High Internal Phase Emulsions Stabilized with Polyphenol-Amyloid Fibril Supramolecules for Encapsulation and Protection of Lutein

Effects of rice bran rancidity on the interfacial adsorption properties of rice bran protein fibril aggregates and stability of high internal phase Pickering emulsions

The effects of rice bran rancidity-induced protein oxidation and heating time on the stability of rice bran protein fibril aggregates (RBPFA)-high internal phase Pickering emulsions (HIPPEs) were investigated. The optimal conditions for RBPFA-HIPPEs were 8 mg/mL RBPFA with an oil phase volume fraction of 75 %. Moderate oxidation (rice bran stored for 3 d) and moderate heating (8 h) enhanced the wettability, flexibility, diffusion rate, and adsorption rate of RBPFA, meanwhile, the rheological properties of RBPFA-HIPPEs increased. RBPFA-HIPPEs could be stably stored for 50 d at 25 °C. Moderate oxidized and moderate heated RBPFA-stabilized HIPPEs could remain stable after heat treatment and could be re-prepared after freeze-thaw (3 cycles). Additionally, the stability of RBPFA-HIPPEs was significantly related to the structural characteristics and interfacial properties of RBPFA. Overall, moderate oxidation and moderate heating enhanced the storage, thermal, and freeze-thaw stability of RBPFA-HIPPEs by improving the interfacial properties of RBPFA.

The influence of unique interfacial networks based on egg white proteins for the stabilization of high internal phase Pickering emulsions: Physical stability and free fatty acid release kinetics

This study was oriented towards the impacts of unique interfacial networks, formed by glycosylated and non-glycosylated egg white proteins, on the characteristics of high internal phase Pickering emulsions (HIPPEs). Glycosylated egg white protein particles (EWPG) manifested a more compact protein tertiary structure and amplified surface hydrophobicity, forming durable coral-like networks at the oil-water interface. The non-glycosylated egg white protein particles (EWP) could form spherical cluster interfacial networks. Raman spectroscopy analysis illuminated that EWPG could exhibit better interactions with aliphatic amino acids via hydrogen bonds and hydrophobic interactions. The release of free fatty acid (FFA) from both HIPPEs followed the first-order kinetic model with a combination of diffusion. EWPG-stabilized HIPPEs demonstrated superior physical stability and cellular antioxidant activity. This research shed light on the promising prospects of HIPPEs as promising amphiphilic delivery systems with capabilities to co-deliver hydrophilic and hydrophobic nutraceuticals and amplify their intracellular biological potency.

Stability protection of lutein emulsions by utilizing a functional conjugate of collagen and Lycium barbarum L. leaf flavonoid

Lutein exhibits excellent functional activity making it useful in many fields. Nevertheless, its use is limited by its physical and chemical instability. Here, collagen and Lycium barbarum L. leaf flavonoids (LBLF) were used as emulsifiers, their structures were characterized, the properties of the complexes were evaluated, and their stabilizing effects on lutein emulsions were explored. According to the results, the encapsulation rate of the complex of collagen-LBLF was (68.67 ± 1.43) % and the drug loading was (6.92 ± 0.13) %. Collagen compounded LBLF with a changed structure and morphology, resulting in improved antioxidant capacity, better foaming and emulsification, and reduced hydrophobicity. In addition, the thiobarbituric acid value of collagen-LBLF stabilized lutein emulsion (0.0012 ± 0.00011) mg/kg was significantly lower than that of collagen stabilized lutein emulsion (0.0021 ± 0.00016)  mg/kg (P < 0.05), indicating that the composite stabilized lutein emulsion obtained higher stability. LBLF contributed a high free radical scavenging effect and inhibited lutein degradation during storage. During simulated digestion, collagen-LBLF effectively stabilized the emulsion and protected lutein from destruction, made it release more slowly, and benefited the bio-accessibility of lutein during the next utilization step. Based on the present study, improved storage and digestion stabilities of lutein wereachievedby the utilization of collagen-LBLF complex, which provides a new method for the preparation and application of composite functional emulsifiers.

Development of composite electrospun films utilizing soy protein amyloid fibrils and pullulan for food packaging applications

Electrospun films (ESF) are gaining attention for active delivery due to their biocompatibility and biodegradability. This study investigated the impact of adding soy protein amyloid fibrils (SAFs) to ESF. Functional ESF based on SAFs/pullulan were successfully fabricated, with SAFs clearly observed entangled in the electrospun fibers using fluorescence microscopy. The addition of SAFs improved the mechanical strength of the ESF threefold and increased its surface hydrophobicity from 24.8° to 49.9°. Moreover, the ESF demonstrated antibacterial properties against Escherichia coli and Staphylococcus aureus. In simulated oral disintegration tests, almost 100% of epigallocatechin gallate (EGCG) dissolved within 4 min from the ESF. In summary, the incorporation of SAFs into ESF improved their mechanical strength, hydrophobicity, and enabled them to exhibit antibacterial properties, making them promising candidates for active delivery applications in food systems. Additionally, the ESF showed efficient release of EGCG, indicating their potential for controlled release of bioactive compounds.

Development of protein-polyphenol particles to stabilize high internal phase Pickering emulsions by polyphenols' structure

Protein-polyphenol colloidal particles are promising stabilizers for high internal phase Pickering emulsions (HIPPEs). However, the relationship between the structure of the polyphenols and its ability to stabilize HIPPEs has not been studied thus far. In this study, bovine serum albumin (BSA)-polyphenols (B-P) complexes were prepared, and their ability to stabilize HIPPEs was investigated. The polyphenols were bound to BSA via non-covalent interactions. Optically isomeric polyphenols formed similar bonds with BSA, whereas a greater number of trihydroxybenzoyl groups or hydroxyl groups in the dihydroxyphenyl moieties of polyphenols increased the B-P interactions. Polyphenols also reduced the interfacial tension and enhanced the wettability at the oil-water interface. The HIPPE stabilized by BSA-tannic acid complex exhibited the highest stability among the B-P complexes and resisted demixing and aggregation during centrifugation. This study promotes the potential applications of polyphenol-protein colloidal particles-stabilized HIPPEs in the food industry.

Enhanced encapsulation of lutein using soy protein isolate nanoparticles prepared by pulsed electric field and pH shifting treatment

In this study, soy protein isolate (SPI) was modified by a pulsed electric field (PEF) combined with pH shifting treatment (10 kV/cm, pH 11) to prepare SPI nanoparticles (PSPI11) for efficient loading of lutein. The results showed that when the mass ratio of SPI to lutein was 25:1, the encapsulation efficiency of lutein in PSPI11 increased from 54% to 77%, and the loading capacity increased by 41% compared to the original SPI. The formed SPI-lutein composite nanoparticles (PSPI11-LUTNPs) had smaller, more homogeneous sizes and larger negative charges than SPI7-LUTNPs. The combined treatment favored the unfolding of the SPI structure and could expose its interior hydrophobic groups to bind with lutein. Nanocomplexation with SPIs significantly improved the solubility and stability of lutein, with PSPI11 showing the greatest improvement. As a result, PEF combined with pH shifting pretreatment is an effective method for developing SPI nanoparticles loaded and protected with lutein.

Reversibility of freeze-thaw/re-emulsification on Pickering emulsion stabilized with gliadin/sodium caseinate nanoparticles and konjac glucomannan

The reversibility of freeze-thaw/re-emulsification of Pickering emulsion stabilized by gliadin/sodium caseinate nanoparticles (Gli/CAS NPs) was improved by adding konjac glucomannan (KGM). With the increase in the KGM concentration, the delamination of emulsions after freeze-thaw treatment was significantly improved. The microstructure showed that the presence of KGM helped to maintain the network structure of continuous phases. In particular, the particle size of the emulsion did not increase significantly after three freeze-thaw cycles when the KGM concentration was 0.6 % and the oil phase fraction was 60 %. The results of flocculation degree and coalescence degree also indicated that KGM promoted the cross-linking between particles on the surface of the droplet and increased the thickness of the interfacial film of the droplet. Rheological analysis also proved the same result: the elastic modulus of the emulsion was still larger than the viscous modulus, which showed the ideal freeze thaw reversibility. After adding KGM, the emulsion formed a strong network structure with good stability for long-term storage and reversibility for freeze-thaw cycling/re-emulsification. Thus, the emulsion has broad application prospects in food, cosmetics, and pharmaceutical fields.

Pickering emulsions stabilized by Chlorella pyrenoidosa protein-chitosan complex for lutein encapsulation

Lutein has many physiological functions like antioxidation, anti-cancer, and anti-inflammation, which presents good potential in the development of functional food for eye protection. However, the hydrophobicity and harsh environment factors during digestive absorption process will greatly reduce lutein bioavailability. In this study, Chlorella pyrenoidosa protein-chitosan complex stabilized Pickering emulsions were prepared, and lutein was encapsulated into corn oil droplets to increase its stability and bioavailability in gastrointestinal digestion. The interaction between Chlorella pyrenoidosa protein (CP) and chitosan (CS), and the effect of chitosan concentration on the emulsifying ability of the complex and emulsion stability were studied. With the increase of CS concentration from 0% to 0.8%, the emulsion droplet size obviously decreased, and the emulsion stability and viscosity increased significantly. In particular, when the concentration was 0.8%, the emulsion system was stable at 80 °C and 400 mM sodium chloride. After ultraviolet irradiation for 48 h, the retention rate of lutein encapsulated in Pickering emulsions was 54.33%, which was significantly higher than that (30.67%) of lutein dissolved in corn oil. The retention rate of lutein in Pickering emulsions stabilized by CP-CS complex was significantly higher than that in Pickering emulsions stabilized by CP only and corn oil after heating at 90 °C for 8 h. The results of simulated gastrointestinal digestion showed that the bioavailability of lutein encapsulated in Pickering emulsions stabilized by CP-CS complex reached 44.83%. These results explored the high-value utilization of Chlorella pyrenoidosa and provided new insights into the preparation of Pickering emulsions and the protection for lutein.

Structure and properties of Pickering emulsions stabilized solely with novel buckwheat protein colloidal particles

In this paper, buckwheat protein colloidal particles (BPCPs) were prepared by heat treatment to stabilize oil-water interface. The results of particle size, surface hydrophobicity and wettability indicated that the prepared BPCPs could be used as novel Pickering emulsifier. The effects of BPCPs concentration, ionic strength and heat treatment on the structure and properties of Pickering emulsions were explored. The microstructure results showed that BPCPs could tightly coated on the surface of oil droplets to form a tight interfacial film, confirming that BPCPs could be used as an effective Pickering-like stabilizer. With the increase of BPCPs concentration, the droplet size of the Pickering emulsion gradually decreased, and the viscoelasticity and storage stability of the emulsion were effectively improved. Different from the effect of ionic strength, heat treatment was beneficial to increasing the viscoelasticity of BPCPs-stabilized Pickering emulsion. The Pickering emulsions exhibited certain flocculation at different temperatures and ionic strengths, while still maintained good solid-like behavior. These results suggest that the structure and properties of BPCPs-stabilized Pickering emulsion could be regulated by changing the ionic strength and temperature.

Progress in the Application of Food-Grade Emulsions

The detailed investigation of food-grade emulsions, which possess considerable structural and functional advantages, remains ongoing to enhance our understanding of these dispersion systems and to expand their application scope. This work reviews the applications of food-grade emulsions on the dispersed phase, interface structure, and macroscopic scales; further, it discusses the corresponding factors of influence, the selection and design of food dispersion systems, and the expansion of their application scope. Specifically, applications on the dispersed-phase scale mainly include delivery by soft matter carriers and auxiliary extraction/separation, while applications on the scale of the interface structure involve biphasic systems for enzymatic catalysis and systems that can influence substance digestion/absorption, washing, and disinfection. Future research on these scales should therefore focus on surface-active substances, real interface structure compositions, and the design of interface layers with antioxidant properties. By contrast, applications on the macroscopic scale mainly include the design of soft materials for structured food, in addition to various material applications and other emerging uses. In this case, future research should focus on the interactions between emulsion systems and food ingredients, the effects of food process engineering, safety, nutrition, and metabolism. Considering the ongoing research in this field, we believe that this review will be useful for researchers aiming to explore the applications of food-grade emulsions.