable increases with increasing colloidal particle concentration or oil fraction. Increasing oil fractions from 20% to 60% (w/w) or colloidal particle concentrations 0.12% to 2.40% (w/w) can pronouncedly facilitate the inhibition of lipid oxidation, as confirmed by detecting the formation of primary and secondary oxidation products.

Enhanced stability and controlled gastrointestinal digestion of β-carotene loaded Pickering emulsions with particle-particle complex interfaces

In this study, we used large, rigid, and hydrophilic zein-propylene glycol alginate composite particles (ZPCPs) and small, soft, and hydrophobic whey protein microgel (WPM) particles to synergistically stabilize a Pickering emulsion for delivery of β-carotene. The photothermal stability and storage stability of β-carotene were improved with the combined use of different particles. Microstructural observations showed that ZPCPs were effectively adsorbed at the oil/water interface despite the substantial interparticle gaps. WPM particles could swell and stretch on the interface due to their deformable structure, thereby forming an interfacial layer of flattened particles to cover a large surface area. The interfacial structure and macroscopic properties of Pickering emulsions were modulated by adjusting the mass ratio and addition sequence of different particles. The combination of ZPCPs and WPM delayed the lipolysis during gastrointestinal digestion. Through controlling the composition of the complex interface, the free fatty acid (FFA) release rate of Pickering emulsions in the small intestinal phase was reduced from 15.64% to 9.03%. When ZPCPs were used as the inner layer and WPM as the outer layer and the mass ratio of ZPCPs to WPM was 4 : 1, the Pickering emulsion showed the best stability and β-carotene bioaccessibility. The Pickering emulsion with particle-particle complex interfaces could be applied in foods and pharmaceuticals for the purpose of enhanced stability, delayed lipolysis or sustained nutrient release.

Zein Colloidal Particles and Cellulose Nanocrystals Synergistic Stabilization of Pickering Emulsions for Delivery of β-Carotene

In this study, we utilized different types of particles to stabilize β-carotene-loaded Pickering emulsions: spherical hydrophobic zein colloidal particles (ZCPs) (517.3 nm) and rod-shaped hydrophilic cellulose nanocrystals (CNCs) (115.2 nm). Either of the particles was incapable of stabilizing Pickering emulsions owing to their inappropriate wettability. When the mass ratio of ZCPs and CNCs was 1:4, the Pickering emulsion showed the best physical and photothermal stability. Compared to the ZCP-stabilized Pickering emulsion (9.29%), the retention rate of β-carotene in the Pickering emulsion costabilized by ZCPs and CNCs was increased to 60.23% after 28 days of storage at 55 °C. Confocal microscopy and cryoscanning electron microscopy confirmed that different types of particles could form a multilayered structure or induce the formation of an interparticle network. Furthermore, the complexation of ZCPs and CNCs delayed the lipolysis of the emulsion during in vitro digestion. The free fatty acid (FFA) release rate of Pickering emulsions in the small intestinal phase was reduced from 19.46 to 8.73%. Accordingly, the bioaccessibility of β-carotene in Pickering emulsions ranged from 9.14 to 27.25% through adjusting the mass ratio and addition sequence of distinct particles at the interface. The Pickering emulsion with the novel particle-particle complex interface was designed in foods and pharmaceuticals for purpose of enhanced stability, delayed lipolysis, or sustained nutrient release.

Metal-Organic Framework-Stabilized High Internal Phase Pickering Emulsions Based on Computer Simulation for Curcumin Encapsulation: Comprehensive Characterization and Stability Mechanism

High internal phase Pickering emulsions (HIPPEs) have taken a center stage in the arena of delivery systems in the food industry because of their high loading capacity and stability. In addition, metal-organic frameworks (MOFs), a type of cutting-edge designable porous scaffolding material, have attracted attention in reticular chemistry, which satisfies fundamental demands for delivery research in the past years. Here, we demonstrate a novel metal-organic framework (MOF)-stabilized HIPPE delivery system for hydrophobic phytochemicals. First, a novel high-biocompatibility and stable MOF particle, UiO-66-NH₂, was selected from atomic simulation screening, which showed proper electronegativity and amphiphilic properties to develop the HIPPE system. Monodispersed UiO-66-NH₂ nanoparticles with the particle size of 161.36 nm were then prepared via solvothermal synthesization. Pickering emulsions with inner phase ratios from 50 to 80% with varied contents of polyethylene glycol (PEG) were prepared by in situ high-pressure homogenization, and their physicochemical properties including crystallography, morphology, and rheology were systematically characterized. Subsequently, curcumin, a model antioxidant, was loaded in the HIPPE system and named cur@UiO-66-NH₂/HIPPE. It exhibited high loading capacity, up to 6.93 ± 0.41%, and encapsulation efficiency (19.76 ± 3.84%). This novel MOF nanoparticle-stabilized HIPPE delivery system could be practically utilized for other bioactive components and antimicrobial agents, which would find applications in food safety and biomedical areas in the future.

Delivery of curcumin using a zein-xanthan gum nanocomplex: Fabrication, characterization, and in vitro release properties

This study aimed to use xanthan gum as a stabilizer to improve the stability of zein nanoparticles. Zein-xanthan gum composite nanoparticles were prepared via anti-solvent precipitation at pH 4.0. The particle size, zeta potential, and stability of the system were related to the amount of xanthan gum added. When 20 mg of xanthan gum was added, spherical nanoparticles with a small particle size (179 ± 2.1 nm) and sufficient negative zeta potential (-42 ± 1.6 mV) were obtained. The zeta potential and Fourier transform infrared spectroscopy results indicated that electrostatic attraction was the main driving force, followed by hydrogen bonding and hydrophobic interactions. Composite nanoparticles were coated by xanthan gum and remained stable over a wide pH range and at high temperatures and salt concentrations; they did not precipitate or aggregate after 30 days of storage. Moreover, the addition of xanthan gum considerably improved the encapsulation efficiency and loading capacity of nanoparticles containing high curcumin amounts, which facilitated slow and sustained release of curcumin in simulated intestinal fluid. Therefore, zein-xanthan gum nanoparticles can be used for the delivery of biologically active compounds in food and pharmaceutical preparations.

Development of β-carotene loaded oil-in-water emulsions using mixed biopolymer-particle-surfactant interfaces

In this study, β-carotene loaded oil-in-water emulsions were stabilized by complex interfaces composed of propylene glycol alginate (PGA), rhamnolipids (Rha), and zein colloidal particles (ZCPs). The influence of mixed biopolymer-surfactant, biopolymer-particle, surfactant-particle and biopolymer-surfactant-particle interfaces on the performance of the emulsions was investigated. The stability, microstructure, rheological properties, and in vitro gastrointestinal digestion of the emulsions were controlled by regulating the adding sequence and mass ratio of the multiple stabilizers. The droplet size of the emulsion was in the range of 14-77 μm. After encapsulation into the emulsions stabilized by the complex interfaces, the photothermal stability of β-carotene were increased by 41.53% and 21.52%, respectively. The co-existence of particles, biopolymers, and surfactants could induce competitive displacement, multilayer deposition and an interparticle network at the interface. Compared with a single PGA- or Rha-stabilized emulsion, the complex interface-stabilized emulsion reduced the release of FFA by 28.06% and 26.16%, respectively. The interfacial composition of the emulsion and the delayed lipid digestion further affected the bioaccessibility of β-carotene in the gastrointestinal tract (GIT). The mixed biopolymer-particle-surfactant interface-stabilized emulsion could be incorporated in foods, pharmaceuticals and cosmetics for excellent stability, targeted nutrient delivery and controlled lipolysis.

Prolamin-based complexes: Structure design and food-related applications

Prolamins are a group of safe food additives that are biocompatible, biodegradable, and sustainable. Zein, gliadin, kafirin, and hordein are common prolamins that have been extensively studied, particularly as these form colloidal particles because of their amphiphilic properties. Prolamin-based binary/ternary complexes, which have stable physicochemical properties and superior functionality, are formed by combining prolamins with polysaccharides, polyphenols, water-soluble proteins, and surfactants. Although the combination of prolamins with other components has received attention, the relationship between the structural design of prolamin-based complexes and their functionalities remains uncertain. This review discusses the production methods of prolamin-based complexes, the factors influencing their structural characteristics, and their applications in the food industry. Further studies are needed to elucidate the structure-function relationships between prolamins and other biopolymers, as well as the toxicological effects of these complexes in food.

Stability, Interfacial Structure, and Gastrointestinal Digestion of β-Carotene-Loaded Pickering Emulsions Co-stabilized by Particles, a Biopolymer, and a Surfactant

Novel Pickering emulsions were stabilized by complex interfaces in the presence of zein colloidal particles (ZCPs), propylene glycol alginate (PGA), and rhamnolipid (Rha) for delivery of β-carotene. The influence of the particle-surfactant, particle-biopolymer, and particle-biopolymer-surfactant mixed interfaces on the physiochemical properties and digestion fate of Pickering emulsions was investigated. It is the first time that three different types of emulsifiers have been used to synergistically stabilize food Pickering emulsions for delivery of lipophilic nutraceuticals. The physicochemical stability, microstructure, rheological properties, and in vitro gastrointestinal digestion of Pickering emulsions were controlled by the addition sequence and mass ratio of multiple stabilizers, which showed the enhanced stability and delayed lipid digestion of the particle-biopolymer-surfactant-stabilized Pickering emulsions. After encapsulation into Pickering emulsions, the retention rate of β-carotene increased 2-fold under UV radiation for 8 h. The coexistence of ZCPs, PGA, and Rha could induce the competitive displacement, multilayer deposition, and interparticle network at the interface. The combination of particles, a biopolymer, and a surfactant delayed the lipolysis during in vitro gastrointestinal tract. By modulating the interfacial composition, the release rate of free fatty acids from Pickering emulsions was reduced from 19.46% to 2.83% through different mechanisms. The novel Pickering emulsion could be incorporated in foods as well as pharmaceuticals for controlled lipid digestion or targeted nutrient delivery purposes.

Effects of microfluidization and thermal treatment on the characterization and digestion of curcumin loaded protein–polysaccharide–tea saponin complex nanoparticles

Microfluidization (50–150 MPa) and thermal treatment (45–85 °C) were applied to modulate the stability, molecular interaction and microstructure of zein–proplyene glycol alginate (PGA)–tea saponin (TS) complex nanoparticles for delivery of curcumin.

Effect of oleogelation on physical properties and oxidative stability of camellia oil-based oleogels and oleogel emulsions

In this work, the camellia oil-based oleogels and O/W oleogel emulsions were prepared with glycerol monolaurate (GML) as an oleogelator, which had a critical gelation concentration of 3 wt%. Results showed that with the increasing GML concentration, a more densely needle-like morphology was formed by the network of GML crystals within the oil, presenting the enhanced thermal stability due to the occurrence of van der Waals interactions and intermolecular hydrogen bonds. In turn, a more compact three-dimensional network was obtained in the emulsions with a larger droplet size, leading to a transition from a predominately elastic to viscous state. Moreover, a lower oxidation rate was observed by the POV and TBARS values as a function of storage time in either the oleogels or oleogel emulsions, indicating a better oxidative stability. These results contribute to a better understanding of oleogelation in camellia oil-based oleogels and oleogel emulsions for formulating food, pharmaceutical and person care products with desired physical properties and oxidative stability.

Stabilizing the Oil-in-Water Emulsions Using the Mixtures of Dendrobium Officinale Polysaccharides and Gum Arabic or Propylene Glycol Alginate

Coconut oil-in-water emulsions were prepared using three polysaccharides: Dendrobium officinale polysaccharide (DOP), propylene glycol alginate (PGA), gum arabic (GA) and their polysaccharide complexes as emulsifiers. The effects of the ratio of the compounded polysaccharides on their apparent viscosity and interfacial activity were explored in this study. The average particle size, zeta potential, microstructure, rheological properties, and physical stability of the emulsions prepared with different compound-polysaccharides were studied. The results showed that mainly DOP contributed to the apparent viscosity of the compound-polysaccharide, while the interfacial activity and zeta potential were mainly influenced by PGA or GA. Emulsions prepared with compound-polysaccharides exhibited smaller average particle sizes, and microscopic observations showed smaller droplets and less droplet aggregation. In addition, the stability analysis of emulsions by a dispersion analyzer LUMiSizer showed that the emulsion prepared by compounding polysaccharides had better physical stability. Finally, all of the above experimental results showed that the emulsions prepared by PGA:DOP = 2:8 (total concentration = 1.5 wt%) and 2.0% GA + 1.5% DOP were the most stable.

Fabrication, Physicochemical Stability, and Microstructure of Coenzyme Q10 Pickering Emulsions Stabilized by Resveratrol-Loaded Composite Nanoparticles

The aim of this study was to develop a novel system for the co-delivery of resveratrol and coenzyme Q10 (CoQ10). It was achieved with a combination of resveratrol-loaded composite nanoparticles and CoQ10-loaded Pickering emulsions. Different levels of resveratrol (0.05-0.30%, w/v) were entrapped into composite nanoparticles by the method of emulsification-evaporation. The size of composite nanoparticles was around 300-600 nm, and the maximum loading capacity of resveratrol was up to 13.88% (w/w). Hydrogen bonds, hydrophobic effects, and electrostatic attraction participated in the self-assembly of composite nanoparticles. The stability of CoQ10 Pickering emulsions was monitored under simulated environmental stresses (pH, ionic strength, UV radiation, and heat) and accelerated storage conditions. The physical stability of Pickering emulsions was dependent on the particle compositions, and the CoQ10 entrapped was also protected by the resveratrol-loaded nanoparticles. The morphology of Pickering emulsions was observed with the aid of optical microscopy, confocal laser scanning microscopy, and cryo-scanning electronic microscopy. The nutraceutical Pickering emulsions were designed for the co-delivery of resveratrol and CoQ10, which has the potential to be a novel vehicle for bioactive ingredients.

Novel Bilayer Emulsions Costabilized by Zein Colloidal Particles and Propylene Glycol Alginate. 2. Influence of Environmental Stresses on Stability and Rheological Properties

Novel bilayer emulsions co-stabilized by zein colloidal particles (ZCPs) and propylene glycol alginate (PGA) were designed to overcome some limitations of conventional emulsions or Pickering emulsions. The bilayer emulsions of various concentrations of PGA (0.01-1.50%, w/v) and different incorporation sequences of ZCPs and PGA (ZCPs/PGA and PGA/ZCPs) were fabricated using the layer by layer (LBL) electrostatic deposition technique. Influence of environmental stresses (pH 2.5-8.5; temperature 60-80 °C ; ionic strength 0-100 mM NaCl) was focused on the stability and rheological properties of the novel bilayer emulsions. In comparison to the Pickering emulsion stabilized by ZCPs alone, bilayer emulsions exhibited improved stability and unique rheological characteristics under environmental stresses. The microstructure of well-defined spheres existing a branchlike network was observed in bilayer emulsions by TEM. A comprehensive evaluation was made of the physical characteristics and stimuli-responsive behavior of bilayer emulsions. The result provided meaningful information for understanding the changing mechanism of rheology of bilayer emulsions under environmental stresses.