High Emulsion Research Articles

Influence of Proteins on Bioaccessibility of α-Tocopherol Encapsulation within High Diacylglycerol-Based Emulsions.

α-Tocopherol has been widely used in medicine, cosmetics, and food industry as a nutritional supplement and antioxidant. However, α-tocopherol showed low bioaccessibility, and there is a widespread α-tocopherol deficiency in society today. The preparation of oil-in-water emulsions with high safety and low-calorie property is necessary. The aim of this research was to investigate the effects of different protein emulsifiers (whey protein isolate (WPI), soy protein isolate (SPI), and sodium casein (SC)) on the properties of emulsions delivery system, and diacylglycerol (DAG) was picked as a low-accumulated lipid. The interfacial changes, microstructural alterations, and possible interactions of the protein-stabilized DAG emulsions were investigated during the in vitro digestion. The results show that different proteins affect the degree of digestibility and α-tocopherol bioaccessibility of the emulsions. Both WPI- and SPI-coated emulsions showed good digestibility and α-tocopherol bioaccessibility (77.64 ± 2.93%). This might be due to the strong hydrolysis resistance of WPI (β-lactoglobulin) and the good emulsification ability of SPI. The SC-coated emulsion showed the lowest digestibility and α-tocopherol bioaccessibility, this might be due to the emulsification property of hydrolysis products of SC and the potential interaction with calcium ions. This study provides new possibilities for the application of DAG emulsions in delivery systems.

Fabrication of natural W1/O/W2 double emulsions stabilized with gliadin colloid particles and soybean lecithin

In this study, we successfully fabricated W1/O/W2 double emulsions and high internal phase double emulsions with gliadin colloid particles (GCPs) as the hydrophilic emulsifier and soybean lecithin as the hydrophobic emulsifier, which were obtained from natural resources and avoided the use of surfactants such as PGPR. The effects of lecithin concentration, GCP concentration, W1/O volume ratio, and pH of the external aqueous phase on the physical properties and encapsulation efficiency of the double emulsions were investigated. The double emulsions presented an encapsulation efficiency (tartrazine was used as an aqueous marker) up to 91.1 ± 0.2% under the optimised conditions (GCP concentration 2% (w/v), lecithin concentration 1% (w/v), pH 6 of the W2 phase, W1/O volume ratio 1:5). After 30-days of storage at room temperature, the encapsulation efficiency of the double emulsions remained stable at 88.8 ± 0.2%, indicating good encapsulation stability. The double emulsions exhibited pH response characteristics; their appearance changed from a semi-solid to a flow state as the pH of the W2 phase increased, and the formation of the gel net structure facilitated the maintenance of the internal aqueous phase during fabrication and storage. This study provides a strategy for the fabrication of natural double emulsions with satisfactory encapsulation efficiency.

Insight into oil-water interfacial behaviors of whey protein isolate and sterol towards stabilizing high internal phase Pickering emulsion gels

This investigation elucidated stabilization of high internal phase Pickering emulsion gels (HIPPEGs) on the basis of oil-water interfacial adsorption properties of particles. The particles were prepared by whey protein isolate (WPI) and two structurally different sterols, including ergosterol (ES) and γ-oryzanol (γS). Initially, oil-water interfacial adsorption properties were improved in the presence of sterol. And WPI-γS exhibited higher contact angle and lower dynamic interfacial tension than WPI-ES. Quartz crystal microbalance with dissipation monitoring measurement further proved that adsorption mass and viscoelasticity of WPI-γS was higher than those of WPI-ES. Furthermore, WPI-sterol HIPPEGs showed lower average particle size and moisture content, higher absolute value of ζ-potential than WPI-stabilized HIPPEGs. Apparent viscosity, storage modulus and loss modulus of WPI were improved after the addition of sterol. Moreover, WPI-γS HIPPEGs exhibited higher stabilities and viscoelasticity than WPI-ES HIPPEGs. Additionally, compared with WPI-stabilized HIPPEGs, WPI-γS-loaded HIPPEGs showed shorter relaxation time and more uniform color distribution, indicating that droplet flow was restricted and more uniform, followed by WPI-ES-loaded HIPPEGs. Finally, super-resolution microscope results exhibited that sterol inhibited emulsion droplets aggregation due to steric hindrance. HIPPEGs stabilized by WPI-γS showed more homogeneous and smaller droplets than WPI-ES-loaded HIPPEGs. This work provided a theoretical support for stable HIPPEGs formed with protein-sterol particles, which would be applied to replace trans fats and cholesterol in various food products.

High internal phase Pickering emulsions stabilised by ultrasound-induced soy protein-β-glucan-catechin complex nanoparticles to enhance the stability and bioaccessibility of curcumin

Aims To evaluate the potential applications of soy protein–glucan–catechin (SGC) complexes prepared with different ultrasound times in stabilising high internal phase Pickering emulsion (HIPPE) and delivering curcumin. Methods The SGC complexes were characterised by particle size, morphology, zeta potential, Fourier transform infra-red, and fluorescence spectroscopy. Formation and stability of curcumin emulsions were monitored by droplet size, microstructure, rheological property, lipid oxidation, and in vitro digestion. Results Short-time ultrasound-induced complexes (SGC-U15) exhibited a small size and wettability of ∼82.5°. The chemical stability and bioaccessibility of curcumin was greatly improved by SGC-U15-stabilised HIPPEs, even after 70 days of storage, heating at 100 °C for 30 min, ultraviolet irradiation for 120 min, and in vitro digestion, owing to the formation of elastic gel-like structure at the oil/water interfaces. Conclusion Our findings may contribute to the design of emulsion-based delivery systems using ultrasound-induced protein–polysaccharide–polyphenol complexes.

Recent progress in food‐grade double emulsions: Fabrication, stability, applications, and future trends

AbstractCompared with ordinary emulsions, the unique structures endow double emulsions with special functions, which makes them have broad prospects in delivering biologically active substances and replacing fats. In recent years, due to the instability of double emulsions, numerous experiments have been carried out on their preparation technology as well as stabilization methods. This review emphatically summarizes the research progress of double emulsions, including preparation techniques, factors affecting stability, stabilization mechanisms, and related applications. At present, in addition to the traditional mechanical agitation and ultrasonic emulsification, membrane emulsification, phase inversion, and microfluidic emulsification are the main research directions, all of which can improve the stability. Moreover, the stabilizer is also a crucial factor affecting the stability of the double emulsion. Hence, in this article emphasis is placed on surfactants, biopolymers, and solid particles. The applications of double emulsions in food industry can be divided into the following categories: encapsulating substances, controlling the release, and being served as fat substitutes. Furthermore, in the future, the main challenges are to commercialize the double emulsions and enhance their safety in food applications. Additionally, developing high internal phase Pickering double emulsions and O/W/O double emulsions may become the major research trends.

High internal phase Pickering emulsions stabilized by modified sturgeon myofibrillar protein for quercetin delivery

In this study, the modified sturgeon myofibrillar protein was prepared by the combination of malondialdehyde and ultrasonic induction and used as the emulsifier to form a stable high internal phase Pickering emulsion (HIPPEs) with internal phase up to 75%. The results showed that combined modification reduced the fluorescence intensity, enhanced the surface hydrophobicity, changed the secondary structure, and made the protein particles smooth. The confocal laser scanning microscopy confirmed the formation of a stable HIPPEs. The interfacial tension and rheological properties of protein stabilized HIPPEs were improved by the combined modification and the encapsulation efficiency of quercetin reached 89.32%. In vitro digestion showed that the combined modified protein-stabilized HIPPEs significantly improved the rate of lipid digestion and the bioavailability of quercetin while reducing the degradation of quercetin. The findings indicated that the utilization of modified sturgeon myofibrillar protein to stabilize HIPPEs hold significant promise for various biological applications, owing to its capacity as a carrier for the regulated discharge of bioactive agents.

Potential influence of nutrients intake by adults on the population dynamics of Athetis lepigone (Lepidoptera: Noctuidae)

Athetis lepigone is an important pest on corn, but little is known about the nutritional requirements of adult A. lepigone and how nutrients affect their reproduction and longevity. Here, we explored the effects of different nutrients on the reproduction, longevity, and population growth of A. lepigone. Carbohydrates were beneficial for adult reproduction and longevity, with feeding 5% sucrose having the best effect by resulting in an average of 424.83 eggs per female. When females consumed carbohydrates, the net reproductive rate (R0) and the intrinsic rate of increase (rm) were higher. However, the fecundity of adults fed only amino acids and high concentration fat emulsion decreased significantly, with an average of 60 to 160 eggs per female. The main food source of Lepidoptera insects is the nectar from flowering plants in the field. Due to compound planting patterns, flowering plants are widely distributed around farmland. The nectar secreted by them usually contains rich carbohydrates, which can be provided for adults. Therefore, we must also consider the potential impact of flowering plants on A. lepigone, in order to improve pest control efficiency.

High internal phase Pickering emulsions stabilized by ε-poly-l-lysine grafted cellulose nanofiber for extrusion 3D printing

An effective method for preparing food-grade three-dimensional (3D) printing materials was the use of highly concentrated oil-in-water emulsions. This research reported 3D printable materials constructed from food-grade high internal phase Pickering emulsions (HIPPEs) that were stabilized by ε-poly-l-lysine grafted cellulose nanofiber (ε-PL-TOCNs). The ε-PL-TOCNs were prepared via ε-poly-l-lysine grafting of 2, 2, 6, 6-tetramethylpiperidine-N-oxyl (TEMPO)-oxidized cellulose (TOC) and the successive mechanical treatment. Subsequently, the chemical structure, microstructure and surface properties of ε-PL-TOCNs were characterized. The results showed that the prepared ε-PL-TOCNs had excellent dispersion performances, cationic properties brought by amino groups, and hydrophilic/hydrophobic functions of chain structure, which confirmed the feasibility of preparing HIPPEs. The HIPPEs with an internal phase volume fraction of 82 % were obtained at 0.8 wt% ε-PL-TOCNs concentration and pre-emulsification followed by continuous oil feeding. The HIPPEs' storage stability, morphology, and rheological behavior were further discussed. The ultra stable HIPPEs with apparent shear-thinning behavior and high solid viscoelasticity were successful produced, which was suitable for 3D printing. This work expanded the application of nanocellulose in emulsions field and provided a new thinking to prepare food-grade 3D printable materials and porous foam.

Robust, Flame-Retardant, and Anti-Corrosive Waterborne Polyurethane Enabled by a PN Synergistic Flame-Retardant Containing Benzimidazole and Phosphinate Groups.

Waterborne polyurethanes (WPUs) have attracted great interest owing to their environmentally friendly properties, and are wildly applied in production and daily life. However, waterborne polyurethanes are flammable. Up to now, the challenge remains to prepare WPUs with excellent flame resistance, high emulsion stability, and outstanding mechanical properties. Herein, a novel flame-retardant additive, 2-hydroxyethan-1-aminium (2-(1H-benzo[d]imidazol-2-yl)ethyl)(phenyl)phosphinate (BIEP-ETA) has been synthesized and applied to improve the flame resistance of WPUs, which has both phosphorus nitrogen synergistic effect and the ability to form hydrogen bonds with WPUs. The WPU blends (WPU/FRs) exhibited a positive fire-retardant effect in both the vapor and condensed phases, with significantly improved self-extinguishing performance and reduced heat release value. Interestingly, thanks to the good compatibility between BIEP-ETA and WPUs, WPU/FRs not only have higher emulsion stability, but also have better mechanical properties with synchronously improved tensile strength and toughness. Moreover, WPU/FRs also exhibit excellent potential as a corrosion-resistant coating.

Whey protein-tannic acid conjugate stabilized high internal phase Pickering emulsions: Interfacial stability based on covalent crosslinking

Protein-stabilized high internal phase Pickering emulsions (HIPEs) have potential usage in food and cosmetic fields. However, the poor interfacial activity of proteins in HIPEs is still a key bottleneck. In this work, whey protein (WP)-tannic acid (TA) conjugates by covalent crosslinking were used to fabricate HIPEs, and then the emulsifying ability and stability of HIPEs were also studied. The result indicated that covalent bonds formed between WP and TA. WP-TA conjugates had better oil-water interfacial activities and more suitable wettabilities than free WP. WP-TA conjugate stabilized HIPEs had a narrower size distribution, a more compact droplet structure and a denser gel network compared with free WP stabilized HIPEs, especially at high TA mass ratios and alkaline conditions. At the same time, the conjugates stabilized HIPEs exhibited better stability against heat treatment and centrifugation. Covalent crosslinking in WP-TA conjugates formed network based on TA molecules as bridges among emulsion droplets and played an important role in stabilizing HIPEs. This study expects to provide a new perspective for investigating the stabilizing mechanism of protein-polyphenol conjugate stabilized HIPEs.

Light-induced reversible destabilization of responsive latex particles prepared via high solids content emulsion polymerization

Light-induced reversible destabilization of responsive latex particles prepared via high solids content emulsion polymerization

Assembly and utilization of a millifluidic-inverse gelation platform for the gastrointestinal delivery of cinnamon oil emulsion

The present study focused on using the millifluidic-inverse gelation platform to produce core-shell millicapsule filled with cinnamon W/O emulsion as an intestinal delivery system. Effects of variables in the designed encapsulation method (flow rates of two phases and alginate concentration) on encapsulation efficiency (EE), loading capacity (LC), size, sphericity factor (SF), and Young modulus were optimized. The best-selected ranges of emulsion Z-average diameter and alginate viscosity were 800–1400 nm, and 16.63–153.61 mPa.s, respectively. According to the Capillary and Weber numbers, the dripping regime was confirmed in the tube during droplet formation. The optimal millicapsule had a 2.50 mm diameter, 0.97 SF, 95.83% EE, 51.39% LC, and 8.5× 104 Pa Young modulus. The smooth surface of the millicapsules and the uniform distribution of the oil and water droplets inside the emulsion dispersed phase were evidenced by SEM and CLSM, respectively. In-vitro digestion demonstrated that millicapsules act as a pH-dependent delivery system to release the oil into the small intestine. Mechanical stability reached a maximum in the gastric phase. High emulsion loading acted as a soft filler, which improved the mechanical stability of millicapsules. Peppas-Sahlin was the best model to describe the release behavior in the mouth, stomach, and small intestine.

Studies on stabilized mechanism of high internal phase Pickering emulsions from the collaboration of low dose konjac glucomannan and myofibrillar protein

In this study, the effects of different concentrations (0%, 0.25%, 0.5%, 1%, 1.5%, w/v) of konjac glucomannan (KGM) on the structure and interfacial adsorption of myofibrillar protein (MP) and the mechanism of co-emulsification of high internal phase Pickering emulsions (Pickering HIPEs) by KGM and MP were investigated. The results showed that for interfacial MPs, KGM addition promoted MP structure unfolding and improved MP wettability with a three-phase contact angle from 73.69° (control) to 89.41° (0.5% KGM), thereby lowering the energy barriers to MP penetrating and rearranging at the interface. Furthermore, the adsorption kinetics and protein adsorption percentage (AP%) indicated that KGM (≤1%) facilitated the adsorption of MP from the aqueous phase to the oil-water interface. For MP in the aqueous phase, KGM induced a denser MP network structure by promoting “concentrated” MP and connecting MP through hydrogen bonding, which formed a stronger spatial site resistance and hindered oil droplet aggregation. KGM (≤1%, especially 0.5%) resulted in reduced droplet size, relaxation time (T2), lipid oxidation, and improved storage stability and energy storage modulus of Pickering HIPEs. However, the competitive adsorption of KGM (>1%) significantly decreased the interface MP, and the formation of continuous KGM hydrogel formed an unaggregated MP network structure, decreasing the emulsion performance further. Overall, KGM could modulate the physical properties of MP-stabilized Pickering HIPEs by altering the interfacial adsorption and network structure.

Fabrication of soy protein isolate - High methoxyl pectin composite emulsions for improving the stability and bioavailability of carotenoids

A handy and efficient emulsifying emulsion was developed based on self-assembled soy protein isolate (SPI) and high methoxy pectin (HMP) for entrapping and loading carotenoids. The complex, ca. 195 nm, showed a significant improvement in solubility, emulsification (32.42 m2/g) and stability (83.86%). Moreover, the physical stability of torularhodin was remarkably improved after entrapping into the SPI-HMP complex. The retention rate for entrapped torularhodin could be up to 66.03%, 95.14% and 84.31% under treatment with ultraviolet irradiation for 8 h, thermal stock at 25 and 50 °C for 28 days, respectively. Increase of two affinities, enhancement of intermolecular hydrogen bond and hydrophobic interaction and charge changes caused by the preparation process of the complex were the main reasons for improving the properties of emulsion. At the same time, composite lotion encapsulation significantly improves the bioavailability of torularhodin, including the absorption of carotenoids in the small intestine, the content in the systemic circulation and the storage capacity in the liver. Therefore, the preparation of low price, safer, green and efficient SPI-HMP complex emulsion has long-term application prospects on the development, transportation and application of antioxidants.

Preparation of high complex concentration emulsion stabilized by soy protein/dextran sulfate composite particles.

Soy protein isolate (SPI) could be used as an emulsifier to stabilize emulsions, while SPI is unstable under low acidic conditions. The stable composite particles of SPI and dextran sulfate (DS) could be formed by the electrostatic interaction at the pH was 3.5. And the SPI/DS composite particles were used to prepare the high complex concentration emulsion. The stabilization properties of high complex concentration emulsion were investigated. Compared to uncompounded SPI, the particle size of SPI/DS composite particles was smaller at 1.52 μm, and the absolute value of the potential increased to 19.9 mV when the mass ratio of SPI to DS was 1:1 and the pH was 3.5. With the DS ratio increased, the solubility of the composite particles increased to 14.44 times of the untreated protein at pH 3.5, while the surface hydrophobicity decreased. Electrostatic interactions and hydrogen bonds were the main forces between SPI and DS, and DS was electrostatically adsorbed on the surface of SPI. The emulsion stability significantly enhanced with the increase of complex concentration (38.88 times higher than at 1% concentration), the emulsion average droplet size was the lowest (9.64 μm), and the absolute value of potential was the highest (46.67 mV) when the mass ratio of SPI to DS was 1:1 and the complex concentration of 8%. The stability of the emulsion against freezing was improved. The SPI/DS complex has high solubility and stability under low acidic conditions, and the SPI/DS complex' emulsion has a well stability. This article is protected by copyright. All rights reserved.

Earth Worming-An Evaluation of Earthworm (Eisenia andrei) as an Alternative Food Source.

Aside from their bioremediation roles, little is known about the food and feed value of earthworms. In this study, a comprehensive evaluation of the nutritional composition (proximate analysis and profiles of fatty acids and minerals) and techno-functional properties (foaming and emulsion stability and capacity) of earthworm (Eisenia andrei, sourced in New Zealand) powder (EAP) were investigated. Lipid nutritional indices, ω6/ω3, atherogenicity index, thrombogenicity index, hypocholesterolemic/hypercholesterolemic acid ratio, and health-promoting index of EAP lipids are also reported. The protein, fat, and carbohydrate contents of EAP were found to be 53.75%, 19.30%, and 23.26% DW, respectively. The mineral profile obtained for the EAP consisted of 11 essential minerals, 23 non-essential minerals, and 4 heavy metals. The most abundant essential minerals were potassium (8220 mg·kg-1 DW), phosphorus (8220 mg·kg-1 DW), magnesium (744.7 mg·kg-1 DW), calcium (2396.7 mg·kg-1 DW), iron (244.7 mg·kg-1 DW), and manganese (25.6 mg·kg-1 DW). Toxic metals such as vanadium (0.2 mg·kg-1 DW), lead (0.2 mg·kg-1 DW), cadmium (2.2 mg·kg-1 DW), and arsenic (2.3 mg·kg-1 DW) were found in EAP, which pose safety considerations. Lauric acid (20.3% FA), myristoleic acid (11.20% FA), and linoleic acid (7.96% FA) were the most abundant saturated, monounsaturated, and polyunsaturated fatty acids, respectively. The lipid nutritional indices, such as IT and ω-6/ω-3, of E. andrei were within limits considered to enhance human health. A protein extract derived from EAP (EAPPE), obtained by alkaline solubilisation and pH precipitation, exhibited an isoelectric pH of ~5. The total essential amino acid content and essential amino acid index of EAPPE were 373.3 mg·g-1 and 1.36 mg·g-1 protein, respectively. Techno-functional analysis of EAPPE indicated a high foaming capacity (83.3%) and emulsion stability (88.8% after 60 min). Heat coagulation of EAPPE was greater at pH 7.0 (12.6%) compared with pH 5.0 (4.83%), corroborating the pH-solubility profile and relatively high surface hydrophobicity (1061.0). These findings demonstrate the potential of EAP and EAPPE as nutrient-rich and functional ingredients suitable as alternative food and feed material. The presence of heavy metals, however, should be carefully considered.

Preparation of underwater superoleophobic ZIF-67 composite membrane with high antibacterial activity and emulsion separation efficiency

Bacteria and oils can be found in domestic sewage and wastewater from biomedical industries, however, traditional membranes have limitation in bacterial resistance, so it is high demand to design oil-water separation membranes with antibacterial activity. In this work, a novel TCN-ZIF-67/PVA@NM composite membrane with underwater superoleophobic property was prepared by in-situ growth method. The effects of ZIF-67 on emulsion separation and antibacterial activity were investigated in details. Results show that TCN-ZIF-67/PVA@NM have high separation efficiencies for oil-in-water emulsions stabilized by SDS, CTAB or Tween 80. Due to the positive charge of ZIF-67, the separation flux shows a trend of SDS>CTAB>Tween 80. The separation efficiency and antibacterial activity of the composite membrane increased and the separation flux decreased with the increase of the particle size of ZIF-67. In addition, the composite membrane had good inhibitory effects against the biofilm formation of S. aureus and MASR. It was found that when the reaction time was more than 6 h, the separation efficiencies of oil-in-water emulsions were more than 99%, and the bacterial inhibition ratios against S. aureus and E. coli. and biofilm inhibition ratios against S. aureus and MASR were more than 90%. When separating the emulsion containing bacteria, the composite membrane can simultaneously purify the emulsion and kill the bacteria in the water. Overall, ZIF-67 plays key roles in both emulsion separation and bacterial resistance, and the ZIF-67 composite membrane shows a promising potential in oil-water emulsion separation application.

High-internal phase Pickering emulsion stabilized by crystals of nobiletin: assembly of supramolecular metal-polyphenolic coordination complexes for surface coating.

High internal phase Pickering emulsion has attracted extensive attention due to its unique properties, and has broad application prospects in the food field, such as as a fat replacer, packaging and delivery of nutrients or probiotics, and 3D printing of food. However, efficient and edible high-internal phase Pickering stabilizer is still a persistent challenge for food scientists. Herein, the nobiletin (NOB) was selected as a model substance, the particle physicochemical properties (droplet size, rheological behavior, and transmission profile) showed that supramolecular metal-polyphenolic coordination networks could suppress the ripening and growth of crystals on the oil-water interface. When the ratio of tannic acid (TA) and Fe3+ was 3:1, the crystallization growth of NOB could be effectively inhibited. Due to the reduction of energy steric hindrance in the adsorption process, the resulting NOB-TA3 -Fe3+ 1 (NT3 Fe1 ) nanoparticles had the greatest potential to extend emulsion storage time. This particle could stabilise a high-internal phase emulsion, of which the oil phase was 80%, for at least 30 days and eventually lead to high system viscosity. The findings in this work provided a novel selection of healthy emulsifiers as well as an effective emulsion delivery system for hydrophobic and crystalline nutrients. This article is protected by copyright. All rights reserved.

Covalent Bond Interfacial Recognition of Polysaccharides/Silica Reinforced High Internal Phase Pickering Emulsions for 3D Printing.

Significant challenges remain in designing sufficient viscoelasticity polysaccharide-based high internal phase Pickering emulsions (HIPPEs) as soft materials for 3D printing. Herein, taking advantage of the interfacial covalent bond interaction between modified alginate (Ugi-OA) dissolved in the aqueous phase and aminated silica nanoparticles (ASNs) dispersed in oil, HIPPEs with printability were obtained. Using multitechniques coupling a conventional rheometer with a quartz crystal microbalance with dissipation monitoring, the correlation between interfacial recognition coassembly on the molecular scale and the stability of whole bulk HIPPEs on the macroscopic scale can be clarified. The results showed that Ugi-OA/ASNs assemblies (NPSs) were strongly retargeted into the oil-water interface due to the specific Schiff base-binding between ASNs and Ugi-OA, further forming thicker and more rigid interfacial films on the microscopic scale compared with that of the Ugi-OA/SNs (bared silica nanoparticles) system. Meanwhile, flexible polysaccharides also formed a 3D network that suppressed the motion of the droplets and particles in the continuous phase, endowing the emulsion with appropriately viscoelasticity to manufacture a sophisticated "snowflake" architecture. In addition, this study opens a novel pathway for the construction of structured all-liquid systems by introducing an interfacial covalent recognition-mediated coassembly strategy, showing promising applications.

High internal phase pickering emulsions stabilized by ODSA-functionalized cyclodextrin metal-organic frameworks for extrusion 3D printing application

Cyclodextrin metal-organic frameworks (CD-MOFs) are novel ordered porous materials with high adsorption and interfacial stabilization. Herein, oil-in-water emulsions stabilized by octadecenylsuccinic anhydride (ODSA) modified CD-MOFs (OCMs) with a volume fraction of 0.8 were prepared. A contact angle of 92° was achieved when 5 wt% ODSA was added to OCMs, which promoted the stabilization of OCMs-emulsions with homogeneous and spherical droplets. Moreover, the emulsion possessed a small droplet size of 7–9 μm (d4,3), long-term storage stability and flocculation resistance. At the pH range of 10–12, the emulsions had a more desirable structure with a gel-like elastic network and a dense particle layer covered onto the droplets, which were verified by SEM and cryo-SEM. The 2D cross-linked particle film at the water-oil interface and the 3D cross-linked gel-like particle network in the continuous phase synergistically improved the stability of coalescence and flocculation of the OCMs-HIPPEs. Afterwards, the OCMs-HIPPEs with no discernible oil were used as printing ink, which had no droplet coalescence in the freeze-thaw and showed high 3D printing quality and shape retention. Overall, this study demonstrates that the ODSA-modified CD-MOFs with favorable properties may be used to fabricate high-quality edible HIPPEs for extrusion 3D printing ink.