Lauroyl Arginate Research Articles

Waste Orange Peels as a Source of Cellulose Nanocrystals and Their Use for the Development of Nanocomposite Films.

To date, approximately 30-50% of food is wasted from post-harvesting to consumer usage. Typical examples of food by-products are fruit peels and pomace, seeds, and others. A large part of these matrices is still discarded in landfills, while a small portion is valorized for bioprocessing. In this context, a feasible strategy to valorize food by-products consists of their use for the production of bioactive compounds and nanofillers, which can be further used to functionalize biobased packaging materials. The focus of this research was to create an efficient methodology for the extraction of cellulose from leftover orange peel after juice processing and for its conversion into cellulose nanocrystals (CNCs) for use in bionanocomposite films for packaging materials. Orange CNCs were characterized by TEM and XRD analyses and added as reinforcing agents into chitosan/hydroxypropyl methylcellulose (CS/HPMC) films enriched with lauroyl arginate ethyl (LAE®). It was evaluated how CNCs and LAE® affected the technical and functional characteristics of CS/HPMC films. CNCs revealed needle-like shapes with an aspect ratio of 12.5, and average length and width of 500 nm and 40 nm, respectively. Scanning electron microscopy and infrared spectroscopy confirmed the high compatibility of the CS/HPMC blend with CNCs and LAE®. The inclusion of CNCs increased the films' tensile strength, light barrier, and water vapor barrier properties while reducing their water solubility. The addition of LAE® improved the films' flexibility and gave them biocidal efficacy against the main bacterial pathogens that cause foodborne illness, such as Escherichia coli, Pseudomonas fluorescens, Listeria monocytogenes, and Salmonella enterica.

Efficacy testing of non-oxidizing biocides for polyamide membrane biofouling prevention using a modified CDC biofilm reactor

AbstractBiofouling is one of the most challenging obstacles faced by reverse osmosis (RO) membrane systems to supply potable water. Currently, biofouling is imperfectly handled by RO feed water pre-chlorination, which is associated with the production of carcinogenic disinfection by-products. To propose a safer alternative to control biofouling in RO drinking water applications, this study investigates the efficacy of five biocides to prevent and remove Pseudomonas aeruginosa biofilms from RO membranes: 2-methyl-4-isothiazolin-3-one (MIT); 2,2-dibromo-3-nitrilopropionamide (DBNPA); sodium bisulfite (SBS); sodium benzoate (SB); and ethyl lauroyl arginate (LAE). Experiments were conducted on the Center for Disease Control (CDC) Biofilm Reactor (CBR) with biocidal dosing estimated on 96-well microtiter plates. Confocal Scanning Laser Microscopy (CLSM) and Scanning Electron Microscopy (SEM) were used to analyze the biocides' anti-biofilm efficacies under dynamic conditions relative to minimum biofilm inhibitory and eradication concentrations. The results in this study indicated that LAE presented the best anti-biofilm efficacies in treating P. aeruginosa biofilms when compared to all studied biocides; it not only prevented biofilm formation (>98%) but also it effectively removed pre-established biofilms (>99%) from RO membrane coupons. Therefore, due to safety and efficacy, LAE is an excellent candidate for controlling biofouling in drinking water RO membrane systems.

Development of a sustainable and antibacterial food packaging material based in a biopolymeric multilayer system composed by polylactic acid, chitosan, cellulose nanocrystals and ethyl lauroyl arginate

Biodegradable packaging materials with antimicrobial properties are main key for developing sustainable active packages able to protect different foodstuff. Thus, the aim of this research was developing a biopolymeric and antibacterial packaging material with a trilayer structure through the combination of extrusion, electrospinning and coating techniques. This trilayer system was composed by a support extruded layer of polylactic acid (PLA), an intermediate PLA electrospun layer loaded with ethyl lauroyl arginate (LAE) and cellulose nanocrystals (CNC), and a third inner chitosan coating. Morphological, wettability, antibacterial and disintegrability properties of this material were evaluated. The morphological surface analysis evidenced the heterogeneity of the chitosan coating over the electrospun PLA layer, and this effect affected negatively the evaluation of wettability of this trilayer material. Antibacterial assays evidenced a fast and strong bactericidal effect against Gram(+) and (−) bacteria that maintained this activity for 15 days. Finally, the biodegradable properties of different layers favored the disintegration of developed trilayer material at 21 days under composting conditions.

The Influence of the Surface Chemistry of Cellulose Nanocrystals on Ethyl Lauroyl Arginate Foam Stability.

Guanidine-based surfactant ethyl lauroyl arginate (LAE) and cellulose nanocrystals (CNCs) form complexes of enhanced surface activity when compared to pure surfactants. The LAE-CNC mixtures show enhanced foaming properties. The dynamic thin-film balance technique (DTFB) was used to study the morphology, drainage and rupture of LAE-CNC thin liquid films under constant driving pressure. A total of three concentrations of surfactant and the corresponding mixtures of LAE with sulfated (sCNC) and carboxylated (cCNC) cellulose nanocrystals were studied. The sCNC and cCNC suspension with LAE formed thin films, with stability increasing with surfactant concentration and with complex rheological properties. In the presence of LAE, the aggregation of CNC was observed. While the sCNC aggregates were preferentially present in the film volume with a small fraction at the surface, the cCNC aggregates, due to their higher hydrophobicity, were preferentially located at film interfaces, forming compact layers. The presence of both types of aggregates decreased the stability of the thin liquid film compared to the one for the LAE solution with the same concentration. The addition of CNC to LAE was critical for foam formation, and foam stability was in qualitative agreement with the thin films' lifetimes. The foam volume increased with the LAE concentration. However, there was an optimum surfactant concentration to achieve stable foam. In particular, the very resistant foam was obtained with cCNC suspensions that formed the interfaces with a complex structure and rheology. On the other hand, at high LAE concentrations, the aggregates of CNC may exhibit antifoaming properties.

Ethyl lauroyl arginate-based hydrophobic ion pair complex in lipid nanocapsules: A novel oral delivery approach of rosmarinic acid for enhanced permeability and bioavailability

Limited oral bioavailability due to high hydrophilicity restricts the beneficial use of Rosmaranic acid (RM) that is characterized by many biological and pharmacological effects. The present work was addressed to extract RM from Rosmarinus officinalis L. leaves and then increase its lipophilicity and permeability through the application of hydrophobic ion pair (HIP) approach using ethyl lauroyl arginate (ELA) as a novel counter-ion. Different RM:ELA ratios were screened to optimize HIP formation process. The encapsulation of the optimized HIP into lipid nanocapsules (LNCs) was then achieved to facilitate oral administration. The results of % transmittance, % complexation efficiency (87.32 ± 0.19%) and partition coefficient revealed the successful formation of the HIP complex occurred at RM:ELA molar ratio of 1:2. The formed HIP was successfully loaded into spherical small sized (39.32 ± 0.18 nm) LNCs. The ex vivo permeability studies across porcine intestine showed that the cumulative RM amount permeated/area after 6 h from HIP and LNCs were 3.79 ± 0.57 and 5.71 ± 0.32 µg/cm2, respectively. Pharmacokinetic study results showed that the maximum RM concentrations in plasma (Cmax) can be arranged in a descending manner as follows; 61.33 ± 8.89 < 42.13 ± 11.22 < 20.96 ± 3.12 ng/ml attained after 4.80, 8.00 and 10.40 h in case of LNC, HIP and solution, respectively. Moreover, the HIP and LNC formulae showed higher total drug amounts in plasma reaching 1.46 and 1.88-fold relative to RM solution, respectively. In conclusion, the HIP complex and HIP loaded LNCs prosper in enhancing the permeability and absorption of the low permeable drugs.

Developing ethyl lauroyl arginate antimicrobial films to combat Listeria monocytogenes in cured ham

Widespread use of plastics poses a serious environmental hazard to our planet and should be substituted by eco-friendly and biodegradable alternatives, simultaneously reducing waste of perishable food products and the risk of transmission of pathogenic microbes. In our study, we describe how the water solubility of the antimicrobial surfactant ethyl lauroyl arginate (LAE) can be reduced through complexation with a Keggin-type polyoxometalate (POM), K8[SiW11O39]. The POM-LAE complex, LAE7K[SiW11O39], was effective against Listeria monocytogenes (L. monocytogenes) and Escherichia coli (E. coli) with minimal inhibitory concentrations (MICs) of 32 and 64 μg/mL, respectively, with the important finding that the concentrations of LAE required to inhibit bacterial growth were as much as two times lower in the POM-LAE complex, compared with LAE on its own. In addition, our results demonstrate that POM-LAE is both an effective inhibitor of biofilm formation and is also able to destroy pre-formed biofilms of L. monocytogenes and E. coli at MIC concentrations. Further, POM-LAE was incorporated into carboxymethyl cellulose (CMC) films that were able to reduce 7–8 log (CFU/mL) of L. monocytogenes at concentrations of 5–10% POM-LAE. In vivo assays of the POM-LAE-CMC films with cured ham prevented initialk bacterial growth with a 0.77 log significative reduction in bacterial counts. Overall, this work provides new alternatives for the development of antimicrobial biodegradable films for ready-to-eat (RTE) foods prone to contamination with pathogenic bacteria, such as L. monocytogenes, while also circumventing practical issues related to the incorporation of LAE into active packaging films.

Nanostructured lipid carriers (NLCs) stabilized by natural or synthetic emulsifiers for lutein delivery: Improved physicochemical stability, antioxidant activity, and bioaccessibility

This study investigated the impacts of individual emulsifiers on the physicochemical stability, antioxidant ability, and in vitro digestion behavior of lutein-loaded nanostructured lipid carriers (NLCs). NLCs particles stabilized by ethyl lauroyl arginate, rhamnolipid, or tea saponin were fabricated by high-pressure microfluidization method. Differential scanning calorimetry and X-ray diffraction results confirmed the regulatory effect of emulsifiers on the crystallization behavior of NLCs. NLCs stabilized by rhamnolipid presented higher encapsulation efficiency (94.73%) for lutein than those stabilized by tea saponin (90.39%) or ethyl lauroyl arginate (88.86%). Meanwhile, the stability of embedded lutein during storage or photothermal treatments was greatly enhanced. Individual emulsifiers, together with lutein, endowed NLCs with excellent antioxidant capacity. During in vitro digestion, rhamnolipid-stabilized NLCs showed the slowest release of free fatty acids (50.87%) and provided an optimal sustained release for lutein with relatively high bioaccessibility (23.01%).

Enhancing the Matrix–Fiber Interface with a Surfactant Leads to Improved Performance Properties of 3D Printed Composite Materials Containing Cellulose Nanofibrils

Cellulose nanofibrils (CNFs) exhibit characteristics that make them a desirable addition to new composite materials. CNFs are usable in a wide variety of applications such as coatings, personal and healthcare products, packaging, and advanced structural materials. They can also help overcome some performance issues with objects 3D printed by stereolithography (SLA) including dimensional instability and poor mechanical properties. However, CNFs are hydrophilic, making their dispersion in hydrophobic resins common to SLA difficult. Therefore, improvement of performance properties will not be fully realized. In this work, we treated TEMPO-oxidized CNFs (TOCNFs) with the hydrochloride salt of lauroyl arginate ethyl ester (LAE·HCl), a cationic surfactant, to investigate how this coating would affect the performance properties of multicomponent uncured SLA resins and subsequently printed objects. We hypothesized this coating would enhance the dispersion of the cellulose nanomaterials when compared to their uncoated counterparts, which would lead to quantifiable differences among the sample groups. We found that the viscosity of a commercial 3D printing resin (0.34 Pa·s at 30 Hz) increased by nearly an order of magnitude upon addition of even 1 wt % uncoated TOCNFs (2.96 Pa·s at 30 Hz). Moreover, the tensile strength (19.9(5) MPa) and modulus (0.65(5) GPa) of objects printed from the commercial resin decreased when adding 4 wt % uncoated TOCNF (12.5(2) MPa and 0.58(8) GPa, respectively). In contrast, resins having 4 wt % TOCNFs coated with LAE were less viscous (1.25 Pa·s at 30 Hz), and objects printed from them had enhanced tensile strength (24.7(7) MPa) and modulus (0.78(8) GPa) when compared to both the unadulterated resin and that having uncoated TOCNFs. Our findings show the general utility of using a surfactant with cellulose nanomaterials to homogenize multicomponent resins for 3D printing composite materials with enhanced performance properties.

Development of pH-Indicative and Antimicrobial Films Based on Polyvinyl Alcohol/Starch Incorporated with Ethyl Lauroyl Arginate and Mulberry Anthocyanin for Active Packaging

Antibacterial and pH-responsive composite films for active food packaging were fabricated based on polyvinyl alcohol (PVA), cassava starch, ethyl lauroyl arginate (LAE), and mulberry anthocyanin. With the incorporation of LAE and mulberry anthocyanin, the PVA/starch blend films exhibited a less compact and more heterogeneous surface structure. The tensile strength and elongation at break of the active films were not significantly affected when the mulberry anthocyanin content was less than 20%. Moreover, the incorporation of mulberry anthocyanin effectively improved the UV barrier property of the blend films. Notably, while mulberry anthocyanin showed obvious color changes in buffer solutions with different pH values, the changes were indistinguishable for the PVA/starch/mulberry anthocyanin films. By contrast, the color changes of the PVA/starch/LAE/mulberry anthocyanin films were more noticeable, indicating the addition of LAE increased the pH sensitivity of the blend films. Furthermore, the PVA/starch/LAE/mulberry anthocyanin films efficiently inhibited the growth of both Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) due to the strong antibacterial activity of LAE. According to the spoilage test, the active films containing 5% mulberry anthocyanin and 5% LAE effectively indicated and slowed down the spoilage process of dairy milk. Our results demonstrate that PVA/starch/LAE/mulberry anthocyanin films have high potential as bioactive packaging materials applied in the food industry.

Electrostatic complexes of ethyl lauroyl arginate/nano-montmorillonite as a food-grade pickering stabiliser: Emulsification performance and mechanism

Compared with traditional surfactant-stabilised emulsions, Pickering emulsions, stabilised by clay nanoparticles, have the advantages of strong interface stability, strong versatility, and low toxicity. Moreover, they have excellent application potential in the fields of food and medicine. In this study, a food-grade Pickering emulsion stabiliser was prepared by physically adsorbing the cationic surfactant ethyl lauroyl arginate (LAE) on the surface of nano-montmorillonite (NMMT). Different LAE/NMMT combinations were assessed for their capacity to stabilise an oil-in-water emulsion at a low solid concentration (0.5%, w/v). The controllability of the droplet diameter and stability of the Pickering emulsions can be realised by changing the content of LAE. Scanning electron microscopy (SEM), atomic force microscopy (AFM), and laser confocal microscopy (CLSM) confirmed the successful preparation of sunflower oil Pickering emulsion droplets stabilised by LAE/NMMT (0.0075%/1%). Additionally, the LAE/NMMT studied in this work could be used as a highly effective antibacterial surfactant with inorganic nanoparticles to efficiently stabilise Pickering emulsions, thus expanding the potential of preparing edible Pickering emulsion formulae.

Effects of Ethyl Lauroyl Arginate (LAE) on Biofilm Detachment: Shear Rate, Concentration, and Dosing Time

Biofilm formation is one of the main obstacles in membrane treatment. The non-oxidizing biocide ethyl lauroyl arginate (LAE) is promising for mitigating biofilm development on membrane surfaces. However, the operating conditions of LAE and their impact on biofilm detachment are not comprehensively understood. In this study, a real-time in vitro flow cell system was utilized to observe biofilm dispersal caused by the shear rate, concentration, and treatment time of LAE. This confirmed that the biofilm was significantly reduced to 68.2% at a shear rate of 3.42 s−1 due to the increased physical lifting force. LAE exhibited two different mechanisms for bacterial inactivation and biofilm dispersal. Biofilms treated with LAE at sub-growth inhibitory concentrations for a longer time could effectively detach the biofilm formed on the surface of the glass slides, which can be attributed to the increased motility of microorganisms. However, a high concentration (i.e., bactericidal concentration) of LAE should be seriously considered because of the inactivated sessile bacteria and their residual debris remaining on the surface. This study sheds light on the effect of LAE on biofilm detachment and provides insights into biofouling mitigation during the membrane process.

Development of antimicrobial films with cinnamaldehyde stabilized by ethyl lauroyl arginate and cellulose nanocrystals

Antimicrobial films were developed by incorporating cellulose nanocrystals (CNC) and cinnamaldehyde-based Pickering emulsions into polyvinyl alcohol. The food-grade cationic surfactant, ethyl lauroyl arginate (LAE), was used to modify CNC for emulsion stability improvement. We contend that the LAE reduced the electrostatic repulsion by partially neutralizing the CNC surface charge and increased its packing density around the droplet interface. The CNC/LAE and cinnamaldehyde mixture formed an oil-in-water Pickering emulsion with an average droplet size of 5.54 µm. The emulsion-added films led to significant inhibition of microbial growth of E. coli, S. aureus, and B. cinerea. Moreover, there was no significant adverse effect on the films' mechanical properties, water vapor permeability, or solubility with 1% and 2% emulsions added. Lastly, the antimicrobial films with 2% emulsion inhibited the deterioration rate of strawberries by 52.2%. The CNC-LAE-cinnamaldehyde Pickering emulsions-added films demonstrate a promising application for antimicrobial food packagings.

The Effect of Electrolytes and Urea on the Ethyl Lauroyl Arginate and Cellulose Nanocrystals Foam Stability

Carboxylated cellulose nanocrystals (cCNC) are highly dispersible particles useful in many industries. In particular, they can be applied to form Pickering emulsions and foams for “green” applications in the cosmetics, pharmaceutical industry or food processing. We demonstrated that carboxylated cellulose nanocrystals enhance foamability and foam stability when mixed with cationic surfactant ethyl lauroyl arginate (LAE), having superior properties over sulfated cellulose nanocrystals (sCNC) concerning surfactant concentration range and foam volume. Mixtures of LAE and cCNC were characterized for their hydrodynamic diameter, zeta potential, surface tension and surface rheological properties. The influence of electrolytes, namely, sodium chloride, guanidine hydrochloride and sodium salicylate, and the addition of concentrated urea to LAE-cCNC mixtures on foamability and foam stability were investigated. Electrolytes in the concentration of 5 mM showed a moderate effect on foam stability. In contrast, spectacular foam collapse was detected after adding concentrated urea. The preliminary rheological data from the pendant drop oscillations revealed low elastic modulus upon urea addition and the loss modulus that increased with the frequency, which suggested a viscous interfacial layer.

Electrostatic Complexes of Nano-Montmorillonite/Ethyl Lauroyl Arginate Stabilized Sunflower Oil Pickering Emulsions

Compared with traditional surfactant-stabilised emulsions, Pickering emulsions, stabilised by clay nanoparticles, have the advantages of strong interface stability, strong versatility, and low toxicity. Moreover, they have excellent application potential in the fields of food and medicine. In this study, a food-grade Pickering emulsion stabiliser was prepared by physically adsorbing the cationic surfactant ethyl lauroyl arginate (LAE) on the surface of nano-montmorillonite (NMMT). Different LAE/NMMT combinations were assessed for their capacity to stabilise an oil-in-water emulsion at a low solid concentration (0.5%, w/v). The controllability of the droplet diameter and stability of the Pickering emulsions can be realised by changing the content of LAE. Scanning electron microscopy (SEM), and laser confocal microscopy (CLSM) confirmed the successful preparation of sunflower oil Pickering emulsion droplets stabilised by LAE/NMMT (0.0075%/1%). Additionally, the LAE/NMMT studied in this work could be used as a highly effective antibacterial surfactant with inorganic nanoparticles to efficiently stabilise Pickering emulsions, thus expanding the potential of preparing edible Pickering emulsion formulae.

Development of an antibacterial coaxial bionanocomposite based on electrospun core/shell fibers loaded with ethyl lauroyl arginate and cellulose nanocrystals for active food packaging

Developing antimicrobial electrospun bionanocomposites with core/shell structure is an innovative strategy for producing active food packaging materials. The aim of this study was developing an antibacterial electrospun mat based on polylactic acid (PLA) coaxial fibers containing ethyl lauroyl arginate (LAE) and cellulose nanocrystals (CNC) through electrospinning. The effect of the coaxial structure and the incorporation of both components on the structural, thermal and release properties of the electrospun PLA was analyzed. LAE release studies were carried out in 10% and 95% EtOH, and results correlated with antibacterial assays. Structural analysis only indicated some chemical interactions through hydrogen bonding between PLA and LAE in the core structure. The incorporation of LAE and CNC produced a plasticizing effect in the PLA, and the crystallinity of polymer was maintained by the presence of CNC. Core/shell structure and the presence of CNC slowed down the LAE release. Furthermore, the bionanocomposite exhibited strong bactericidal activities.

Development of electrospun films enriched with ethyl lauroyl arginate as novel antimicrobial food packaging materials for fresh strawberry preservation

Antimicrobial packaging based on biodegradable material is a novel strategy to ensure food safety without posing threats to the environment. In this study, poly(lactic acid) (PLA) nanofibers containing Ethyl-Nα-dodecanoyl-l-arginate hydrochloride (LAE) were fabricated using the electrospinning method. The microstructure, inter-molecular interaction, thermal stability, and antimicrobial properties of electrospun films were characterized. The LAE embedded nanofibers had an average diameter of 325–364 nm, which was 43.5%–49.5% thinner compared to the neat PLA nanofibers. The active films demonstrated outstanding antimicrobial capability against Escherichia coli O157:H7, Staphylococcus aureus, and Botrytis cinerea. The active films with LAE could also effectively extend the shelf-life of strawberries at 25°C, suggesting that PLA films incorporating with LAE could be used as an environmental-friendly antimicrobial packaging material.

Effect of the emulsifier type on the physicochemical stability and in vitro digestibility of a lutein/zeaxanthin-enriched emulsion.

Lutein (L) and zeaxanthin (Z), as macular pigments, are water-insoluble, chemically unstable, and have low bioaccessibilities; they are often emulsified to overcome these limitations. This study investigated the impact of various emulsifiers (ethyl lauroyl arginate (LAE); Tween 80; and sodium dodecyl sulfate (SDS)) on the physicochemical properties and in vitro digestibilities of L/Z-fortified oil-in-water emulsions. Droplet aggregation and creaming extents were dependent on the emulsifier type. The ζ-potentials of emulsions stabilized by LAE, Tween 80, and SDS were + 87, - 26, and - 95mV, respectively. SDS-stabilized emulsion had the smallest particles, while the particle sizes for the LAE- and Tween 80-stabilized emulsions were larger and not significantly different. The rates of L/Z degradation were sensitive to the emulsifier type and to heat, not to light. The L/Z bioaccessibility was the highest for the Tween 80 emulsion. Surfactants should therefore be carefully selected to optimize L/Z physicochemical stability and bioaccessibility in emulsions.

Development of poly(vinyl alcohol)/starch/ethyl lauroyl arginate blend films with enhanced antimicrobial and physical properties for active packaging

Active packaging films have emerged as alternatives to replace petroleum-based packaging materials. In this work, poly(vinyl alcohol) (PVA)/starch/ethyl lauroyl arginate (LAE) films possessing enhanced properties were prepared. Scanning electron microscopy (SEM) showed that PVA and starch were compatible, the concentrations of LAE greatly affected the structural integrity. Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction showed that the inclusion of LAE did not significantly affect the intermolecular interactions and crystal structures of the polymer matrix. With an increase of the LAE content, the tensile strength (TS) was slightly decreased due to the altered microstructures, the elongation at break (EB) significantly increased ascribed to the synergistic effect of acetic acid, glycerol and LAE. The values of TS and EB were 17.25 MPa and 586.08%, respectively when LAE was 10%. Active films showed good barrier properties from UV while retaining the transmittance in the visible light region. The films containing 1% of LAE exhibited antibacterial activity against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), the inhibition zone of bacterial growth gradually expanded with increasing LAE content. This study demonstrates the potential of using LAE as the antibacterial agent for synthesizing natural-based polymeric films for active packaging applications.

Ethyl Lauroyl Arginate, an Inherently Multicomponent Surfactant System.

Ethyl lauroyl arginate (LAE) is an amino acid-based cationic surfactant with low toxicity and antimicrobial activity. It is widely used as a food preservative and component for food packaging. When stored, LAE decomposes by hydrolysis into surface-active components Nα-lauroyl–l-arginine (LAS) or dodecanoic (lauric) acid. There are only a limited number of reports considering the mechanism of surface activity of LAE. Thus, we analysed the surface tension isotherm of LAE with analytical standard purity in relation to LAE after prolonged storage. We used quantum mechanical density functional theory (DFT) computations to determine the preferred hydrolysis path and discuss the possibility of forming highly surface-active heterodimers, LAE-dodecanoate anion, or LAE-LAS. Applying molecular dynamics simulations, we determined the stability of those dimers linked by electrostatic interactions and hydrogen bonds. We used the adsorption model of surfactant mixtures to successfully describe the experimental surface tension isotherms. The real part surface dilational modulus determined by the oscillation drop method follows a diffusional transport mechanism. However, the nonlinear response of the surface tension could be observed for LAE concentration close to and above Critical Micelle Concentration (CMC). Nonlinearity originates from the presence of micelles and the reorganisation of the interfacial layer.

Interfacial properties and antioxidant capacity of pickering emulsions stabilized by high methoxyl pectin-surfactant-pea protein isolate-curcumin complexes: Impact of different types of surfactants

In the present study, high methoxyl pectin-surfactant-pea protein isolate-curcumin (HMP-surfactant-PPI-Cur) complexes were used as stabilizers for Pickering emulsions. The impact of different types of surfactants in the complexes, including rhamnolipid (Rha), tea saponin (TS) and ethyl lauroyl arginate hydrochloride (LAE), on the interfacial properties and antioxidant capacity of Pickering emulsions was investigated. The pH for the fabrication of complexes with desirable wettability of both aqueous and oil was determined by turbidimetric titration and contact angle measurement. The results showed that the pH of 3.2 was an optimal value to fabricate the complexes. Among these complexes, the HMP-Rha-PPI-Cur complex exhibited the optimal emulsifying property, since it exhibited a relatively low initial interfacial tension of 38.99 mN/m. Moreover, the result of the interfacial tension measurement indicated that the HMP-Rha-PPI-Cur complex could be rapidly adsorbed on droplets, and the adsorbed protein fraction was 99%. Furthermore, after 30 days of storage, the emulsion stabilized by the HMP-Rha-PPI-Cur complex exhibited the lowest serum index of 9.86% and peroxide value of 47.52 mmol/L. In summary, the interfacial properties, stability and antioxidant capacity of emulsions could be more effectively enhanced in the presence of Rha in the complex.