Characteristics of Pickering emulsions stabilized by tea water-insoluble protein nanoparticles at different pH values

Pickering emulsion stabilized by egg derived reconstituted lipid nanoparticles for encapsulation and oral delivery of curcumin

The demand for high-quality, nutritious, and sustainable food products has led to a significant interest in the development of durable and effective emulsions. Pickering emulsions are promising candidates but the currently adopted stabilizers still have limitations. Here in this study, we introduce a novel egg derived reconstituted lipid nanoparticles (E-rLNPs) as stabilizer for Pickering emulsions. The lipids extraction from de-oiled egg yolk powder was firstly optimized using response surface methodology by Box-Behnken Design and then prepared into E-rLNPs by a straightforward solvent-diffusion method. The E-rLNPs were found to form stable Pickering emulsions that can resist to various environmental stresses. Moreover, the optimal Pickering emulsion offers excellent protection and significantly improves the oral availability of curcumin. This research presents a promising approach for the development of functional foods and nutraceuticals, showcasing the potential of natural food-derived rLNPs as stabilizers for Pickering emulsions, thereby advancing delivery technologies in the food science.

Preparation and characterization of a new food-grade Pickering emulsion stabilized by mulberry-leaf protein nanoparticles

BACKGROUND

Food-grade Pickering particles, particularly plant proteins, have attracted significant interest due to their bio-based nature, environmental friendliness, and edibility. Mulberry-leaf protein (MLP) is a high-quality protein with rich nutritional value and important functional properties. It has special amphoteric and emulsifying characteristics, making it valuable for use in Pickering emulsions. This study aimed to investigate the feasibility of using MLP nanoparticles as solid particles to stabilize Pickering emulsions.

RESULTS

The particle size of MLP nanoparticles was less than 300 nm under neutral and alkaline conditions. At pH 9, the zeta potential value reached -34.3 mV, indicating the electrostatic stability of the particles. As ion concentration increased, the particle size of MLP nanoparticles increased, and the zeta potential decreased. Throughout the storage process, no obvious aggregation or precipitation was observed in the dispersion of MLP nanoparticles, indicating strong stability. The particle size of the Pickering emulsion decreased with the increase in protein concentration. When the protein concentration was low, the particles on the oil-water interface became sparse, resulting in poor stability of the prepared emulsion and making it susceptible to aggregation and thus larger particle sizes. Increasing the oil-phase ratio to 70% (v/v) promotes the formation of Pickering emulsions, which exhibit exceptional stability when MLP nanoparticles are fixed at a concentration of 20 mg mL-1.

CONCLUSION

The overall findings indicated that MLP nanoparticles have potential as food-grade materials for Pickering emulsions, marking a novel application of these nanoparticles in the food industry. © 2024 Society of Chemical Industry.

High-efficient nanoemulsions separation by surface manipulation of sands

Oil-in-water (O/W) nanoemulsions, prevalent in the cosmetics, pharmaceutical, and petroleum industries, present significant threats to aquatic ecosystems and human health upon their inadvertent release into the environment. However, the nanoscale droplet size and robust interfacial film of nanoemulsions confer exceptional stability, rendering their separation a formidable challenge. Developing an economical and efficient method to remove nanoemulsions is crucial, offering a cost-effective and energy-saving alternative to traditional techniques. Here we present a sand filtration system integrating oleophilic and oleophobic sands, achieving cost-effective, high-flux, and efficient separation of nanoemulsions. The synergistic effect of hydrophobic silane treatment and a rough surface structure endows the oleophilic sands with exceptional oil absorption capacity. Meanwhile, the hydration layer on the oleophobic sands confers strong anti-oil adhesion properties in aqueous environments, facilitating swift water permeation. Remarkably, under gravity alone, the mixed rough sand filter (MRSF) achieves a separation flux exceeding 2519 L.m-2.h-1 with a separation efficiency of up to 98.7 %. This work offers a promising approach for achieving high-flux, efficient nanoemulsion separation.

Insight into low methoxyl pectin enhancing thermal stability and intestinal delivery efficiency of algal oil nanoemulsions

BACKGROUND

Algae oil has garnered widespread acclaim due as a result of its high purity of docosahexaenoic acid (DHA) and excellent safety profile. The present study aimed to develop stable nanoemulsions (NEs) systems containing DHA from algae oil through thermal sterilization by combining modified whey protein concentrate (WPC) with low methoxyl pectin (LMP), as well as to investigate the impact of LMP concentration on the thermal stability and the gastrointestinal delivery efficiency of DHA NEs.

RESULTS

The addition of LMP enhanced the stability of the emulsion after sterilization, at the same time as improving the protective and sustained release effects of DHA in the gastrointestinal tract. Optimal effect was achieved at a LMP concentration of 1% (10 g kg-1 sample), the stability of the emulsion after centrifugation increased by 17.21 ± 5.65% compared to the group without LMP, and the loss of DHA after sterilization decreased by only 0.92 ± 0.09%. Furthermore, the addition of 1% LMP resulted in a substantial reduction in the release of fatty acids from the NEs after gastrointestinal digestion simulation, achieving the desired sustained-release effect. However, excessive addition of 2% (20 g kg-1 sample) LMP negatively impacted all aspects of the NEs system, primarily because of the occurrence of depletion effects.

CONCLUSION

The construction of the LMP/WPC-NEs system is conducive to the protection of DHA in algae oil and its sustained-release in the gastrointestinal tract. The results of the present study can provide reference guidance for the application of algae oil NEs in the food field. © 2024 Society of Chemical Industry.

The construction of Moringa oleifera seed protein emulsion: in vitro digestibility and delivery of β-carotene

BACKGROUND

β-Carotene (BC) is difficult to apply effectively in the food industry due to its low solubility and bioavailability. This work aimed to fabricate Moringa oleifera seed protein (MOSP) stabilized emulsions as delivery vehicles for BC and investigate the effect of aqueous phase conditions including pH and ionic strength on this system.

RESULTS

All MOSP samples were positively charged and the particle size of MOSP increased with the increase of pH. At pH 5.0 and 0.2 mol L-1 sodium chloride (NaCl), the MOSP emulsion demonstrated the highest stability coefficient and minimal creaming index, while exhibiting a lower release rate in vitro digestion. The rheological behavior of all MOSP emulsions within the frequency range of 0.1-10 Hz was dominated by viscoelasticity, forming an elastic network structure through dispersed droplets. Additionally, the MOSP emulsion loaded with BC prepared at pH 5.0 and 0.2 mol L-1 NaCl displayed enhanced ultraviolet light stability (52.31 ± 0.03% and 51.86 ± 0.05%) as well as thermal stability (72.39 ± 8.67% and 86.78 ± 10.69%). Furthermore, the BC in the emulsion at pH 7.0 exhibited favorable stability (65.14 ± 0.02%) and optimal bioaccessibility (40.30 ± 0.04%) in vitro digestion.

CONCLUSION

The results provided reference data for utilizing MOSP as a novel emulsifier and broadening the application of BC in the food industry. © 2024 Society of Chemical Industry.

Fabrication, structure, characterization and emulsion application of citrate agar

In this study, citric acid successfully reacted with agar through the dry heat method, and citrate agar (CA) gel was used to stabilize O/W emulsions. The mechanisms of the CA structure and emulsion pH that affected emulsion stabilization were analyzed, and the application of CA gel emulsion (CAGE) was explored. Compared with native agar (NA), CA showed lower gel strength, higher transparency, and higher water contact angle. These changes indicate that a cross-linking reaction occurred, and it was demonstrated via FTIR and NMR. The emulsion properties were evaluated using particle size, ζ-potential, and the emulsification activity index. Results showed that CAGEs had a smaller particle size and lower ζ-potential than the native agar gel emulsion (NAGE). Meanwhile, confocal laser scanning microscopy confirmed that the CA gels stabilized the emulsions by forming a protective film around the oil droplets. Stability experiments revealed that CAGE (prepared with CA gel [DS = 0.145]) exhibited better stability than NAGE in the pH range of 3-11, and the rheological results further confirmed that the stability of the emulsions was influenced by the network structure and oil droplet interaction forces. Afterward, the application prospect of CAGE was evaluated by encapsulating vitamin D3 and curcumin.

Thermo-induced changes in the structure of lentil protein isolate (Lens culinaris) to stabilize high internal phase emulsions

This study aims to assess the impact of heat treatment on the emulsifying properties of lentil protein isolate (LPI) dispersion to produce high internal phase emulsions (HIPEs). The heat-treated LPI dispersion was characterized by size, turbidity, solubility, zeta potential, free sulfhydryl group, electrophoresis, differential scanning calorimetry, circular dichroism, Fourier transforms infrared spectroscopy and intrinsic fluorescence. HIPEs were produced with 25% of LPI dispersion (2%, w/w) and soybean oil (75%) using a rotor-stator (15,500 rpm/1 min). HIPEs were evaluated for their droplet size, zeta potential, centrifugal stability, microscopy, appearance, Turbiscan stability, and rheology over 60 days (25 °C). Heat treatment reduced the size of LPI, resulting in increased turbidity, solubility, and exposure of hydrophobic groups. HIPEs produced with heat-treated LPI at 70 °C (HIPE70) and 80 °C (HIPE80) for 20 min exhibited lower droplet sizes, increased stability, reduced oil loss, and a homogeneous appearance compared to HIPE produced with untreated LPI (HIPEc). In addition, HIPE70 and HIPE80 displayed resistance to shear stress, higher apparent viscosity, and increased storage modulus than HIPEc. HIPEs produced with heat-treated LPI were stable, suggesting that the treatment was efficient for improving the functional properties of the protein and the possibility of future research focusing on fat substitutes in food applications.

Stabilization of High Internal Phase Oil-in-Water Emulsions Using "Whole" Gracilaria lemaneiformis Slurry

In this study, a Gracilaria lemaneiformis slurry (GLS) was prepared using low-energy mechanical shearing. The resulting GLS, which was rich in polysaccharides, was utilized as an effective stabilizer for oil-in-water emulsions. The microstructures and stability of the resulting emulsions were controlled by adjusting the emulsion formulations, including Gracilaria lemaneiformis (GL) mass concentration and oil volume fraction (φ). The optimized GL mass concentration and φ conditions yielded high internal phase emulsions (HIPEs) with gel-like textures. Moreover, the presence of exogenous Ca2+ resulted in bridging structures in the emulsions, enhancing their viscoelasticity and forming a robust physical barrier against droplet coalescence. Our findings highlight the effectiveness of the GLS as an emulsifier for stabilizing HIPEs. Notably, this method relies solely on physical processes, aligning with the desirability of avoiding chemical additives, particularly in the food industry.

Enhanced detection of endocrine disrupting chemicals in on-chip microfluidic biosensors using aptamer-mediated bridging flocculation and upconversion luminescence

Exposure to endocrine-disrupting chemicals (EDCs) can lead to detrimental impacts on human health, making their detection a critical issue. A novel approach utilizing on-chip microfluidic biosensors was developed for the simultaneous detection of two EDCs, namely, bisphenol A (BPA) and diethylstilbestrol (DES), based on upconversion nanoparticles doped with thulium (Tm) and erbium (Er), respectively. From the perspective of single nanoparticles, the construction of an active core-inert shell structure enhanced the luminescence of nanoparticles by 2.28-fold (Tm) and 1.72-fold (Er). From the perspective of the nanoparticle population, the study exploited an aptamer-mediated bridging flocculation mechanism and effectively enhanced the upconversion luminescence of biosensors by 8.94-fold (Tm) and 7.10-fold (Er). A chip with 138 tangential semicircles or quarter-circles was designed and simulated to facilitate adequate mixing, reaction, magnetic separation, and detection conditions. The on-chip microfluidic biosensor demonstrated exceptional capabilities for the simultaneous detection of BPA and DES with ultrasensitive detection limits of 0.0076 µg L-1, and 0.0131 µg L-1, respectively. The first reported aptamer-mediated upconversion nanoparticle bridging flocculation provided enhanced luminescence and detection sensitivity for biosensors, as well as offering a new perspective to address the instability of nanobiosensors.

Quantitative Analysis of Bioactive Compounds in Commercial Teas: Profiling Catechin Alkaloids, Phenolic Acids, and Flavonols Using Targeted Statistical Approaches

Tea, an extensively consumed and globally popular beverage, has diverse chemical compositions that ascertain its quality and categorization. In this investigation, we formulated an analytical and quantification approach employing reversed-phase ultra-high-performance liquid chromatography (UHPLC) methodology coupled with diode-array detection (DAD) to precisely quantify 20 principal constituents within 121 tea samples spanning 6 distinct variants. The constituents include alkaloids, catechins, flavonols, and phenolic acids. Our findings delineate that the variances in chemical constitution across dissimilar tea types predominantly hinge upon the intricacies of their processing protocols. Notably, green and yellow teas evinced elevated concentrations of total chemical moieties vis à vis other tea classifications. Remarkably divergent levels of alkaloids, catechins, flavonols, and phenolic acids were ascertained among the disparate tea classifications. By leveraging random forest analysis, we ascertained gallocatechin, epigallocatechin gallate, and epicatechin gallate as pivotal biomarkers for effective tea classification within the principal cadre of tea catechins. Our outcomes distinctly underscore substantial dissimilarities in the specific compounds inherent to varying tea categories, as ascertained via the devised and duly validated approach. The implications of this compositional elucidation serve as a pertinent benchmark for the comprehensive assessment and classification of tea specimens.

Synergistic effect of microfluidization and transglutaminase cross-linking on the structural and oil-water interface functional properties of whey protein concentrate for improving the thermal stability of nanoemulsions

Generally, whey protein concentrate (WPC) undergoes high-temperature denaturation and aggregation, which reduces its emulsifying properties and is not conducive to as an emulsifier to maintain the thermal stability of emulsions. In this study, dynamic high-pressure microfluidization technology (DHPM) combined with TGase (TG) cross-linking was applied to prepare DHPM-TG-WPC, and the thermal stabilization mechanism of nanoemulsions prepared with DHPM-TG-WPC was explored. Results showed DHPM treatment could promote the formation of TG-crosslinked WPC polymers. Compared to WPC, the free sulfhydryl and free amino group content of DHPM-TG-WPC was significantly decreased (P < 0.05), the surface hydrophobicity and interfacial tension of DHPM-TG-WPC were increased by 45.23 % and 62.34 %, respectively. And its emulsifying stability index and interface protein adsorption was significantly enhanced (P < 0.05). Furthermore, compared to WPC, DHPM-WPC and TG-WPC, DHPM-TG-WPC-stabilized nanoemulsions showed the best 15 days of storage stability after thermal sterilization. This study provides a theoretical basis for the application of modified-WPC emulsion.

Characteristics and in vitro digestion of resveratrol encapsulated in Pickering emulsions stabilized by tea water-insoluble protein nanoparticles

This study focused on the characteristics and in vitro digestion of resveratrol encapsulated in Pickering emulsions stabilized by tea water-insoluble protein nanoparticles (TWINs). The absolute value of zeta potential of Pickering emulsions stabilized by TWIPNs (TWIPNPEs) encapsulating resveratrol was above 40 mV. Resveratrol encapsulated in TWIPNPEs was located at a hydrophobic environment of emulsion droplets. Additionally, the encapsulation efficiency (EE) of TWIPNPEs at TWIPN concentrations of 3.0% and 4.0% was above 85%. The resveratrol encapsulated in TWIPNPEs at a TWIPN concentration of 4.0% was still greater than 80% after UV irradiation to reduce the susceptibility of resveratrol for photodegradation. Moreover, the bioavailability of resveratrol in TWIPNPEs was improved in the simulated in vitro digestion. The bioavailability of resveratrol in TWIPNPEs in the simulated system was two times higher than unencapsulated resveratrol. This research could be useful for the encapsulation and application of nutraceuticals like resveratrol based on TWIPNPEs.

"Potential Scalpel": A Bioassisted Ultrafast Staining Lateral Flow Immunoassay from De Novo to Results

It is of great importance to overcome potential incompatibility problems between dyestuffs and antibodies (mAbs) for extensive commercial application of a dyestuff-chemistry-based ultrafast colorimetric lateral flow immunoassay (cLFIA). Herein, inspired by traditional staining technologies, a basic dyestuff gallocyanine (GC)-assisted biogenic "potential scalpel"-based cLFIA (GC-ABPS-based cLFIA) by employing clenbuterol (CLE) as proof-of-concept was proposed to solve a high degree of incompatibility between the same potential dyestuffs and mAbs. Goat antimouse immunoglobulin (Ab₂) could serve as the "potential scalpel" to form the positive potential value biomolecular network self-assemblers (BNSA) with anti-CLE mAbs (Ab_CLE) by noncovalent force. The cLFIA completed the entire detection process from de novo to detection results within 30 min thanks to the easy availability and ideal marking efficiency (≤1 min, saving 0.4-10 h) of GC. Encouragingly, the proposed ultrafast GC-ABPS-based cLFIA has also exhibited high sensitivity (0.411 ng mL^-1) and low cost (300 times) compared with other cLFIAs. Also, the feasibility of the proposed cLFIA was demonstrated by detecting CLE in beef, pork ham, and skim milk. Finally, the proposed GC-ABPS-based cLFIA has broadened the application range of dyestuffs and provided an effective reference strategy for the application of dyestuffs in food safety monitoring.

Efficient Utilization of Tea Resources through Encapsulation: Dual Perspectives from Core Material to Wall Material

With the high production and consumption of tea around the world, efficient utilization of tea byproducts (tea pruning, tea residues after production, and drinking) is the focus of improving the economy of the tea industry. This review comprehensively discusses the efficient utilization of tea resources by encapsulation from the dual perspectives of core material and wall material. The core material is mainly tea polyphenols, followed by tea oils. The encapsulation system for tea polyphenols includes microcapsules, nanoparticles, emulsions, gels, conjugates, metal-organic frameworks, liposomes, and nanofibers. In addition, it is also diversified for the encapsulation of tea oils. Tea resources as wall materials refer to tea saponins, tea polyphenols, tea proteins, and tea polysaccharides. The application of the tea-based delivery system widely involves functionally fortified food, meat preservation, film, medical treatment, wastewater treatment, and plant protection. In the future, the coencapsulation of tea resources as core materials and other functional ingredients, the precise targeting of these tea resources, and the wide application of tea resources in wall materials need to be focused on. In conclusion, the described technofunctional properties and future research challenges in this review should be followed.

Pickering Emulsions Stabilized by Tea Water-Insoluble Protein Nanoparticles From Tea Residues: Responsiveness to Ionic Strength

Tea water-insoluble protein nanoparticles (TWIPNs) can be applied to stabilize Pickering emulsions. However, the effect of ionic strength (0–400 mmol/L) on the characteristics of Pickering emulsions stabilized by TWIPNs (TWIPNPEs) including volume-averaged particle size (d_4,3), zeta potential, microstructure and rheological properties is still unclear. Therefore, this work researched the effect of ionic strength on the characteristics of TWIPNPEs. The d_4,3 of TWIPNPEs in the aquatic phase increased with the increase in ionic strength (0–400 mmol/L), which was higher than that in the SDS phase. Furthermore, the flocculation index of TWIPNPEs significantly (P < 0.05) increased from 24.48 to 152.92% with the increase in ionic strength. This could be verified from the microstructure observation. These results indicated that ionic strength could promote the flocculation of TWIPNPEs. Besides, the absolute values of zeta potential under different ionic strengths were above 40 mV in favor of the stabilization of TWIPNPEs. The viscosity of TWIPNPEs as a pseudoplastic fluid became thin when shear rate increased from 0.1 to 100 s⁻¹. The viscoelasticity of TWIPNPEs increased with increasing ionic strength to make TWIPNPEs form a gel-like Pickering emulsion. the possible mechanism of flocculation stability of TWIPNPEs under different ionic strengths was propose. TWIPNs adsorbed to the oil-water interface would prompt flocculation between different emulsion droplets under the high ionic strength to form gel-like behavior verified by CLSM. These results on the characteristics of TWIPNPEs in a wide ionic strength range would provide the theoretical basis for applying Pickering emulsions stabilized by plant proteins in the food industry.