Novel colloidal particles and natural small molecular surfactants co-stabilized Pickering emulsions with hierarchical interfacial structure: Enhanced stability and controllable lipolysis

Exploring the role of γ-Oryzanol on stabilization mechanism of Pickering emulsion gels loaded by α-Lactalbumin or β-Lactoglobulin via multiscale approaches

The research explored the role of γ-oryzanol (γs) on stabilization behavior of Pickering emulsion gels (PEGs) loaded by α-lactalbumin (α-LA) or β-lactoglobulin (β-LG), being analyzed by experimental and computer methods (molecular dynamic simulation, MD). Primarily, the average particle size of β-LG-γS was expressed 100.07% decrease over that of α-LA-γS. In addition, γs decreased the dynamic interfacial tension of two proteins with the order of β-LG < α-LA. Meanwhile, quartz crystal microbalance with dissipation proved that β-LG-γS exhibited higher adsorption mass and denser rigid interface layer than α-LA-γS. Moreover, the hydrophobic group of γS had electrostatic repulsion with polar water molecules in the aqueous phase, which spread to the oil phase. β-LG-γS had lower RMSD/Rg value and narrower fluctuation compared with α-LA-γS. This work strength the exploration of interfacial stabilization mechanism of whey protein-based PEGs, which enriched its theoretical research for industrial-scale production as the replacement of trans fat and cholesterol.

Advances of protein-based emulsion gels as fat analogues: Systematic classification, formation mechanism, and food application

Fat plays a pivotal role in the appearance, flavor, texture, and palatability of food. However, excessive fat consumption poses a significant risk for chronic ailments such as obesity, hypercholesterolemia, and cardiovascular disease. Therefore, the development of green, healthy, and stable protein-based emulsion gel as an alternative to traditional fats represents a novel approach to designing low-fat food. This paper reviews the emulsification behavior of proteins from different sources to gain a comprehensive understanding of their potential in the development of emulsion gels with fat-analog properties. It further investigates the emulsifying potential of protein combined with diverse substances. Then, the mechanisms of protein-stabilized emulsion gels with fat-analog properties are discussed, mainly involving single proteins, proteins-polysaccharides, as well as proteins-polyphenols. Moreover, the potential applications of protein emulsion gels as fat analogues in the food industry are also encompassed. By combining natural proteins with other components such as polysaccharides, polyphenols, or biopolymers, it is possible to enhance the stability of the emulsion gels and improve its fat-analog texture properties. In addition to their advantages in protecting oil oxidation, limiting hydrogenated oil intake, and delivering bioactive substances, protein-based emulsion gels have potential in food 3D printing and the development of specialty fats for plant-based meat.

Soy protein isolate-xanthan gum complexes to stabilize Pickering emulsions for quercetin delivery

This study aimed to prepare soy protein isolate-xanthan gum complexes (SPI-XG) at pH 7.0 and as emulsifiers to prepare Pickering emulsions for delivering quercetin (Que). The results showed that SPI-XG exhibited a gel network structure in which protein particles were embedded. Fourier transform infrared spectroscopy (FTIR) and molecular docking elucidated that SPI-XG formed through hydrogen bonding, hydrophobic, and electrostatic interactions. Three-phase contact angle (θo/w) of SPI-XG approached 90° with biphasic wettability. SPI-XG adsorbed at the oil-water interface to form an interfacial layer with a gel network structure, which prevented droplet aggregation. Following in vitro simulated digestion, Que displayed higher bioaccessibility in SPI-XG stabilized Pickering emulsions (SPI-XG PEs) than SPI stabilized Pickering emulsions. In conclusion, SPI-XG PEs were a promising system for Que delivery.

Investigating the impact of ultrasound-assisted treatment on the crafting of mulberry leaf protein and whey isolate complex: A comprehensive analysis of structure and functionality

Mulberry leaf protein (MLP) is a nutrient-rich protein, but its applicability is limited because of its poor solubility. To address this issue, this study combines MLP with whey protein isolates (WPI), known for the high nutritional value, and subsequently forms composite protein nanoparticles using the ultrasound-assisted pH shifting method. Microscopic observation and SDS-PAGE confirmed the binding between these two proteins. Fluorescence spectra and Fourier Transform infrared spectroscopy (FTIR) analysis supported the involvement of electrostatic interactions, hydrophobic attractions, and hydrogen bonding in the formation of stable complex nanoparticles. The interactions between the proteins became stronger after ultrasound-assisted pH-shifting treatment. Solubility, emulsification capacity, foaming, and antioxidant activity, among other indicators, demonstrate that the prepared composite nanoparticles exhibit favorable functional properties. The study successfully illustrates the creation of protein-based complex nanoparticles through the ultrasound-assisted pH shifting method, with potential applications in the delivery of bioactive compounds.

Structural characteristics and stability analysis of coconut oil body and its application for loading β-carotene

In this work, we investigated structural characteristics and stability analysis of the coconut oil body (COB) and its application for loading β-carotene (β-CA). The COB contained neutral lipids (81.1 ± 2.1 %), membrane proteins (0.6 ± 0.0 %), and moistures (18.3 ± 3.2 %), in which the molecular weights of membrane proteins ranged from 12 kDa to 40 kDa, as analyzed by the SDS-PAGE. The COB exhibited a small droplet diameter (5.1 ± 0.3 µm) with a monomodal diameter distribution, as reflected by the dynamic light scattering. The COB showed stable states at alkaline pH values (pH 8-10) and instability against ionic strengths (50-200 mmol/L) and thermal treatment (30-90℃) after analyzing the instability indexes. COB-based emulsions were favorable for the loading and retention of β-CA, as reflected by free fatty acids release rates and bioaccessibility in the simulated gastrointestinal digestion. This study will contribute to using the coconut oil bodies for loading bioactive nutraceuticals to enhance their bioaccessibility.

Multiscale approach to the characterization of the interfacial properties of micellar casein and whey protein blends and their effects on recombined dairy creams

In this study, whipped cream with blends of micellar casein (MCN) and whey protein (WPI) in different ratios were prepared to investigate the role of protein interfacial behavior in determining foam properties at multiple scales, using theoretical modeling, and microscopic and macroscopic analysis. Fluid force microscopy has been used for the first time as a more realistic and direct means of analyzing interfaces properties in multiphase systems. The adsorption kinetics showed that the interfacial permeability constant of WPI (4.24 × 10-4 s-1) was significantly higher than that of the MCN (2.97 × 10-4 s-1), and the WPI interfacial layer had a higher modulus of elasticity (71.38 mN/m) than that of the MCN (47.89 mN/m). This model was validated via the mechanical analysis of the fat globules in real emulsions. The WPI-stabilized fat globule was found to have a higher Young's modulus (219.67 Pa), which contributes to the integrity of its fat globule morphology. As the ratio of MCN was increased in the sample, however, both the interfacial modulus and Young's modulus decreased. Moreover, the rate of partial coalescence was found to increase, a phenomenon that decreased the stability of the emulsion and increased the rate of aeration. The mechanical analysis also revealed a higher level of adhesion between MCN-stabilized fat globule (25.16 nN), which increased fat globule aggregation and emulsion viscosity, while improving thixotropic recovery. The synergistic effect of the blended MCN and WPI provided the highest overrun, at 194.53 %. These studies elucidate the role of the interfacial behavior of proteins in determining the quality of whipped cream and provide ideas for the application of proteins in multiphase systems.

Fabrication of soy protein-polyphenol covalent complex nanoparticles with improved wettability to stabilize high-oil-phase curcumin emulsions

BACKGROUND

Recent studies have shown that the wettability of protein-based emulsifiers is critical for emulsion stability. However, few studies have been conducted to investigate the effects of varying epigallocatechin gallate (EGCG) concentrations on the wettability of protein-based emulsifiers. Additionally, limited studies have examined the effectiveness of soy protein-EGCG covalent complex nanoparticles with improved wettability as emulsifiers for stabilizing high-oil-phase (≥ 30%) curcumin emulsions.

RESULTS

Soy protein isolate (SPI)-EGCG complex nanoparticles (SPIEn) with improved wettability were fabricated to stabilize high-oil-phase curcumin emulsions. The results showed that EGCG forms covalent bonds with SPI, which changes its secondary structure, enhances its surface charge, and improves its wettability. Moreover, SPIEn with 2.0 g L -1 EGCG (SPIEn-2.0) exhibited a better three-phase contact angle (56.8 ± 0.3o) and zeta potential (-27 mV) than SPI. SPIEn-2.0 also facilitated the development of curcumin emulsion gels at an oil volume fraction of 0.5. Specifically, the enhanced network between droplets as a result of the packing effects and SPIEn-2.0 with inherent antioxidant function was more effective at inhibiting curcumin degradation during long-term storage and ultraviolet light exposure.

CONCLUSION

The results of the present study indicate that SPIEn with 2.0 g L -1 EGCG (SPIEn-2.0) comprises the optimum conditions for fabricating emulsifiers with improved wettability. Additionally, SPIEn-0.2 can improve the physicochemical stability of high-oil-phase curcumin emulsions, suggesting a novel strategy to design and fabricate high-oil-phase emulsion for encapsulating bioactive compounds. © 2024 Society of Chemical Industry.

Fabrication of chitosan-based emulsion as an adjuvant to enhance nasal mucosal immune responses

Nasal vaccine is a non-invasive vaccine that activates systemic and mucosal immunity in the presence of an adjuvant, thereby enhancing immune function. In this work, chitosan/oligochitosan/tween 80 (CS-COS-T80) co-stabilized emulsion was designed and further used as the nasal adjuvant. CS-COS-T80 emulsion exhibited outstanding stability under pH 6-8 with uniformly dispersed droplets and nano-scale particle size (<0.25 μm), and maintained stable at 4 °C for 150-day storage. Addition of model antigen ovalbumin (OVA) had no effect on the stability of CS-COS-T80 emulsion. In vivo nasal immunity indicated that CS-COS-T80 emulsion prolonged the retention time of OVA in the nasal cavity (from 4 to 8 h to >12 h), as compared to T80-emulsion. CS-COS-T80 emulsion produced a stronger mucosal immune response to OVA, with secretory IgA levels 5-fold and 2-fold higher than those of bare OVA and commercial adjuvant MF59, respectively. Compared to MF59, CS-COS-T80 induced a stronger humoral immune response and a mixed Th1/Th2 immune response of OVA after immunization. Furthermore, in the presence of CS-COS-T80 emulsion, the secretion of IL-4 and IFN-γ and the activation of splenocyte memory T-cell differentiation increased from 173.98 to 210.21 pg/mL and from 75.46 to 104.01 pg/mL, respectively. Therefore, CS-COS-T80 emulsion may serve as a promising adjuvant platform.

Metal-Phenolic Network-Coated Nanoparticles as Stabilizers for the Engineering of Pickering Emulsions with Bioactivity

Pickering emulsions stabilized by functional nanoparticles (NPs) have received considerable attention for improving the physical stability and biological function of NPs. Herein, hydrophobic polyphenols were chosen as phenolic ligands to form metal-phenolic network (MPN) coatings on NPs (e.g., silica, polystyrene) mediated by the sono-Fenton reaction. The MPN coatings modulated the surface wettability and charges of NPs and achieved emulsification behavior for preparing Pickering emulsions with pH responsiveness and oxidation resistance. A series of polyphenols, including resveratrol, rutin, naringin, and curcumin, were used to form MPN coatings on NPs, which served as stabilizers for the engineering of functionalized oil-in-water (O/W) Pickering emulsions. This work provides a new avenue for the use of hydrophobic polyphenols to modulate NP emulsifiers, which broadens the application of polyphenols for constructing Pickering emulsions with antioxidant properties.

Interfacial engineering method to regulate the performances of bilayer emulsions co-stabilized by casein/butyrylated dextrin nanoparticles and chitosan

In present study, bilayer emulsions with different interfacial structures stabilized by casein/butyrylated dextrin nanoparticles (CDNP), chitosan (CS) and chitosan nanoparticles (CSNP) were prepared to overcome the limitations of conventional emulsions. The effects of chitosan morphology and incorporation sequences on the bilayer emulsions were examined. Bilayer emulsions prepared with CDNP as the inner layer and CS/CSNP as the outer layer were observed to have smaller droplet sizes (1.39 ± 86.74 um and 1.45 ± 7.87 um). Bilayer emulsions prepared with CDNP as the inner layer and CS as the outer layer exhibited the lowest creaming index (2.38 %) after 14 days of storage, indicating excellent stability. Furthermore, bilayer emulsion prepared with CDNP as the inner layer and CS as the outer layer also exhibited a uniform water distribution, excellent protein oxidative stability, and uniformly distributed droplets by the measurement of Low-field NMR, intrinsic tryptophan fluorescence and laser confocal laser scanning microscopy. These results indicated that the study provided a theoretical basis for the development and design of bilayer emulsions with different interfacial structures. This study also provides a new material for the preparation of delivery systems that protect biologically active compounds. Bilayer emulsions are promising for applications in traditional and manufactured food products.

Research progress on plant-based protein Pickering particles: Stabilization mechanisms, preparation methods, and application prospects in the food industry

At present, there have been many research articles reporting that plant-based protein Pickering particles from different sources are used to stabilize Pickering emulsions, but the reports of corresponding review articles are still far from sufficient. This study focuses on the research hotspots and related progress on plant-based protein Pickering particles in the past five years. First, the article describes the mechanism by which Pickering emulsions are stabilized by different types of plant-based protein Pickering particles. Then, the extraction, preparation, and modification methods of various plant-based protein Pickering particles are highlighted to provide a reference for the development of greener and more efficient plant-based protein Pickering particles. The article also introduces some of the most promising applications of Pickering emulsions stabilized by plant-based protein Pickering particles in the food field. Finally, the paper also discusses the potential applications and challenges of plant-based protein Pickering particles in the food industry.

Exploring the diverse applications of Carbohydrate macromolecules in food, pharmaceutical, and environmental technologies

Carbohydrates are a class of macromolecules that has significant potential across several domains, including the organisation of genetic material, provision of structural support, and facilitation of defence mechanisms against invasion. Their molecular diversity enables a vast array of essential functions, such as energy storage, immunological signalling, and the modification of food texture and consistency. Due to their rheological characteristics, solubility, sweetness, hygroscopicity, ability to prevent crystallization, flavour encapsulation, and coating capabilities, carbohydrates are useful in food products. Carbohydrates hold potential for the future of therapeutic development due to their important role in sustained drug release, drug targeting, immune antigens, and adjuvants. Bio-based packaging provides an emerging phase of materials that offer biodegradability and biocompatibility, serving as a substitute for traditional non-biodegradable polymers used as coatings on paper. Blending polyhydroxyalkanoates (PHA) with carbohydrate biopolymers, such as starch, cellulose, polylactic acid, etc., reduces the undesirable qualities of PHA, such as crystallinity and brittleness, and enhances the PHA's properties in addition to minimizing manufacturing costs. Carbohydrate-based biopolymeric nanoparticles are a viable and cost-effective way to boost agricultural yields, which is crucial for the increasing global population. The use of biopolymeric nanoparticles derived from carbohydrates is a potential and economically viable approach to enhance the quality and quantity of agricultural harvests, which is of utmost importance given the developing global population. The carbohydrate biopolymers may play in plant protection against pathogenic fungi by inhibiting spore germination and mycelial growth, may act as effective elicitors inducing the plant immune system to cope with pathogens. Furthermore, they can be utilised as carriers in controlled-release formulations of agrochemicals or other active ingredients, offering an alternative approach to conventional fungicides. It is expected that this review provides an extensive summary of the application of carbohydrates in the realms of food, pharmaceuticals, and environment.

An overview of tea saponin as a surfactant in food applications

The residue of Camellia seeds after oil extraction contains many bioactive ingredients, including tea saponin. Tea saponin has many pharmacological effects and is an excellent nonionic surfactant. The development of natural surfactants has become a hot topic in food research. This review gathers the applications of tea saponin as a surfactant in food. It focuses on the application of tea saponin in emulsions, delivery systems, extraction and fermentation, as well as the challenges and development prospects in food applications. Tea saponin shows great potential as a surfactant in food applications, which can replace some synthetic surfactants. The full utilization of tea saponin improves the comprehensive utilization value of Camellia seed residue, contributes to the sustainable development of Camellia industry and avoids resource waste.

CO2 responsive self-standing Pickering emulsion gel stabilized with rosin-based surfactant modified cellulose nanofibrils

Emulsion gel was developed to provide desirable texture, palatability and functionality to food products. Tunable stability of emulsions is often desired, as in certain situations, the chemical content release usually relies on emulsion induced destabilization of the droplet. However, the destabilization for emulsion gel is difficult because of the formation of highly entangled networks. To address this issue, a fully biobased Pickering emulsion gel stabilized by cellulose nanofibrils (CNF) modified with a CO2 responsive rosin-based surfactant, maleopimaric acid glycidyl methacrylate ester 3-dimethylaminopropylamine imide (MPAGN) was reported. The emulsification/de-emulsification can be reversibly regulated because this surfactant has sensitive CO2 responsive property. MPAGN can be reversibly between active cationic (MPAGNH+) and inactive nonionic (MPAGN) responsive to CO2 and N2. The microstructure of the emulsion gel was observed and compared before and after the response. The rheological properties of emulsion gel stabilized by different concentrations of MPAGNH+ and different contents of CNF were studied separately. As 0.2 wt% CNF was dispersed in 1 mM MPAGNH+ solution, the obtained emulsion can be self-standing for long duration. The rheology study indicated that these emulsions show typical gel characteristics with shear-thinning behavior. The stabilization mechanism of these gel emulsion is a synergistic effect caused by the combination of CO2 responsive Pickering emulsion and intertwined network caused by the hydrogen-bond interaction among CNF.

Influence of the Emulsifier Sodium Caseinate-Xanthan Gum Complex on Emulsions: Stability and Digestive Properties

In this study, virgin coconut oil (VCO) nanoemulsions were prepared by ultrasonication using a sodium caseinate (SC) and xanthan gum (XG) complex as an emulsifier. The stability and digestion characteristics of SC/XG-VCO emulsions formed by co-adsorption and SC-VCO-XG emulsions formed by layer adsorption were compared. The stability of the two emulsions was studied under different pH, ionic strength, heat treatment, freeze-thaw cycles, and storage conditions, and the droplet size and zeta potential were used as indicators to assess the stability. In addition, the stability of oxidation and the digestive properties of both emulsions were studied. It was found that the SC-VCO-XG emulsions had better environmental stability, oxidative stability, storage stability, and digestibility compared to SC/XG-VCO emulsions. This study has shown that the formation method of protein-polysaccharide stabilized emulsions has an impact on the stability and digestibility properties of the emulsions, and that the emulsion carriers constructed by layer adsorption are more suitable for subsequent industrial production and development.

Soy protein isolate-citrus pectin-gallic acid ternary composite high internal phase Pickering emulsion for delivery of β-carotene: Physicochemical, structural and digestive properties

The structure properties, stability and β-carotene slow-release mechanism of soybean protein isolate-citrus pectin-gallic acid complex (SPI-CP-GA) stabilized high-internal phase Pickering emulsion (HIPPE) were investigated. The results showed that compared with the SPI-CP binary complex, the turbidity of the SPI-CP-GA ternary complex increased from 2.174 ± 0.001 to 3.027 ± 0.001, the surface wettability was increased, the infrared peaks was blue-shifted, changed from hydrophilic to hydrophobic, and the equilibrium interfacial tension of particles increased from 10.77 ± 0.02 mN/m to 13.46 ± 0.03 mN/m, the complex was more stable. When the GA was 2.0 mg/mL, the encapsulation efficiency of β-carotene was higher. With increased GA concentration and oil phase volume fraction (φ), the apparent viscosity and viscoelastic behavior of HIPPE performed well, forming a stable gel network structure. After 30 days of storage, there was no oil separation in the sample group with GA concentration of 2.0 mg/mL and φ = 0.7, and the stability was strong. After gastrointestinal digestion, the particle size of the HIPPE decreased from 13.51 ± 0.86 μm to 7.70 ± 0.68 μm, the free fatty acid (FFA) release rate was 22.03%, and the bioaccessibility of β-carotene was 6.67 ± 0.19%, and the sustained-release effect was obvious. These results indicated that the SPI-CP-GA ternary complex is a potential stabilizer for HIPPE, and providing theoretical guidance for the design of protein-polysaccharide-polyphenol stabilized HIPPE.

Mesoporous carbon hollow spheres encapsulated phase change material for efficient emulsification of high-viscosity oil

Low fluidity of high-viscosity oil usually hinders its emulsification. Facing this dilemma, we proposed a novel functional composite phase change material (PCM) with in situ heating feature coupled with emulsification capability. This composite PCM consisting of mesoporous carbon hollow spheres (MCHS) and polyethylene glycol (PEG) shows excellent photothermal conversion ability, thermal conductivity and Pickering emulsification. Compared with the currently reported composite PCMs, the unique hollow cavity structure of MCHS not only enables excellent encapsulation of PCM, but also protects the PCM from leaking and direct contact with oil phase. Importantly, the thermal conductivity of 80% PEG@MCHS-4 was determined to be 1.372 W/m·K, which was 2.887 times superior to that of pure PEG. MCHS endows the composite PCM with excellent light absorption capacity and photothermal conversion efficiency. The viscosity of high-viscosity oil can be facilely reduced in situ once it comes into contact with the heat-storing PEG@MCHS, thus the emulsification is greatly enhanced. In view of the in situ heating feature and emulsification capability of PEG@MCHS, this work puts forward a novel solution to address the problem of emulsification of high-viscosity oil through the integration of MCHS and PCM.

A combined experimental and computational study on the interfacial distribution behavior in colloidal particle-surfactant co-stabilized Pickering emulsions

Recently, co-stabilized Pickering emulsion (CPE) that stabilized by colloidal particles and surfactant has received increased research attention, owing to its improved stability and fluid properties comparing with conventional emulsions stabilized by particles or surfactants alone. Herein, the dynamic distribution behavior at multi-scale and the synergistic-competitive interfacial absorption in CPE co-stabilized by Tween20 (Tw20) and zein particles (Zp) were studied by experiment combined simulation method. The experimental studies identified the delicate synergistic-competitive stabilization phenomenon tuned by the molar ratio of Zp and Tw20. Meanwhile, dissipative particle dynamic (DPD) simulation was utilized to reveal the distribution and kinetic motion. Based on the two- and three-dimensional simulation on the formation of CPE, simulation revealed that Zp - Tw20 aggregates were formed when anchoring at the interface. The interfacial adsorption efficiency of Zp was improved at low Tw 20 concentration (0-1.0%wt), Tw20 inhibited the Brownian motion of Zp at the interface and competed them out at high concentrations (1.5-2.0%wt). Zp was departured from the interface 4.5 Å to 10 Å, as Tw20 increased from 1.06% to 5%. The study offers a novel approach to reveal the dynamic distribution behavior of surface active substances during the dynamic formation process of CEP, which will expand our current strategies for interface engineering of emulsions.

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

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

Effect of Different Polymerization Degrees and Fatty Acids of Polyglycerol Esters on the Physical Properties and Whippability of Recombined Dairy Cream

Polyglycerol esters (PGEs) are used as emulsifiers in recombined dairy cream (RDC) to improve product quality. In this study, the effects of four PGEs with different polymerization degrees and esterification on the particle size, viscosity, zeta potential, and microrheology of RDC emulsions were investigated, and the whipping time, overrun, serum loss, and firmness of the RDC emulsions were recorded. The results show that the addition of the PGEs reduced the particle size (from 2.75 μm to 1.48-1.73 μm) and increased the viscosity (from 41.92 cP to 73.50-100 cP) and stability (from 0.354 to 0.105-0.128), which were related to the change in interfacial properties and the weakening of Brownian motion, but there were differences in the effect on the whipping behavior of the RDCs. Although the addition of 0.9% triglyceride monolaurate gave the emulsion the best stability, the RDC had a longer whipping time (318 s) and a lower overrun (116.6%). Comparatively, the 0.7-0.9% concentrations of PGE55 and tripolycerol monostearate (TMS) provided RDC with good stability and aeration characteristics, allowing inflation within 100 s and expansion rates of up to 218.24% and 186.88%, respectively. In addition, the higher degree of polymerization of polyglyceryl-10 monstearate (PMS) did not work well at any concentration. These results contribute to understanding the mechanism of action of PGEs and improving the quality of RDC.

Ex vivo UV-vis and FTIR photoacoustic spectroscopy of natural nanoemulsions from cellulose nanocrystals and saponins topically applied into the skin: Diffusion rates and physicochemical evaluation

Nanoemulsions are increasingly gaining importance in the development of topically applied medicine and cosmetic products because their small droplets favor the penetration rates of active compounds into the body. In this scenario, the measurements of their diffusion rates as well as eventual physicochemical changes in the target tissues are of utmost importance. It is also recognized that the use of natural surfactants can avoid allergic reactions as frequently observed for synthetic products. The natural saponins extracted from Sapindus Saponaria have the property of forming foam and are exploited as biocompatible and biodegradable, while cellulose nanocrystals are known to increase the stability of a formulation avoiding the coalescence of drops at the interface. Therefore, nanoemulsions combining natural saponins and cellulose nanocrystals are promising systems that may facilitate greater diffusion rates of molecules into the skin, being candidates to substitute synthetic formulations. This study applied the Photoacoustic Spectroscopy technique to measure the diffusion rates and the physicochemical properties of nanoemulsified formulations containing saponins and cellulose nanocrystals topically applied to the skin. The ex vivo study combined the first-time photoacoustic measurements performed in both ultraviolet-visible and mid-infrared spectral regions. The toxicity of these formulations in L929 cells was also evaluated. The results showed that the formulations were able to propagate throughout the skin to a depth of approximately 756 μm, reaching the dermal side. The non-observation of absorbing band shifting or new bands in the FTIR spectra suggests that there were no structural changes in the skin as well as in the formulations after the nanoemulsions administration. The cytotoxicity results showed that the increase of cellulose nanocrystals concentration decreased cellular toxicity. In conclusion, the results demonstrated the advantage of combining photoacoustic methods in the ultraviolet-visible and mid-infrared spectral regions to analyze drug diffusion and interaction with the skin tissues. Both methods complement each other, allowing the confirmation of the nanoemulsion diffusion through the skin and also suggesting there were no detectable physicochemical changes in the tissues. Formulations stabilized with saponins and cellulose nanocrystals showed great potential for the development of topically administered cosmetics and drugs.

Properties of curcumin-loaded zein-tea saponin nanoparticles prepared by antisolvent co-precipitation and precipitation

The properties of nutraceutical-loaded biopolymer nanoparticles fabricated by antisolvent co-precipitation (ASCP) and precipitation (ASP) were compared. Curcumin-loaded zein-tea saponin nanoparticles were fabricated using both methods and then their structural and physicochemical properties were characterized. The diameter of the nanoparticles prepared by ASCP were smaller (120-130 nm) than those prepared by ASP (140-160 nm). The encapsulation efficiency of the ASCP-nanoparticles (80.0%) was higher than the ASP-ones (71.0%) at a zein-to-curcumin mass ratio of 3:1, which was also higher than previous studies. The storage and light stability of curcumin was higher in zein-saponin nanoparticles than in zein nanoparticles. All nanoparticles had good water dispersibility after freeze-drying and rehydration. This study shows that nanoparticles produced by antisolvent co-precipitation have superior properties to those produced by antisolvent precipitation. The co-precipitation method leads to a higher encapsulation efficiency, smaller particle size, and greater storage stability, which may be advantageous for some applications.

Fabrication of food-grade Pickering high internal phase emulsions (HIPEs) stabilized by a dihydromyricetin and lysozyme mixture

This study evaluated the feasibility of fabricating food-grade HIPEs using a dihydromyricetin and lysozyme mixture. The effects of the oil phase volume fraction (φ), composition (lysozyme:dihydromyricetin, k), and addition amount (w) of the mixture on the formation and properties of the HIPEs were analyzed. Then, the interactions of dihydromyricetin and lysozyme were investigated. The results indicated that when w was 0.4%, HIPEs with φ value of 90% could be obtained. Furthermore, the k also affected the microstructure, mechanical properties, oil oxidation, and lutein protection ability of the HIPEs. However, the presence of dihydromyricetin did not affect lysozyme activity. Both isothermal titration calorimetry and molecular simulations proved that they did not form a typical host-guest complex. But, dihydromyricetin could absorb on the lysozyme surface. Therefore, we speculated that lysozyme and dihydromyricetin particles could overlap and form a 3D network structure to stabilize the HIPEs, which was consistent with the microstructure observations.

Effects of different surfactants on the conjugates of soybean protein-polyphenols for the preparation of β-carotene microcapsules

In this study, we investigated the spray-drying microencapsulation of β-carotene in oil co-stabilized by soy protein isolate-epigallocatechin-3-gallate conjugate (SPE) and small molecule surfactants [sodium dodecyl sulfate (SDS), hexadecyl trimethyl ammonium bromide (CTAB), and tea saponin (TS)] of different concentrations [0.1, 0.5, and 1.0% (w/v)], as a prospective approach to stabilize β-carotene. The results show that different surfactant types and concentrations significantly affect the encapsulation efficiency, water dispersibility, microstructure, and digestion of the microcapsules. Interactions between the surfactants and the SPE at the interface were found to include both synergistic and competitive effects, and they depended on the surfactant type and concentration. Moreover, the addition of SDS and TS before spray drying significantly improved the microencapsulation performance of the microcapsules and the water dispersion behavior of the corresponding spray-dried powders. The highest encapsulation efficiency was achieved for the SPE-0.1TS-encapsulated β-carotene microcapsules. In contrast, the addition of CTAB was not conducive to microcapsule formation, resulting in poor encapsulation efficiency, water dispersibility, thermal stability, β-carotene retention rate, and oxidation stability. In vitro gastrointestinal digestion results revealed that the addition of CTAB promotes the release of β-carotene and improves the bioaccessibility of β-carotene. In contrast, except for SPE-1.0SDS, the addition of SDS and TS inhibited β-carotene release and reduced β-carotene bioaccessibility. This study demonstrated that this novel β-carotene encapsulation formulation can overcome stability limitations for the development of β-carotene supplements with a high bioaccessibility.

Recyclable and re-usable smart surfactant for stabilization of various multi-responsive emulsions alone or with nanoparticles

A novel multi-responsive surfactant (abbreviated as N⁺-8P8-N) was synthesized, in which one octyl trimethylamine group (quaternary ammonium) and one octyl dimethylamine group are connected to a benzene ring through ether bonds. This novel surfactant can stabilize conventional oil-in-water (O/W) emulsions alone, and O/W Pickering emulsions and novel oil-in-dispersion emulsions together with oppositely and similarly charged nanoparticles, respectively. In all cases rapid demulsification can be achieved through either pH or CO₂/N₂ triggers, by which the surfactant is reversibly converted between a normal cationic surfactant form (N⁺-8P8-N) and a strongly hydrophilic and surface-inactive bola form (N⁺-8P8-NH⁺). Notably, the bola form N⁺-8P8-NH⁺ dissolves in the aqueous phase alone or together with nanoparticles after demulsification without contamination of the oil phase, and the aqueous phase can be recycled many times triggered by pH or CO₂/N₂ in accordance with the principle of green chemistry. This newly designed re-usable smart surfactant is significant for the development of various temporarily stable emulsions, which are extensively applied in emulsion polymerization, new material synthesis, heterogeneous catalysis and oil transportation.

Formation and Physical Stability of Zanthoxylum bungeanum Essential Oil Based Nanoemulsions Co-Stabilized with Tea Saponin and Synthetic Surfactant

The purpose of this work was to evaluate the possibility of adding tea saponin (TS) to reduce the synthetic surfactant concentration, and maintain or improve the shelf stability of nanoemulsions. The Zanthoxylum bungeanum essential oil (2.5 wt%) loaded oil-in-water nanoemulsions were co-stabilized by Tween 40 (0.5–2.5 wt%) and TS (0.1–5 wt%). A combination of several analytical techniques, such as dynamic laser scattering, interfacial tension, zeta potential, and transmission electron microscope, were used for the characterization of nanoemulsions. Low levels of TS (0.1–0.5 wt%) with Tween 40 had significant effects on the emulsification, and a nanoemulsion with the smallest droplet diameter of 89.63 ± 0.67 nm was obtained. However, in the presence of high TS concentration (0.5–5 wt%), micelles generated by the non-adsorbed surfactants in the aqueous lead to droplets growth. In addition, the combinations of Tween 40 and TS at the high level (>3.5 wt%) exerted a synergistic effect on stabilizing the nanoemulsions and preventing both Ostwald ripening and coalescence. The negative charged TS endowed the droplets with electrostatic repulsion and steric hinderance appeared to prevent flocculation and coalescence. These results would provide a potential application of natural TS in the preparation and stabilization of nanoemulsions containing essential oil.

Enhancing bioaccessibility and bioavailability of carotenoids using emulsion-based delivery systems

The consumption of foods rich in antioxidants, vitamins, minerals including carotenoids etc. can boost the immune system to help fight off various infections including SARS- CoV 2 and other viruses. Carotenoids have been gaining attention particularly in food and pharmaceutical industries owing to their diverse functions including their role as pro-vitamin A activity, potent antioxidant properties, and quenching of reactive oxygen (ROS), such as singlet oxygen and lipid peroxides within the lipid bilayer of the cell membrane. Nevertheless, carotenoids being lipophilic, have poor solubility in aqueous medium and are also chemically instable. They are susceptible to degrade under stimuli environmental conditions during food processing, storage and gastrointestinal passage. They also exhibit poor oral bioavailability, thus, their applications in aqueous-based foods are limited. As a consequent, suitable delivery systems including colloids-based are needed to enhance the solubility, stability and bioavailability of carotenoids. This review presents challenges of incorporation and delivery of carotenoids focusing on stability and factors affecting bioavailability. Furthermore, designed factors impacting bioaccessibility and bioavailability of carotenoids using emulsion-based delivery systems are explicitly explained. Each delivery system exhibits its own advantages and disadvantages; thus, the delivery systems should be designed based on their targets and their further applications.

Enhanced stability and controlled gastrointestinal digestion of β-carotene loaded Pickering emulsions with particle-particle complex interfaces

In this study, we used large, rigid, and hydrophilic zein-propylene glycol alginate composite particles (ZPCPs) and small, soft, and hydrophobic whey protein microgel (WPM) particles to synergistically stabilize a Pickering emulsion for delivery of β-carotene. The photothermal stability and storage stability of β-carotene were improved with the combined use of different particles. Microstructural observations showed that ZPCPs were effectively adsorbed at the oil/water interface despite the substantial interparticle gaps. WPM particles could swell and stretch on the interface due to their deformable structure, thereby forming an interfacial layer of flattened particles to cover a large surface area. The interfacial structure and macroscopic properties of Pickering emulsions were modulated by adjusting the mass ratio and addition sequence of different particles. The combination of ZPCPs and WPM delayed the lipolysis during gastrointestinal digestion. Through controlling the composition of the complex interface, the free fatty acid (FFA) release rate of Pickering emulsions in the small intestinal phase was reduced from 15.64% to 9.03%. When ZPCPs were used as the inner layer and WPM as the outer layer and the mass ratio of ZPCPs to WPM was 4 : 1, the Pickering emulsion showed the best stability and β-carotene bioaccessibility. The Pickering emulsion with particle-particle complex interfaces could be applied in foods and pharmaceuticals for the purpose of enhanced stability, delayed lipolysis or sustained nutrient release.

Zein Colloidal Particles and Cellulose Nanocrystals Synergistic Stabilization of Pickering Emulsions for Delivery of β-Carotene

In this study, we utilized different types of particles to stabilize β-carotene-loaded Pickering emulsions: spherical hydrophobic zein colloidal particles (ZCPs) (517.3 nm) and rod-shaped hydrophilic cellulose nanocrystals (CNCs) (115.2 nm). Either of the particles was incapable of stabilizing Pickering emulsions owing to their inappropriate wettability. When the mass ratio of ZCPs and CNCs was 1:4, the Pickering emulsion showed the best physical and photothermal stability. Compared to the ZCP-stabilized Pickering emulsion (9.29%), the retention rate of β-carotene in the Pickering emulsion costabilized by ZCPs and CNCs was increased to 60.23% after 28 days of storage at 55 °C. Confocal microscopy and cryoscanning electron microscopy confirmed that different types of particles could form a multilayered structure or induce the formation of an interparticle network. Furthermore, the complexation of ZCPs and CNCs delayed the lipolysis of the emulsion during in vitro digestion. The free fatty acid (FFA) release rate of Pickering emulsions in the small intestinal phase was reduced from 19.46 to 8.73%. Accordingly, the bioaccessibility of β-carotene in Pickering emulsions ranged from 9.14 to 27.25% through adjusting the mass ratio and addition sequence of distinct particles at the interface. The Pickering emulsion with the novel particle-particle complex interface was designed in foods and pharmaceuticals for purpose of enhanced stability, delayed lipolysis, or sustained nutrient release.

Inter-droplet force between magnetically polarizable Pickering oil-in-water nanoemulsions stabilized with γ-Al2O3 nanoparticles: Role of electrostatic and electric dipolar interactions

HYPOTHESIS

The presence of nanoparticles at oil-water interface influences the interaction forces between Pickering emulsions. When charged nanoparticles are at the oil-water interface of an electrostatically stabilized emulsion, in addition to the screened Coulombic interaction, electric dipolar force also influences the total inter-droplet force profiles. An in-depth understanding of the effects of such electric dipolar forces is essential for designing colloidally stable Pickering nanoemulsions for various applications.

EXPERIMENTS

Inter-droplet forces between γ-Al₂O₃ nanoparticle stabilized oil-in-water nanoemulsion, containing superparamagnetic nanoparticles (magnetically polarizable) in the oil phase, are measured using the magnetic-chaining technique at different pH and salt concentrations. The role of mono-, di- and tri-valent salts on the inter-droplet force profiles are assessed.

FINDINGS

Force measurement studies reveal a lowering of inter-droplet spacing, within the linear chains, for higher salt concentrations due to an increased screening. Strong interfacial attachment of the charged nanoparticles results in the formation of an asymmetric charge cloud leading to an electric dipolar interaction. Incorporating the contributions of electric dipolar and screened Coulombic interactions, the theoretically estimated total repulsive force magnitudes are in good agreement with the experimental data. The obtained results offer better insights into the nature of colloidal force between charged particle stabilized nanoemulsions.

Effect of Bile Salts on the Interfacial Dilational Rheology of Lecithin in the Lipid Digestion Process

The effects of bile salts on the emulsifier adsorption layer play a crucial role in lipid digestion. The current study selected sodium cholate (NaCh) and lecithin as model compounds for bile salts and food emulsifiers, respectively. The interface dilational rheological and emulsification properties of NaCh and lecithin were carried out. The results showed that the NaCh molecules could quickly diffuse from the bulk to interface, which broke the tightly-arranged interfacial layer of lecithin and enhanced the viscoelasticity of interfacial film. As a result, the interfacial adsorption layer, which was originally dominated by the slow relaxation processes within the interface, was transformed into one controlled by the fast molecular diffusion exchange. This accelerated the exchange of materials between the bulk and interface, thereby creating suitable conditions for the interfacial adsorption of lipases, which promoted the digestion process. These results provided a mechanism for the promotion of lipid digestion by bile salts from the perspective of interfacial viscoelasticity and relaxation processes. A deeper understanding of the interfacial behavior of bile salts with emulsifiers would provide a basis for the rational design of interfacial layer for modulating lipid digestion.

The construction of resveratrol-loaded protein-polysaccharide-tea saponin complex nanoparticles for controlling physicochemical stability and in vitro digestion

The novel zein-propylene glycol alginate (PGA) -tea saponin (TS) ternary complex nanoparticles were fabricated to deliver resveratrol. TS was firstly introduced to modulate the functional attributes, microstructure, molecular interactions and gastrointestinal digestion of the complex nanoparticles. The size of zein-PGA-TS complex nanoparticles was between 281.9 and 309.7 nm. In the presence of TS, the encapsulation efficiency of resveratrol was significantly elevated from 58.43% to 85.58%. The environmental stability of resveratrol was improved through entrapping into the complex nanoparticles with the rise in TS proportion. Multiple spectroscopic methods revealed that TS altered the micro-environment and secondary structure of the protein. Hydrogen bonds, hydrophobic effects and electrostatic interactions contributed to the formation of complex nanoparticles. Differential scanning calorimetry (DSC) and X-ray diffraction (XRD) patterns showed the amorphous nature of the encapsulated resveratrol. Field emission scanning electron microscopy (FE-SEM) confirmed the globular shape of the nanoparticles and their different aggregation states were dependent on the particle compositions. Moreover, the zein-PGA-TS complex nanoparticles exhibited the best sustained release in the small intestine when the mass ratio of zein to TS was 5 : 1 (23.20% in the stomach and 63.11% in the small intestine). These findings indicated the influence of TS on the properties and applications of the protein-polysaccharide complexes, which provided a new insight into the development of novel food grade nanoparticles with desirable stability and digestion behaviour.

Carboxymethyl konjac glucomannan coating on multilayered emulsions for improved bioavailability and targeted delivery of curcumin

Curcumin was entrapped in multilayered emulsions to increase its stability and bioavailability. Curcumin emulsion stabilized by whey protein isolate (WPI) was coated with chitosan (CHI) or carboxymethyl konjac glucomannan (CMKGM) alone to form secondary emulsions and their combination in sequence to form the tertiary emulsion, in which, the polyelectrolyte concentrations were 1.0% WPI for the primary emulsion, 0.4% CMKGM for the secondary emulsion -CMKGM, 0.2% CHI for the secondary emulsion -CHI, and 0.1% CMKGM for the tertiary emulsion. The characteristics of the emulsions, including their particle size, ζ potential, microstructure, creaming stability, and biopolymer distribution, were investigated and their colon-targeted delivery potential was evaluated through both in vitro and in vivo studies as well. The curcumin-loaded secondary and tertiary emulsions were stable with a narrow size distribution and were generated by layer-by-layer assembly according to confocal laser scanning microscope observation. When CMKGM was located at the outermost layer, the corresponding secondary and tertiary emulsions showed a greatly reduced release of curcumin in the simulated gastric fluid, but exhibited increased release in the β-mannanase-containing simulated colonic fluid. In vivo evaluation in mice demonstrated that the bioavailability of curcumin in the CMKGM-coated secondary and tertiary emulsions was increased by about 4 folds compared with that of free curcumin and curcumin could be released in a sustainable manner. These results demonstrated that multilayered emulsions coated with CMKGM could promote curcumin absorption in the gastrointestinal tract and hence is a promising colon-targeted delivery system for curcumin.

Development of β-carotene loaded oil-in-water emulsions using mixed biopolymer-particle-surfactant interfaces

In this study, β-carotene loaded oil-in-water emulsions were stabilized by complex interfaces composed of propylene glycol alginate (PGA), rhamnolipids (Rha), and zein colloidal particles (ZCPs). The influence of mixed biopolymer-surfactant, biopolymer-particle, surfactant-particle and biopolymer-surfactant-particle interfaces on the performance of the emulsions was investigated. The stability, microstructure, rheological properties, and in vitro gastrointestinal digestion of the emulsions were controlled by regulating the adding sequence and mass ratio of the multiple stabilizers. The droplet size of the emulsion was in the range of 14-77 μm. After encapsulation into the emulsions stabilized by the complex interfaces, the photothermal stability of β-carotene were increased by 41.53% and 21.52%, respectively. The co-existence of particles, biopolymers, and surfactants could induce competitive displacement, multilayer deposition and an interparticle network at the interface. Compared with a single PGA- or Rha-stabilized emulsion, the complex interface-stabilized emulsion reduced the release of FFA by 28.06% and 26.16%, respectively. The interfacial composition of the emulsion and the delayed lipid digestion further affected the bioaccessibility of β-carotene in the gastrointestinal tract (GIT). The mixed biopolymer-particle-surfactant interface-stabilized emulsion could be incorporated in foods, pharmaceuticals and cosmetics for excellent stability, targeted nutrient delivery and controlled lipolysis.