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.

Rice proteins - Gum arabic coacervates: Effect of pH and polysaccharide concentration in oil-in-water emulsion stability.

In the context of replacing animal proteins in food matrices, rice proteins (RP) become promised because they come from an abundant plant source, are hypoallergenic, and have high digestibility and nutritional value. However, commercial protein isolates obtained by spray drying have low solubility and poor functionality, especially in their isoelectric point. One way to modify these properties is through interaction with polysaccharides, such as gum arabic (GA). Therefore, this work aims to evaluate the effects of pH and GA concentration on the interaction and emulsifying activity of RP:GA coacervates. First, the effects of pH (2.5 to 7.0) and GA concentrations (0.2 to 1.0 wt%, giving rise to RP:GA mass ratios of 1:0.2 to 1:1.0) in RP:GA blends were evaluated. The results demonstrated that biopolymers present opposite net charges at pH between 2.5 and 4.0. At pH 3.0, insoluble coacervates with complete charge neutralization were formed by electrostatic interactions, while at pH 5.0 it was observed that the presence of GA prevented the RP massive aggregation. Second, selected blends with 0.4 or 1.0 wt% of GA (RP:GA mass ratios of 1:0.4 or 1:1.0) at pH 3.0 or 5.0 were tested for their ability to stabilize oil-in-water emulsions. The emulsions were characterized for 21 days. It was observed that the GA increased the stability of RP emulsions, regardless of the pH and polysaccharide concentration. Taken together, our results show that it is possible to combine RP and GA to improve the emulsifying properties of these plant proteins at pH conditions close to their isoelectric point, expanding the possibility of implementation in food systems.

Enhancing the usability of pea protein in emulsion applications through modification by various approaches: A comparative study.

The extensive utilization in food industry of pea protein is often impeded by its low water solubility, resulting in poor functional properties. Various methods, including pH-shifting (PS), ultrasonication (US), high-pressure micro-fluidization (MF), pH-shifting combined with ultrasonication (PS-US), and pH-shifting with micro-fluidization (PS-MF), were utilized to modify pea protein isolate (PPI) in order to enhance its functionality in emulsion formulation. The physicochemical properties and structural changes of the protein were investigated by assessing solubility, particle size, surface charge, protein profile, surface hydrophobicity, free sulfhydryl groups, and secondary structure content. The extent of modification induced by each treatment method on PPI-stabilized emulsions was compared based on parameters such as adsorbed interfacial protein concentration, particle size, zeta potential, and microstructure of the prepared emulsions. All modification increased the solubility of pea protein in the sequence of PS (4-fold) < MF (7-fold) < US (11-fold) < PS-US (13-fold) < PS-MF (14-fold). For single treatments, proteins dissolved more readily under US, resulting in the most uniform emulsions with small particle. The combined processes of PS-US and PS-MF further improved solubility, decreased emulsions particle size, promoted uniformity of emulsions. PS-US-stabilized emulsions displayed more smaller droplet size, narrower size distribution, and slightly higher stability than those prepared by PS-MF. The relatively higher emulsifying capacity of PPI treated by PS-US than those by PS-MF may be attributed to its higher surface hydrophobicity.

Effects and mechanisms of ultrasound-assisted emulsification treatment on the curcumin delivery and digestive properties of myofibrillar protein-carboxymethyl cellulose complex emulsion gel.

Different emulsion gel systems are widely applied to deliver functional ingredients. The effects and mechanisms of ultrasound-assisted emulsification (UAE) treatment and carboxymethyl cellulose (CMC) modifying the curcumin delivery properties and in vitro digestibility of the myofibrillar protein (MP)-soybean oil emulsion gels were investigated. The rheological properties, droplet size, protein and CMC distribution, ultrastructure, surface hydrophobicity, sulfhydryl groups, and zeta potential of emulsion gels were also measured. Results indicate that UAE treatment and CMC addition both improved curcumin encapsulation and protection efficiency in MP emulsion gel, especially for the UAE combined with CMC (UAE-CMC) treatment which encapsulation efficiency, protection efficiency, the release rate, and bioaccessibility of curcumin increased from 86.75 % to 97.67 %, 44.85 % to 68.85 %, 18.44 % to 41.78 %, and 28.68 % to 44.93 % respectively. The protein digestibility during the gastric stage was decreased after the CMC addition and UAE treatment, and the protein digestibility during the intestinal stage was reduced after the CMC addition. The fatty acid release rate was increased after CMC addition and UAE treatment. Apparent viscosity, storage modulus, and loss modulus were decreased after CMC addition while increased after UAE and UAE-CMC treatment especially the storage modulus increased from 0.26 Pa to 41 Pa after UAE-CMC treatment. The oil size was decreased, the protein and CMC concentration around the oil was increased, and a denser and uniform emulsion gel network structure was formed after UAE treatment. The surface hydrophobicity, free SH groups, and absolute zeta potential were increased after UAE treatment. The UAE-CMC treatment could strengthen the MP emulsion gel structure and decrease the oil size to increase the curcumin delivery properties, and hydrophobic and electrostatic interaction might be essential forces to maintain the emulsion gel.

Droplet size dependency and spatial heterogeneity of lipid oxidation in whey protein isolate-stabilized emulsions.

Spatiotemporal assessment of lipid and protein oxidation is key for understanding quality deterioration in emulsified food products containing polyunsaturated fatty acids. In this work, we first mechanistically validated the use of the lipid oxidation-sensitive fluorophore BODIPY 665/676 as a semi-quantitative marker for local peroxyl radical formation. Next, we assessed the impact of microfluidic and colloid mill emulsification (respectively producing mono- and polydisperse droplets) on local protein and lipid oxidation kinetics in whey protein isolate (WPI)-stabilized emulsions. We further used BODIPY 581/591 C11 and CAMPO-AFDye 647 as colocalisation markers for lipid and protein oxidation. The polydisperse emulsions showed an inverse relation between droplet size and lipid oxidation rate. Further, we observed less protein and lipid oxidation occurring in similar sized droplets in monodisperse emulsions. This observation was linked to more heterogeneous protein packing at the droplet surface during colloid mill emulsification, resulting in larger inter-droplet heterogeneity in both protein and lipid oxidation. Our findings indicate the critical roles of emulsification methods and droplet sizes in understanding and managing lipid oxidation.

Constructing myosin/high-density lipoprotein composite emulsions: Roles of pH on emulsification stability, rheological and structural properties.

The emulsification activity of myosin plays a significant role in affecting quality of emulsified meat products. High-density lipoprotein (HDL) possesses strong emulsification activity and stability due to its structural characteristics, suggesting potential for its utilization in developing functional emulsified meat products. In order to explore the effect of HDL addition on emulsification stability, rheological properties and structural features of myosin (MS) emulsions, HDL-MS emulsion was prepared by mixing soybean oil with isolated HDL and MS, with pH adjustments ranging from 3.0 to 11.0. The results found that emulsification activity and stability in two emulsion groups consistently improved as pH increased. Under identical pH, HDL-MS emulsion exhibited superior emulsification behavior as compared to MS emulsion. The HDL-MS emulsion under pH of 7.0-11.0 formed a viscoelastic protein layer at the interface, adsorbing more proteins and retarding oil droplet diffusion, leading to enhanced oxidative stability, compared to the MS emulsion. Raman spectroscopy analysis showed more flexible conformational changes in the HDL-MS emulsion. Microstructural observations corroborated these findings, showing a more uniform distribution of droplet sizes in the HDL-MS emulsion with smaller particle sizes. Overall, these determinations suggested that the addition of HDL enhanced the emulsification behavior of MS emulsions, and the composite emulsions demonstrated heightened responsiveness under alkaline conditions. This establishes a theoretical basis for the practical utilization of HDL in emulsified meat products.

Young bamboo flour as a substitute for emulsifying salts in requeijão cremoso processed cheese and the effect on the quality parameters.

The effect of the substitution of emulsifying salt by the young bamboo flour (BF) (0, 25, 50, 75, 100 % w/w) on requeijão cremoso processed cheese [REQ, REQ 25, REQ 75 REQ 100]) processing was investigated. Gross composition, calcium and sodium values, functional properties (melting rate), color parameters (L, a*, b*, C*, and Whiteness Index, WI), texture profile, fatty acid profile, volatile organic compounds (VOCs), and sensory profiling were evaluated. No effect was observed on the gross composition; however, sodium and melting rate values were decreased, and calcium values presented the opposite behavior. BF could modify the optical parameters, observing an increase in WI values. Higher BF addition increased hardness and lowered elasticity, and regarding the fatty acid profile, there is no significant difference. Different volatile compounds were noted in a proportional form with the BF addition, which was reflected in similar sensory acceptance for REQ 25 and control samples. Although some aspects require further in-depth studies, using BF as a substitute for emulsifying salt in requeijão cremoso processed cheese appears to be a viable option, especially when considering partial replacements.

Regulation of fat crystals in water-in-oil emulsions by high-intensity ultrasound: Crystal size and tracing of droplet distribution.

In this paper, two emulsion systems with high and low solid fat contents were prepared from 20 % water phase and 80 % oil phase by adjusting the palm oil/palm stearin/soybean oil ratio. Different ultrasonic power and time were used for the pretreatment of emulsion with different solid fat content, and the application characteristics of ultrasonic in W/O emulsions were explored and evaluated. Directly using high-intensity ultrasound to prepare fatty emulsions would weaken the hardness and storage modulus G' of the samples. Although ultrasound reduced the size of fat crystals in emulsions, the interaction between water droplets and fat crystals needs to be considered. After ultrasonic treatment, water droplets were difficult to immobilize on the crystal surface and thus acted as an active filler to stabilize the emulsion together with the fat crystal network. In high solid fat emulsion systems, an increase in ultrasound power (from 100 W to 200 W) could more affect the crystallization behavior of fats than an increase in ultrasound duration (from 30 s to 60 s), and the distribution of crystals and droplets was more uniform. In the low solid fat emulsion system, the texture of the sample after ultrasonic treatment was softer, and the surface was more delicate and smoother. However, the higher ultrasonic intensity (200 W) was not conducive to the preparation of the spread. Although the ultrasound with excessive intensity promoted the formation of small crystals, it would also lead to the aggregation of small crystals. These small crystals cannot form a uniform crystal network, which increases the fluidity of emulsions.

Encapsulation of antioxidants with colloidal lipid particles for enhancing the photooxidation stability of phytosterol in Pickering emulsions.

In order to prevent the photooxidation of phytosterols, a new type of Pickering emulsion was developed by regulating the oriented distribution of antioxidants in colloidal lipid particles (CLPs) at the oil-water interface. High-melting-point and low-melting-point lipids were tested to modulate their protective effect against phytosterols photooxidation. Results showed that CLPs could stabilize Pickering emulsion and encapsulate antioxidants, providing a dual functional delivery system for phytosterols protection. The Pickering emulsion formed had a particle size of around 350-820 nm, and the crystallization and melting temperatures of tripalmitin particles were approximately 32 °C and 63.8 °C, respectively. The addition of tributyrin or tricaprylin reduced the crystallization and melting temperatures of Pal CLPs and improved the photooxidation emulsion stability. The prepared Pickering emulsion remained stable for a maximum of 12 days under accelerated light-induced oxidation. Among all formulations, the emulsion primarily composed of tripalmitin CLPs, with added tributyrin and resveratrol, exhibited the highest photooxidation stability.

Physicochemical properties of active films of rose essential oil produced using soy protein isolate-polyphenol conjugates for cherry tomato preservation.

Soy protein isolate (SPI)-polyphenol conjugates were produced by grafting SPI individually with curcumin, naringenin, and catechin. The resulting conjugates showed better emulsifying properties and were used to develop active films containing rose essential oil. The effect of conjugation on the physicochemical and mechanical properties of these emulsion-based films was evaluated. The results showed that the barrier and mechanical properties of the films were improved when the SPI-polyphenol conjugates were used to emulsify the essential oil; in particular, the SPI-curcumin conjugate showed significant improvement. The improvements on the water vapor and oxygen barrier properties in the films were attributed to the formation of compact structure. Emulsion-based films stabilized by SPI-polyphenol conjugates showed antioxidant and antibacterial activities. They also demonstrated an ability to extend the shelf life of cherry tomatoes, as indicated by better preservation of weight, firmness, and ascorbic acid content.

Optimizing Process Parameters for Controlled Drug Delivery: A Quality by Design (QbD) Approach in Naltrexone Microspheres.

The formulation of microspheres involves a complex manufacturing process with multiple steps. Identifying the appropriate process parameters to achieve the desired quality attributes poses a significant challenge. This study aims to optimize the critical process parameters (CPPs) involved in the preparation of naltrexone microspheres using a Quality by Design (QbD) methodology. Additionally, the research aims to assess the drug release profiles of these microspheres under both in vivo and in vitro conditions. Critical process parameters (CPPs) and critical quality attributes (CQAs) were identified, and a Box-Behnken design was utilized to delineate the design space, ensuring alignment with the desired Quality Target Product Profile (QTPP). The investigated CPPs comprised polymer concentration, aqueous phase ratio to organic phase ratio, and quench volume. The microspheres were fabricated using the oil-in-water emulsion solvent extraction technique. Analysis revealed that increased polymer concentration was correlated with decreased particle size, reduced quench volume resulted in decreased burst release, and a heightened aqueous phase ratio to organic phase ratio improved drug entrapment. Upon analyzing the results, an optimal formulation was determined. In conclusion, the study conducted in vivo drug release testing on both the commercially available innovator product and the optimized test product utilizing an animal model. The integration of in vitro dissolution data with in vivo assessments presents a holistic understanding of drug release dynamics. The QbD approach-based optimization of CPPs furnishes informed guidance for the development of generic pharmaceutical formulations.

Potential application of munguba butter in the formulation of nanoemulsified systems.

Munguba butter has bioactive compounds such as vitamin E and phytosterols, which has valued its application in the development of new products, with advantages in its use in emulsified formulations. Therefore, the objective was to develop and evaluate the stability of a nanoemulsion containing munguba butter as the oily phase. Munguba butter was extracted by the ultrasound assisted method and its HLB (hydrophilic-lipophilic balance) was determined. Next, formulations varying the concentration of butter from 1-40% were developed and classified into liquid or solid emulsion and phase separation. Liquid emulsions were evaluated for hydrodynamic particle diameter, polydispersity index (PDI), Zeta potential (ζ), rheological characterization, and stability assays. The butter had an HLB of 6.98. The NE 1.0% formulation was selected and demonstrated to be unstable at high temperatures (45 ± 2 °C) and remained stable at room temperature, refrigeration and light radiation for 90 days. Munguba butter, because it has high amounts of saturated fatty acids, hinders its application in the development of new products. However, the success in the development of the NE 1.0% formulation is noteworthy, remaining stable when exposed to refrigeration, room temperature and light radiation.

Microencapsulation of apricot kernel oil: Utilization of mushroom by-product as an emulsifier in oil-in-water emulsion.

The present study investigated mushroom by-products as a substitute for emulsifiers in the microencapsulation of apricot kernel oil. Mushroom by-product emulsions were more viscous and had higher centrifugal (85.88±1.19 %) and kinetic (90.52±0.98 %) stability than control emulsions (Tween 20 was used as emulsifier). Additionally, spray-drying mushroom by-product emulsions yielded a high product yield (62.56±1.11 %). Furthermore, the oxidative stability of powder products containing mushroom by-products was observed to be higher than that of the control samples. For an accelerated oxidation test, the samples were kept at various temperatures (20, 37, and 60 °C). TOTOX values were assessed as indicators of oxidation, with values exceeding 30 indicating oxidation of the samples. Of the samples stored at 60 °C, the non-microencapsulated apricot kernel oil oxidized by the fifth day (41.12±0.13 TOTOX value), whereas the powder samples containing the mushroom by-products remained unoxidized until the end of the tenth day (37.05±0.08 TOTOX value). This study revealed that mushroom by-products could be a viable alternative for synthetic emulsifiers in the microencapsulation of apricot kernel oil. It has been observed that using mushroom by-products instead of synthetic emulsifiers in oil microencapsulation can also delay oxidative degradation in microencapsulated powders.

Formulation and Characterization of Soybean Oil-in-Water Emulsions Stabilized Using Gelatinized Starch Dispersions from Plant Sources.

Consumers are concerned about employing green processing technologies and natural ingredients in different manufacturing sectors to achieve a "clean label" standard for products and minimize the hazardous impact of chemical ingredients on human health and the environment. In this study, we investigated the effects of gelatinized starch dispersions (GSDs) prepared from six plant sources (indica and japonica rice, wheat, corn, potatoes, and sweet potatoes) on the formulation and stability of oil-in-water (O/W) emulsions. The effect of gelatinization temperature and time conditions of 85-90 °C for 20 min on the interfacial tension of the two phases was observed. Emulsification was performed using a primary homogenization condition of 10,000 rpm for 5 min, followed by high-pressure homogenization at 100 MPa for five cycles. The effects of higher oil weight fractions (15-25% w/w) and storage stability at different temperatures for four weeks were also evaluated. The interfacial tension of all starch GSDs with soybean oil decreased compared with the interfacial tension between soybean oil and water as a control. The largest interfacial tension reduction was observed for the GSD from indica rice. Microstructural analysis indicated that the GSDs stabilized the O/W emulsion by coating oil droplets. Emulsions formulated using a GSD from indica rice were stable during four weeks of storage with a volume mean diameter (d4,3) of ~1 µm, minimal viscosity change, and a negative ζ-potential.

Green Synthesis of Blumea balsamifera Oil Nanoemulsions Stabilized by Natural Emulsifiers and Its Effect on Wound Healing.

In this study, we developed a green and multifunctional bioactive nanoemulsion (BBG-NEs) of Blumea balsamifera oil using Bletilla striata polysaccharide (BSP) and glycyrrhizic acid (GA) as natural emulsifiers. The process parameters were optimized using particle size, PDI, and zeta potential as evaluation parameters. The physicochemical properties, stability, transdermal properties, and bioactivities of the BBG-NEs under optimal operating conditions were investigated. Finally, network pharmacology and molecular docking were used to elucidate the potential molecular mechanism underlying its wound-healing properties. After parameter optimization, BBG-NEs exhibited excellent stability and demonstrated favorable in vitro transdermal properties. Furthermore, it displayed enhanced antioxidant and wound-healing effects. SD rats wound-healing experiments demonstrated improved scab formation and accelerated healing in the BBG-NE treatment relative to BBO and emulsifier groups. Pharmacological network analyses showed that AKT1, CXCL8, and EGFR may be key targets of BBG-NEs in wound repair. The results of a scratch assay and Western blotting assay also demonstrated that BBG-NEs could effectively promote cell migration and inhibit inflammatory responses. These results indicate the potential of the developed BBG-NEs for antioxidant and skin wound applications, expanding the utility of natural emulsifiers. Meanwhile, this study provided a preliminary explanation of the potential mechanism of BBG-NEs to promote wound healing through network pharmacology and molecular docking, which provided a basis for the mechanistic study of green multifunctional nanoemulsions.

Investigation of the Inhibitory Effects of Illicium verum Essential Oil Nanoemulsion on Fusarium proliferatum via Combined Transcriptomics and Metabolomics Analysis.

Fusarium proliferatum is the main pathogen that causes Panax notoginseng root rot. The shortcomings of strong volatility and poor water solubility of Illicium verum essential oil (EO) limit its utilization. In this study, we prepared traditional emulsion (BDT) and nanoemulsion (Bneo) of I. verum EO by ultrasonic method with Tween-80 and absolute ethanol as solvents. The chemical components of EO, BDT, and Bneo were identified by gas chromatography-mass spectrometry (GC-MS) and the antifungal activity and mechanism were compared. The results show that Bneo has good stability and its particle size is 34.86 nm. The contents of (-) -anethole and estragole in Bneo were significantly higher than those in BDT. The antifungal activity against F. proliferatum was 5.8-fold higher than BDT. In the presence of I. verum EO, the occurrence of P. notoginseng root rot was significantly reduced. By combining transcriptome and metabolomics analysis, I. verum EO was found to be involved in the mutual transformation of pentose and glucuronic acid, galactose metabolism, streptomycin biosynthesis, carbon metabolism, and other metabolic pathways of F. proliferatum, and it interfered with the normal growth of F. proliferatum to exert antifungal effects. This study provide a theoretical basis for expanding the practical application of Bneo.

Development of 1 Month Sustained-Release Microspheres Containing Liraglutide for Type 2 Diabetes Treatment.

Liraglutide has been extensively applied in the treatment of type 2 diabetes mellitus (T2DM), but its 11-15 h half-life resulted in daily administration, which led to poor patient compliance. This study aimed to solve this problem by developing liraglutide-loaded microspheres with a 1 month sustained release prepared by the W1/O/W2 method combined with the premix membrane emulsification technique to improve therapeutic efficacy. Remarkably, we found that the amphiphilic properties of liraglutide successfully reduced the oil-water interfacial tension, resulting in a stable primary emulsion and decreasing the level of drug leakage into the external water phase. As a result, exceptional drug loading (>8%) and encapsulation efficiency (>85%) of microspheres were achieved. Furthermore, the uniformity in microsphere size facilitated an in-depth exploration of the structural characteristics of liraglutide-loaded microspheres. The results indicated that the dimensions of the internal cavities of the microspheres were significantly influenced by the size of the inner water droplets in the primary emulsion. A denser and more uniform cavity structure decreased the initial burst release, improving the release process of liraglutide from the microspheres. To evaluate the release behavior of liraglutide from microspheres, a set of in vitro release assays and in vivo pharmacodynamics were performed. The liraglutide-loaded microspheres effectively decreased fasting blood glucose (FBG) levels and hemoglobin A1c (HbA1c) levels while enhancing the pancreatic and hepatic functions in db/db mice. In conclusion, liraglutide sustained-release microspheres showed the potential for future clinical applications in the management of T2DM and provided an effective therapeutic approach to overcoming patient compliance issues.

Microemulsions based on Acer truncatum seed oil and its fatty acids: fabrication, rheological property, and stability.

AIMS: To construct the microemulsion delivery system (ME) loading ATSO and NA and study their physicochemical characteristics to enhance their stability and water solubility. METHODS: By plotting ternary phase diagrams, the composition and proportions of the MEs were determined. The physicochemical characteristics and stability of MEs were evaluated by mean diameter, polydispersity index (PDI), pH, electrical conductivity, transmission electron microscopy (TEM), rheological behaviour measurement, and phase inversion temperature (PIT). RESULTS: The MEs was composed with EL-40 as a surfactant and specifically with the addition of ethanol as a cosurfactant in NA-loaded ME. The mean diameters of ATSO-loaded ME and NA-loaded ME were 39.65 ± 0.24 nm and 32.90 ± 2.65 nm, and PDI were 0.49 ± 0.01 and 0.28 ± 0.14, respectively. The TEM confirmed the spherical and smooth morphology of MEs. The rheological results indicated that MEs are dilatant fluids with the advantages of low viscosity, high fluidity, and tolerance to temperature fluctuations. The mean diameter and PDI of MEs showed no significant change after storage at 25 °C for 28 days and centrifugation. CONCLUSION: The prepared microemulsions could expand the application prospects of ATSO and NA products in cosmetics, medicine, foods and other fields.

Cosmetically Approved Short-Chain Alcohol/Triethyl Citrate/Water Surfactant-Free Microemulsions and Potential Application to Transdermal Penetration of α-Arbutin.

Surfactant-free microemulsions (SFMEs) exhibited remarkable advantages and potential, attributed to their similarity to traditional surfactant-based microemulsions and the absence of surfactants. Herein, a novel SFME was developed utilizing cosmetically approved materials, such as short-chain alcohol as an amphi-solvent, triethyl citrate (TEC) as the nonpolar phase, and water as the polar phase. 1,2-Pentanediol (PtDO)/TEC/water combination can form the largest monophasic zone, accounting for ∼74% of the total phase diagram area, due to an optimal hydrophilic (water)-lipophilic (TEC) balance. Comparable to surfactant-based microemulsion, PtDO/TEC/water SFME can also be categorized into three types: water-in-oil, discontinuous, and oil-in-water. As TEC or water is increased, or PtDO is decreased, the nanoaggregates in PtDO/TEC/water SFME grow from <5 nm to tens of nanometers. The addition of α-arbutin (ABN) does not disrupt PtDO/TEC/water SFME, but rather enhances its formation, resulting in a larger monophasic area and consistent size (2.8-3.8 nm) through participating in interface assembly. Furthermore, ABN-loaded PtDO/TEC/water SFME exhibits remarkable resistance to dilution, exceptional stability, and minimal irritation. Notably, PtDO/TEC/water SFME significantly boosts ABN's solubility in water by 2 times, its percutaneous penetration rate by 3-4 times, and enables a slow-release DPPH• radical scavenging effect. This SFME serves as a safe and cosmetically suitable nanoplatform for the delivery of bioactive substances.

From Antagonism to Enhancement: Triton X-100 Surfactant Affects Phenanthrene Interfacial Biodegradation by Mycobacteria through a Shift in Uptake Mechanisms.

Polycyclic aromatic hydrocarbons (PAHs), as persistent environmental pollutants, often reside in nonaqueous-phase liquids (NAPLs). Mycobacterium sp. WY10, boasting highly hydrophobic surfaces, can adsorb to the oil-water interface, stabilizing the Pickering emulsion and directly accessing PAHs for biodegradation. We investigated the impact of Triton X-100 (TX100) on this interfacial uptake of phenanthrene (PHE) by Mycobacteria, using n-tetradecane (TET) and bis-(2-ethylhexyl) phthalate (DEHP) as NAPLs. Interfacial tension, phase behavior, and emulsion stability studies, alongside confocal laser scanning microscopy and electron microscope observations, unveiled the intricate interplay. In surfactant-free systems, Mycobacteria formed stable W/O Pickering emulsions, directly degrading PHE within the NAPLs because of their intimate contact. Introducing low-dose TX100 disrupted this relationship. Preferentially binding to the cells, the surfactant drastically increased the cell hydrophobicity, triggering desorption from the interface and phase separation. Consequently, PAH degradation plummeted due to hindered NAPL access. Higher TX100 concentrations flipped the script, creating surfactant-stabilized O/W emulsions devoid of interfacial cells. Surprisingly, PAH degradation remained efficient. This paradox can be attributed to NAPL emulsification, driven by the surfactant, which enhanced mass transfer and brought the substrate closer to the cells, despite their absence at the interface. This study sheds light on the complex effect of surfactants on Mycobacteria and PAH uptake, revealing an antagonistic effect at low concentrations that ultimately leads to enhanced degradation through emulsification at higher doses. These findings offer valuable insights into optimizing bioremediation strategies in PAH-contaminated environments.