High Internal Phase Emulsion Research Articles

Fabrication of hierarchically porous trabecular bone replicas via 3D printing with high internal phase emulsions (HIPEs)

Combining emulsion templating with additive manufacturing enables the production of inherently porous scaffolds with multiscale porosity. This approach incorporates interconnected porous materials, providing a structure that supports cell ingrowth. However, 3D printing hierarchical porous structures that combine semi-micropores and micropores remains a challenging task. Previous studies have demonstrated that using a carefully adjusted combination of light absorbers and photoinitiators in the resin can produce open surface porosity, sponge-like internal structures, and a printing resolution of about 150µm. In this study, we explored how varying concentrations of tartrazine (0, 0.02, 0.04, and 0.08 wt%) as a light absorber affect the porous structure of acrylate-based polymerized medium internal phase emulsions fabricated via vat photopolymerization. Given the importance of a porous and interconnected structure for tissue engineering and regenerative medicine, we tested cell behavior on these 3D-printed disk samples using MG-63 cells, examining metabolic activity, adhesion, and morphology. The 0.08 wt% tartrazine-containing 3D-printed sample (008 T) demonstrated the best cell proliferation and adhesion. To show that this high internal phase emulsion (HIPE) resin can be used to create complex structures for biomedical applications, we 3D-printed trabecular bone structures based on microCT imaging. These structures were further evaluated for cell behavior and migration, followed by microCT analysis after 60 days of cell culture. This research demonstrates that HIPEs can be used as a resin to print trabecular bone mimics using additive manufacturing, which could be further developed for lab-on-a-chip models of healthy and diseased bone.

Single nickel atoms anchored on porous N-doped nanocarbon with dual reaction sites for highly-efficient transfer hydrogenation of furfural to furfuryl alcohol

The non-precious metal single-atom catalysts (SACs) supported on carbon materials for the catalytic transfer hydrogenation (CTH) of α,β-unsaturated aldehydes (UAL) still suffer from the problems of harsh reaction conditions and low activity. In this work, nickel SACs anchored on porous N-doped nanocarbon (Ni1/NC900) with dual reaction sites were synthesized using the high internal-phase emulsion (HIPE) template method combined with impregnation. The Ni1/NC900 catalyst exhibited remarkable catalytic activity for the CTH of furfural (FF) to furfuryl alcohol (FFA), achieving >99.0 % conversion and selectivity at 100 °C for 60 min, with a turnover frequency (TOF) of 2908.1 h−1, surpassing other reported nickel-based catalysts by 1–3 orders of magnitude. The excellent catalytic performance of Ni1/NC900 was attributed to the high mass transfer efficiency (HMTE) of the support and the dual reaction sites of Ni–N4 and pyridinic N, where Ni–N4 as Lewis acidic site for adsorption of FF and isopropanol (i-PrOH), while the adjacent pyridinic N as Lewis basic site for the deprotonation of i-PrOH. The isotope labeling experiments revealed that the hydrogenation of FF was accomplished by proton transfer with i-PrOH, in agreement with the intermolecular hydride transfer mechanism. Furthermore, Ni1/NC900 demonstrated excellent stability and well general applicability, demonstrating its potential for industrial applications. This work provides a reference for the application of carbon-based non-precious metal SACs in the CTH reaction of UAL.

Highly stable and flexible electronic separator prepared through photo-polymerizing fluorinated acrylate high internal phase emulsion

Highly stable and flexible electronic separator prepared through photo-polymerizing fluorinated acrylate high internal phase emulsion

Highly porous polycaprolactone microspheres for skeletal repair promote a mature bone cell phenotype in vitro.

Improving our ability to treat skeletal defects is a critical medical challenge that necessitates the development of new biomaterials. One promising approach involves the use of degradable polymer microparticles with an interconnected internal porosity. Here, we employed a double emulsion to generate such round microparticles (also known as microspheres) from a polycaprolactone-based polymerised high internal phase emulsion (polyHIPE). These microspheres effectively supported the growth of mesenchymal progenitors over a 30-day period, and when maintained in osteogenic media, cells deposited a bone-like extracellular matrix, as determined by histological staining for calcium and collagen. Interestingly, cells with an osteocyte-like morphology were observed within the core of the microspheres indicating the role of a physical environment comparable to native bone for this phenotype to occur. At later timepoints, these cultures had significantly increased mRNA expression of the osteocyte-specific markers dentin matrix phosphoprotein-1 (Dmp-1) and sclerostin, with sclerostin also observed at the protein level. Cells pre-cultured on porous microspheres exhibited enhanced survival rates compared to those pre-cultured on non-porous counterparts when injected. Cells precultured on both porous and non-porous microspheres promoted angiogenesis in a chorioallantoic membrane (CAM) assay. In summary, the polycaprolactone polyHIPE microspheres developed in this study exhibit significant promise as an alternative to traditional synthetic bone graft substitutes, offering a conducive environment for cell growth and differentiation, with the potential for better clinical outcomes in bone repair and regeneration.

Bottlebrush Random Copolymers at Oil‐Oil Interfaces

Comprehensive SummaryOil‐in‐oil nonaqueous emulsions are of great interest for developing emulsion‐templated polymers and encapsulation systems that are incompatible with water‐sensitive substances. Tailor‐made amphiphilic block copolymers are by far the most efficient stabilizers for oil‐in‐oil emulsions while less attention is given to copolymers with more complex architectures. Here, we report the stabilization of DMSO‐silicone oil interface by bottlebrush random copolymers (BRCPs) containing norbornene backbones with densely grafted poly(methyl methacrylate) (PMMA) and polystyrene (PS) side chains. The assembly kinetics of BRCPs at the DMSO‐silicone oil interface can be divided into three processes, including diffusion, reconfiguration and reorganization, and can be varied by tuning the degree of polymerization of the backbone (NB). Due to the high efficiency of BRCPs in reducing the interfacial tension, when using BRCPs as stabilizers, stable silicone oil‐in‐DMSO traditional emulsions and high internal phase emulsions (HIPEs) can be successfully obtained, while no stable emulsions can be achieved with linear PMMA‐b‐PS serving as the stabilizer. This study, for the first time, underscores the great potential of amphiphilic bottlebrush copolymers in preparing oil‐in‐oil emulsions. Given the advances in polymerization strategy, a broad variety of amphiphilic bottlebrush copolymers are expected to be synthesized and applied in the stabilization of nonaqueous biphasic systems.

Zein-cyclodextrin complex used to prepare high internal phase pickering emulsions with various oil phases

Biobased solid particles for stabilizing high internal phase emulsions (HIPEs) are widely used in food and cosmetics industries. This study report a kind of zein-cyclodextrin complex particles which could HIPEs with various oil phases (log P values: 1.14–9.26), showcasing their wide applicability across different oil types. This versatility due to the slight differences (6–8°) in the three-phase contact angles for different oils. Furthermore, the complex particles showed a marked improvement in emulsification performance, as evidenced by their significantly higher diffusion rates (7–15 times faster) and reorientation speeds (2–5 times faster) at the oil-water interface. Moreover, the emulsions prepared were stable across a broad pH range (3–9), successfully addressing the common stability challenges associated with protein-based emulsifiers near their isoelectric points. Therefore, these complex particles have great potential in cosmetics, waste oil treatment and food field, such as multifunctional 3D bioprinting ink.

Construction of Lactobacillus casei-loaded Water-in-oil High Internal Phase Emulsion and its Study on Anti-breast Cancer Properties

Objective: To prepare an oil-in-water high internal phase emulsion containing Lactobacillus casei, and to optimize and characterize the preparation process. To explore the therapeutic effect of the probiotic-carrying emulsion on in situ breast cancer in mice. Methods: Using corn oil, sodium alginate, polyglycerin ricinoleate and L. casei as raw materials, the high internal phase emulsion containing probiotic oil-in-water was prepared by high-speed homogenization method. The optimal preparation process was obtained through single factor investigation, microstructure characterization, stability investigation and in vitro simulation digestion experiment. Ten female BALB/c mice (SPF grade, 18–20 g) were selected. After the in situ breast cancer model was successfully established, the mice were randomly divided into experimental group and control group, with 5 mice in each group. The mice were administrated with probiotic-loaded emulsion and normal saline respectively, and were administrated with the stomach every other day for 10 days. The change of tumor volume during treatment and tumor mass at the end of treatment were recorded. Results: The optimum process of emulsion was: With the concentration of 5% Polyglycerin ricinolate, 75% aqueous volume, 3000r/min homogenizing speed, 30 s homogenizing time and 2% aqueous sodium alginate concentration, a high internal phase emulsion with a particle size of 9.33 ± 1.74 μm and an appearance of milky paste was prepared. The inclusion rate of probiotics reached 90.97 ± 27.09%. Breast cancer anti-tumor experiment showed that the tumor inhibition rate of the experimental group reached 33.78% compared with the control group. Conclusion: Water-in-oil high internal phase emulsion can effectively protect L. casei and reduce the loss of live probiotic when probiotics pass through the digestive fluid environment. Oral intragastric high internal phase emulsion containing L. casei oil-in-water has a certain therapeutic effect on breast cancer.

Citrus fibers improve rheology of OSA starch-based high internal phase emulsion for 3D printed elderly foods

3D printing ready-to-eat emulsions using trans-fat-free edible oil, presents a significant challenge due to the complexities involved in achieving the necessary material structure, rheological properties, and stability. This study fabricated High Internal Phase Emulsions (HIPEs) stabilized with citrus fibers and octenyl succinic anhydride (OSA) modified waxy starch, serving as the printable inks for 3D-printable elderly foods. These printable inks exhibited a pseudoplastic gel structure, which provided enhanced extrudability and improved shape retention. The incorporation of citrus fiber, water, OSA starch, sunflower oil at a concentration of 0.3 wt%, 22.7 % wt %, 2 % wt%, 75 wt% in the 3D-printed HIPEs resulted in optimal addition, yielding the highest level of shape accuracy. Compared to the addition of OSA-modified starch, microstructural analysis and rheological testing (using Lissajous-Bowditch plots) indicated that the addition of citrus fiber had a greater impact on the rheological and textural properties of the HIPEs, which improved shape retention and fluidity of the HIPEs, and ensure the stability of continuous extrusion printing. Additionally, bionic tribological properties demonstrated that tribological properties of the prepared HIPEs were very close to the ones of mayonnaise, which indicating that the prepared HIPEs had smooth texture and easy-to-chew properties for the elderly. These findings offered a comprehensive understanding of the structure–function relationship between the molecular structures of HIPEs and their 3D printability, providing technical insights for the development of 3D-printed emulsion-based ready-to-eat elderly food products. This study provided a good industrialized method for HIPEs stabilized with only fruit dietary fiber and modified starch, and facilitated the development of emulsion-based ready-to-eat food products with 3D printability.

A novel route to 3D printable protein-based HIPEs developed with shiitake oil

Tuning protein-based Pickering high internal phase emulsions (HIPEs) into 3D printing inks is promising in the food fields. Currently, the correlation between the changes in oil phase composition and the regulation of protein-based HIPEs 3D printing performance is still unclear. In this study, spiking the shiitake oil (ranging from 0 to 60 %) into the soybean oil phase of HIPEs can enhance their rheological properties and induce the formation of 3D printable HIPEs. The rheological tests showed that the yield stress and viscosity of the HIPEs respectively increased from 81.8 ± 4.84 Pa to 309 ± 16.3 Pa and from 409 to 1.74 Pa.s to 1762–2.93 Pa.s with increasing the shiitake oil concentration (0 % to 60 %) in the oil phase. In this study, the spontaneous interaction between phenolic compounds in shiitake oil and interfacial casein promoted the aggregation of protein, which led to the formation of casein cross-linking network in emulsion droplets, thus realizing the self-supporting and printing fidelity required for 3D printing. These findings provide a new perspective for enhancing the 3D printing properties of protein-based HIPEs.

Construction and characterization of sesame meal-stabilized Pickering high internal phase emulsions and their application in cake production

Pickering high internal phase emulsions (HIPEs) show promise for solid fat replacement and nutrient delivery, but the availability of safe and easily accessible food-borne particulate emulsifiers is a bottleneck limiting their practical application. In this study, the feasibility of using sesame meal as an emulsifier for the construction of sunflower oil-based Pickering HIPEs was evaluated. These HIPEs were then characterized in terms of their microstructural and mechanical properties, and utilized as a substitute for butter in cake production. Results showed that sesame meal is rich in protein, and has a particle size (median diameter, 46.40 ± 0.83 μm), and wettability that makes it suitable for use as an emulsifier. It stabilized O/W type Pickering HIPEs formulated with sunflower oil with a volume fraction of up to 80 %. The mechanical properties of these Pickering HIPEs were positively correlated with the concentration of sesame meal. Sunflower oil-based HIPEs prepared from sesame meal can partially replace butter for cake preparation when φ = 80 % and c = 9.0 %, and enhance the internal pore structure of cake when butter substitution (Wb) ≤ 30 %. This provides a new way to use sesame meal and new type of food-grade Pickering HIPEs.

Development and characterisation of a novel bigel based on pea protein hydrogel and rice bran wax oleogel: Enhancement of rheological properties and freeze-thaw stability

In this study, a novel pea protein (PP)-based bigel was developed, featuring a high internal phase emulsion. The impact of gelling agent concentration on the gel properties and freeze-thaw stability of the bigel was investigated. The bigel was comprised of two distinct gel phases: an aqueous-phase gel with a covalent network formed by PP and transglutaminase (TGase), and an oil-phase gel with a crystal network structure of rice bran wax (RBW). Microstructural analysis revealed a bi-continuous network structure in the bigel, with network density increasing as TGase and RBW concentrations rose. Rheological analysis showed that storage modulus (G′), apparent viscosity, and structural recovery of the bigel increased with higher TGase and RBW concentrations. Temperature scanning experiments confirmed that the bigel maintained its elastic solid behavior even at elevated temperatures. Optimal sensory properties and low coefficient of friction were achieved at 0.4 % TGase and 7 % RBW concentrations. Additionally, the bigel exhibited notable freeze-thaw stability at TGase and RBW concentrations exceeding 0.2 % and 5 %, respectively. These findings highlight the excellent gelation properties and stability of the PP-RBW-based bigel, suggesting its potential as a fat substitute in the food industry.

Photothermally enhanced ion-transport in solid-state, non-Faradic energy storage devices for sub-freezing operability

The universal direct dependence of ionic mobility on temperature severely restricts the low-temperature operation of energy storage devices. We overcome this limitation by synergizing photothermal conversion with electrochemical energy storage, using non-graphitizable nanocarbon florets (NCF) as multi-functional electrodes. NCF-based supercapacitors leverage the photothermal energy, directing it to the High Internal Phase Emulsion polymer (poly-HIPE) infused ionic conductor [BMIm]-[TFSI], resulting in 15% increase in specific capacitance (Csp) at 30 °C and a 45% at −30 °C. This is the first solid-state energy storage device usable at sub-freezing conditions (< − 4 °C) without compromising its performance. Importantly, the device exhibits identical characteristics at 10 °C (with sunlight) and 30 °C (in the dark), thereby offsetting a temperature difference of 20 °C. Experimental evidences points to the reduction in electrolyte resistance by 86% and 34% in relaxation time constant as the origin of such improved functioning. Furthermore, the advantage of processability is translated to configurational form-factor to efficiently heat the ionic conductor and thereby realise a 15% increase in Csp.

Enhancing lutein stability and bioaccessibility with high internal phase emulsions stabilized by octenylsuccinylated starch

AbstractLutein possesses antioxidant properties and is a main component of the macular pigment, vital for infant eye and brain development. However, its use is constrained by its poor aqueous solubility and low stability. High internal phase emulsions (HIPEs) are valued in food development for encapsulating and protecting hydrophobic nutraceuticals. The objective of this study is to improve lutein's stability and bioaccessibility using HIPEs stabilized by biopolymer octenylsuccinylated starch (OSS). Three types of commercial OSS, including CAPSUL TA (CTA), HI‐CAP 100 (HC), and Purity Gum 2000, were tested for their emulsification properties in forming lutein HIPEs. Lutein HIPEs stabilized by 15%–25% CTA and 15%–30% HC had no phase separation and were selected for subsequent testing. After 21 days of storage at room temperature, lutein HIPEs showed higher lutein retention compared to free lutein. Lutein HIPEs stabilized with higher emulsifier concentrations (25% CTA and 30% HC) exhibited greater droplet diameter stability than those with lower concentrations. Additionally, lutein HIPEs significantly enhanced lutein retention under UV exposure and thermal stress. The in vitro bioaccessibility of lutein was highest in the HIPE stabilized by 20% CTA, reaching 54.36%. In conclusion, lutein HIPEs stabilized by 20% CTA demonstrated superior lutein stability and bioaccessibility, showing significant potential as an effective lutein delivery system.

Edible jammed deep eutectic solvent-in-oil emulsions for 3D food printing

Concentrated emulsions, when their volume fractions exceed a critical value, tend to adopt a jammed structure and exhibit solid-like behavior. In this work, we develop a novel, edible high internal phase emulsion that incorporates an edible deep eutectic solvent (DES) as the dispersed phase, along with sunflower oil and Span 80 as the continuous phase, to formulate DES-in-oil emulsions. The rheological properties of the resulting DES-in-oil emulsions are thoroughly examined, focusing on the yield stress and storage modulus, which are indicative of solid-like characteristics. Additionally, the emulsion’s microstructure is analyzed using optical microscopy to determine the size distribution of the DES droplets. Our study further explores the impact of agitation time on the emulsion’s formation, revealing that prolonged agitation strengthens the emulsion’s mechanical properties by reducing droplet sizes. This innovative emulsion showcases potential applications in 3D food printing, where it can be used to directly form predefined solid structures. Such printed food can assume various shapes without requiring post-processing, maintaining shape integrity and self-sustainability for up to four months.

Effect of fat replacement in high internal phase emulsions constructed by high temperature saccharification of grafted proteins on gel properties and flavor profiles of sausages

In order to mitigate the risk of cardiovascular diseases associated with excessive saturated fatty acid intake, utilizing high internal phase emulsions (HIPEs) as a substitute for animal fat in producing high-quality fat-substituted meat products is an ideal approach. This study involves the preparation of glycosylation products of egg white protein (EWP) through saccharification at high temperatures in the presence of fructooligosaccharides (FO). The resulting glycation products of EWP were employed to create colloidal particles, forming HIPEs, which were further utilized to induce the formation of HIPEs gels (HIPEs-Gs). The study investigated the effects of substituting different ratios (25%, 50%, 75%, and 100%) of animal fat with HIPEs and HIPEs-Gs on the gel properties and flavor characteristics of sausages. Results showed that, compared to the control group, substituting fat with HIPEs significantly improved the gel properties, cooking yield, and G' of sausages, while excessive HIPEs-Gs substitution yielded negative effects. Low-field nuclear magnetic resonance results also demonstrated that adding HIPEs improved water and oil distribution in the sausage batter, enhancing protein's binding capacity with water. Scanning electron microscope revealed that HIPEs substitution led to a denser gel network with smaller pores, effectively "locking in" more water. Analysis of volatile compounds indicated accelerated release of aromatic compounds, alkanes, sulfides, and lipids when fat was substituted with HIPEs and HIPEs-Gs. Electronic tongue analysis suggested that HIPEs-Gs substitution reduced response values for umami and saltiness. In conclusion, compared to HIPEs-Gs, using HIPEs as a fat substitute improves the quality of sausages.

Regulating emulsion properties through tannin acid-mediated gelatin/cellulose nanocrystal complexes: From low-oil emulsion to high internal phase emulsion gel for 3D printing

In this study, a stabilized low-oil emulsion and high internal phase emulsion gels (HIPE gels) integrated preparation method is proposed. Highly stable low-oil emulsions, prepared using tight ternary complexes formed by incorporating tannic acid (TA) into gelatin/cellulose nanocrystals (GLT/CNC) complexes mainly through strengthening hydrogen-bonding interaction. The subsequent heating-centrifugation process was used to enable the conversion of GLT/CNC/TA stabilized low-oil emulsions to stabilized HIPE gels, and systematically investigated the regulation of emulsion properties by TA concentrations. The ternary complexes formed by appropriate concentration of TA (0.6 %) can form stable low-oil emulsions with smallest average particle (36.1 ± 0.25 μm) size and best rheological properties, while the rheological properties of HIPE gels were similarly regulated by the TA concentration (0 %, 0.2 %, 0.6 %, 1.0 %, 1.2 %). Heating induced flocculation of low-oil emulsions without causing demulsification, allowed for the subsequent centrifugation to yield stable HIPE gels, significantly superior to the GLT/CNC/TA-stabilized HIPE gels prepared by conventional methods that typically exhibit thermal instability. TA effectively promoted the interfacial adsorption of GLT/CNC and tight stacking of oil droplets to build a more stable network structure in the continuous phase. HIPE gels with 0.6 % TA demonstrated excellent 3D printability with optimal dimensional resolution and surface quality, presenting a novel strategy for HIPE gel preparation and versatile emulsion applications.

High internal phase emulsions stabilized by fluorescent phycocyanin for improved stability and bioaccessibility of β-carotene.

High internal phase emulsions (HIPE) are distinguished from ordinary emulsions by higher oil-phase percentage and better storage stability. Recently, HIPE stabilized with protein-based particles has received more attention. However, organic precipitation, chemical cross-linking and thermal denaturation are often needed to stabilize emulsions with natural proteins, and there is an urgent need to reduce the pollution of organic reagents. HIPE loaded with β-carotene stabilized by phycocyanin was prepared under mild conditions. It demonstrated strong stability in terms of temperature and storage, as evidenced by its 94.17% retention rate and 81.06% bioavailability. This stability was ascribed to the efficient defense against heat and UV rays, which was probably associated with the oil-droplet environment and interfacial protection of phycocyanin. It is speculated that the possible main interaction site between phycocyaninand sorbitol exists near amino acids 110 to 120 of the B chain. The hydrogen bond and hydrophobic interaction between them make the phycocyanin fully adsorbed on the oil-water interface when sorbitol is stable, forming a strong oil-water structure, which increases the stability of the emulsion. The outstanding fluorescence characteristics provide a feasible alternative for fluorescent emulsions to distribute and trace active compounds in vitro. HIPE loaded with β-carotene might have potential as a 3D printing material for edible functional foods. © 2024 Society of Chemical Industry.

Raman spectroscopy and molecular dynamics simulations of protein microgels at the oil-water interface

The real-time structural changes of the molecular space conformation of myofibrillar protein microgels (MPM) after heat treatment (90 °C, 30 min) were analyzed by molecular dynamics simulation, and the structural properties and changes of MPM at the oil-water interface were analyzed by the combination of Raman spectroscopy and molecular dynamics simulation. The shift in the oil ratio had a major impact on the transformation of disulfide bonds within the protein molecule. Simultaneously, it caused tryptophan and tyrosine residues (I850 cm−1/ I850 cm−1 > 1) to become exposed, increasing the locations of amino acid residues in the protein that interact with the oil phase. HIPE with different oil phases influenced the change in spatial structural conformation of MPM, and there was a flexible structural change in the molecular space. The HIPE system, which was stabilized by 3.0 wt% MPM and 0.75 oil phase, exhibited a thixotropic recovery of >70 % and the highest elastic modulus G′ (822.14 Pa) based on the rheological behavior. It is expected to provide a theoretical basis for the development and utilization of high internal phase emulsion stabilized by microgel protein in food industry.

Whey protein isolate-tamarind seed gum complexes stabilized dysphagia friendly high internal phase emulsions: The effects of pH conditions and mass ratios

Dysphagia is a common malfunction affecting a large population worldwide, yet the range of food available to the patients is limited. The objective of this study was to utilize a complex of whey protein isolate (WPI) and tamarind seed gum (TG) as novel emulsifiers to stabilize HIPEs, and further explore WPI-TG-based HIPEs' potential as dysphagia-friendly foods for special medical purposes (FSMP). The results indicated that WPI-TG forms complexes through hydrogen bonding and electrostatic interactions (pH 3 and 4). Additionally, TG induced changes in the secondary and tertiary structures of WPI. The particle size of HIPEs prepared from WPI-TG complexes was found to be reduced. Meanwhile, with the decrease in pH from 7 to 3, the variation in complexes ζ-potential led to an initial increase followed by a subsequent drop in the particle size of HIPEs. The rheological results indicated that WPI-TG-based HIPEs exhibit low-risk swallow characteristics, including shear thinning, high storage modulus, and good recovery ability. Further analysis using the IDDSI testing demonstrated that WPI-TG-based HIPEs under pH 3 and 4 can potentially be dysphagia-friendly FSMPs. After undergoing thermal treatment or long-term storage, WPI-TG-based HIPEs at pH 3 and 4 consistently maintained compliance with the IDDSI testing. These findings provided valuable insights for the future utilization of HIPEs in developing dysphagia-friendly FSMPs.

Exploring the emulsifying properties of biopolymers from Ulva lactuca in stabilizing high internal phase emulsions

Seaweed is a promising raw material for food emulsion stabilizers due to its abundance, low cost, and rich content of various natural biological macromolecules. This study explores the potential of using Ulva lactuca (UL) to stabilize emulsions by employing high-pressure homogenization (HPH) to release its interfacial active components. The results demonstrate that UL extract (ULE) with emulsifying activity was gradually extracted as the HPH pressure increased from 100 to 800 MPa. Concentrating the macromolecular components, specifically polysaccharides and proteins, in the ULE via membrane filtration resulted in a concentrated fraction, referred to as ULER, which exhibited enhanced emulsification performance. By optimizing the oil volume fraction (φ) and pH, it was found that high internal phase emulsions (φ = 0.7–0.8) showed superior viscoelasticity and stability at pH 3–7. In terms of stability, it was observed that the emulsions stabilized by ULER maintained their structure over extended periods without significant phase separation. The strong interaction between exogenous Ca2⁺ and ULER increased the apparent viscosity and viscoelasticity of the emulsion. However, the addition of Ca2⁺ did not significantly enhance the stability of the ULER-stabilized emulsions and, in some cases, even led to a decrease in emulsion stability. This effect may be probably due to the specific interactions between the Ca2⁺ ions and the polysaccharides and proteins in the ULER, which can affect the network structure of the emulsion. Overall, this study highlights the potential of HPH treatment in processing UL to transform it into an effective emulsion stabilizer for applications in the food industry.