Effect of a collagen peptide-fish oil high internal phase emulsion on the printability and gelation of 3D-printed surimi gel inks

The effect of a high internal phase emulsion (HIPE) on three-dimensional-printed surimi gel inks was studied. Increasing the concentration of collagen peptide decreased the particle size of HIPE droplets and improved the viscoelasticity and stability. For example, when the collagen peptide concentration was 5 wt%, the viscoelasticity of the HIPE was high, as indicated by the presence of small and uniform particles, which formed a monolayer in the outer layer of the oil droplets to form stable a HIPE. A HIPE was used as the filling material to fill the surimi gel network, which reduced the porosity of the network. Surimi protein and peptides have dual emulsifying effects on the stabilization of oil. After adding the emulsion, the texture, gel properties and rheological properties of the surimi were reduced, and its printing adaptability was improved. This study provides new ideas for the production of surimi and its application in 3D printing.

Oxidation with potassium ferrate for the one-pot preparation of carboxylated cellulose II nanocrystals

Cellulose II nanocrystals (CNC II) possess a higher thermal stability and improved emulsifying capability than cellulose I nanocrystals (CNC I) owing to the higher density of their hydrogen bonds and more larger surface areas. Therefore, CNC II exhibit substantial advantages for value-added nanocomposite materials. Current CNC II preparation methods are mainly based on a two-pot reaction involving acid hydrolysis and crystal transformation. In this study, considering the oxidative nature of potassium ferrate (K2FeO4) in an alkaline environment containing a small amount of sodium hypochlorite (NaClO), a one-step and efficient approach was developed for the preparation of carboxyl-bearing CNC II from cotton pulp, affording a maximum CNC II yield of 45.14 %. Atomic force microscopy analysis revealed that the prepared CNCs exhibited a "rod-like" shape with a width of ~7 nm and a length of ~269 nm. The resulting CNC II also exhibited excellent thermal stability (Tonset = 311.4 °C). Furthermore, high-internal-phase Pickering emulsions (HIPPEs) stabilized by CNC II were prepared to stabilize liquid paraffin in the absence of surfactant. The results revealed that CNC II could be used as an effective emulsifier to fabricate the stable and gel-like HIPPEs, and are promising for the preparation of high value-added nanocomposite materials.

Stabilizing effect of silver carp myofibrillar protein modified by high intensity ultrasound on high internal phase emulsions: Protein denaturation, interfacial adsorption and reconfiguration

This study evaluated the impact of high intensity ultrasound (HIU) on myofibrillar proteins (MP) from silver carp, and investigated the stabilizing effect of HIU-treated MP (UMP) on high internal phase emulsions (HIPEs). Ultrasonic cavitation induced protein denaturation by decreasing size and unfolding conformation, to expose more hydrophobic groups, particularly UMP at 390 W, showing the smallest particle size (181.71 nm) and most uniform distribution. These structural changes caused that UMP under 390 W exhibited the highest surface hydrophobicity, solubility (92.72 %) and emulsibility (115.98 m2/g and 70.4 min), all of which contributed to fabricating stable HIPEs with oil volume fraction up to 0.8. UMP-based HIPEs possessed tightly packed gel network and self-supporting appearance due to the adsorption of numerous proteins at the oil-water interface and the reduction of interfacial tension by protein reconfiguration. The larger interface coverage reinforced cross-linking between interfacial proteins, thus increasing the viscoelasticity and recoverability of HIPEs, also the resistance to centrifugal force, high temperature (90 °C, 30 min) and freeze-thaw cycles. These findings furnished insightful perspectives for MP deep processing through HIU, expanding the high-value application of UMP-based HIPEs in fat replacer, nutritional delivery system with high encapsulation content and novel 3D printing ink.

Effect of NaCl concentration on the formation of high internal phase emulsion based on whey protein isolate microgel particles

At present, the effect of structural modification of microgel particles on high internal phase emulsions (HIPEs) is less studied. In this study, the structural modification effect of NaCl on whey protein isolate microgels (WPIMPs) was comprehensively characterized and applied to the construction of HIPEs. WPIMPs were prepared with NaCl (0-150 mM) and the structural changes were analyzed by measuring the particle size, Zeta-potential, and endogenous fluorescence spectra. The results showed that inducing WPIMPs by NaCl enhanced the surface hydrophobicity, decreased the Zeta potential, and elevated the degree of cross-linking. The interfacial behavior of WPIMPs was characterized by measuring interfacial tensions and adsorbed layer properties. The results showed that NaCl induction decreased the interfacial tension, increased the thickness of the adsorbed layer, and improved the viscoelasticity. The HIPEs were analyzed for micromorphology and particle sizes. The results indicated that NaCl-induced WPIMPs favored the formation of HIPEs with small particle sizes and provided HIPEs with superior environmental stability. This study provides a new idea for the structural modification of microgels and a new theoretical basis for the construction conditions of HIPE.

Modulating the properties of myofibrillar proteins-stabilized high internal phase emulsions using chitosan for enhanced 3D-printed foods

The 3D printability of myofibrillar proteins (MP)-based high internal phase emulsions (HIPEs) is a concern. This study investigated the influence of chitosan (CS) concentrations (0-1.5 wt%) on the physicochemical properties, microstructure, rheological properties, and stability of MP-based HIPEs. Results showed that the interaction between MP and CS efficiently modulated the formation of HIPEs by modifying interfacial tension and network structure. The addition of CS (≤ 0.9 wt%, especially at 0.6 wt%) acted as a spatial barrier, filling the network between droplets, which triggered electrostatic repulsion between CS and MP particles, enhancing MP's interfacial adsorption capacity. Consequently, droplet sizes decreased, emulsion stability increased, and HIPEs became more stable during freeze-thaw cycles, centrifugation, and heat treatment. The rheological analysis further demonstrated that the low energy storage modulus (G', 330.7 Pa) of MP-based HIPEs exhibited sagging and deformation during the self-supporting phase. However, adding CS (0.6 wt%) significantly increased the G' (1034 Pa) of MP-based HIPEs. Conversely, increasing viscosity and spatial resistance attributed to CS (> 0.9 wt%) noticeably caused larger droplet sizes, thereby diminishing the printability of MP-based HIPEs. These findings provide a promising strategy for developing high-performance and consumer-satisfaction 3D printing inks using MP-stabilized HIPEs.

Formulation and stabilization of high internal phase emulsions via mechanical cellulose nanofibrils/ethyl lauroyl arginate complexes

Motivated by the quest for biocompatibility, we report on oil-in-water (O/W), high-internal-phase Pickering emulsions stabilized via complexes of mechanical cellulose nanofibrils (CNF) and food-grade cationic surfactant ethyl lauroyl arginate (LAE). The complexation of oppositely charged CNF and LAE can be held together by electrostatic interaction. Their effect on suspensions electrostatic stabilization, heteroaggregation state, and emulsifying ability was studied and related to properties of resultant interfacial tension between oil and water and 3D printing of emulsions. The Pickering system with adjustable droplet diameter and stability against creaming and oiling-off during storage was achieved resting with LAE loading. Complexes formed by LAE adjustment act as Pickering stabilizers and three-dimensional networks in emulsion system, forming a scaffold with elastoplastic rheological properties that flows above critical stress while, without any additional treatment, exhibiting the required self-standing properties for 3D printing. By understanding the properties of CNF/LAE behavior in bulk and on interfaces, printing edible functional foods of CNF/LAE-based emulgel inks has been demonstrated to enable regulation of oil release.

Influence of varying oil phase volume fractions on the characteristics of flaxseed-derived diglyceride-based Pickering emulsions stabilized by modified soy protein isolate

This research aimed to create Pickering emulsions using modified soy protein isolate (SPI) as a stabilizer and flaxseed-derived diglyceride (DAG) as an oil phase. The SPI was modified through a process involving both heating and ultrasound treatment. The result indicated that the droplet size of emulsions increased with the increase in oil content (p < 0.05). For instance, the largest droplet size (23 µm) was observed at an oil-to-SPI dispersion ratio of 4:1 ratio (φ = 80), whereas the smallest droplet size (6.39 µm) was noticed at the 1:4 ratio. During the 7-day storage period, the emulsions with a 4:1 ratio (φ = 80) showed the lowest droplet size increase (from 23 µm to 25.58 µm). In contrast, the emulsions with a 1:1 ratio displayed the highest increase (from 19.39 µm to 74.29 µm). Creaming index results revealed that emulsions with a 4:1 ratio (φ = 80) showed no signs of creaming and phase separation than all other treatments (p < 0.05). Backscattering fluctuations (ΔBS) and turbiscan stability index (TSI) showed that emulsions with 4:1, 2:1, and 1:1 oil-to-SPI dispersion ratios had consistent ΔBS curves with higher and TSI curves with lower values. Optical microscopy, confocal laser scanning, and cryo-scanning electron microscopy revealed that emulsions with oil-to-SPI dispersion ratios of 4:1 and 2:1 had well-organized structures with no visible coalescence. Macromorphological and microrheological investigations demonstrated that emulsions with 80% oil content had the highest viscosity, both moduli, elasticity index, macroscopic viscosity index, and the lowest fluidity index and solid-liquid balance values. Moreover, these emulsions were more resistant to centrifugation and storage environments. In conclusion, the study determined that flaxseed-derived DAG-based high internal phase Pickering emulsions (φ = 80) had superior stability, improved viscoelasticity, and better rheological properties.

Effect of simulated saliva on rheological and tribological properties of oleogel-in-water HIPEs during oral processing

HYPOTHESIS

High internal phase emulsions (HIPEs) have great potentials in the food industry to control fat consumption. Textural perception of HIPEs during oral processing is strongly influenced by saliva, which has not been systematically investigated. Therefore, we investigated the roles of saliva in the rheological and tribological properties of HIPEs during oral processing.

EXPERIMENTS

HIPEs (O/W) stabilized by oleogel and a protein were fabricated. Small (SAOS) and large (LAOS) amplitude oscillatory shearing measurements and tribological tests were performed, in combination with structural characterization of the emulsions.

FINDINGS

Particle size and CLSM observation indicated that saliva induced coalescence of droplets by weakening the interface and more EC resulted in faster clustering. SAOS tests revealed that emulsions mixed with saliva had weaker structural strength and lower resistance to deformation. Particularly in large deformation, the HIPEs mixed with saliva presented an acceleration in the droplet-droplet structure breakdown, which led to the pronounced strain-thinning behavior and energy dissipation. Tribological curves further revealed that the corporation of saliva contributed to the release of oil to reduce friction coefficient.

Tunable rheological properties of high internal phase emulsions stabilized by phosphorylated walnut protein/pectin complexes: The effects of pH conditions, mass ratios, and concentrations

The current study reported high internal phase emulsions (HIPEs) stabilized by phosphorylated walnut protein/pectin complexes (PWPI/Pec) and elucidated how their rheological properties were modulated by pH conditions, mass ratios, and concentrations of the complexes. At pH 3.0, the HIPEs stabilized by PWPI/Pec exhibited smaller oil droplet sizes, as well as higher storage modulus (G') and flow stress, in comparison to those stabilized by the complexes formed at pH 4.0-6.0. These observations can be directly linked to pH-dependent changes in particle size, surface hydrophobicity, and wettability of the PWPI/Pec complexes. Rheological analysis revealed that all generated HIPEs displayed weak strain overshoot behavior, irrespective of pH conditions. Notably, HIPEs stabilized by PWPI/Pec at mass ratios of 2:1 and 4:1 showed enlarged oil droplet sizes, lower G' and flow stress but higher flow strain with unaffected loss factor compared to those stabilized by PWPI/Pec 1:1. However, reducing the concentration of PWPI/Pec led to a simultaneous decrease in G', flow stress, and flow strain, along with a significant increase in the loss factor of the HIPEs. Furthermore, the HIPEs formed with 1% PWPI/Pec 1:1 at pH 3.0 demonstrated excellent stability against heat treatment and long-term storage. These results provide valuable insights into the modulation of rheological characteristics of HIPEs and offer guidance for the application of walnut protein-based stabilizers in HIPE systems.

High-temperature glycosylation of saccharides to modify molecular conformation of egg white protein and its effect on the stability of high internal phase emulsions

This paper investigates the freeze-thaw stability of oil-in-water emulsions stabilized by high-temperature wet heating glycosylation products. Glucose (Glu), D-fructose (Fru), xylose (Xyl), maltodextrin (MD), oligofructose (FO), and oligomeric isomaltulose (IMO) were chosen as sugar sources for the glycosylation reaction with egg white proteins (EWPs) at 120 °C to prepare the GEWPs. The study reveals that the type of sugar significantly influences the Maillard reactions with EWPs. The degree of glycosylation was highest in the Xyl group with the greatest reducing capacity and lowest in the MD, FO, and IMO groups. High-temperature wet glycosylation treatment induced changes in the secondary and tertiary structures of EWP. Elevated temperature exposed hydrophobic groups within the protein, while covalent binding of hydrophilic carbohydrates via the Maillard reaction decreased the protein's H0 value. Improved foaming and emulsifying properties were attributed to the increase in α-helix content, disulfide bond formation, and reduced surface tension. Emulsions prepared from GEWPs exhibited higher apparent viscosity and G' compared to those from natural EWPs, with the GEWP/Xyl group showing the highest values. After freeze-thaw treatment, the GEWP/Fru and GEWP/FO groups demonstrated superior stability and reduced freezing point, along with minimal microstructural alterations. These findings underscore the importance of sugar type in the stability of high internal phase emulsions (HIPEs) stabilized by GEWPs, indicating that a tailored Maillard reaction can yield stabilizers with exceptional freeze-thaw stability for emulsions.

Stabilization of oil-in-water high internal phase emulsions with octenyl succinic acid starch and beeswax oleogel

High internal phase emulsions (HIPEs) based on beeswax (BW) oleogels and octenyl succinic acid starch (OSA starch) were prepared by a facile one-step method. Effects of the oleogelation of internal phase on the formation, stability and functionality of the HIPEs were investigated. OSA starch absorbed at the interface allowed high surface charge (|ζ| > 25 mV) of the droplets, and small droplet size (d ≈ 5 m). Microstructural observation suggested that the HIPEs were of O/W type with droplets packed tightly. With the increase in BW content (0-4 %), the particle size (4-7 μm) and ζ-potential (-25 ~ -30 mV) of the HIPEs were first decreased and then increased. Stability analysis revealed that the addition of BW effectively improved emulsion stability against centrifugation, freeze-thawing, changes in pH and ionic strength, and the HIPE with 2 % BW presented the best stability. Rheological tests indicated that the HIPEs with higher content of BW exhibited higher storage modulus, solid-like properties, and shear thinning behaviors. Creep-recovery results implied that the oleogelation enhanced the structure of HIPEs and improved the deformation resistance of the systems. When subjected to light and heat, oleogel-in-water HIPEs showed advantages in protecting β-carotene from degradation, and β-carotene in the HIPEs with 2 % BW had the lowest degradation rate. These findings suggested that gelation of oil phase could improve the stability of HIPEs and the encapsulation capability, which would be meaningful for the development of novel healthy food.

High internal phase emulsions stabilized by alkaline-extracted walnut protein isolates and their application in food 3D printing

Alkaline-extracted walnut protein isolates showed relatively poor solubility and emulsifying properties in many previous studies. However, whether they can be used as potential emulsifiers to stabilize high internal phase emulsions (HIPEs) remains unknown. Herein, walnut protein isolates were prepared by alkaline extraction from walnut kernels with or without pellicles (named PAWPI and AWPI, respectively). PAWPI conjugated with pellicle polyphenols showed improved solubility and higher antioxidant capacity than AWPI. HIPEs were fabricated via a one-step method using AWPI or PAWPI as the sole protein emulsifier. HIPEs (oil fraction of 0.8, with 0.1% β-carotene) could be stabilized by PAWPI at a relatively low concentration of 0.2% (w/v), while at least 1% (w/v) AWPI was required to effectively stabilize HIPEs. HIPEs stabilized by PAWPI had smaller oil droplet sizes than those stabilized by AWPI. Rheological analysis indicated that PAWPI-stabilized HIPEs showed higher viscosity and better viscoelasticity than AWPI-stabilized HIPEs. Large-amplitude oscillation shearing analysis suggested that PAWPI-stabilized HIPEs were stiffer but more brittle than AWPI-stabilized HIPEs. Moreover, both PAWPI- and AWPI-stabilized HIPEs exhibited good storage stability and were relatively stable against heat treatment and ionic strength. PAWPI-stabilized HIPEs showed a higher protective capacity for encapsulated β-carotene than AWPI-stabilized HIPEs. In addition, PAWPI-stabilized HIPEs showed good 3D printability and could be used as a promising edible ink.

Nanolignin-based high internal phase emulsions for efficient protection of curcumin against UV degradation

As an emulsifier, lignin exhibits excellent UV resistance on drug-loaded emulsion systems for drug delivery. However, due to the structural variation and complexity of lignins from various origins, their UV shielding performance varies with the techniques for lignin extraction, which impacts properties and the protection efficiency of lignin-based HIPEs (high internal phase emulsions). In this work, lignin nanoparticles, prepared from three lignin preparations of Eucalyptus, were used in HIPEs delivery systems to protect curcumin from degradation by UV radiation. Structures of the lignin preparations were characterized using 2D HSQC (heteronuclear single-quantum coherence) NMR (nuclear magnetic resonance), ³¹P NMR, and GPC (gel permeation chromatography). The residual curcumin level after 36 h UV exposure in the nanolignin-based HIPEs was over 72 %, much higher than that (< 10 % after 24 h UV exposure) in the oil phase without lignin, indicating that the nanolignin-based HIPEs with enhanced UV shielding ability protect curcumin better. Of the three lignin preparations, AL (alkali lignin), with the lowest molecular weight, highest contents of phenolic hydroxyl and carboxyl groups, and highest S/G ratio, displayed the best anti-UV radiation ability and the most uniform nanoparticle size.

Development and application of hydrophilic-hydrophobic dual-protein Pickering emulsifiers: EGCG-modified caseinate-zein complexes

Zein nanoparticles are commonly used as colloidal emulsifiers to form and stabilize Pickering emulsions. However, the strong surface hydrophobicity of zein nanoparticles limits their widespread application. In this study, composite colloidal emulsifiers were fabricated from zein, sodium caseinate (NaCas), and epigallocatechin gallate (EGCG). Initially, NaCas-EGCG conjugates were formed using either an alkaline or enzymatic method. The enzymatic method led to conjugates containing more EGCG and with a higher thermal stability and surface hydrophilicity. Colloidal emulsifiers were prepared using an antisolvent precipitation method that involved titrating an ethanolic zein solution into an aqueous NaCas-EGCG conjugate solution. The potential application of these emulsifiers for forming and stabilizing high internal phase emulsions (HIPEs) was then explored. The emulsification properties of the zein nanoparticles were improved after they were complexed with NaCas-EGCG conjugates. Pickering HIPEs containing closely packed polygon oil droplets were formed from the colloidal emulsifiers, even at low particle concentrations (0.3% w/v). Overall, our results show that the functional performance of zein nanoparticles can be improved by complexing them with NaCas-EGCG conjugates. The novel colloidal emulsifiers developed in this study may therefore have useful applications in the food and other industries.

High internal phase emulsions stabilized solely by sonicated quinoa protein isolate at various pH values and concentrations

In this study, stable high internal phase emulsions (HIPEs) constructed solely by sonicated quinoa protein isolate (QPI) at various pH values and protein concentrations (c) were constructed, and differences of HIPE microstructures at these conditions were discussed. HIPEs stabilized by QPI at pH 7.0, 9.0 possessed smaller droplet size (14-24 μm), smoother appearance, and higher physical stability which were caused by polyhedral framework microstructure. However, at acidic conditions, QPI aggregates filled in the gaps between droplets (30-52 μm) instead of adsorbing to oil-water interface, which decreased the stability. The solid-like viscoelasticity of HIPEs were enhanced when the c increased while the increment of pH value had the significant opposite effect (decreased from about G' 1000 Pa, G″ 280 Pa to G' 350 Pa, G″ 50 Pa) due to the microstructure difference. This study broadens the commercial applications of quinoa protein in novel food products like fat substitutes.

High internal phase emulsions stabilized by native and heat-treated lactoferrin-carboxymethyl chitosan complexes: Comparison of molecular and granular emulsifiers

While the high internal phase emulsions (HIPEs) have been formed by food-grade biopolymers and granules have been widely reported, it is not known which components are more effective. In this work, we first used heat-treated lactoferrin (LF)-carboxymethyl chitosan (CMCTS) granules and native LF-CMCTS physical mixtures as emulsifiers to form HIPEs. The results showed that the interfacial behavior and emulsifying properties of the two complexes were controlled by the ratio of LF-CMCTS and the optimal ratio of LF to CMCTS was 1:1. Heated LF-CMCTS granules anchored to the water-oil interface and formed an elastic shell to stabilize HIPEs, while unheated LF-CMCTS complexes formed a thick film layer to stabilize HIPEs. Both HIPEs could act as delivery systems loaded with curcumin, and they showed better protection of curcumin than Tween-80 under light. This study provides a new basis for the design of LF-based HIPEs systems loaded with lipophilic food functional ingredients.

Facile and scalable synthesis of functional Janus nanosheets - A polyethoxysiloxane assisted surfactant-free high internal phase emulsion approach

HYPOTHESIS

Janus nanosheets, which have two surfaces of different functionalities, exhibit unique interfacial properties. In this work, we propose a facile and scalable technique for preparation of silica-based Janus nanosheets, which is based on formation of high internal phase water-in-oil emulsions stabilized solely by alkyl-substituted polyethoxysiloxanes due to their hydrolysis-induced interfacial activity.

EXPERIMENTS

Janus nanosheets are then obtained by crushing the silica foams converted from such emulsions. The morphology of Janus nanosheets is investigated by field-emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM). The chemical structure of functional silica materials is characterized by Fourier transform infrared spectroscopy (FT-IR). The asymmetric structure of silica nanosheets is observed by confocal laser scanning microscopy.

FINDINGS

The resulting nanosheets have a rough hydrophobic surface and a smooth hydrophilic one, and are capable of stabilizing Pickering oil-in-water emulsions. Remarkably, pH-responsiveness of emulsions can be attained using the nanosheets whose hydrophilic surface is substituted with amino groups. Fast oil-water separation is achieved by the Janus nanosheets, which has been demonstrated by the nanosheets with a polystyrene-coated hydrophobic surface. This work paves a new avenue for large-scale production of functional silica-based Janus nanosheets suitable for numerous promising applications.

Plant-based high internal phase emulsions stabilized by dual protein nanostructures with heat and freeze-thaw tolerance

The formation of coherent, three-dimensional (3D) networks by particles either at the interface or in the bulk phase is vital for the stability of emulsions. In this study, nanoparticles of walnut proteins (WPs) were associated by unfolded fibrillar rice proteins (RPs), forming dual protein nanostructures (DPNs) characteristic of coherent 3D networks. The DPNs emulsified walnut oil and formed high internal phase emulsions (HIPEs), which were stable against 2-month storage and 30-min heating at 95 °C. Furthermore, the interfacial structures can be further reinforced by sodium chloride (50 mM and above), and became invulnerable to repeated freeze-thaw treatments. Based on the above results, a plant-based walnut sauce was developed with superior freeze-thaw stability to three arbitrary commercial mayonnaises. The HIPEs with tunable rheological properties in response to salt concentration and excellent stabilities against long-term storage, heating, and freeze-thaw may be potential surrogates of futuristic plant-based textural and sensory materials in foods.

Fabrication of pickering high internal phase emulsions stabilized by pecan protein/xanthan gum for enhanced stability and bioaccessibility of quercetin

The stabilizing effect of pecan protein (PP)/xanthan gum (XG) complex on the Pickering high internal phase emulsion (HIPE) has been examined in this study. Shear viscosity of HIPEs increased with respect to XG concentration due to the formation of hydrogen bonds between PP and XG. Confocal laser scanning microscopy (CLSM) imaging showed fairly even distribution and polygonal shapes of oil droplets (30-70 μm). When used to encapsulate quercetin, this Pickering HIPE exhibited high retention rate and improved gel strength. Furthermore, the interface film of PP/XG on oil-water interface contributed to the high retention of quercetin in Pickering HIPEs when exposure to heat, iron ions, and hydrogen peroxide in aqueous phase. The bioaccessibility of quercetin after in vitro simulated digestion were also improved by HIPE encapsulation than that in oil. To conclude, PP/XG complex stabilized HIPEs may be suitable delivery systems for improving colloidal stability and bioaccessibility of hydrophobic bioactives.

One-pot synthesis of polymer-reinforced silica aerogels from high internal phase emulsion templates

HYPOTHESIS

Conventional strategies for strengthening silica aerogels through polymer modification always lead to a significant density increase and an obvious sacrifice of thermal insulation performance. In this work, we propose a facile one-pot method for the preparation of polymer-reinforced silica aerogels via polymerization of water-in-oil high internal phase emulsion (HIPE) templates.

EXPERIMENTS

Hyperbranched vinyl-modified polyethoxysiloxane (VPEOS) is used as both emulsion stabilizer and silica source. FT-IR spectra of VPEOS are recorded to confirm the successful incorporation of vinyl groups. The pore structure of polymer-functionalized silica aerogels is characterized by a scanning electron microscope (SEM), nitrogen adsorption-desorption and mercury intrusion porosimetry.

FINDINGS

The Young's modulus is increased from 0.69 to 19.28 MPa, nearly 28 times that of unmodified silica aerogels. Moreover, the silica aerogels present a superhydrophobicity with a water contact angle of 152.4° and good thermal insulation. The superior performance properties of the polymer-reinforced silica aerogels over pure silica aerogels may guarantee their wide applications in energy and aerospace fields.

High internal phase emulsions stabilized with carboxymethylated lignin for encapsulation and protection of environmental sensitive natural extract

Oil-in-water (O/W) high internal phase emulsions (HIPEs) are widely used in foods, pharmaceuticals and cosmetics due to the high drug loading ratio, specific rheological behaviors and long shelf life. However, protective performance of active components within HIPEs maintains a low level. Herein, a series of carboxymethylated enzymatic hydrolysis lignin (EHL-CM-x) were synthesized by nucleophilic substitution and applied as macromolecular surfactant to stabilize the O/W HIPEs. It was found that EHL-CM-x combined with a small dosage of alkyl polyglycoside (APG) are able to stabilize HIPEs with 87 vol% soybean oil under neutral condition, which could be recognized as the highest internal phase reported in foods and pharmaceuticals. As a bioactive compound carrier, such EHL-CM-x stabilized HIPEs enable to provide outstanding UV, thermal and oxidation protection for sensitive natural extracts. The residual drug level obtained in this work is more than two times other gliadin/chitosan hybrid particles and sulfomethylated lignin stabilized HIPEs after UV irradiation. In vitro experiments showed that the minimum inhibitory concentration of curcumin within HIPEs against S. aureus and E. coli was 3.13 mg/mL and 12.5 mg/mL, respectively. Such lignin stabilized HIPEs could be potentially used in various areas, especially those with high stability and biosafety requirements.

A porous carbon absorbent based on high internal phase emulsion for separation and enrichment of trifluralin from soil

A porous carbon absorbent was obtained by using high internal phase emulsions (HIPEs) polymerization followed by high temperature carbonization under nitrogen protection. Graphene oxide (GO) and silica nanoparticles were doped into the HIPEs to enhance the adsorption ability and reusability. Fourier infrared spectroscopy, X-ray photoelectron spectroscopy and scanning electron microscopy were used for characterization and several parameters of separation and enrichment of trifluralin. The results showed that a hyper-crosslink framework material was obtained with abundant porous (pore size of about 30 μm) and a good adsorption and separation efficiency. The adsorption rate was up to 100% and trifluralin was completely eluted from the absorbent by 2.0 mL of an acetic acid-acetonitrile mixture. Graphical abstractSchematic representation of synthesis of porous carbon absorbent by GO and SiO₂ doped HIPEs.POLYHIPES-GO&SiO₂: Polymerized High Internal Phase Emulsions doped with Silica and Graphene oxide.

Polyacrylate/polyacrylate-PEG biomaterials obtained by high internal phase emulsions (HIPEs) with tailorable drug release and effective mechanical and biological properties

The paper focuses on the preparation of polyacrylate based biomaterials designed as patches for dermal/transdermal drug delivery using materials obtained by the high internal phase emulsion (HIPE) technique. In particular, butyl acrylate and glycidyl methacrylate were selected, respectively, as backbone and functional monomer while two different crosslinkers, bifunctional or trifunctional, were used to form the covalent network. The influence of PEG on the main properties of the materials was also investigated. The obtained materials show a characteristic and interconnected internal structure as confirmed by SEM studies. By an industrial point of view, an interesting feature of this system is that it can be shaped as needed, in any form and thickness. The physiochemically characterized materials showed a tailorable curcumin (model of hydrophobic drugs) drug release, effective mechanical properties and cell viability and resulted neither pro nor anti-angiogenic as demonstrated in vivo by the chick embryo choriallantoic membrane (CAM) assay. Based on these results, the obtained polyHIPEs could be proposed as devices for dermal/transdermal drug delivery and/or for the direct application on wounded skin.