Bioactive substances possess superior antioxidant, anti-hypertensive, and anti-tumor activities. However, their susceptibility to degrade at low pH often limit their application. Compare with the ...conventional oil-in-water (W/O) emulsions, the lack of natural hydrophobic stabilizers resulted in difficulties in fabricating water-in-oil (W/O) high internal phase emulsion (HIPE). Further, the instability of W/O HIPE also limit its industrial application in food industry. In the present study, a natural, conventional, eco-friendly, and structured W/O HIPE was developed using glyceryl monostearate (GMS) as emulsifier and beeswax and gellan gum as structurant. The system with the synergetic effect of emulsifier and structurant, accounted for 0.25 wt % of GMS and hydrogel, and 1.25 wt % of beeswax in total system endowed the W/O HIPE with biphasic rigid network and impressive storage stability. The microstructures of these newly developed W/O HIPEs could be controlled by the beeswax concentration (cb), GMS concentration (cg), and aqueous phase volume (Φ). Moreover, the GMS-based emulsion encapsulation improved the retention rate of betanin by 36.68% after 7 days of storage. Meanwhile, this emulsion gel could prevent the nucleophilic attack of hydrogen ions against betanin at room temperature under a low pH environment, which greatly improved the stability of betanin under highly acid conditions. Furthermore, the GMS stabilized W/O HIPE possessed pH-sensitive, which could achieve controlled-release of both hydrophilic and hydrophobic functional compounds in an in vitro simulated release assay.
Display omitted
•W/O HIPE was formed by GMS and beeswax.•The stability of the W/O HIPE was significantly improved by consolidating the biphasic network.•The stability of betanin was improved in the gel-in-gel HIPE.•The release profile of curcumin and betanin were evaluated.
This study mainly focused on the preparation and physical stability of easily industrialized gelatin microgel-stabilized high internal phase emulsion (HIPE) through different preparation conditions ...and its regulation mechanism. The droplet size of emulsion was smaller at higher dispersion speed (> 15,000 rpm) and time (> 60 s). The interfacial behavior results demonstrated that increasing gelatin concentration (0.1– 2.0 wt%) could promote its adsorption at the oil/water interface (π10800 increased from 12.12 to 19.96 mM/m), making more gelatin molecules participate in the formation of interface and continuous phase network structure. At a higher gelatin concentration (2.0 wt%), the obtained HIPE presented a smaller droplet size and higher viscosity, and exhibited good thermal stability (90 °C for 20 min) and storage stability. This work systematically analyzed the effect of preparation conditions on the formation and stability of HIPE stabilized by gelatin microgel, which could provide a beneficial and innovative reference for its industrial application and design.
•Higher dispersion speed and longer dispersion time were facilitated to the formation of stable gelatin microgel-stabilized HIPE.•Interfacial adsorption of gelatin was positively correlated to gelatin concentration.•Physical stability of HIPE stabilized by gelatin microgel was concentration-dependent.
Food-grade microgel-stabilized emulsions have been attracting much attention due to their promising applications in food formulations. In this study, the use of hydrophobically modified chitosan ...microgels (h-CSMs) as particle emulsifiers to stabilize high internal phase emulsions (HIPEs) was demonstrated for the first time. Four hydrophobically modified chitosan (h-CS) were obtained by grafting deoxycholic acid (DA) with chitosan (CS) at grafting rates of 4.64%, 13.21%, 15.12% and 30.29%, respectively. The selected modified chitosan were further cross-linked with sodium tripolyphosphate (TPP) to form h-CSMs. It was found that, compared to pure CS and the modified h-CS, the h-CSMs have higher hydrophobicity, and can stabilize oil-in-water HIPEs effectively. The interfacial properties of the h-CSMs, and the formation, microstructure and rheological properties of HIPEs were characterized by dynamic interfacial adsorption, contact angle, visual observation, laser confocal microscopy and rheological measurements, respectively. The results show that stable HIPEs with oil concentration up to 90 wt% can be formed using very low h-CSM particle concentration (only 0.05 wt% for the HIPE with 90 wt% oil), and the HIPEs stabilized by h-CSMs displayed higher rheological compliance than other solid particle stabilized HIPEs at high oil volume fraction. The strong emulsification properties of the h-CSMs are attributed to their increased hydrophobicity, the enhanced exposure of hydrophobic groups during microgelation process, and the viscoelasticity of h-CSMs.
Display omitted
This study investigated the interaction between egg white protein particles (EWPP) and rhamnolipid (Rha) as co-emulsifiers in high internal phase emulsions (HIPEs). To reveal the effect between EWPP ...and Rha on the properties of HIPEs, the physicochemical properties (particle size, zeta-potential and microstructure) and emulsifying capacity were investigated. The results showed that, with the increase in Rha content, the EWPP-Rha complex could be divided into three regions according to the emulsifying capacity. The emulsion properties at different regions were analyzed by microstructure, rheology and nuclear magnetic resonance etc. The addition of Rha may compete interface with EWPP, adjusting the properties of constructed HIPEs. Generally, the replacement of EWPP by Rha from interface decreased emulsion droplets and disrupted the inter-droplet network, resulting to the formation of soft and flexible emulsions. The incorporation with Rha was beneficial for improving the emulsifying capacity of EWPP. In Rha sufficient system, more EWPP distributed in the aqueous phase of constructed HIPEs and functioned as a stabilizer to increase coalescence stability. The study was meaningful for revealing the complicated relation between protein particle and surfactant, and improving properties of high internal phase emulsions combining the advantages of each emulsifier.
Display omitted
•The combination of EWPP and Rha improved the emulsifying capacity immensely.•The addition of Rha was helpful for decreasing the droplet size of HIPEs.•EWPP was beneficial for improving coalescence and thermal stability of the HIPEs.
Display omitted
•Tunable structures of hierarchically porous MOF derived aerogels.•Bimetallic framework containing heterogeneous aerogels.•3D interconnected macroporous framework having mesoporous ...cages.•Photodegradation, oil-water separation, and exclusion of adsorbates.•Airborne water supply, air clean up, sensor, capacitor, and electrode material.
Among the multifunctional smart lightweight materials, there is an uprising demand of metal organic framework (MOF) based aerogels because of their hierarchically porous tunable structures constituting various combinations of structural motifs tailor made for diverse applications including removals of heavy metals, dyes, and organic contaminants; CO2 capture and reduction; photodegradation and removal of pollutants; oil-water separation; absorber of electromagnetic radiation; real time monitoring sensor; capacitor; electrode materials of battery; airborne water supply; and air clean up. Indeed, compared to pure MOFs or pure aerogels, the enhanced structural diversity, stability, textural properties, and application prospects of MOF aerogels and metal organic aerogels are contributed by hierarchically porous tunable structures dependent on the methods of synthesis and drying. Nowadays, researchers are continuously engaged in developing the newer strategies to exploit the performance potential and application prospects of these tailor made heterogeneous materials both in the biomedical and non-biomedical sectors. Accordingly, in the present review, recent developments, unique set of structures, characterizations, properties, diverse applications, and structure-property-performance interrelationships of these high-performance state-of-the-art heterogeneous materials have been chronologically discussed and presented starting from its discovery in 2009.
The β-cyclodextrin (β-CD) based high internal phase emulsions (HIPEs) were prepared as building blocks for engineering high-quality 3D shapes and achieving 4D color transformation. The increase of ...β-CD concentration, the decrease of pH value, and the addition of NaCl contributed to the adsorption of β-CD molecules at the oil-water interface and the improvement of the microstructure, rheological properties and printing quality of the Pickering HIPEs. Moreover, the 4D printing of Pickering HIPEs was achieved by introducing pH-sensitive curcumin and heat-labile NaHCO3. With the increase in heating temperature, heating time and NaHCO3 concentration, the decomposition of HCO3− to CO32− led to an elevation in pH, which induced the conformational change in curcumin, accompanied by a decrease in L* and b* values and an increase in a* value of the samples. These findings dramatically improve the pleasure of diet and take full advantage of the custom design benefits of 3D printing technology.
•High internal phase emulsions prepared by β-CD exhibited viscoelastic behavior.•Microstructure, interfacial and rheological properties of emulsions were evaluated.•The printability of emulsions was regulated by β-CD concentrations and pH values.•The pH-triggered color change was achieved by heating emulsions containing curcumin.
Display omitted
Among three-dimensional (3D) scaffold fabrication methods, porous polymers templated using high internal phase emulsions (HIPEs) have emerged as an attractive method due to the facile ...generation of interconnected porosity through a variety of synthetic routes. These include a bottom-up approach to selectively incorporate nanomaterials onto the inner walls in a nonaqueous environment. In this work, novel nonaqueous HIPEs made of different (meth)acrylate monomers and a deep eutectic solvent (DES) were formulated with nonfunctionalized nanohydroxyapatite (NHA), which also played the role of cosurfactant. Free radical polymerization of HIPEs yielded free-standing nanocomposites with 3D interconnected macroporosity and nonfunctionalized NHA selectively decorating the scaffolds’ inner surface. The influence of different polymer functionalities, acrylate or methacrylate, their alkyl tail length, and the presence of NHA on MC3T3-E1 preosteoblast cell proliferation in vitro, reactive oxygen species (ROS) production and alkaline phosphatase (ALP) activity were evaluated. All materials presented promising biocompatibility, non-hemolytic activity, negligible inflammatory response along to remarkably enhanced cell proliferation (e.g., up to 160-fold cell proliferation increase compared with polystyrene plate) in vitro, which open the path for the development of scaffolds in regenerative medicine. It is noteworthy that polyHIPEs studied here were obtained using a green synthetic protocol where nonfunctionalized nanoparticles can be selectively incorporated into a scaffolds’ inner walls. This versatile technique allows for the simple construction of 3D bioactive nanocomposite scaffolds with varied compositions for cell culture.
The aim of this study was to determine the influence of non-/deacetylated konjac glucomannan (KG/DKG) on the intermolecular forces, microstructure and gelling properties of chicken gels filled ...with/without high internal phase emulsion (HIPE). Results showed that a synergistic effect of HIPE and DKG addition was found with improvements on the gel hardness (5636 g) and cooking loss (0.21%). However, the co-addition of KG (2%) and HIPE could hinder hydrophobic interactions of proteins, leading to the poor gel strength of the chicken gel due to the formation of phase separation. HIPE increased the immobilized water, G′ values and gelation rates, and promoted the transformation of α-helices to β-sheets. The addition of DKG could further increase the hydrophobic interaction, hydrogen bonds and disulfide bonds, and improved the stability of HIPE droplets, leading to the formation of a compact gel network structure. The KG (≤1%) improved gelling properties of chicken gels filled with HIPE through moisture stability.
Display omitted
•HIPE and DKG synergistically improved the gelling properties of chicken gels.•The co-addition of HIPE and 2% KG impeded the aggregation of chicken gel networks.•The chicken gels containing HIPE and 2% DKG have highest gel strength.
A novel stable porous solid amine adsorbent with three-dimensional interpenetrating network structure was prepared by polymerization of divinylbenzene using high internal phase emulsion (HIPE) ...template method, and followed by further introducing polyethyleneimine (PEI) by impregnation-crosslinking method. Fixed bed dynamic adsorption experiment proved that under wet condition, the former exhibited not only a higher capacity of 6.22 mmol/g but also a better adsorption kinetics process with faster adsorption rate and longer lag in breakthrough point, which makes it potential to be used in gas separation. In CO2/CH4 separation experiment, PolyHIPE-PE30-4 showed a CO2/CH4 separation selectivity of 253 at 298 K and 1 bar, and meanwhile exhibited an extra-high operating capacity. The pure methane productivity of PolyHIPE-PE30-4 was 24.1 mmol/g from CO2/CH4 (80:20, v/v) mixed gas, 4.5 times to that of PE30-4 gel (5.36 mmol/g). Significantly, PolyHIPE-PE30-4 could maintain an excellent regeneration performance after at least 7 cycles, while PolyHIPE-P30 exhibited a remarkably decrease in adsorption capacity after only three adsorption-desorption process in wet condition, demonstrating the advantage of impregnation-crosslinking method for amine functionalization. The superior CO2 adsorption capacity and regeneration stability, combined with its superior adsorption kinetics property make it a broad prospect in the field of CO2/CH4 separation.
•The solid amine adsorbents process interconnected open-cell structure.•PolyHIPE-PE30-4 showed superior CO2 adsorption kinetics and extra-high adsorption capacity.•PolyHIPE-PE30-4 maintained stable regeneration performance in humidity.•PolyHIPE-PE30-4 showed excellent CO2/CH4 separation performance.
