Tunable high internal phase emulsions (HIPEs) formulated using lactoferrin-gum Arabic complexes

Mechanism on microbial transglutaminase and Tremella fuciformis polysaccharide-mediated modification of lactoferrin: Development of functional food

Lactoferrin (LF) with various biological functions demonstrates great application potential. However, its application was restricted by its poor gelation and instability. The aim of this work was to explore the effect of microbial transglutaminase (MTGase) and Tremella fuciformis polysaccharide (TP) on the functional properties of LF. The formation of a self-supporting LF gel could be induced by MTGase through generating covalent crosslinks between the LF protein molecules. Meanwhile, TP was introduced into the gel system to improve the strength of LF-TP composite gels by enhancing non-covalent interactions such as hydrogen bond and electrostatic interactions during gel formation. Additionally, the LF-TP composite gel exhibited outstanding functional characteristics such as gastrointestinal digestive stability and antioxidant property. This work clarified the mechanism on MTGase and TP-mediated modification of lactoferrin, offered a novel strategy to increase the functional characteristics of LF, and enlarged the application range of LF and TP.

Hot-water soluble fraction of starch as particle-stabilizers of oil-in-water emulsions: Effect of dry heat modification

Dry heat treatment (DHT) ranging from 130 to 190 °C was employed to modify corn starch. The hot-water soluble fraction (HWS) of the DHT-modified starch was isolated, and its capacity and mechanism for stabilizing O/W emulsions were investigated. Corn starch underwent a significant structural transformation by DHT at 190 °C, characterized by a 7.3 % reduction in relative crystallinity, a tenfold decrease in weight-average molecular weight from 95.21 to 8.11 × 106 g/mol, and a degradation of over one-third of the extra-long chains of amylopectin (DP > 36) into short chains (DP 6-12). These structural modifications resulted in a substantial formation of soluble amylopectin, leading to a sharp increase in the HWS content of corn starch from 3.16 % to 85.06 %. This augmented HWS content surpassed the critical macromolecule concentration, prompting the formation of HWS nanoaggregates. These nanoaggregates, with an average particle size of 33 nm, functioned as particle stabilizers, ensuring the stability of the O/W emulsion through the Pickering mechanism. The O/W emulsion stabilized by HWS nanoaggregates exhibited noteworthy centrifugal and storage stability, with rheological properties remaining nearly unchanged over a storage period of 180 days. Given its straightforward preparation process, the HWS of DHT-modified starch could be a promising natural emulsifier.

Fabrication and Stability Improvement of Monoglyceride Oleogel/Polyglycerol Polyricinoleate-Stabilized W/O High Internal Phase Pickering Emulsions

To decrease the lipid content in water-in-oil (W/O) emulsions, high internal phase Pickering W/O emulsions (HIPPE) were fabricated using magnetic stirring using a combination of monoglyceride (MAG) oleogel and polyglycerol polyacrylate oleate (PGPR) as stabilizers. Effects of MAGs (glyceryl monostearate-GMS, glycerol monolaurate-GML and glycerol monocaprylate-GMC) and internal phase components on the formation and properties of HIPPEs were investigated. The results showed that milky-white stabilized W/O HIPPE with up to 85 wt% aqueous phase content was successfully prepared, and the droplet interfaces presented a network of MAG crystals, independent of the MAG type. All HIPPEs exhibited great stability under freeze-thaw cycles but were less plastic. Meanwhile, GML-oleogel-based HIPPEs had larger particle size and were less thermal stable than GMS and GMC-based HIPPEs. Compared to guar gum, the internal phase components of sodium chloride and sucrose were more effective in reducing the particle size of HIPPEs, improving their stability and plasticity, and stabilizing them during 100-day storage. HIPPEs presented great spreadability, ductility and plasticity after whipping treatment. This knowledge provides a new perspective on the use of oleogels as co-stabilizers for the formation of W/O HIPPEs, which can be used as a potential substitute for creams.

Effect of pH on the soybean whey protein-gum arabic emulsion delivery systems for curcumin: Emulsifying, stability, and digestive properties

A novel curcumin (CUR) delivery system was developed using soybean whey protein (SWP)-based emulsions, enhanced by pH-adjustment and gum arabic (GA) modification. Modulating electrostatic interactions between SWP and GA at oil/water interface, pH provides favorable charging conditions for stable distribution between droplets. GA facilitated the SWP form a stable interfacial layer that significantly enhanced the emulsifying properties and CUR encapsulation efficiency of the system at pH 6.0, which were 90.15 ± 0.67%, 870.53 ± 3.22 m2/g and 2157.62 ± 115.31%, respectively. Duncan's test revealed significant improvements in thermal, UV, oxidative, and storage stabilities of CUR (P < 0.05). At pH 6.0, GA effectively protected CUR by inhibiting SWP degradation during gastric digestion and promoting the release of CUR by decreasing steric hindrance with oil droplets during intestinal digestion, achieving the highest CUR bioaccessibility (69.12% ± 0.28%) based on Duncan's test. The SWP-GA-CUR emulsion delivery system would be a novel carrier for nutrients.

Ovotransferrin Fibril-Gum Arabic Complexes as Stabilizers for Oleogel-in-Water Pickering Emulsions: Formation Mechanism, Physicochemical Properties, and Curcumin Delivery

This project aimed to explore the influence of the interaction between ovotransferrin fibrils (OTF) and gum arabic (GA) on the formation mechanism, physicochemical properties, and curcumin delivery of the oleogel-in-water Pickering emulsion. Cryo-scanning electron microscopy results showed that OTF-GA complexes effectively adsorbed on the oil-water interface, generating spatial hindrance to inhibit droplet coalescence. The texture analysis also proved that OTF-GA complexes endowed oleogel-in-water Pickering emulsion with preferable springiness (0.49 ± 0.03 mm), chewiness (0.43 ± 0.07 mJ), and adhesion (0.31 ± 0.01 mJ). By exploring the coalescence stability, droplet size, and rheological properties of OTF-GA complexes-stabilized oleogel-in-water Pickering emulsion (OGPE), the higher coagulation stability, larger average droplet size (46.22 ± 0.08 μm), and stronger gel strength were observed. The microrheological results also exhibited stronger attraction between the OGPE droplets, a more pronounced solid-like structure, and a slower speed of movement than OTF-stabilized oleogel-in-water Pickering emulsion (OPE). Meanwhile, OGPE significantly enhanced the extent of lipolysis, stability, and bioaccessibility of curcumin, suggesting that it possessed superior performance as a delivery system for bioactive substances. This project provided adequate theoretical references for protein-polysaccharide complexes-stabilized oleogel-in-water Pickering emulsion, and contributed to expanding the application of oleogel-in-water Pickering emulsion in the food industry.

Design of colloid structure to realize gel salt reduction: a review

Excessive consumption of salt is associated with increased incidence of cardiovascular diseases, hypertension, diabetes, and other health issues. However, it is challenging to find appropriate strategies that balance sensory qualities while achieving sodium reduction as salt plays a crucial role in providing desired appearance, texture, and taste. The impact of hydrocolloid properties (addition and type) on saltiness perception were reviewed. Additionally, considering the interactions between food components, both covalent and noncovalent, we propose designing specialized colloidal structures capable of binding sodium ions to enhance salt-taste perception. The effects of hydrocolloids on the physicochemical, structural, and sensory qualities of gel foods are then discussed. Finally, by addressing current issues with low-salt foods and consumer demands, we provide a future outlook for low-salt food development. The selection of suitable hydrocolloids and precise control of the addition are crucial considerations for achieving salt reduction. The interaction between hydrocolloids and other food components can be utilized to design specialized colloidal structures, thereby accomplishing gel-based salt reduction and enhancing properties. This review serves as a theoretical reference for developing healthy, nutritious, and flavorful low-salt foods that can aid in the prevention and mitigation of diseases associated with excessive salt consumption.

Phycocyanin-chitosan complex stabilized emulsion: Preparation, characteristics, digestibility, and stability

Phycocyanin is a natural pigment protein with antioxidant, anti-tumor, and anti-inflammatory properties, but its relatively poor emulsibility limits its use in the food industry. In order to improve the emulsifying capacity of phycocyanin, a novel phycocyanin-chitosan complex was prepared, and the characteristics, digestibility, and stability of emulsion containing oil droplets stabilized by the complex were investigated. The results showed that the phycocyanin-chitosan complex had better stability and lower interfacial tension at pH 6.5 than phycocyanin, and it significantly improved the stability of emulsion and inhibited the aggregation of oil droplets. The phycocyanin-chitosan complex stabilized emulsion showed better physical stability, digestibility, and oxidation stability than the phycocyanin emulsion. The particle size of the phycocyanin-chitosan complex stabilized emulsion was very small (from 0.1 to 2 μm), and its absolute value of zeta potential was high. Overall, this study suggests that the phycocyanin-chitosan complex effectively improved the emulsifying capacity of phycocyanin.

Fabrication, characterization and emulsifying properties of myofibrillar protein-chitosan complexes in acidic conditions

Polysaccharides are employed to modify proteins, forming complexes that enhance the functional properties of proteins, such as emulsification and stability. In this study, myofibrillar protein (MP)-chitosan (CS) complexes were formed between CS and MP under acidic conditions (pH 3.0-6.0). Results showed that CS can improve the solubility and emulsifying properties of MP, and the MP-CS complexes at pH 3.0 and 6.0 had better emulsifying properties. Concurrently, the particle size results indicated that better the emulsifying properties of the complex, the smaller the particle size. Consequently, the characteristics of the MP-CS complexes (at pH 3.0 and 6.0) were investigated. Our analysis using Fourier transform infrared spectroscopy revealed that the amide I band of MP was blue-shifted with the addition of CS, signifying a decrease in hydrogen bonding within MP. The endogenous fluorescence spectra showcased that the hydrophobicity surrounding the tryptophan residues in the protein changed, leading to enhanced polarity. Thermogravimetric analysis and differential scanning calorimetry further confirmed that the addition of CS improved the thermal stability of MP. These findings provide valuable insights into the interactions between MP and CS. Furthermore, the MP-CS complex can be leveraged to create a Pickering emulsion system for the efficient delivery of bioactive substances.

Quinoa protein/polysaccharide electrostatic complex stabilized vegan high internal phase emulsions for 3D printing: Role of complex state and gelling-type polysaccharides

Rational selection of the complex state and polysaccharide type may enhance the performance of electrostatic complex stabilized high internal phase emulsions (HIPEs). Herein, quinoa proteins were extracted to form electrostatic complexes separately with three gelling-type polysaccharides to fabricate HIPEs. Results showed that the complexes in soluble state (pH 8.4-5.6) exhibited moderate size, high negative potential and enhanced protein hydrophobicity, and could achieve HIPEs with 84% oil phase upon acidification to pH 6 at low concentrations. Its excellent interfacial structure enhanced stability during heating, freeze-thawing and long-term storage, and exhibited promising 3D printing potential. Furthermore, the complexes formed by sulfated polysaccharide carrageenan had higher amphiphilicity than those formed by carboxylated polysaccharide pectin or sodium alginate, and their stabilized HIPE had preferable droplet size, stability and 3D printing resolution than its counterparts. This study may provide new insights into the performance enhancement of protein/polysaccharide electrostatic complex stabilized HIPEs.

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.

Composite formation of whey protein isolate and OSA starch for fabricating high internal phase emulsion: A comparative study at different pH and their application in biscuits

The composites formed by whey protein isolate (WPI) and octenyl succinate anhydride (OSA)-modified starch were characterized with a focus on the effect of pH, and their potential in fabricating high internal phase emulsions (HIPEs) as fat substitutes was evaluated. The particles obtained at pH 3.0, 6.0, 7.0, and 8.0 presented a nanosized distribution (122.04 ± 0.84 nm-163.24 ± 4.12 nm) while those prepared at pH 4.0 and 5.0 were remarkably larger. Results from the shielding agent reaction and Fourier transform infrared spectroscopy (FT-IR) showed that the interaction between WPI and OSA starch was mainly hydrophobic at pH 3.0-5.0, while there was a strong electrostatic repulsion at pH 6.0-8.0. A quartz crystal microbalance with dissipation (QCM-D) study showed that remarkably higher ΔD and lower Δf/n were observed at pH 3.0-5.0 after successive deposition of WPI and OSA starch, whereas slight changes were noted for those made at higher pH values. The WPI-OSA starch (W-O) composite-based HIPEs made at pH 3.0 and 6.0-8.0 were physically stable after long-term storage, thermal treatment, or centrifugation. Incorporation of HIPE into the biscuit formula yielded products with a desirable sensory quality.

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.

AKD Emulsions Stabilized by Guar Gel: A Highly Efficient Agent to Improve the Hydrophobicity of Cellulose Paper

The aim of the present study was to investigate highly efficient alkyl ketene dimer (AKD) emulsions to improve the hydrophobicity of cellulose paper. AKD emulsions stabilized by guar gel were obtained; the guar gel was prepared by hydrogen bond cross-linking sodium tetraborate and guar gum. The cross-linking was confirmed by combining FTIR and SEM. The effect of guar gel on the performance of the AKD emulsions was also studied by testing AKD emulsions stabilized by different guar gel concentrations. The results showed that with increasing guar gel concentration, the stability of the AKD emulsions improved, the droplet diameter decreased, and the hydrophobicity and water resistance of the sized packaging paper were gradually enhanced. Through SEM, the guar gel film covering the AKD emulsion droplet surface and the three-dimensional structure in the aqueous dispersion phase were assessed. This study constructed a scientific and efficient preparation method for AKD emulsions and provided a new method for the application of carbohydrate polymer gels which may avoid the adverse effect of surfactant on paper sizing and environmental problems caused by surfactant bioaccumulation.

Understanding the structure, interfacial properties, and digestion fate of high internal phase Pickering emulsions stabilized by food-grade coacervates: Tracing the dynamic transition from coacervates to complexes

Although protein-polysaccharide complexes have shown tremendous potential in stabilizing high internal phase Pickering emulsions (HIPPEs), it is unclear whether coacervates have the same potential to be used as effective Pickering stabilizers. In this study, HIPPEs were prepared by ovalbumin (OVA)-pectin (PE) coacervates during the transition from coacervates to complexes. The results showed that enhanced OVA-PE interactions significantly affected the wettability and surface-tension reduction ability of the OVA-PE coacervates. At pH 2, the coacervate-stabilized HIPPEs exhibited smaller oil droplet sizes (21.3±2.3 μm), tighter droplet packing, and finer solid-like structures through the bridging of droplets and the generation of stronger gel-like network structures to prevent coalescence and lipid oxidation. The gastrointestinal digestion results proved that the OVA-PE coacervates promoted lipid hydrolysis and improved the bioaccessibility (from 19.7±0.7% to 36.5±2%) of curcumin-loaded HIPPEs. Our work provides new ideas for the development of biopolymer particles as effective Pickering stabilizers in the food industry.

High internal phase emulsion gels stabilized by phosphorylated perilla protein isolate for protecting hydrophobic nutrients: Adjusting emulsion performance by incorporating chitosan-protocatechuic acid conjugate

The delivery vehicles based on protein-polysaccharide-polyphenol are promising methods to encapsulate bioactive components with the aim of improving their solubility and bioavailability. In this study, chitosan-protocatechuic acid (CSPA) conjugate interacted with phosphorylated perilla protein isolate (LZPI) to engineer a composite antioxidant interfacial architecture to delay lipid oxidation and regulate the stability and digestion profiles of β-carotene loaded in high internal phase emulsions (HIPEs). Compared to LZPI, the LZPI-CSPA complexes formed by hydrogen bond and electrostatic interaction showed improved wettability and reduced interfacial tension, which facilitated their adsorption at the interface. Furthermore, the addition of CSPA conjugate promoted the formation of interconnected network structure of LZPI-stabilized HIPEs, thereby endowing them with excellent viscoelasticity and storage stability. Moreover, the denser interfacial film based on LZPI-CSPA complexes effectively decreased the contents of lipid hydroperoxide and malondialdehyde in HIPEs, thus improving their oxidation stability. The encapsulation of β-carotene by LZPI-CSPA complex-stabilized HIPEs could further enhance its retention rate against different environmental stresses. After in vitro simulated digestion, the bioaccessibility of β-carotene also improved, reaching the highest value in HIPEs containing 1.5 % CSPA conjugate. These findings will give a reference for the fabrication of delivery vehicles to enhance the stability and bioaccessibility of bioactive components.

Storage stability and interfacial rheology analysis of high-internal-phase emulsions stabilized by soy hull polysaccharide

High-internal-phase emulsions (HIPEs) are more promising candidates for development to replace hydrogenated fatty acids, yet the current HIPEs are limited for stabilizers require very high surface activity. This study showed that HIPEs could be prepared with 1.0-2.2 wt% soy hull polysaccharide (SHP) and the related stability indicators of HIPEs were analyzed. The plasticity, stress resistance, stability of the HIPEs were positively correlated with the SHP content. The interfacial adsorption experiments showed that SHP had the good ability to reduce interfacial tension and formed an elastic interfacial layer. Dilatational rheological results showed the interfacial film reached jammed saturation at about 1.8 wt% of SHP concentration, and the zeta potential results were consistent. This study demonstrated that SHP was an efficient stabilizer of HIPEs, which was useful both for the preparation of HIPEs and for developing uses for SHP.

Protein-Based High Internal Phase Pickering Emulsions: A Review of Their Fabrication, Composition and Future Perspectives in the Food Industry

Protein-based high internal phase Pickering emulsions (HIPEs) are emulsions using protein particles as a stabilizer in which the volume fraction of the dispersed phase exceeds 74%. Stabilizers are irreversibly adsorbed at the interface of the oil phase and water phase to maintain the droplet structure. Protein-based HIPEs have shown great potential for a variety of fields, including foods, due to the wide range of materials, simple preparation, and good biocompatibility. This review introduces the preparation routes of protein-based HIPEs and summarizes and classifies the preparation methods of protein stabilizers according to their formation mechanism. Further outlined are the types and properties of protein stabilizers used in the present studies, the composition of the oil phase, the encapsulating substances, and the properties of the constituted protein-based HIPEs. Finally, future development of protein-based HIPEs was explored, such as the development of protein-based stabilizers, the improvement of emulsification technology, and the quality control of stabilizers and protein-based HIPEs.

Chitosan films with tunable droplet size of Pickering emulsions stabilized by amphiphilic konjac glucomannan network

In this work, chitosan (CS) emulsion films were prepared with grapefruit essential oil (GEO) Pickering emulsions (OGEOs) stabilized by amphiphilic octenyl succinic anhydride (OSA) konjac glucomannan (OSA-KGM) network. The droplet size of emulsion was regulated by altering oil content in OGEOs (10 %, 20 %, 30 % and 40 %, w/w). The structural and physicochemical properties of CS films with tunable emulsion droplets (OGEOs) were investigated. The droplet size of OGEOs increased with the increasing content of GEO. FT-IR revealed that the formation of CS-OGEOs films was attributed to hydrogen bonding. CS-OGEOs films with large droplets presented smoother surface, enhanced water resistance, UV-shielding property, mechanical properties, but increased water vapor permeability (WVP) compared with CS-OGEOs films with small droplets. In addition, CS-OGEOs films with large droplets also presented compact film structure, controlled release of GEO, high efficiency of DPPH free radical scavenging and antibacterial activity. To sum up, incorporation of emulsion droplets was a good strategy for improving the structural and physicochemical properties of CS films.

Research Progress of Food-Grade High Internal Phase Pickering Emulsions and Their Application in 3D Printing

High internal phase Pickering emulsion (HIPPE) is a type of emulsion stabilized by solid particles irreversibly adsorbed on an interfacial film, and the volume fraction of the dispersed phase (Φ) is larger than the maximum packing volume fraction (Φ_max). Proteins, polysaccharides, and their composite particles can be used as good particle stabilizers. The contact angle can most intuitively demonstrate the hydrophilicity and hydrophobicity of the particles and also determines the type of emulsions (O/W or W/O type). Particles' three-phase contact angles can be adjusted to about 90° by compounding or modification, which is more conducive to emulsion stability. As a shear thinning pseudoplastic fluid, HIPPE can be extruded smoothly through 3D printer nozzles, and its high storage modulus can support the structure of printed products. There is huge potential for future applications in 3D printing of food. This work reviewed the biomacromolecules that can be used to stabilize food-grade HIPPE, the stabilization mechanism of the emulsions, and the research progress of food 3D printing to provide a reference for the development of advanced food products based on HIPPE.

Fabrication and digestive characteristics of high internal phase Pickering emulsions stabilized by ovalbumin-pectin complexes for improving the stability and bioaccessibility of curcumin

In this study, ovalbumin (OVA) interacted with pectin (PE) to form soluble electrostatic complexes to improve the functional properties of high internal phase Pickering emulsions (HIPEs) under extreme conditions. The results showed that the stability of the OVA-PE soluble complexes-stabilized HIPEs was significantly better than that of the free OVA-stabilized HIPEs and was modulated by the biopolymer ratio. In particular, the complexes at an OVA:PE ratio of 1:1 (C-1:1) may form particulates with a core-shell structure by a flocculation mechanism. The C-1:1-stabilized HIPEs had the smallest oil droplet size (11.34 ± 1.14 μm) and the best resistance to extreme environmental stresses due to their strong, rigid structure and dense interfacial architecture. The in vitro digestion results showed that the bioaccessibility (from 18.3% ± 0.5% to 38.8% ± 4.8%) of curcumin improved with increasing PE content. Our work is helpful in understanding OVA-PE complexes as stabilizers for HIPEs and their potential applications in food delivery systems.

High internal phase oil-in-water emulsions stabilized by supercritical carbon dioxide extruded whey protein concentrate

High Internal Phase Emulsions (HIPEs) were stabilized by functionalized whey protein concentrate (WPC-80). Functionalization of WPC-80 was done by supercritical CO₂ assisted extrusion technology. HIPEs were formed by 80% oil and 1-4 wt% of control (untreated) whey protein concentrate, extruded/functionalized whey protein concentrates (f-WPC-80) at pH 3.0 and 5.4, and sodium caseinate (NaCas) separately and were characterized for their stability at two temperatures (25 and 40 °C) for 20 days. Results indicated that f-WPC-80-pH3.0 formed self-standing gels at 1 wt% concentrations which were more stable, without phase separation, than those stabilized by commercially used stabilizer NaCas and native c-WPC. At 4% concentration of f-WPC-80-pH3.0, the compressed droplets produced emulsions with self-standing and viscoelastic features. While control WPC-80, could not form stable HIPEs at any investigated concentrations. The reported high internal phase oil-in-water emulsions, offer a potential new system for delivery of nutritionally superior and clean-label products of commercial utility.

Progress in Colloid Delivery Systems for Protection and Delivery of Phenolic Bioactive Compounds: Two Study Cases—Hydroxytyrosol and Curcumin

Insufficient intake of beneficial food components into the human body is a major issue for many people. Among the strategies proposed to overcome this complication, colloid systems have been proven to offer successful solutions in many cases. The scientific community agrees that the production of colloid delivery systems is a good way to adequately protect and deliver nutritional components. In this review, we present the recent advances on bioactive phenolic compounds delivery mediated by colloid systems. As we are aware that this field is constantly evolving, we have focused our attention on the progress made in recent years in this specific field. To achieve this goal, structural and dynamic aspects of different colloid delivery systems, and the various interactions with two bioactive constituents, are presented and discussed. The choice of the appropriate delivery system for a given molecule depends on whether the drug is incorporated in an aqueous or hydrophobic environment. With this in mind, the aim of this evaluation was focused on two case studies, one representative of hydrophobic phenolic compounds and the other of hydrophilic ones. In particular, hydroxytyrosol was selected as a bioactive phenol with a hydrophilic character, while curcumin was selected as typical representative hydrophobic molecules.

Improvement of O/W emulsion performance by adjusting the interaction between gelatin and bacterial cellulose nanofibrils

This study was designed to improve the stability of medium internal phase emulsion by adjusting the electrostatic interaction between gelatin (GLT) and TEMPO-oxidized bacterial cellulose nanofibrils (TOBC). The influences of polysaccharide-protein ratio (1:10, 1:5, and 1:2.5) and pH (3.0, 4.7, 7.0, and 11.0) on the emulsion properties were investigated. The droplet size of TOBC/GLT-stabilized emulsion was increased with the TOBC proportion increasing at pH 3.0-11.0. Additionally, emulsion had a larger droplet size at pH 4.7 (the electrical equivalence point pH of mixtures). However, the addition of TOBC significantly improved the emulsion stability. The emulsions prepared with TOBC/GLT mixtures (mixing ratio of 1:2.5) at pH 3.0-7.0 were stable without creaming during the storage. It was because the formation of nanofibrils network impeded the droplet mobility, and the emulsion viscosity and viscoelastic modulus were increased with the addition of TOBC. These findings were meaningful to modulate the physical properties of emulsions.

Enhancing the bioaccessibility of puerarin through the collaboration of high internal phase Pickering emulsions with β-carotene

Puerarin is a medicinal and edible flavonoid compound found in the traditional Chinese medicine Pueraria lobata rhizome that has potential biological benefifits, including for the treatment of diabetes and memory...

High internal phase Pickering emulsions stabilized by co-assembled rice proteins and carboxymethyl cellulose for food-grade 3D printing

In this study, high internal phase Pickering emulsions (HIPPEs) stabilized by protein-polysaccharide complexes were used as inks for food-grade three-dimensional printing (3DP). The complexes (RCs) structured by synergistic interactions between rice proteins (RPs) and carboxymethyl cellulose (CMC) displayed outstanding biphasic wettability with excellent ability to reduce the oil/water interfacial tension. The interfacial structures formed by RCs provided a steric barrier and sufficient electrostatic repulsion, preventing droplet coalescence against heating treatment as well as long-term storage. Moreover, the rheological behaviors of the HIPPEs can be tuned by the substitution degree (DS) of CMC for tailorable hydrophobic/hydrophilic properties of RCs, allowing their controllable injectability and printability during 3DP. The HIPPEs stabilized by RCs with a DS 1.2 showed the most favorable printing resolution, hardness, adhesiveness, and chewiness. Associating the hydrophobic RPs with hydrophilic CMC, our study enabled on-demand amphiphilicity of RCs for effective stabilization of HIPPEs that can be manipulated for 3DP.

Development of Encapsulation Strategies and Composite Edible Films to Maintain Lactoferrin Bioactivity: A Review

Lactoferrin (LF) is a whey protein with various and valuable biological activities. For this reason, LF has been used as a supplement in formula milk and functional products. However, it must be considered that the properties of LF can be affected by technological treatments and gastrointestinal conditions. In this article, we have revised the literature published on the research done during the last decades on the development of various technologies, such as encapsulation or composite materials, to protect LF and avoid its degradation. Multiple compounds can be used to conduct this protective function, such as proteins, including those from milk, or polysaccharides, like alginate or chitosan. Furthermore, LF can be used as a component in complexes, nanoparticles, hydrogels and emulsions, to encapsulate, protect and deliver other bioactive compounds, such as essential oils or probiotics. Additionally, LF can be part of systems to deliver drugs or to apply certain therapies to target cells expressing LF receptors. These systems also allow improving the detection of gliomas and have also been used for treating some pathologies, such as different types of tumours. Finally, the application of LF in edible and active films can be effective against some contaminants and limit the increase of the natural microbiota present in meat, for example, becoming one of the most interesting research topics in food technology.

All-natural oil-in-water high internal phase Pickering emulsions featuring interfacial bilayer stabilization

HYPOTHESIS

Synergistic stabilization of high internal phase Pickering emulsions (HIPPEs) by food-grade colloidal particles are necessary for food, pharmaceuticals or cosmetics owing to their biocompatibility and multi-functionality. By tuning the interfacial structure of adsorbed binary particles, the HIPPE may exhibit extraordinary characteristics compared to conventional all-natural HIPPEs solely stabilized by single-component particle or composite particle, which should have potential applications in varies fields.

EXPERIMENTS

HIPPEs were prepared by using zein protein nanoparticles (ZNPs) and starch nanocrystals (SNCs) as stabilizers. We systematically investigated the effect of particle concentration and internal phase fraction on HIPPEs morphology, stability and rheological behaviors. Further, the stabilization mechanism as well as potential applications were demonstrated.

FINDINGS

HIPPEs were prepared with excellent stability against centrifugation and high temperature (50 °C). Our result indicates the successful construction of unique bilayer interfacial structures consisting of inner ZNPs layer and outer SNCs layer. Since SNCs could gelatinize at 50 °C, dense shells can form around droplets afterwards. Such thermally responsive interfacial structures can be used to protect hydrophobic bioactive substances at higher temperatures while still allowing controlled release at certain conditions. Furthermore, with high internal phase fraction, HIPPEs can possibly replace mayonnaise and salad dressing on the market due to comparable appearance and properties. Following the removal of inner oil, porous materials can be further fabricated, which have potential applications in environmental protection or tissue engineering.

Recent Innovations in Emulsion Science and Technology for Food Applications

Emulsion technology has been used for decades in the food industry to create a diverse range of products, including homogenized milk, creams, dips, dressings, sauces, desserts, and toppings. Recently, however, there have been important advances in emulsion science that are leading to new approaches to improving food quality and functionality. This article provides an overview of a number of these advanced emulsion technologies, including Pickering emulsions, high internal phase emulsions (HIPEs), nanoemulsions, and multiple emulsions. Pickering emulsions are stabilized by particle-based emulsifiers, which may be synthetic or natural, rather than conventional molecular emulsifiers. HIPEs are emulsions where the concentration of the disperse phase exceeds the close packing limit (usually >74%), which leads to novel textural properties and high resistance to gravitational separation. Nanoemulsions contain very small droplets (typically d < 200 nm), which leads to useful functional attributes, such as high optical clarity, resistance to gravitational separation and aggregation, rapid digestion, and high bioavailability. Multiple emulsions contain droplets that have smaller immiscible droplets inside them, which can be used for reduced-calorie, encapsulation, and delivery purposes. This new generation of advanced emulsions may lead to food and beverage products with improved quality, health, and sustainability.

Fabrication of Oil-in-Water Emulsions with Whey Protein Isolate-Puerarin Composites: Environmental Stability and Interfacial Behavior

Protein–polyphenol interactions influence emulsifying properties in both directions. Puerarin (PUE) is an isoflavone that can promote the formation of heat-set gels with whey protein isolate (WPI) through hydrogen bonding. We examined whether PUE improves the emulsifying properties of WPI and the stabilities of the emulsions. We found that forming composites with PUE improves the emulsifying properties of WPI in a concentration-dependent manner. The optimal concentration is 0.5%, which is the highest PUE concentration that can be solubilized in water. The PUE not only decreased the droplet size of the emulsions, but also increased the surface charge by forming composites with the WPI. A 21 day storage test also showed that the maximum PUE concentration improved the emulsion stability the most. A PUE concentration of 0.5% improved the stability of the WPI emulsions against environmental stress, especially thermal treatment. Surface protein loads indicated more protein was adsorbed to the oil droplets, resulting in less interfacial WPI concentration due to an increase in specific surface areas. The use of PUE also decreased the interfacial tension of WPI at the oil–water interface. To conclude, PUE improves the emulsifying activity, storage, and environmental stability of WPI emulsions. This result might be related to the decreased interfacial tension of WPI–PUE composites.