Bacteriostatic Pickering emulsions stabilized by whey protein isolate-vanillin nanoparticles: Fabrication, characterization and stability in vitro

Stabilizing emulsions by ultrasound-treated pea protein isolate - tannic acid complexes: Impact of ultrasonic power and concentration of complexes on emulsion characteristics

This work aimed to investigate the feasibility of stabilizing oil-in-water (O/W) emulsions by ultrasound-treated pea protein isolate-tannic acid (UPPI-TA) complex. The stability and microstructure of the O/W emulsions were evaluated at different ultrasonic powers (0-1000 W) and UPPI-TA complex concentrations (0.25-2.0 wt%). The contact angle (θ) of UPPI-TA was 59.6°, which was suitable for stabilizing O/W emulsions. At an ultrasonic power of 800 W, the droplet size and creaming index (CI) of emulsions decreased, and the apparent viscosity and interfacial protein adsorption content increased with increasing UPPI-TA concentration. In particular, emulsions with 1.5 % UPPI-TA showed the lowest CI, the highest interfacial protein adsorption content and viscoelasticity, as well as the best storage and thermal stability. These results showed that the suitable modifications of ultrasonic emulsification power and particle concentrations were a new potential approach to stabilize the O/W emulsions by ultrasound-treated pea protein isolated-tannic acid complex.

Impact of cold plasma-assisted Non-thermal deamidation and glycosylation on the construction of sugar derivative-zein conjugates for enhancing pickering foam stability: Technical principles and molecular interactions

There is an urgent need for stable, plant-based Pickering foams to address the growing consumer demand for sustainable, low-calorie, aerated sweet foods. This study employed a cold plasma-assisted deamidation and glycosylation (CPDG) approach to promote hydrophilic reassembly of zein, resulting in the formation of sugar derivative-zein conjugates. This was accomplished by coupling deamidated zein with polyhydroxy sugars including sucralose (Suc), maltitol (Mal), mannitol (Man), and stevioside (Ste). The research focused on elucidating the technical mechanisms of conjugate formation and the molecular interactions that enhance foam performance. The CPDG-treated conjugates demonstrated substantially increased foamability (140.00-223.33 %) and foam stability (28.57-105.07 %). Furthermore, microscopy (100 × magnification) revealed enhanced bubble counts (+13-15 bubbles) and interface layer thickness (+1.85-4.60 nm), along with a decrease in the drainage area (+8.47-20.52 %) for all conjugates, except Suc/ZN-CP. Particularly, the amphiphilic nature of Ste, characterized by multiple chiral centers, various hydroxyl groups, and a distinct carbonyl group, resulted in the highest covalent grafting degree (38.82 %), water solubility (0.28 mg/mL), foaming capacity (223.33 %), and foam stability (105.07 %) of ZN/Ste-CP after CPDG treatment. Regarding interaction forces, CPDG treatment enhanced both hydrogen bonding and covalent interactions in zein while diminishing electrostatic and hydrophobic forces. Confocal laser scanning microscopy validated that these changes resulted in a hydrophilic conformational shift of the conjugates, allowing Ste to coat micelle surfaces and form chain-like aggregates through viscous stretching, thereby facilitating favorable adsorption and unfolding at the air/water interface. The CPDG technology proved to be an effective and eco-friendly method for modifying the interface of zein, offering a valuable strategy for its application in highly flexible, stabilized Pickering foamed foods.

Fabrication and characterization of novel TGase-mediated glycosylated whey protein isolate nanoparticles for curcumin delivery

The aim of this study was to fabricate novel transglutaminase (TGase)-mediated glycosylated whey protein isolate (WPI) nanoparticles for the encapsulation and delivery of curcumin. The influences of glycosylation on the physiochemical properties, stability, bioavailability, and antioxidant properties of WPI nanoparticles loaded with curcumin were investigated. Composite nanoparticles exhibited uniform distribution and small particle sizes. The main driving forces for the formation of curcumin nanoparticles were electrostatic interactions, hydrogen bonding, and hydrophobic interactions. The encapsulation and loading efficiency of curcumin after TGase-type glycosylation were significantly increased in comparison to WPI-curcumin nanoparticles. Glycosylated WPI-curcumin nanoparticles had stronger antioxidant properties and stability to resist external environmental changes than WPI-curcumin nanoparticles. In addition, glycosylated WPI-curcumin nanoparticles showed a controlled release and enhanced curcumin bioavailability in vitro gastrointestinal digestion. This study provides novel insights for self-assembled glycosylated protein nanoparticles as delivery systems for protecting hydrophobic nutrients.

Antibacterial mechanism of whey protein isolated-citral nanoparticles and stable synergistic antibacterial eugenol encapsulated Pickering emulsion for grapes preservation

The purpose of this study was to prepare Pickering emulsion with synergistic antibacterial effect using whey protein isolated-citral (WPI-Cit) nanoparticles with eugenol for grape preservation. In this emulsion, eugenol was encapsulated in oil phase. The particle size, ζ-potential, and antibacterial mechanism of the nanoparticles were characterized. The rheological properties, antibacterial effects and preservation effects of WPI-Cit Pickering emulsion were measured. The results showed that the optimal preparation condition was performed at WPI/Cit mass ratio of 1:1, WPI-Cit nanoparticles were found to damage the cell wall and membrane of bacteria and showed more effective inhibition against S. aureus. Pickering emulsion prepared with WPI-Cit nanoparticles exhibited a better antibacterial effect after eugenol was encapsulated in it, which extended the shelf life of grapes when the Pickering emulsion was applied as a coating. It demonstrated that the Pickering emulsion prepared in this study provides a new way to extend the shelf life.

Preparation of ceftiofur-encapsulated hen-egg low-density lipoproteins and their antibacterial effects on intracellular Staphylococcus aureus

Hen egg low-density lipoprotein (heLDL), as alternative of serum-derived LDL, was used as drug delivery system of ceftiofur (CEF). The CEF-loaded hen egg low-density lipoprotein (CEF-heLDL) with complete apolipoprotein structure and high drug loading rate was synthesized, possesses suitable particle size. CEF-heLDL undergoes cellular uptake and colocalizes with lysosomes in vitro. An intracellular infection model of the bovine endometrial epithelial cells and a coeliac-induced inflammation model of mice by Staphylococcus aureus (S. aureus) were established, and significantly lower intracellular S. aureus levels of CEF-heLDL group than CEF-free group (P < 0.001) was observed. The antibacterial efficacy was sustained for 24 h. Up to 400 mg/kg of CEF-heLDL, 20 times the clinical practice, were intraperitoneally administrated, and no significant toxicity signs on mice were observed. HeLDLs is an effective, safe, and cheap drug carrier, and could also be used for transmembrane delivering other antibiotics.

Enhancing cellulose-stabilized multiphase/Pickering emulsions systems: A molecular dynamics perspective

Cellulose stabilized multiphase systems (CSMS) have garnered significant attention due to their ultra-stabilization mechanism and vast potential across different fields. CSMS have found valuable applications in scientific disciplines, including Food Science, Pharmaceutical Science, Material Science, and related fields, owing to their beneficial attributes such as sustainability, safety, renewability, and non-toxicity. Furthermore, MPS exhibit novel characteristics that enable multiple mechanisms to produce HIPEs, aerogels, and oleogels revealing undiscovered information. Therefore, to explore the undiscovered phenomena of MPS, molecular level insights using advanced simulation/computational approaches are essential. The molecular dynamics simulation (MDS), play a valuable role in analyzing the interactions of ternary interphase. The MDS have successfully quantified the interactions of MPS by generating, visualizing, and analyzing trajectories. Through MDS, researchers have explored CSMS at the molecular level and advanced their applications in 3D printing, packaging, preparation, drug delivery, encapsulation, biosensors, electronic devices, biomaterials, and energy conservation. This review highlights the remarkable advancements in CSMS over the past five years, along with contributions of MDS in evaluating the relationships that dictate the functionality and properties of CSMS. By integrating experimental and computational methods, we underscore the potential to innovate and optimize these multiphase systems for groundbreaking applications.

Multifunctional bacterial cellulose-bentonite@polyethylenimine composite membranes for enhanced water treatment: Sustainable dyes and metal ions adsorption and antibacterial properties

Developing multifunctional materials for water treatment remains a significant challenge. Bacterial cellulose (BC) holds immense potential as an adsorbent with high pollutant-binding capacity, hydrophilicity, and biosafety. In this study, N-acetylglucosamine was used as a carbon source to ferment BC, incorporating amide bonds in situ. Bentonite, renowned for its adsorption properties, was added to the culture medium, resulting in BC-bentonite composite membranes via a one-step fermentation process. Polyethyleneimine (PEI) was crosslinked with amide bonds on the membrane via glutaraldehyde through Schiff base reactions to enhance the performance of the composite membrane. The obtained membrane exhibited increased hydrophilicity, enhanced active adsorption sites, and enlarged specific surface area. It not only physically adsorbed contaminants through its unique structure but also effectively captured dye molecules (Congo red, Methylene blue, Malachite green) via electrostatic interactions. Additionally, it formed stable complexes with metal ions (Cd²⁺, Pb²⁺, Cu²⁺) through coordination and effectively adsorbed their mixtures. Moreover, the composite membrane demonstrated the broad-spectrum antibacterial activity, effectively inhibiting the growth of tested bacteria. This study introduces an innovative method for fabricating composite membranes as adsorbents for complex water pollutants, showing significant potential for long-term wastewater treatment of organic dyes, heavy metal ions, and pathogens.

Physicochemical properties and antibacterial property of pickering emulsion stabilized by smart Janus nanospheres

In this study, responsive Janus nanospheres were prepared by grafting LMA and DMAEMA monomers on both sides of SiO2 nanospheres using the Pickering emulsion stencil method and RAFT polymerization. The successful synthesis was verified through infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA), scanning electron microscopy (SEM) characterizations. Subsequently, Pickering emulsion was formulated using Janus nanospheres as emulsifiers. The particle size of the emulsion droplets was systematically investigated by manipulating factors such as pH, nanosphere dosage, water to oil ratio, and oil phase polarity. Notably, the Pickering emulsion exhibited responsive properties to pH, temperature, and CO2. Furthermore, Janus nanospheres exhibited excellent emulsification property for real oil phases, including canola oil, kerosene, gasoline, and diesel oil. Building upon this, a smart antibacterial Pickering emulsion was developed using Janus nanospheres, and its inhibition rate against E. coli could reach 100% within 4 h, which would be beneficial for its application in the food field.

Desmodium intortum (Mill.) Urb. Protein Isolate Aggregates as Pickering Stabilizers: Physicochemical Characteristics and Emulsifying Properties

This work aimed to investigate the feasibility of fabricating Pickering emulsions stabilized by Desmodium intortum protein isolate (DIPI) aggregates. The DIPI aggregates were formed using heat treatment, and the effects of ionic strength and pH on their properties were investigated. The heat-treated protein exposes its hydrophobic groups due to structural damage, resulting in rapid aggregation of the protein into aggregates with a size of 236 nm. The results showed that the aggregates induced by ionic strength had larger particle size and higher surface hydrophobicity and partial wettability. Moreover, this study explored effective strategies for bolstering Pickering emulsion stability through optimized DIPI aggregate concentration (c) and oil fraction (ø). The DIPI Pickering emulsion (DIPIPE) formed at c = 5% and ø = 0.7 was still highly stable after 30 days of storage. As confirmed by laser confocal microscopy, DIPI aggregates could be adsorbed onto the oil-water interface to form a network structure that could trap oil droplets in the network. Collectively, the Pickering emulsion stabilized by DIPI aggregates exhibited excellent stability, which not only deeply utilizes the low-value protein resources in the Desmodium intortum for the first time, but also demonstrates the potential of DIPI for the bio-based field.

Stimuli-responsive antioxidant Pickering emulsions stabilized by functionalized cellulose nanocrystals

Stimuli-responsive antioxidant Pickering emulsions play crucial role in many industrial areas. This study demonstrated for the first time oil-in-water Pickering emulsions with outstanding antioxidation and responsive demulsification stabilized by functionalized cellulose nanocrystals (CNCs). Dialdehyde cellulose nanocrystals (DACs) were first prepared through the oxidation of CNCs with periodate, followed by the grafting of p-aminophenols (PAPs) onto their surfaces through Schiff base reaction, affording PAP grafted DACs (DAC-g-PAP) via dynamic covalent linkage. The degree of the oxidation (DO) of DACs had a significant effect on the yield of the targeting DAC-g-PAP nanoparticles. High DO (≥40 %) potentially led to the degradation of DACs during the grafting of PAP. The introduced PAP endowed DACs with excellent radical scavenging capability, thereby providing antioxidant properties while improving the hydrophobicity. DAC-g-PAP nanoparticles were then applied as Pickering emulsifiers to prepare oil-in-water Pickering emulsions. The resultant Pickering emulsions indicated exceptional antioxidant and pH-responsiveness together with good freezing-thaw stability. The structures of DAC-g-PAP nanoparticles were thoroughly characterized in this study.

Preparation and Properties of Walnut Protein Isolate-Whey Protein Isolate Nanoparticles Stabilizing High Internal Phase Pickering Emulsions

To enhance the functional properties of walnut protein isolate (WalPI), hydrophilic whey protein isolate (WPI) was selected to formulate WalPI-WPI nanoparticles (nano-WalPI-WPI) via a pH cycling technique. These nano-WalPI-WPI particles were subsequently employed to stabilize high internal phase Pickering emulsions (HIPEs). By adjusting the mass ratio of WalPI to WPI from 9:1 to 1:1, the resultant nano-WalPI-WPI exhibited sizes ranging from 70.98 to 124.57 nm, with a polydispersity index of less than 0.326. When the mass ratio of WalPI to WPI was 7:3, there were significant enhancements in various functional properties: the solubility, denaturation peak temperature, emulsifying activity index, and emulsifying stability index increased by 6.09 times, 0.54 °C, 318.94 m2/g, and 552.95 min, respectively, and the surface hydrophobicity decreased by 59.23%, compared with that of WalPI nanoparticles (nano-WalPI), with the best overall performance. The nano-WalPI-WPI were held together by hydrophobic interactions, hydrogen bonding, and electrostatic forces, which preserved the intact primary structure and improved resistance to structural changes during the neutralization process. The HIPEs stabilized by nano-WalPI-WPI exhibited an average droplet size of less than 30 μm, with droplets uniformly dispersed and maintaining an intact spherical structure, demonstrating superior storage stability. All HIPEs exhibited pseudoplastic behavior with good thixotropic properties. This study provides a theoretical foundation for enhancing the functional properties of hydrophobic proteins and introduces a novel approach for constructing emulsion systems stabilized by composite proteins as emulsifiers.

Insight into oil-water interfacial adsorption of protein particles towards regulating Pickering emulsions: A review

Over the past decade, Pickering emulsions (PEs) stabilized by protein particles have been the focus of researches. The characteristics of protein particles at the oil-water interface are crucial for stabilizing PEs. The unique adsorption behaviors of protein particles and various modification methods enable oil-water interface to exhibit controllable regulation strategies. However, from the perspective of the interface, studies on the regulation of PEs by the adsorption behaviors of protein particles at oil-water interface are limited. Therefore, this review provides an in-depth study on oil-water interfacial adsorption of protein particles and their regulation on PEs. Specifically, the formation of interfacial layer and effects of their interfacial characteristics on PEs stabilized by protein particles are elaborated. Particularly, complicated behaviors, including adsorption, arrangement and deformation of protein particles at the oil-water interface are the premise of affecting the formation of interfacial layer. Moreover, the particle size, surface charge, shape and wettability greatly affect interfacial adsorption behaviors of protein particles. Importantly, stabilities of protein particles-based PEs also depend on properties of interfacial layers, including interfacial layer thickness and interfacial rheology. This review provides useful insights for the development of PEs stabilized by protein particles based on interfacial design.

Novel Pickering emulsion stabilized by glycosylated whey protein isolate: Characterization, stability, and curcumin bioaccessibility

Pickering emulsions prepared from protein-polysaccharide complexes have attracted increasing attention. In this study, whey protein isolates (WPI) were modified with oligochitosan using transglutaminase (TGase)-type to fabricate Pickering emulsions, and loaded with curcumin. The curcumin/protein ratio of 1:25 and oil phase fraction (φ = 17 %) are the most optimal condition for emulsions stabilization, and particle size of glycosylated WPI emulsion was 31.70 μm. Glycosylated WPI emulsion had the highest encapsulation efficiency (96.64 %) of curcumin. Microstructure analysis showed that glycosylated WPI had small droplets covered by dense interface layers. The modified WPI emulsions exhibited optimal emulsifying properties and emulsion stability, which effectively inhibited the premature water-oil stratification in emulsion. In vitro digestion results showed that WPI-oligochitosan complexes enhanced curcumin bioaccessibility (40.34 %). The antioxidant activity of glycosylated WPI emulsions was significantly increased. The results of this study provide helpful references for applying glycosylated WPI-stabilized Pickering emulsions, which can be used as transport carriers of curcumin.

Modulation the Synergistic Effect of Chitosan-Sodium Alginate Nanoparticles with Ca2+: Enhancing the Stability of Pickering Emulsion on D-Limonene

Pickering emulsions (PEs) have been regarded as an effective approach to sustaining and preserving the bioactivities of essential oils. The aim of this research is to prepare a PE stabilized by chitosan/alginate nanoparticles (CS-SA NPs) for the encapsulation and stabilization of D-limonene. In this work, the influence of calcium ions (Ca2+) on the morphology and interaction of nanoparticles was studied, and then the preparation technology of CS-SA/Ca2+ NPs was optimized. The results showed that the presence of Ca2+ reduced the size of the nanoparticles and made them assume a spherical structure. In addition, under the conditions of 0.2 mg/mL CaCl2, 0.6 mg/mL SA, and 0.4 mg/mL CS, the CS-SA/Ca2+ NPs had the smallest size (274 ± 2.51 nm) and high stability (-49 ± 0.69 mV). Secondly, the PE was prepared by emulsifying D-limonene with CS-SA/Ca2+ NPs, and the NP concentrations and homogenization speeds were optimized. The results showed that the small droplet size PE could be prepared with 2 mg/mL NP and a homogenization speed of 20,000 r/min, and it had excellent antibacterial and antioxidant activities. Most importantly, the emulsion showed higher activity, higher resistance to ultraviolet (UV) and a higher temperature than free D-limonene. This research provides a feasible solution for the encapsulation, protection and delivery of essential oils.