Stable Pickering Emulsions Research Articles

Effect of degree of esterification on the stability of high internal phase Pickering emulsions (HIPPEs) fabricated with pectin‐whey protein isolate complexes

SummaryThis study examined the effects of different degree of esterification (DE) on the stability of high internal phase Pickering emulsions (HIPPEs) fabricated using pectin‐whey protein isolate complexes. The modified pectin with different DE was prepared using the alkali de‐esterification method with high methoxyl pectin (HMP). The impact of DE on the conformational changes of pectin and whey protein isolate (WPI) during the complexes formation was examined using Fourier transform infrared spectroscopy (FTIR) and fluorescence spectroscopy. Citrus pectin (CP)–WPI complexes and camellia oil were used to create an emulsion with a self‐supporting structure of 75% internal phase volume. The thermal, centrifugal, storage and freeze–thaw stabilities of CP–WPI stabilised HIPPEs with different DE were evaluated and the results revealed that the low methoxyl pectin (LMP) produced via alkali de‐esterification altered the charge density of pectin. Compared with the untreated pectin, the electrostatic interaction between CP–WPI complexes was enhanced and the stability of CP–WPI stabilised HIPPEs was improved. The study will help to better understand the interaction between CP and WPI, enhance the efficiency of the pectin–protein delivery system and improve the utilisation rate of citrus pectin, which has important guiding significance.

Ultrafine Starch Particles as Pickering Emulsion Stabilizers With Different Interfacial Behaviors

AbstractNative starch Pickering stabilizer without chemical modification has attracted research interest in food field. However, the behaviors of starch particles at interface are seldom studied. In this paper, ultrafine starch particles (USPs) are grounded with a planetary ball mall from various starch species down to 1–2 µm in size. USP and starches are used to prepare Pickering emulsions. With size decrease, USP has more negative zeta potentials, stronger hydrogen bonds, better hydrophilicity, and better emulsifying abilities than their counterparts of starches. Millet starch has better emulsion stability than OSA modified starch. Glutinous USP outperforms in stabilization due to higher emulsion height and no oil phase separation. USP behaves differently at interface or in water phase, which is attributed to starch species, amylose and amylopectin contents, and gelatinization. This work can inspire the behavior investigation of starch particles in nano/micrometers at interface during storage.

Konjac glucomannan-based highly antibacterial active films loaded with thyme essential oil through bacterial cellulose nanofibers/Ag nanoparticles stabilized Pickering emulsions

The aim of this study was to develop novel konjac glucomannan (KGM)-based highly antibacterial active films, where five types of films were prepared and compared. The microstructure results showed that KGM-based films loaded with thyme essential oil (TEO) through bacterial cellulose nanofibers/Ag nanoparticles (BCNs/Ag nanoparticles) stabilized Pickering emulsions (Type V films) displayed the smoothest surface and the most evenly dispersed TEO droplets as compared with the other four types of films. Moreover, Type V films showed the highest contact angle value (86.28°), the best thermal stability and mechanical properties. Furthermore, Type V films presented the highest total phenol content (13.23 mg gallic acid equivalent/g film) and the best antioxidant activity (33.96 %) as well as the best sustained-release property, thus showing the best antibacterial activity, which was probably due to that BCNs/Ag nanoparticles and TEO displayed a synergistic effect to some extent. Consequently, Type V film-forming solutions were used as coatings for tangerines. The results showed that the tangerines treated with Type V coatings displayed excellent fresh-keeping properties. Therefore, the coatings, KGM-based film-forming solutions loaded with TEO through BCNs/Ag nanoparticles stabilized Pickering emulsions, have great potential for the preservation of fruits and vegetables.

Pickering emulsions with high ionic strength resistance stabilized by pea protein isolate-polyglycerol conjugate particles with good biocompatibility

Among various biopolymers, protein particles are widely used for stabilizing Pickering emulsions, yet their emulsifying ability are easily influenced by the ion concentration, pH, and high temperatures. To address these challenges, this study utilized chemical modification to prepare pea protein isolate-polyglycerol (PPI-PG) conjugates by Schiff-base reaction. Compared with other chemical modifications, this method produces conjugate particles with excellent biocompatibility, capable of promoting cell proliferation by up to 177 %. These conjugates showed improved dispersibility, with diffusion coefficients 3.5 times greater than pure PPI, and the isoelectric points shift from pH 4.6 to pH 1.5, which contribute to the pH stability of emulsions (pH 3–9). Additionally, the anisotropic nature of the conjugate particles, with a three-phase contact angle close to 90°, make particles need more energy for detachment from the oil-water interface, leading to good thermal stability of emulsion (80 °C, 48 h). Notably, after conjugation, these particles rely more on PG chains for dispersibility, which are less affected by ions, resulting in emulsions with high ionic strength resistance (3000 mM). Furthermore, the prepared Pickering emulsion demonstrates remarkable antioxidative properties (only a 10 % decrease), indicating widely potential applications in food, cosmetics, and pharmaceutical sectors.

Encapsulation of antioxidants with colloidal lipid particles for enhancing the photooxidation stability of phytosterol in Pickering emulsions

In order to prevent the photooxidation of phytosterols, a new type of Pickering emulsion was developed by regulating the oriented distribution of antioxidants in colloidal lipid particles (CLPs) at the oil-water interface. High-melting-point and low-melting-point lipids were tested to modulate their protective effect against phytosterols photooxidation. Results showed that CLPs could stabilize Pickering emulsion and encapsulate antioxidants, providing a dual functional delivery system for phytosterols protection. The Pickering emulsion formed had a particle size of around 350–820 nm, and the crystallization and melting temperatures of tripalmitin particles were approximately 32 °C and 63.8 °C, respectively. The addition of tributyrin or tricaprylin reduced the crystallization and melting temperatures of Pal CLPs and improved the photooxidation emulsion stability. The prepared Pickering emulsion remained stable for a maximum of 12 days under accelerated light-induced oxidation. Among all formulations, the emulsion primarily composed of tripalmitin CLPs, with added tributyrin and resveratrol, exhibited the highest photooxidation stability.

Stabilization of Pickering emulsions with bacterial cellulose nanofibrils (BCNFs) fabricated by electron beam irradiation

Bacterial cellulose (BC) had been considered as a promising Pickering stabilizer for its non-toxicity, high purity, and biocompatibility. The electron beam irradiation (EBI) technology had gained significant attention in the field of cellulose degradation due to its operational convenience and mild reaction conditions. Pickering emulsions using BC degraded by EBI as Pickering stabilizers were successfully prepared. Irradiated bacterial cellulose nanofibers (IBCNFs) exhibited a high aspect ratio(30–80 μm in length and 21–109 nm in width) and high absolute zeta potential (-50 mV). The optimal emulsification performance of IBCNFs was observed at an irradiation dosage of 100 kGy (IBC-100). The emulsions based on IBC-100 achieved an EI value of 96.15 ± 0.19%, while those based on IBC-500 obtained an EI value of 59.93 ± 1.47%. Stable Pickering emulsions were prepared when the concentration of IBC-100 stabilizer exceeded 0.3 wt% with a fixed oil phase of 30%, or when the rapeseed oil phase was below 50% while maintaining a fixed suspension of 0.5 wt% IBCNFs. Confocal laser scanning microscopy (CLSM) demonstrated that IBCNFs facilitated the formation of a dense interfacial layer at the oil-water interface and formed a three-dimensional network within the water phase. Which effectively hindered the aggregation and flocculation between individual oil droplets. Furthermore, rheological findings demonstrated that emulsions possessed primarily exhibited properties of elasticity, and their gel strength could be enhanced by adjusting the irradiation dosages of IBCNFs. Moreover, environmental stability experiments indicated that IBCNFs-based emulsions exhibited exceedingly high temperature (20–80 °C) and pH tolerance (4–12). Flocculation occurred under high acid (pH = 2) conditions and at high ionic levels (≥ 40 mM NaCl), without causing disruption to the emulsion droplet structure. This study provided an innovative approach to preparing cellulose nanofibers with high aspect ratio, which could be utilized as emulsion stabilizers. The study also demonstrated that Pickering emulsions based on IBCNFs exhibit excellent stability and rheological properties. IBCNFs have promising potential to serve as a natural Pickering emulsifier for stabilizing oil-in-water emulsions in various food applications, cosmetic and pharmaceutical formulations.

Pickering emulsions stabilized by β-Lactoglobulin-Rosmarinic acid-Pectin nanoparticles: Influence of interfacial behavior and rheology performance

Grafting polyphenols and glycosylation are effective means to enhance the wettability and emulsifying properties of natural protein particles. A stable pickering emulsion (PE) with antioxidant properties was prepared using β-Lactoglobulin-Rosmarinic acid-Pectin (β-LG-RA-PC) conjugates as stabilizers in this study. When PC and β-LG-RA with the same mass were covalently combined, the solid protein-based particles exhibited ideal wettability (84.2 ± 0.3°), emulsification performance, and molecular flexibility. PEs with an oil content of 66.7% were successfully prepared using a 10 mg/mL concentration of the complex. The intrinsic reasons for the stabilization of the PE were explored through interfacial tension (from 16.02 mN/m to 12.18 mN/m), adsorption kinetics, interfacial expansion viscoelastic modulus (the tangent of the phase angle was 0.22), microstructure, and rheological properties, revealing that the dense, ideally viscoelastic interface layer formed was the main factor. The electrostatic repulsion between droplets, and the formation of a robust spatial network structure, facilitated PEs’ stability. These studies confirmed the possibility of implementing protein-based particles to yield food-grade PE.

The effect of lipophilicity of corrosion bacteria on the stability of crude oil Pickering emulsions in produced water

A major environmental challenge often encountered during the production of crude oil is the formation of extremely stable oil-in-water emulsions in the effluent. The stability of these emulsions is so high that it reduces the efficiency of treatment methods. Among different parameters, the absorption of corrosion bacteria (CB) on the surfaces of crude oil droplets even more increases the emulsions stability. Therefore, in this study the lipophilicity and surface charge of three types of CBs (SRB, APB and IRB) with respect to three types of crude oil samples (paraffinic, aromatic and naphthenic) were investigated experimentally. The results revealed that based on the Langmuir adsorption isotherm a portion of CBs are adsorbed on the surface of crude oil droplets as monolayer, while another portion adheres to this monolayer leading to form a multilayer CBs. On the other hand, it was showed that the nature and chemical characteristics of droplet's organic phase affects the reversibility of the adsorbed layer of CBs. The CBs adsorption on the surface of paraffinic crude oil droplets was determined to be completely irreversible, while those of aromatic and naphthenic oil droplets were semi-reversible and reversible, respectively. The lipophilicity of SRB cells was decreased in acidic and alkaline media while it was maximum at pH = 5 corresponding to the critical zeta potential (ζC ≈ −15 mV).

Characteristics of Pickering emulsions stabilized by microgel particles of five different plant proteins and their application

Pickering emulsions stabilized by protein particles are of great interest for use in real food systems. This study was to investigate the properties of microgel particles prepared from different plant proteins, i.e., soybean protein isolate (SPI), pea protein isolate (PPI), mung bean protein isolate (MPI), chia seed protein isolate (CSPI), and chickpea protein isolate (CPI). MPI protein particles had most desirable Pickering emulsion forming ability. The particles of SPI and PPI had similar particle size (316.23 nm and 294.80 nm) and surface hydrophobicity (2238.40 and 2001.13) and emulsion forming ability, while the CSPI and CPI particle stabilized emulsions had the least desirable properties. The MPI and PPI particle stabilized Pickering emulsions produced better quality ice cream than the one produced by SPI particle-stabilized emulsions. These findings provide insight into the properties of Pickering emulsions stabilized by different plant protein particles and help expand their application in emulsions and ice cream.

Controllable Regulation of Diesel Oil-in-Water Pickering Emulsion Stability by Multiresponsive Recyclable Magnetic Polymer Brush Microvessels.

To ensure safety and efficiency in the production and transportation of fuel oil, there is an urgent demand to develop intelligent emulsifiers to deal with this challenge. Fe3O4@PDA-P(NIPAM-b-MAA-b-LMA) (MNPDNML) microspheres were prepared by modifying polydopamine and the triblock polymer brush P(NIPAM-b-MAA-b-LMA) on the surface of Fe3O4 nanoparticles via oxidative autopolymerization and SI-RAFT polymerization. Therefore, the MNPDNML microspheres exhibited sensitive stimulus-responsive behavior to pH, temperature, near-infrared (NIR) laser radiation, and magnetic fields. The stability state of the emulsion could be modulated by changing pH, temperature, magnetic field, and NIR radiation, and the reversible switching of emulsification/breaking behavior could be reached at least 10 times. This "intelligent emulsifier" exhibited high emulsification efficiency, long-term stability, and on-demand emulsification/breaking properties. It was notable that MNPDNML microspheres showed excellent emulsification ability for olive oil, kerosene, gasoline, and crude oil, which allowed the material to be widely used in the controlled transportation and separation of fuel oil.

Pickering emulsions stabilized by starch nanocrystals prepared from various crystalline starches by ultrasonic assisted acetic acid: Stability and delivery of curcumin

Ultrasonic assisted acetic acid hydrolysis was applied to prepare starch nanocrystals (SNCs) from native starches with different crystalline structures (A, B, and C types). The structure properties, morphology, Pickering emulsion stability and curcumin deliver capacity of both SNCs and native starches were investigated and compared. Compared with native starches, SNCs showed smaller size and higher crystallinity. The size of SNCs varied with different crystalline types, with C-type starch exhibiting the smallest SNCs (107.4 nm), followed by A-type (113.8 nm), and B-type displaying the largest particle size (149.0 nm). SNCs-Pickering emulsion showed enhanced stability with smaller emulsion droplets, higher static stability, and denser oil/water interface. SNCs-Pickering emulsions displayed higher curcumin loading efficiency (53.53 %–61.41 %) compared with native starch-Pickering emulsions (13.93 %–19.73 %). During in vitro digestion, SNCs-Pickering emulsions proved to be more proficient in protecting and prolonging the biological activity of curcumin due to their smaller size and better interfacial properties. These findings demonstrated the potential of SNCs for application in Pickering emulsion and delivery of bioactive components.

Self-healing epoxy coatings via microencapsulation of aromatic diisocyanate in lignin stabilized Pickering emulsions

Isocyanate-filled microcapsules are gaining increased attention for their role in developing self-healing materials, thereby reducing maintenance costs and increasing polymer durability. Nevertheless, microencapsulating highly reactive -NCO groups remains a challenging task in the literature. Likewise, considerable efforts have been directed towards developing polymers from renewable and biobased sources, which could also be applied to microcapsule synthesis. In this work, lignin, an abundant biopolymer, was used as a solid stabilizer for oil-in-water (O/W) interfaces, enabling the encapsulation of highly reactive isocyanate. Hybrid polyurethane/polyurea microcapsules containing reactive methylenediphenyl diisocyanate (MDI) were obtained via optimized O/W Pickering emulsions using lignin for system stabilization. This optimized process facilitated shell formation via the reaction of diisocyanate with lignin and water, eliminating the need for additional chain extenders. Scanning electron microscopy revealed the formation of spherical and rough microcapsules, while infrared spectroscopy confirmed the presence of residual free -NCO groups, indicating effective encapsulation of MDI. Additionally, a core -NCO concentration of 11 wt% was confirmed by titration. The microcapsules were further assessed as components in self-healing epoxy coatings. Their incorporation resulted in the retardation of corrosion on a low carbon steel panel after 72 h of submersion in a saline solution. Electrochemical impedance spectroscopy (EIS) confirmed a significant increase of approximated 620% in impedance modulus after 83 days of immersion in a 3.5 wt% NaCl solution, compared to the neat epoxy coating. These findings suggest a promising technological application of this material for the advancement of self-healing epoxy-based coatings and composites.

Extraction and preparation of cellulose nanocrystal from Brewer's spent grain and application in pickering emulsions

In recent years, the search for novel Pickering stabilizers has attracted much interest in the food, cosmetic and pharmaceutical industries. In this work, brewer's spent grain cellulose (BSGC) was successfully extracted by diluted acid, alkaline and bleaching treatments, and then brewer's spent grain cellulose nanocrystal (BSGCNC) were obtained by acid hydrolysis treatment of BSGC. The properties of the BSGCNC were characterized, and the results showed that the BSGCNC had a rod-like structure with high crystallinity (67.09%). Then the emulsification properties of BSGCNC were evaluated by different concentrations and water-oil ratios, and the results showed that BSGCNC were able to form stable Pickering emulsions. This study suggested that cellulose nanocrystal (CNC) could be extracted from brewer's spent grain which was used as food waste, as a stabilizer for Pickering emulsions.

Stabilization of Pickering emulsions by oxidized starch/zein nanoparticle complexes

In this study, oxidized starch (OS)/zein nanoparticles (ZNP) complexes were prepared and used to stabilize Pickering emulsions. The effect of starch oxidation using three levels of sodium hypochlorite (2.0%, 3.0%, 4.0% active chlorine, dry basis) on the properties of OS/ZNP complexes and complex-stabilized Pickering emulsions were evaluated. The interaction between oxidized starch and zein nanoparticles was confirmed by X-ray diffractometry (XRD) and Fourier transform infrared (FT-IR) spectrometry. The presence of oxidized starch improved the wettability of OS/ZNP complexes. The optimum contact angle (θ) of OS/ZNP complexes was 90.88°, when starch was oxidized with 3.0% active chlorine (3.0% OS). The appearance, micromorphology and oil droplet-size distribution suggested that OS/ZNP complex-stabilized Pickering emulsions were formed. Rheological measurements indicated that Pickering emulsions showed shear-thinning behavior. Furthermore, the viscoelasticity of Pickering emulsions was dependent on the oxidized starch and oil fractions. Stability test showed that the stability of Pickering emulsion can be improved by increasing the oil fraction from 20% to 50%, and Pickering emulsion stabilized by 3.0% OS/ZNP complexes had the highest stability. This work provides information on OS/ZNP complex-stabilized Pickering emulsions.

Utilization of peanut protein isolate amyloid-like fibers as stabilizers for high internal phase Pickering emulsions

This paper focuses on modifying peanut protein isolate (PPI) through fibrillation to enhance its emulsification properties and investigates the potential application of the fibers in stabilizing high internal phase Pickering emulsions (HIPPEs). Th T result indicates that the optimal conditions for peanut protein isolate amyloid-like fibers (PAFs) preparation are pH=2, 90 °C, and 20 h. Electrophoresis and Transmission electron microscope demonstrate that PPI undergoes peptide hydrolysis and self-assembly during the reaction process, leading to the formation of an elongated linear structure with a diameter approximately 14 nm. Furthermore, infrared spectroscopy, X-ray diffraction, and contact angle results further demonstrate an increase in β-sheet content, crystallinity, and surface hydrophilicity compared to PPI. Notably, the emulsification activity index (EAI) of PAFs (78.62 ± 1.68 m2/g) was found to be increased up to threefold compared to that of PPI (27.89 ± 1.98 m2/g). According to visual observation and microstructural analysis, the addition of 1% PAFs has been found to effectively stabilize HIPPEs (φdisp = 0.75) due to the presence of dense protective layers formed by PAFs. Additionally, the particle size results (D[3,2] = 17.02 ± 2.02 μm) also indicate that the oil droplets are tightly enveloped by the dense protective layers formed by PAFs. Moreover, rheological data indicates that HIPPEs stabilized using PAFs exhibit excellent solid-like viscoelastic behavior. Overall, these findings suggest that the utilization of PAFs has significant potential in enhancing the stability of HIPPEs.

The soybean lecithin-cyclodextrin-vitamin E complex nanoparticles stabilized Pickering emulsions for the delivery of β-carotene: Physicochemical properties and in vitro digestion

In this work, soybean lecithin (LC) was used to modify β-cyclodextrin (β-CD) with hydrophobic fat chains to become amphiphilic (LC-CD), and vitamin E (VE) was encapsulated in former modified β-CD complexes (LC-CD-VE), the new Pickering emulsions stabilized by LC-CD-VE and LC-CD complexes for the delivery of β-carotene (BC) were created. The surface tension, contact angle, zeta potential, and particle size were used to assess the changes in complexes nanoparticles at various pH values. Furthermore, LC-CD-VE has more promise as Pickering emulsion stabilizer than LC-CD because of the smaller particle size (271.11 nm), proper contact angle (58.02°), and lower surface tension (42.49 mN/m). The interactions between β-cyclodextrin, soybean lecithin, and vitamin E were confirmed using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), nuclear magnetic resonance (NMR), and thermogravimetric analysis (TGA). The durability of Pickering emulsions was examined at various volume fractions of the oil phase and concentrations of nanoparticles. Compared to the emulsion stabilized by LC-CD, the one stabilized by LC-CD-VE showed superior storage stability. Moreover, for the delivery of BC, Pickering emulsions stabilized by LC-CD and LC-CD-VE can outperform bulk oil and Tween 80 stabilized emulsions in terms of UV light stability, storage stability, and bioaccessibility. This work could offer fresh perspectives on stabilizer alternatives for Pickering emulsion delivery systems.

Dumbbell-shaped polymeric nanoparticles with one-side anchored Pd-clusters for efficient catalytic hydrogenation at biphasic interfaces

Pickering interfacial catalysts incorporated with amphiphilic architecture significantly expand the sustainability of green catalysis systems. In this work, we present precise and well-designed dumbbell-shaped Janus-structured polymeric nanoparticles with one-side anchored palladium clusters (DB-JPP-Pd) as Pickering interfacial catalyst for static hydrogenations. The large wettability difference of each lobe renders the prominent amphiphilicity of the dumbbell-shaped DB-JPP-Pd. The amphiphilic Janus catalyst displays excellent interfacial activity and extensively reduces the interfacial tension from 34.06 ± 0.13 to 20.54 ± 0.31 mN/m, promoting the formation of a more stable Pickering emulsion than that of the bulk PS-Pd catalyst, which can continuously provide a large interfacial area and shorten the molecular mass transfer distance during the reaction process. As a result, the DB-JPP-Pd catalyzed nitroarene reduction reaction exhibits a normalized reaction rate constant (knor) of 3.39 min−1⋅g−1⋅L under static conditions, which is 56.5 times higher than that of bulk PS-Pd. The constructed Pickering interfacial catalysis (PIC) system converts all the nitrobenzene into aniline within three minutes and possesses excellent selectivity in hydrogenations of different nitro aromatics. In addition, the emulsion catalytic system was conveniently recycled for ten consecutive runs. Hence, this unique amphiphilic dumbbell-shaped catalyst effectively develops an efficient static biphasic catalysis system.

Fabrication and characterization of anthocyanin-loaded double Pickering emulsions stabilized by β-cyclodextrin

Anthocyanins, one of the important water-soluble pigments, are sensitive to environmental factors, which limits the application of anthocyanins in food field. In order to overcome this limitation, double Pickering emulsions stabilized by β-cyclodextrin were developed. The optimum preparation conditions of the emulsions were determined firstly and the performance and structure of emulsions were investigated. Results showed that the optimum preparation conditions of emulsions were the ratio of (W1/O): W2 = 6:4 and 4 % β-cyclodextrin concentration. Optical microscope and confocal laser scanning microscope results confirmed that β-cyclodextrin adsorbed onto the surface of droplets forming stable double Pickering emulsions structure. In vitro gastrointestinal digestion experiments proved that double Pickering emulsions played a controlled-release effect in the small intestine. Rheological analysis proved that the emulsions exhibited elastic properties and demonstrated shear thinning behavior. The emulsions showed excellent stability under centrifugation and thermal conditions. These findings will promote anthocyanins’ application in daily diet.

Deformation and rupture of Janus nanoparticle-stabilized Pickering emulsion in confined channel

The interaction between Pickering emulsions and confined channels is vital for their industrial applications. However, how solid particle shells modulate the deformation stability and rupture limit of Pickering emulsions in contact with wall remains poorly understood. In this work, mechanical deformation and rupture of Janus nanoparticles (JNP)-stabilized Pickering emulsions on solid surfaces are elaborated by molecular dynamics (MD) simulations. A universal master-type predictive model is developed for the first time to describe the contact behavior of Pickering emulsions against surfaces with distinct wettability. The contact stress of an emulsion is determined by the equivalent elastic modulus of the emulsion, geometric deformation function, and the influence of the JNP shell and its interactions. Moreover, hydrophobic surfaces lead to the rupture of Pickering emulsions in compression. The rupture can be delayed by increasing JNP surface coverage (ϕ). Especially, once ϕ reaches a critical value, the JNP shell can form an ordered quasi-solid structure, significantly enhancing the emulsion stability. These results can aid in the design or screening of specific Pickering emulsions to manage their deformation and rupture on the solid surface, in applications ranging from water treatment and drug delivery to environmental remediation and mobility control in oil recovery.

Influence of carboxymethyl cellulose on the stability, rheology, and curcumin bioaccessibility of high internal phase Pickering emulsions

Recently, there has been a focus on using biopolymer-based particles to stabilize high internal phase Pickering emulsions (HIPPEs) due to the notable advances in biocompatibility and biodegradability. In this work, the complex particles of peanut protein isolate and carboxymethyl cellulose (CMC) with various substitution degrees (DS; 0.7 and 0.9) and weight average molecular weights (Mw; 90, 250, and 700 kDa) were prepared and characterized as novel stabilizers. For the obtained four types of morphologically distinct particles, the complex particles formed by CMC (0.9 DS and 250 kDa) showed cluster structures with an average size of 1.271 μm, equally biphasic wettability with three-phase contact angles of 91.5°, and the highest diffusion rate at the oil-water interface. HIPPEs stabilized by these particles exhibited more elastic behavior due to the smaller tanδ and higher viscosity, as well as excellent thixotropic recovery properties and stability against heating, storage, and freeze-thawing. Furthermore, confocal laser scanning microscopy verified that these particles formed a dense interfacial layer around the oil droplets, which could resist flocculation and coalescence between oil droplets during in vitro digestion. The improved bioaccessibility of curcumin-loaded HIPPEs made these delivery systems potentially apply in functional foods.