The essential role of aggregation for the emulsifying ability of a fungal CYS-rich protein.

Biosurfactants are in demand by the global market as natural commodities suitable for incorporation into commercial products or utilization in environmental applications. Fungi are promising producers of these molecules and have garnered interest also for their metabolic capabilities in efficiently utilizing recalcitrant and complex substrates, like hydrocarbons, plastic, etc. Within this framework, biosurfactants produced by two Fusarium solani fungal strains, isolated from plastic waste-contaminated landfill soils, were analyzed. Mycelia of these fungi were grown in the presence of 5% olive oil to drive biosurfactant production. The characterization of the emulsifying and surfactant capacity of these extracts highlighted that two different components are involved. A protein was purified and identified as a CFEM (common in fungal extracellular membrane) containing domain, revealing a good propensity to stabilize emulsions only in its aggregate form. On the other hand, an unidentified cationic smaller molecule exhibits the ability to reduce surface tension. Based on the 3D structural model of the protein, a plausible mechanism for the formation of very stable aggregates, endowed with the emulsifying ability, is proposed. KEY POINTS: • Two Fusarium solani strains are analyzed for their surfactant production. • A cationic surfactant is produced, exhibiting the ability to remarkably reduce surface tension. • An identified protein reveals a good propensity to stabilize emulsions only in its aggregate form.

Effects of polysaccharides on colonic targeting and colonic fermentation of ovalbumin-ferulic acid based emulsion.

Rutin is a polyphenol with beneficial pharmacological properties. However, its bioavailability is often compromised due to low solubility and poor stability. Encapsulation technologies, such as emulsion systems, have been proven to be promising delivery vehicles for enhancing the bioavailability of bioactive compounds. Thus, this study was proposed and designed to investigate the colonic targeting and colonic fermentation characteristics of rutin-loaded ovalbumin-ferulic acid-polysaccharide (OVA-FA-PS) complex emulsions. The results indicate that OVA-FA-PS emulsion effectively inhibits the degradation of rutin active substances and facilitates its transport of rutin to the colon. The analysis revealed that the OVA-FA-κ-carrageenan emulsion loaded with rutin exhibited superior elasticity and colon targeting properties compared to the OVA-FA-hyaluronic acid or OVA-FA-sodium alginate emulsions loaded with rutin in the composite emulsion. Additionally, it was observed that the rutin loaded within the OVA-FA-κ-carrageenan emulsion underwent degradation and was converted to 4-hydroxybenzoic acid during colonic fermentation.

Homologous Overexpression of Tyrosinase in Trichoderma reesei and Its Application in Glycinin Cross-Linking.

Tyrosinase is capable of oxidizing tyrosine residues in proteins, leading to intermolecular protein cross-linking, which could modify the protein network of food and improve the texture of food. To obtain the recombinant tyrosinase with microbial cell factory instead of isolation tyrosinase from the mushroom Agaricus bisporus, a TYR expression cassette was constructed in this study. The expression cassette was electroporated into Trichoderma reesei Rut-C30 and integrated into its genome, resulting in a recombinant strain C30-TYR. After induction with microcrystalline cellulose for 7 days, recombinant tyrosinase could be successfully expressed and secreted by C30-TYR, corresponding to approximately 2.16 g/L tyrosinase in shake-flask cultures. The recombinant TYR was purified by ammonium sulfate precipitation and gel filtration, and the biological activity of purified TYR was 45.6 U/mL. The purified TYR could catalyze the cross-linking of glycinin, and the emulsion stability index of TYR-treated glycinin emulsion was increased by 30.6% compared with the untreated one. The cross-linking of soy glycinin by TYR resulted in altered properties of oil-in-water emulsions compared to emulsions stabilized by native glycinin. Therefore, cross-linking with this recombinant tyrosinase is a feasible approach to improve the properties of protein-stabilized emulsions and gels.

Oil-in-water and oleogel-in-water emulsion encapsulate with hemp seed oil containing Δ9-tetrahydrocannabinol and cannabinol: Stability, degradation and in vitro simulation characteristics.

The present study focused on investigating the stability and in vitro simulation characteristics of oil-in-water (O/W) and oleogel-in-water (Og/W) emulsions. Compared with O/W emulsion, the Og/W emulsion exhibited superior stability, with a more evenly spread droplet distribution, and the Og/W emulsion containing 3 % hemp seed protein (HSP) showed better stability against environmental factors, including heat treatment, ionic strength, and changes in pH. Additionally, the stability of Δ9-tetrahydrocannabinol (Δ9-THC) and cannabinol (CBN) and the in vitro digestion of hemp seed oil (HSO) were evaluated. The half-life of CBN in the Og/W emulsion was found to be 131.82 days, with a degradation rate of 0.00527. The in vitro simulation results indicated that the Og/W emulsion effectively delayed the intestinal digestion of HSO, and the bioaccessibility of Δ9-THC and CBN reached 56.0 % and 58.0 %, respectively. The study findings demonstrated that the Og/W emulsion constructed with oleogel and HSP, exhibited excellent stability.

In vitro digestion and colonic fermentation characteristics of media-milled purple sweet potato particle-stabilized Pickering emulsions.

BACKGROUND: Pickering emulsions stabilized by multicomponent particles have attracted increasing attention. Research on characterizing the digestion and health benefit effects of these emulsions in the human gastrointestinal tract are quite limited. This work aims to reveal the digestive characteristics of media-milled purple sweet potato particle-stabilized Pickering emulsions (PSPP-Es) during in vitro digestion and colonic fermentation. RESULTS: The media-milling process improved the in vitro digestibility and fermentability of PSPP-Es by reaching afree fatty acids release rate of 43.11 ± 4.61% after gastrointestinal digestion and total phenolic content release of 101.00 ± 1.44 µg gallic acid equivalents/mL after fermentation. In addition, PSPP-Es exhibited good antioxidative activity (2,2-diphenyl-1-picrylhydrazyl and ferric reducing antioxidant power assays), α-glucosidase inhibitory activity (half-maximal inhibitory concentration: 6.70%, v/v), and prebiotic effects, reaching a total short-chain fatty acids production of 9.90 ± 0.12 mol L-1, boosting the growth of Akkermansia, Bifidobacterium, and Blautia and inhibiting the growth of Escherichia-Shigella. CONCLUSIONS: These findings indicate that the media-milling process enhances the potential health benefits of purple sweet potato particle-stabilized Pickering emulsions, which is beneficial for their application as a bioactive component delivery system in food and pharmaceutical products. © 2024 Society of Chemical Industry.

Structure-property relationship of pea protein fibrils in stabilization of HIPEs and the encapsulation, protection, controlled release and oral delivery of carotenoids for alleviating intestinal inflammation.

Increasing attentions are paid to high internal phase emulsions (HIPEs) due to their unique properties. In this study, pea protein-based fibrils were used as emulsifier to stabilize HIPEs. We demonstrated that the molecular assembly pathway and interfacial behavior of pea protein-based fibrils are affected by ionic strength. And the increased abundance of highly flexible worm-like nanofibrils facilitated their adsorption and packing on oil droplets, resulting in improved emulsion properties to stabilize the HIPEs with the internal phase volume fraction as high as 90%. Based on this, high loading content of carotenoids up to 0.05 wt% in the prepared HIPEs, protection of their stability against heating, UV and iron ions, and significantly increased bio-accessibilities of the carotenoids were realized. Animal studies using a mouse model of DSS-induced colitis revealed that carotenoid loaded HIPEs can alleviate the colon injury, by downregulating the expression of inflammatory cytokines, and promoting intestinal barrier function. This work will deepen the understanding of the formation of pea protein fibrils and provide a reference for the rational use of carotenoid loaded HIPEs in IBD management.

In vivo and in vitro transdermal availability of Ibuprofen using novel solubility enhancing fluid nanosized carrier systems.

The objective of this study was to explore the benefits of transdermal drug delivery systems as an alternative option for patients who are unable to tolerate oral administration of drugs, such as ibuprofen (IB). To achieve this, nonionic surfactants and three cosolvents were employed to develop new microemulsions (MEs) that contained IB as nanocarriers. The aim was to enhance the solubility and bioavailability of the drug after transdermal administration. The MEs were characterised by droplet size, polydispersity index (PDI), and rheological properties. Furthermore, the flux of IB was evaluated by Franz diffusion cells using excised rat skin and in vivo bioavailability using rats. The results showed that the MEs had ideal viscosity and droplet size below 100 nm. Moreover, using the developed MEs, an improvement in the solubility (170 mg/mL) and flux through the rat skin (94.6 ± 8.0 µg/cm2.h) was achieved. In addition, IB demonstrated a maximum plasma level of 0.064 mg/mL after 8 h of transdermal administration in rats using the ME with an increase in the bioavailability of about 1.5 times in comparison to the commercial IB gel. In conclusion, the developed nonionic MEs containing IB can be ideal nanocarriers and promising formulations for the transdermal administration of IB.

The role of membrane components on the oleosome lubrication properties.

HYPOTHESIS: Oleosomes are natural oil droplets with a unique phospholipid/protein membrane, abundant in plant seeds, from which they can be extracted and used in emulsion-based materials, such as foods, cosmetics and pharmaceutics. The lubrication properties of such materials are essential, on one hand, due to the importance of the in-mouth creaminess for the consumed products or the importance of spreading the topical creams. Therefore, here, we will evaluate the lubrication properties of oleosomes, and how these properties are affected by the components at the oleosome membrane. EXPERIMENT: Oleosomes were extracted, and their oral lubricating properties were evaluated using tribology. To understand the influence of the oil droplet membrane composition, reconstituted oleosomes were also studied, with membranes that differed in protein/lecithin ratio. Additionally, whey protein- and lecithin-stabilised emulsions were used as reference samples. Confocal laser scattering microscopy was used to study the samples visually before and after tribological analysis. FINDINGS: Oleosomes followed a ball-bearing mechanism, which was probably related to their high physical stability due to the presence of membrane proteins. When the membrane protein concentration at the surface was reduced, the droplet stability weakened, leading to plating-out lubrication. Following our results, we elucidated the oleosome lubrication mechanism and showed their possible control by changing the membrane composition.

Salt-Promoted Fibrillation of Legume Proteins Enhanced Interfacial Modulus for Stabilization of HIPEs Encapsulating Carotenoids with Improved Nutritional Performance.

The thermal acidic-treatment-induced fibrillation of legume proteins isolated from cowpea and mung bean was demonstrated to be promoted by salt. Worm-like thin prefibrilar intermediates were formed in low salt concentrations (0-75 mM), which twisted to be the thick and mature amyloid-like fibrils with multistrands as the salt content was elevated (150-300 mM). Absorption of the fibrils fabricated in high salt concentrations to the oil/water interface constructed the protein layer with a significantly higher interfacial modulus compared with the one formed by the fibrils fabricated in low salt concentrations. Consequently, they showed the superiority in stabilizing high internal phase emulsions (HIPEs) with oil volume fraction ratios higher than 74%. HIPEs stabilized by the high salt-concentration-induced legume protein fibrils had stronger capabilities not only in encapsulating liposoluble carotenoids but also in protecting their stability against heating, ultraviolet, and iron ion stimulus, compared with the one stabilized by the low-salt-concentration-induced legume protein fibrils. Bioaccessibilities of the carotenoids in simulating gastrointestinal (GI) digestion were significantly improved after encapsulation by the HIPEs, which were interestingly increased with the elevation of salt concentrations utilized for preparing the legume protein fibrils. Furthermore, the carotenoids-loading-HIPEs were injectable and showed in vivo nutritional functions of mitigating colitis.

Preparation, optimization and evaluation of Osthole transdermal therapeutic system.

In the current study, the solubility and permeability of Osthole-loaded microemulsion were enhanced, which increased bioavailability. In addition, Carbomer 940 was added for prolonged drug delivery. The microemulsion was prepared after the screening of Kukui oil, Labrasol (surfactant), and transcutol-P (co-surfactant). Pseudoternary phase diagrams were employed to find the microemulsion region. Box Behnken Design (BBD) was employed for optimizing microemulsions. Variables were related and compared using mathematical equations and response surface plots (RSP). MEBG was then compared with control gel on the basis of stability studies, drug permeation, skin irritation studies, and anti-inflammatory studies. Microemulsion preparations depicted a pH of 5.27 - 5.80, a conductivity of 139 - 185 µS/cm, a poly-dispersity index of 0.116 - 0.388, a refractive index of 1.330 - 1.427, an average droplet size of 64 - 89 nm, homogeneity, spherical shape, viscosity 52 - 185 cP. Predicted values of Optimized microemulsions showed more reasonable agreement than experimental values. The microemulsion was stable and non-irritating on Rabbit skin. MEBG showed a significant difference from control gel for percent edema inhibition from the standard. The permeation enhancing capability of MEBG using a suitable viscosity fabricates it promising carrier for transdermal delivery of Osthole.

Delivery of free amino acids into and through the stratum corneum of the skin using micro emulsions and microemulsion-based hydrogels: Formulation, characterization, and ex-vivo permeation studies.

Free amino acids constitute the largest portion (40%) of the natural moisturizing factor. Their level might decline and cause dry skin condition. The treatment strategy involves the replenishment of these components to the skin, and, to our knowledge, there are no reports that involve dermal delivery of free amino acids. The purpose of the current study was therefore to prepare and characterize different micro-emulsions, micro-emulsion-based hydrogels, and hydrophilic creams loaded with free amino acids for dermal delivery. Oil-in-water microemulsions were prepared using carefully selected formulation components. Poloxamer® 407 and carbopol® 934 were used to prepare the hydrogels. All the formulations were characterized for physico-chemical, permeation and cytotoxicity properties. The results showed that the prepared microemulsions had desired droplet size, size distribution, zeta potential, refractive index, and pH. In the gel preparations, the elastic properties prevailed over the viscous behavior. The hydrogels had non-Newtonian shear-thinning behavior with some thixotropic properties. The free amino acids permeated into the deeper layers of the stratum corneum from the microemulsions, and microemulsion-based hydrogels as compared to conventional hydrophilic cream. The hydrogels were more effective than the microemulsions to deliver the FAAs to the desired site of the skin in a sustained manner. Poloxamer-based hydrogel permeated into deeper skin layers than Carbopol-based hydrogel. Formulations prepared using standard free amino acids and those extracted and purified from oyster mushroom had similar characteristics. All the formulations were stable and safe to be applied topically. In conclusion, microemulsions and microemulsion-based hydrogels can be considered as safe carrier systems for dermal delivery of free amino acids.

Simultaneous Intranasal Codelivery of Donepezil and Memantine in a Nanocolloidal Carrier: Optimization, Pharmacokinetics, and Pharmacodynamics Studies.

This work focuses on developing nanoemulsions using a low-energy emulsification method for the codelivery of donepezil and memantine in one dosage form intended to be administered via the intranasal route for enhanced brain delivery. The nanoemulsion formulation was prepared using a low emulsification technique and characterized using various microscopy and nasal ciliotoxicity studies. The safe nanoemulsion was intended for preclinical pharmacokinetics with brain distribution and pharmacodynamics in a scopolamine-induced murine model. The formulated nanoemulsion was 16 nm in size, with a zeta potential of -7.22 mV, and exhibited a spherical shape. The brain concentration of IN-administered NE for DPZ and MEM was ∼678 and 249 ng/mL after 15 min. This concentration is more than 2 times higher in amount when compared with NE administered via PO, free drug solution administered via IN and PO route both. However, the plasma concentration of IN-administered NE for DPZ and MEM was ∼3 and 28 ng/mL after 15 min. In pharmacodynamic studies, the efficacy of NE administered via the IN route was higher when compared with other groups in neurobehavioral, biochemical estimation, and gene expression studies. The results suggest that the IN route can be explored in the future for the delivery of actives via nanocolloidal carriers in the brain for neurological disorders and can serve as promising alternatives for conventional dosage forms and routes.

Bioactive and Elastic Emulsion Electrospun DegraPol Tubes Delivering IGF-1 for Tendon Rupture Repair.

Tendon injuries can result in two major drawbacks. Adhesions to the surrounding tissue may limit the range of motion, while fibrovascular scar formation can lead to poor biomechanical outcomes. Prosthetic devices may help to mitigate those problems. Emulsion electrospinning was used to develop a novel three-layer tube based on the polymer DegraPol (DP), with incorporated insulin-like growth factor-1 (IGF-1) in the middle layer. Scanning electron microscopy was utilized to assess the fiber diameter in IGF-1 containing pure DP meshes. Further characterization was performed with Fourier Transformed Infrared Spectroscopy, Differential Scanning Calorimetry, and water contact angle, as well as through the assessment of mechanical properties and release kinetics from ELISA, and the bioactivity of IGF-1 by qPCR of collagen I, ki67, and tenomodulin in rabbit Achilles tenocytes. The IGF-1-containing tubes exhibited a sustained release of the growth factor up to 4 days and showed bioactivity by significantly upregulated ki67 and tenomodulin gene expression. Moreover, they proved to be mechanically superior to pure DP tubes (significantly higher fracture strain, failure stress, and elastic modulus). The novel three-layer tubes intended to be applied over conventionally sutured tendons after a rupture may help accelerate the healing process. The release of IGF-1 stimulates proliferation and matrix synthesis of cells at the repair site. In addition, adhesion formation to surrounding tissue can be reduced due to the physical barrier.

Novel oral microscope gives mechanistic insights into colloidal drivers of friction in oral biofilms.

Texture and mouthfeel are central to the sensory enjoyment of food and beverages. Yet our incomplete understanding of how food boluses are transformed in the mouth limits our texture prediction ability. As well as thin film tribology, the interaction of food colloids with the oral tissue and salivary biofilms plays a key role in texture perception via mechanoreceptors in the papillae. In this study we describe the development of an oral microscope capable of quantitative characterization of the inactions of food colloids with papillae and their concurrent saliva biofilm. We also highlight how the oral microscope revealed key microstructural drivers of several topical phenomena (oral residue formation, coalescence in-mouth, grittiness of protein aggregates and finally microstructural origin of polyphenol astringency) in the domain of texture creation. The coupling of a fluorescent food grade dye with image analysis enabled specific and quantitative determination of the microstructural changes in mouth. Emulsions either underwent no aggregation, small aggregation, or extensive aggregation depending on whether their surface charge facilitated complexation with the saliva biofilm. Quite surprisingly cationic gelatin emulsions that were already aggregated with saliva in mouth underwent coalescence if subsequently exposed to tea polyphenols (EGCG). Large protein aggregates were found to aggregate with the saliva coated papillae, increasing their size tenfold and possibly explaining why there are perceived as gritty. An exciting observation was the oral microstructural changes that occurred upon exposure to tea polyphenols (EGCG). Filiform papillae shrunk, and the saliva biofilm was seen to precipitate/collapse, exposing a very rough tissue surface. These tentative early steps are the first in vivo microstructural insights into the different food oral transformations that are drivers of key texture sensation.

Identification of emulsification proteins released from the cells by inhibiting the synthesis of GPI-anchor or ß-1,3-glucan in Candida albicans.

INTRODUCTION: A previous study demonstrated a strong emulsification ability of the culture supernatant obtained by cultivation of Candida albicans in a medium containing a ß-1,3-glucan synthesis inhibitor and proposed a novel screening method using emulsification as an indicator for ß-1,3-glucan synthesis inhibition (Nerome et al., 2021. Evaluating ß-1,3-glucan synthesis inhibition using emulsion formation as an indicator. J Microbiol Methods. 190:106327). The emulsification was presumed to be caused by the proteins released from the cells; however, which proteins have a strong emulsification ability was unclear. Furthermore, as many cell wall proteins are connected to ß-1,3-glucan via the carbohydrate moiety of the glycosylphosphatidylinositol (GPI)-anchor, which remains when detached from the cell membrane, emulsification might be detected by inhibiting GPI-anchor synthesis. OBJECTIVE: This study aimed to confirm whether emulsification could be detected by inhibiting GPI-anchor synthesis and identifying emulsification proteins released by inhibiting the synthesis of GPI-anchor or ß-1,3-glucan. METHODS: C. albicans was cultured in a medium containing a GPI-anchor synthesis inhibitor, and the emulsification by the culture supernatant was evaluated. We identified cell wall proteins released from the cells upon inhibition of ß-1,3-glucan or GPI-anchor synthesis by mass spectrometry, their recombinant proteins were prepared, and their emulsification efficacy was evaluated. RESULTS: In GPI-anchor synthesis inhibition, a weak emulsification phenomenon was observed compared to the ß-1,3-glucan synthesis inhibition. Phr2 protein was released from the cells upon GPI-anchor synthesis inhibition, and recombinant Phr2 showed a strong emulsification activity. Phr2 and Fba1 proteins were released upon ß-1,3-glucan synthesis inhibition, and recombinant Fba1 showed a strong emulsification activity. CONCLUSIONS: We concluded that the emulsion phenomenon could be used to screen ß-1,3-glucan and GPI-anchor synthesis inhibitors. Also, the two kinds of inhibitors could be distinguished by differences in the growth recovery by osmotic support and strength of emulsification. In addition, we identified the proteins involved in emulsification.

High internal phase emulsions stabilized by alkaline-extracted walnut protein isolates and their application in food 3D printing.

Alkaline-extracted walnut protein isolates showed relatively poor solubility and emulsifying properties in many previous studies. However, whether they can be used as potential emulsifiers to stabilize high internal phase emulsions (HIPEs) remains unknown. Herein, walnut protein isolates were prepared by alkaline extraction from walnut kernels with or without pellicles (named PAWPI and AWPI, respectively). PAWPI conjugated with pellicle polyphenols showed improved solubility and higher antioxidant capacity than AWPI. HIPEs were fabricated via a one-step method using AWPI or PAWPI as the sole protein emulsifier. HIPEs (oil fraction of 0.8, with 0.1% ß-carotene) could be stabilized by PAWPI at a relatively low concentration of 0.2% (w/v), while at least 1% (w/v) AWPI was required to effectively stabilize HIPEs. HIPEs stabilized by PAWPI had smaller oil droplet sizes than those stabilized by AWPI. Rheological analysis indicated that PAWPI-stabilized HIPEs showed higher viscosity and better viscoelasticity than AWPI-stabilized HIPEs. Large-amplitude oscillation shearing analysis suggested that PAWPI-stabilized HIPEs were stiffer but more brittle than AWPI-stabilized HIPEs. Moreover, both PAWPI- and AWPI-stabilized HIPEs exhibited good storage stability and were relatively stable against heat treatment and ionic strength. PAWPI-stabilized HIPEs showed a higher protective capacity for encapsulated ß-carotene than AWPI-stabilized HIPEs. In addition, PAWPI-stabilized HIPEs showed good 3D printability and could be used as a promising edible ink.

Brewer's Spent Yeast Cell Wall Polysaccharides as Vegan and Clean Label Additives for Mayonnaise Formulation.

Brewer's spent yeast (BSY) mannoproteins have been reported to possess thickening and emulsifying properties. The commercial interest in yeast mannoproteins might be boosted considering the consolidation of their properties supported by structure/function relationships. This work aimed to attest the use of extracted BSY mannoproteins as a clean label and vegan source of ingredients for the replacement of food additives and protein from animal sources. To achieve this, structure/function relationships were performed by isolating polysaccharides with distinct structural features from BSY, either by using alkaline extraction (mild treatment) or subcritical water extraction (SWE) using microwave technology (hard treatment), and assessment of their emulsifying properties. Alkaline extractions solubilized mostly highly branched mannoproteins (N-linked type; 75%) and glycogen (25%), while SWE solubilized mannoproteins with short mannan chains (O-linked type; 55%) and (1→4)- and (ß1→3)-linked glucans, 33 and 12%, respectively. Extracts with high protein content yielded the most stable emulsions obtained by hand shaking, while the extracts composed of short chain mannans and ß-glucans yielded the best emulsions by using ultraturrax stirring. ß-Glucans and O-linked mannoproteins were found to contribute to emulsion stability by preventing Ostwald ripening. When applied in mayonnaise model emulsions, BSY extracts presented higher stability and yet similar texture properties as the reference emulsifiers. When used in a mayonnaise formulation, the BSY extracts were also able to replace egg yolk and modified starch (E1422) at 1/3 of their concentration. This shows that BSY alkali soluble mannoproteins and subcritical water extracted ß-glucans can be used as replacers of animal protein and additives in sauces.

Skin pigmentation improvement with resveratrol microemulsion gel using polyoxyethylene hydrogenated castor oil.

OBJECTIVE: To investigate the safety and efficacy of resveratrol microemulsion gel in improving pigmentation. METHODS: Resveratrol microemulsion gel was prepared by the microemulsion solubilization method, and its quality was evaluated. The transdermal and drug retention rates of resveratrol in vivo were assessed using a transdermal test. The inhibitory effects of resveratrol suspension and microemulsion on tyrosinase activity and melanin production of A375 human melanocytes and zebrafish embryos were compared. A skin patch test was used to investigate the safety of the gel on 15 volunteers. RESULTS: The microemulsion gel was homogeneous and stable. Compared with suspension and microemulsion, the drug penetration rate and skin retention in the microemulsion gel group were significantly increased. Compared with the suspension group, the activity of melanocyte tyrosinase in A375 human melanocyte was significantly inhibited in the microemulsion group, and the melanin production rate of A375 human melanocyte and the melanin area of zebrafish yolk was decreased. All 15 volunteers tested negative for the human skin patch. CONCLUSIONS: The microemulsion gel could significantly enhance the ability of resveratrol to inhibit the formation of melanin without causing side effects. These data provide the experimental basis for developing and applying the preparation for improving pigmentation.

Unconventional and conventional Pickering emulsions: Perspectives and challenges in skin applications.

Pickering emulsions are free from molecular and classical surfactants and are stabilized by solid particles, creating long-term stability against emulsion coalescence. Additionally, these emulsions are both environmentally and skin-friendly, creating new and unexplored sensorial perceptions. Although the literature mostly describes conventional emulsions (oil-in-water), there are unconventional emulsions (multiple, oil-in-oil and water-in-water) with excellent prospects and challenges in skin application as oil-free systems, permeation enhancers and topical drug delivery agents, with various possibilities in pharmaceutical and cosmetic products. However, up to now, these conventional and unconventional Pickering emulsions are not yet available as commercial products. This review brings to the discussion some important aspects such as the use of phases, particles, rheological and sensorial perception, as well as current trends in the development of these emulsions.

Competitive binding of maltodextrin and pectin at the interface of whey protein hydrolyzate-based fish oil emulsion under high temperature sterilization: Effects on storage stability and in vitro digestion.

Whey protein hydrolysate (WPH), maltodextrin (MD), low methoxy pectin (LMP) and high methoxy pectin (HMP) were used to study the interface binding under high temperature sterilization conditions (121 °C, 15 min). The effect of competitive binding of MD and pectin with interface protein on the storage stability and gastrointestinal fate of fish oil emulsion was studied. The low-molecular-weight MD and the interface protein undergo a wide range of covalent binding through the Maillard reaction, while a small amount of high-molecular-weight pectin can form a protective shell with the interface protein through electrostatic interaction to inhibit the covalent reaction of MD, which was called competitive binding. However, due to the bridging and depletion flocculation of pectin, the emulsification stability of fish oil emulsion reduced. After 13 days of storage, compared with the particle size of the WPH fish oil emulsion (459.18 nm), the fish oil emulsion added with LMP and HMP reached 693.58 nm and 838.54 nm, respectively. In vitro digestion proved that WPH fish oil emulsion flocculated rapidly in the stomach (1.76 µm), while WPH-MD and WPH-MD-pectin fish oil emulsions flocculated slightly (less than800 nm). WPH-MD-pectin delayed digestion in the gastrointestinal tract, and HMP exhibited a better slow-release effect. This study provides reference for the design of multi-component functional drinks and other bioactive ingredient delivery system.