Emulsion Type Research Articles

Study on Ajuga reptans extracts as potential cosmetic raw materials

Abstract In the study, the possibility of an application of Ajuga reptans leaf and root extracts in antipollution cosmetics was investigated. The influence of Ajuga extracts on the skin condition was also evaluated. Both leaf and root Ajuga ethanolic extracts were obtained and added to the developed cosmetic formulations. Two types of emulsion W/O and O/W, washing gels and eye serum, containing as an active substance Ajuga extracts were prepared. For the stable formulations physicochemical and user properties were studied. The obtained results show that cosmetic products, containing the Ajuga reptans extracts, positively affect the skin condition: causing an improvement in the degree of skin hydration and elasticity, reducing the skin pores size and skin hyperpigmentation, and reducing the wrinkles depth.

Antioxidant Face Cream Formulation of Ethanol Extract from Soursop leaves (Annona muricata L)

Face cream is a treatment cream used to treat facial skin. One of the natural plant ingredients that can be used as an active substance in cream preparations is soursop leaves (Annona muricata L.) which have antioxidant activity. The purpose of this study was to formulate cream preparations from soursop leaf ethanol extract as well as the antioxidant activity of face cream preparations. Soursop leaves were extracted by maceration using a 96% ethanol solvent. Cream preparations in physical quality evaluation include organoleptic, pH, homogeneity, viscosity, spread power, sticking power, centrifugation, determination of emulsion type, and antioxidant activity test with DPPH method at 𝜆 511,5 nm using UV-Vis spectrophotometry. The results that organoleptic cream preparations had color differences. The pH of FI, FII, and FIII creams had an average yield of 6,0-6,6 and were homogeneous. All creams had a viscosity value of 49950 cPs and scatter power at 5,2-5,7 cm. FI, FII, and FIII creams fixed power test with an average value of 26,5-46,5 and physically stable at centrifugation tests with cream emulsion type of O/W. Based on the antioxidant activity, the facial creams of ethanol extract from soursop leaves of FI (3%), FII (5%), and FIII (7%) had IC50 values of 80,64, 46,06, and 10,91 ppm respectively. So this study concluded that the facial cream of ethanol extract from soursop leaves at FI, FII, and FIII meet the physical stability requirements based on organoleptic, pH, homogeneity, viscosity, scatter power, clinging power, centrifugation, and emulsion type tests. FI cream had strong antioxidant activity (IC50 value of 80,64 ppm), then FII and FIII had very strong antioxidant activity (IC50 value of 46,06 and 10,91 ppm. Keywords: Cream, Formulation, Antioxidant, Ethanol extract, Soursop leaves

Effect of synergism of sucrose ester and xanthan gum on the stability of walnut milk.

Single emulsifiers have an effect on the stability of plant protein drinks, giving some improvement. Emulsifiers are more effective in maintaining emulsion stability when combined with polysaccharides such as xanthan gum. In this paper, we studied the food-grade emulsifier sucrose ester and measured the average particle size, polydispersity value, zeta potential, microrheological properties, microstructure and creaming index related to walnut protein emulsion by constructing a walnut protein emulsion simulation system. SDS-PAGE and low-field NMR were used to analyze the relative molecular masses of emulsions and the water distribution of emulsions, respectively, to further investigate the synergistic effects of sucrose esters and xanthan gum on the ease of emulsification and intrinsic mechanisms of different molecular weight proteins of walnut protein emulsions. The results indicate that the synergistic effect of sucrose esters and xanthan gum was to stabilize emulsions better than single emulsifiers. Xanthan gum and protein may form protein-polysaccharide complexes, as well as the hydrophobic interaction between sucrose ester and xanthan gum. The properties of xanthan gum can improve the stability of the emulsion by affecting the mechanical properties of walnut protein emulsion, and the combination of sucrose ester and xanthan gum can better stabilize large protein molecules. The results not only provide a theoretical basis for the stability of plant protein emulsion systems, but also provide technical support for the production and processing of large-molecule plant proteins into emulsions in this field for improving their stability, and also provide more possibilities for other types of emulsions. © 2023 Society of Chemical Industry.

Effect of emulsifiers on the properties of corn starch films incorporated with Zanthoxylum bungeanum essential oil

The use of natural and safe ingredients in green food packaging material is a hot research topic. This study investigated the effect of different emulsifiers on starch film properties. Three types of emulsifiers, including Tween 80 as a small-molecule surfactant, sodium caseinate (CAS), whey protein isolate (WPI), and gelatin (GE) as macromolecule emulsifiers, whey protein isolate fibril (WPIF) as a particle emulsifier, were utilized to prepare Zanthoxylum bungeanum essential oil (ZBO) emulsions. The mechanical, physical, thermal, antibacterial properties, microstructure and essential oil release of starch films were investigated. CAS-ZBO nanoemulsion exhibited the smallest particle size of 198.6 ± 2.2 nm. The film properties changed with different emulsifiers. CAS-ZBO film showed the highest tensile strength value. CAS-ZBO and WPIF-ZBO films exhibited lower water vapor permeability than Tween-ZBO. CAS-ZBO film showed good dispersion of essential oil, the slowest release rate of essential oils in all food simulants, and the best antibacterial effect against Staphylococcus aureus and Listeria monocytogenes. The films composed of CAS-ZBO nanoemulsion, corn starch, and glycerol are considered more suitable for food packaging. This work indicated that natural macromolecule emulsifiers of CAS and WPIF are expected to be used in green food packaging material to offer better film properties.

Fast Interfacial Polymerization for Stabilizing Emulsion Droplets with Polymer Films beyond Emulsifiers.

Stabilizing emulsion droplets with amphiphilic emulsifiers are the current prevailing method, but the extensive use of such amphiphilic substances has caused widespread concerns. In this Perspective, three traditional methods for the stabilization of emulsion droplets according to the type of emulsifiers used are outlined, and the emphasis is placed on the mechanism of steric hindrance for emulsion stabilization. Then, we provide a concise introduction and discussion of the fast interfacial polymerization method as a new strategy for preparing stable emulsifier-free emulsion droplets with a polymer film, including its research background, current progress, and possible development directions. It is anticipated that this paper will promote the development of emulsifier-free emulsion production via fast interfacial polymerization and other related methods.

Amphiphilicity evolution in self-assembled carbon-based nanostructures for stabilizing different types of Pickering emulsions

ABSTRACT Carbon-based nanostructures have been firmly established as highly scalable and versatile platforms, which have found extensive applications in several fields of multifunctional nanocomposites, energy storage, environment protection, and electronics device. Pickering emulsion template method is one of the efficient strategies for assembling metastable carbon nanomaterials into stable macroarchitectures. Here, the combination of graphene oxide (GO) and carbon nanotubes (CNTs) was chemically and continuously treated with 2-ethyl-4-methylimidazole (EMI) to acquire tunable wettability. The hybridization of CNTs and reduction of GO can make the as-synthesized carbon nanohybrids be capable of stabilizing oil-in-water (O/W) and water-in-oil (W/O) Pickering emulsions, respectively. The major shift in the type of Pickering emulsion is conveniently implemented through the catalytic reduction of GO by EMI. The sp2-hybridized carbon networks self-assembled with CNTs and reduced graphene oxide (RGO) are intentionally located at the biphasic liquid interface of different types of Pickering emulsions, which can endow the architecture elaborated from Pickering emulsion strategy with multiple functionalities.

Formation Mechanism of Starch-Based Double Emulsions from the Interfacial Perspective.

Double emulsions are of significant practical value in protecting the core material owing to their multicomponent structure and have thus been applied in various fields, such as food, cosmetics, and drugs. However, the mechanism of double emulsion formation by native starch is not well established. Herein, we demonstrate a facile route to develop type-A, type-B, and type-C double emulsions using native starch and develop an innovative design for a carrier. Interfacial interaction, enthalpy changes of starch, and interfacial properties are key factors governing the formation of double emulsions and controlling the type of double emulsions formed. Therefore, the results of this study provide a better understanding of how and what type of starch-based double emulsions are formed.

Reversible Emulsions from Polyoxometalate-Polymer: A Robust Strategy to Cyclic Emulsion Catalysis and High-Internal-Phase Emulsion Materials.

Reversible Pickering emulsions, achieved by switchable, interfacially active colloidal particles, that enable on-demand emulsification/demulsification or phase inversion, hold substantial promise for biphasic catalysis, emulsion polymerization, cutting fluids, and crude oil pipeline transportation. However, particles with such a responsive behavior usually require complex chemical syntheses and surface modifications, limiting their extensive use. Herein, we report a simple route to generate emulsions that can be controlled and reversibly undergo phase inversion. The emulsions are prepared and stabilized by the interfacial assembly of polyoxometalate (POM)-polymer, where their electrostatic interaction at the interface is dynamic. The wettability of the POMs that dictates the emulsion type can be readily regulated by tuning the number of polymer chains bound to POMs, which, in turn, can be controlled by varying the concentrations of both components and the water/oil ratio. In addition, the number of polymer chains anchored to the POMs can be varied by controlling the number of negative charges on the POMs through an in situ redox reaction. As such, a reversible inversion of the emulsions can be triggered by switching between exposure to ultraviolet light and the introduction of oxygen. Combining the functions of POM itself, a cyclic interfacial catalysis system was realized. Inversion of the emulsion also affords a pathway to high-internal-phase emulsions. The diversity of the POMs, the polymers, and the responsive switching groups open numerous new, simple strategies for designing a wide range of responsive soft matter for cargo loading, controlled release, and delivery in biomedical and engineering applications without time-consuming particle syntheses.

A superhydrophilic battery sponge with positive and negative electrodes for the demulsification of oil-in-water emulsions

A battery sponge (BS), with the superhydrophilic positive and negative electrode, was modified for demulsifying various oil-in-water emulsions without power device. Two mechanisms of BS, same charge-BS (SC-BS, BS electrode first contact with same charged emulsion) and opposite charge-BS (OC-BS, BS electrode first contact opposite charged emulsion), were explored. The positive electrode PEI@PDA@PU (PPP) and negative electrode OA@PEI@PDA@PU (OPPP) were singularly compared with BS to elucidate the demulsification performance and mechanism. Among them, OC-BS achieved the best effect: it reduced the emulsion zeta potential to below 20 mV (absolute value); separation efficiency exceeded 99.9 %; the demulsified oil droplets coalesced inside the sponge; and residual oil droplet size of filtrate was larger than the original emulsions. Furthermore, OC-BS adapted to various emulsions, can be recycled 30 cycles (separation efficiency ≥ 99.5%), and possessed high stability. The optimally-performing OC-BS was due to the repeated action of synergistic superhydrophilic positive and negative electrodes on the charged oil of emulsion, which were demulsified to the maximum degree inside the superhydrophilic sponge. It was electrostatic action, hydrophobic effect, capillary force, and oil viscosity played the main role in oil–water separation. SC-BS only demulsified the oil droplets twice. PPP was affected by emulsion type. OPPP performance was stable but unremarkable. Meanwhile, positively and negatively charged BS could also attract cationic/anionic dyes in wastewater. The results demonstrated that BS can be effectively utilized as a demulsification material and applied to purify various emulsions.

Development of a carbocysteine 10% + urea 5% cream for the topical treatment of congenital ichthyosis

ObjectiveOptimization of a topical formula of N-acetylcystelne and urea for the topical treatment of ichthyosis. MethodWe reviewed the chemical structure of the N-acetylcysteine molecule and its metabolic processes. A search was conducted of possible alternative molecules with a chemical structure similar to that of N-acetyl- cysteine that could have improved organoleptic properties. The following databases were used: PubChem®, Botplus®, the Drug Information Centre of the Spanish Agency of Medicines and Medical Devices. The molecule selection criteria were as follows: structural similarity, same therapeutic group, same mechanism of action, same authorized indication, absence of unpleasant smell, and being marketed as raw material in Spain. To complete the pharmaceutical development and validation of the compound, several tests and controls were conducted following the emulsion production procedure of the National Formulary. In order to establish the validity period, we followed the recommendations of the “Guide to Good Drug Preparation Practices in Hospital Pharmacy Services”. ResultsN-acetylcysteine has a free sulfhydryl group, which is responsible for its smell, and undergoes deacetylation. Its main metabolites are cystine and cysteamine. The following molecules were assessed: cystine, cyst eamine, carbocisteine, cysteine and methionine. Carbocisteine was selected because it met all the selection criteria. Carbocisteine is practically insoluble in water and soluble in mineral acids and alkaline hydroxides solutions. Unlike N-acetylcysteine, it does not have a fetid smell. It reaches its maximum stability at pH 5.5 to 7.5. The composition of the compound (100 g) was as follows: carbocisteine (10 g), urea (5 g), glycerine (15 g), water (44 mL), sodium hydroxide (1 g), and Neo PCL® Oil/Water (O/W) (25 g). It has an expiration period of 30 days. The organoleptic characteristics, emulsion type, and pH remained stable within the established expiration period. The carbocisteine compound has been incorporated into the group of topical treatments available for the treatment of patients with ichthyosis in our hospital. ConclusionsThe carbocisteine molecule is a good therapeutic alternative that lacks the unpleasant smell of N-acetylcysteine. The carbocisteine compound developed has been included as topical treatment for ichthyosis due to its tolerability, acceptability, and effectiveness in the treatment of patients affected by this genodermatosis.

Antioxidant and anti-aging effects of Alpinia galanga L. rhizome extracts and preservation of antioxidant effects in W/O type emulsion

Antioxidant and anti-aging effects of <i>Alpinia galanga</i> L. rhizome extracts and preservation of antioxidant effects in W/O type emulsion

Effect of different composition and emulsifier types on the stability of red palm oil emulsified powder​

Red palm oil (RPO) has high nutritional content such carotene and vitamin E. However, those components in RPO are unstable and sensitive when exposed to light or temperature. Thus, the sensitive and unstable of nature components of red palm oil highlights the importance of encapsulation process via emulsification in early stage. The objective of this study was to investigate the stability of β-carotene in RPO encapsulated powder using α-cyclodextrin as wall material with the comparison of the emulsifier used between sodium caseinate (NaCAS) and lecithin in terms of production of RPO encapsulated powder. The protective effects provided by encapsulated powder process were evaluated in terms of the degradation kinetics of β-carotene at 60 ℃ for 25 days. Stability of β-carotene in RPO emulsified powder was fitted well using a first kinetic model. Degradation of β-carotene in encapsulated powder could be correlated using the first kinetic model. The stability of β-carotene with lecithin as emulsifier in both solid contents (25 wt.% and 35 wt.%) were more stable with degradation rate constant 0.018 day−1day−1 and 0.016 day−1day−1, respectively. Encapsulation process protected RPO during storage, with lecithin emulser performing better than NaCAS emulsifier.

NATURAL KOSMETIK BERBAHAN EKSTRAK CAIR PROPOLIS SEBAGAI AGEN TABIR SURYA DALAM SEDIAAN LOTION DENGAN VARIASI ASAM STEARAT SEBAGAI EMULAGTOR

Sunscreen is a preparation used on the surface of the skin that works to absorb, scatter or reflectrays ultraviolet. One of the compounds that have benefits as a sunscreen is propolis. Propolis has antioxidant activity and its components can be used as a sunscreen formulation. The flavonoids contained in propolis have potential as sunscreen because of the presence of a chromophore group (conjugated double bond) which can absorb both UV B and UV A rays. To make a good preparation, a good formula is needed, one of the components in making lotions is acid. stearicate used as emulgator. This study aims to formulate a lotion with variations of stearic acid which functions as anas emulgator well as to test the physical and chemical properties of thepreparations lotion. The lotion is made in three variations of the composition of stearic acid, namely 2.5%: 5%; 7.5%. The lotion obtained was evaluated for the physical and chemical properties of thepreparation lotion including organoleptic test, homogeneity, emulsion type, pH, spreadability, adhesion and viscosity as well asmeasurement of the SPF value in vitro. The results of the analysis showed that variations in the concentration of stearic acid had a significant effect on the physical properties of the lotion including the results of pH, spreadability, adhesion, and viscosity. Stearic acid the higher the viscosity, consistency, and increased adhesion but the spreadability decreases. The SPF test results on theformula were lotion 6.13 (F1), 6.11 (F2), and 6.05 (F3) and the SPF value decreased after thetest freeze thaw.

MORINGA LEAF (Moringa Oleifera L.) ETHANOL EXTRACT CLAY MASK FORMULATION AS ANTI-AGING

Aging is a human physical change caused by age, psychological, and social factors, especially on the face, neck, upper arms and hands. Aging is unavoidable and goes at different speeds, depending on one's genetics, environment and lifestyle. Synthetic antiocxidant products are many circulated in the market which have a negative impact on health. However Antioxidant compound are widely spread in nature expecially in plant. Moringa leaf is one of plants that contain abundant antioxidant, alkaloids, flavonoids, phenolics, triterpenoids/steroids and tannins. Many of people Switch to natural products. Mask from natural products are not causing irritation or less side effects. clay face mask are mostly used because of their skin rejuvenating abilities. Purpose: To know either Moringa leaf ethanol extract can be formulated in clay mask preparations and the optimal effect is to prevent aging or not. Methods: the research is including how to make clay mask with ethanol extract of Moringa leaves at concentrations of 6%, 8% and 10%. The evaluation of the physical quality of the preparation, testing the effectiveness of clay masks with ethanol extract of Moringa leaves as anti-aging. Result: the preparation is qualify the characteristic test, had a pH of 4.9-5.2, a drying time of 15-23.5 minutes, an o/w emulsion type, was stable for 12 weeks of storage, and was not caused irritation. The best result of anti-aging effectiveness test was at a concentration of 10% with 36.25 moisture content, 23.25 fineness content, 33.75 pores, 20.5 blemishes and 15.5 wrinkles. Conclusion: Moringa leaf ethanol extract can be formulated in clay mask , and is able to give the best anti-aging effect at 10% formula.

Parenteral Nutrition-Associated Cholestasis; A Comparison Between Soy-Based Lipids and Mix-Based Lipids in the High-Risk Surgical Neonates

Background: Parenteral nutrition-associated cholestasis (PNAC) is a significant concern in high-risk surgical neonates, contributing to morbidity and prolonged hospitalization. This retrospective observational study aimed to investigate the impact of different lipid emulsions on the incidence and severity of PNAC in this vulnerable population while controlling for concomitant factors. Material and methods: A cohort of 67 surgical neonates was included, with 35 receiving IntralipidⓇ (IL) and 32 receiving SMOFlipidⓇ (SL). Rigorous inclusion criteria were applied to ensure comparability between the groups, focusing on the type of lipid emulsion as the main difference and selecting patients with prolonged fasting, limited oral intake, and significant PN reliance. The cumulative incidence of PNAC, absolute risk reduction (ARR), odds ratio (OR), and the effect on specific liver function tests, such as conjugated bilirubin (CB) and gamma-glutamyl transferase (GGT), were evaluated. Results: The SL group exhibited a significantly lower incidence of PNAC compared to the IL group (22% vs. 57%, p=0.0057), highlighting the potential protective effect of SL against PNAC development in surgical neonates. Subgroup analysis revealed a lower incidence of PNAC in full-term neonates receiving SL compared to IL (16% vs. 52%, p=0.0219), while the difference did not reach statistical significance in premature neonates. Furthermore, SL was associated with a marked reduction in the rise of CB levels compared to IL (34 vs. 66 umol/l, p=0.0093), indicating a potential hepatoprotective effect. Conclusions: This study emphasizes high-risk surgical neonates' susceptibility to PNAC. The incidence of PNAC exceeded reported rates in lower-risk neonates, highlighting their unique challenges. Although SL reduced PNAC risk compared to IL, the absolute rate remained high and of questionable benefit in surgical premature neonates. These findings prompt further investigation into the optimal lipid emulsion for this vulnerable population, weighing the benefits of SL against potential drawbacks.

Magnetorheological characterization of oil-in-oil magnetic Pickering emulsions

A magnetic Pickering emulsion is a type of emulsion stabilized by magnetic nanoparticles that accumulate at the droplet interface. This makes the emulsion easy to control using an external magnetic field, which, in turn, makes it useful in many applications. Research and development in this field are ongoing, but regardless of the application, control of the formation process is necessary. Rheological measurements are one of techniques used for evaluating the internal structure and stability of emulsions. The main focus of the current research is to investigate the magnetorheological effect of the rarely tested oil-in-oil (O/O) magnetic Pickering emulsions and compare them with better-characterized oil-based magnetic fluids.The magnetoviscous effect typically occurs when magnetic nanoparticles or magnetic Pickering emulsions align with the magnetic field, and this effect depends mainly on the internal structure, such as the size and shape of the particles and droplets. The experimental results indicate that the magnetic emulsion fabricated utilizing ultrasound and an additional electric field exhibits higher dynamic yield stress as a function of the magnetic field compared with the partially covered droplets. This suggests that the stable emulsion becomes a more rigid system and is more resistant to deformation when a magnetic field is applied. Besides that, the magnetoviscous effect of the magnetic emulsions was lower compared with that of magnetic suspensions with the same mass fraction of magnetic nanoparticles.

Nature-inspired construction of multifunctional composited membrane by in situ formation TA-APTES NPs for selective adsorption of tetrabromobisphenol a and oil-water separation

In this work, a novel in-situ synthetic TA-APTES NPs multifunctional imprinted membrane was fabricated by tanning-inspired coating for selective adsorption of tetrabromobisphenol a (TBBPA) and oil-water emulsion separation. Tannic acid (TA) from natural plants can be cross-linked with 3-aminopropyltriethoxysilane (APTES) by a simple green method to form nanosphere structures with secondary reaction sites. With TA-APTES coating, the membrane can be quickly converted from hydrophobic to super-hydrophilic. TEOS is not only used as a cross-linking agent in imprinting process，but also can be used for TA-APTES hybridization on the membrane surface to introduce stable silicone hydroxyl groups to the membrane surface. The modified membranes showed good hydrophilicity with a water flux of 27,272Lm−2 h−1 at 0.1Mpa, which was 18 times higher than that of pure PVDF membranes. In addition, the separation efficiency of four different types of oil-water emulsions (n-hexane, petroleum ether, dichloromethane and kerosene) reached 99.6%, 98.3%, 95.6%, and 98.7%, respectively. Among them, the oil water emulsion flux of dichloromethane could reach 1000.1. what's more, the prepared membranes also maintained relatively high selective separation efficiencies of TBBPA in oil-water mixtures. To better explain the mechanism of the TBBPA reaction process, the active sites in the TBBPA reaction process were calculated and predicted by density generalization theory (DFT). The Br and phenolic hydroxyl groups on the benzene ring of TBBPA showed higher activity and might be the main reaction sites. In addition, the imprinted composite membranes can be easily regenerated and reused without performance loss through a simple cleaning process. The coating process inspired by natural polyphenol chemistry has the advantage of being green, cost-effective and low energy, showing real potential in multifunctional membrane applications.

Towards Effective Antiviral Oral Therapy: Development of a Novel Self-Double Emulsifying Drug Delivery System for Improved Zanamivir Intestinal Permeability.

Self-double emulsifying drug delivery systems have the potential to enhance the intestinal permeability of drugs classified under the Biopharmaceutics Classification System (BCS) class III. One such example is the antiviral agent zanamivir, exhibiting suboptimal oral absorption (with a bioavailability range of 1-5%). To address this challenge, we have developed an innovative oral formulation for zanamivir: a self-double nanoemulsifying Winsor delivery system (SDNE-WDS) consisting of the microemulsion, which subsequently yields final double nanoemulsion (W1/O/W2) upon interaction with water. Two distinct formulations were prepared: SDNE-WDS1, classified as a W/O microemulsion, and SDNE-WDS2, discovered to be a bicontinuous microemulsion. The inner microemulsions displayed a consistent radius of gyration, with an average size of 35.1 ± 2.1 nm. Following self-emulsification, the resultant zanamivir-loaded nanoemulsion droplets for zSDNE-WDS1 and zSDNE-WDS2 measured 542.1 ± 36.1 and 174.4 ± 3.4 nm, respectively. Both types of emulsions demonstrated the ability to enhance the transport of zanamivir across a parallel artificial membrane. Additionally, in situ rat intestinal perfusion studies involving drug-loaded SDNE-WDSs revealed a significantly increased permeability of zanamivir through the small intestinal wall. Notably, both SDNE-WDS formulations exhibited effective permeability (Peff) values that were 3.5-5.5-fold higher than those of the low/high permeability boundary marker metoprolol. This research emphasizes the success of SDNE-WDSs in overcoming intestinal permeability barriers and enabling the effective oral administration of zanamivir. These findings hold promise for advancing the development of efficacious oral administration of BCS class III drugs.

The effect of emulsifier type and oil fraction on Salmonella Typhimurium growth and thermal inactivation in oil-in-water emulsion.

High water activity oil-in-water emulsions can promote survival and growth of Salmonella Typhimurium. Nevertheless, the precise effect of emulsifier type and oil content on bacterial growth and inactivation is not fully understood. Here, emulsions were prepared using different emulsifiers (Tween 20, Tween 80, and Triton X-100) and different oil fractions (20%, 40%, and 60% (v/v)). TSB (control), emulsifier solutions, and emulsions were inoculated with S. Typhimurium. Bacterial growth rate was measured at 7, 22, and 37°C, whereas thermal inactivation was performed at 55°C. Growth and inactivation data was fitted into Logistic and Weibull models, respectively. At an incubation temperature of 37°C, the presence of high amount of oil (60%) in Tween 20 and Triton X stabilized emulsions extended the lag phase (5.83±2.20 and 9.43±1.07h, respectively, compared to 2.28±1.54h for TSB, p<0.05), whereas individual emulsifiers had no effect on growth behavior compared to TSB. This effect was also prevalent but attenuated at 22°C, whereas no growth was observed at 7°C. In thermal inactivation, we observed protective effect in Tween 80 and Triton X-100 solutions, where time required for five-log reduction was 1914.70±706.35min and 795.34±420.09min, respectively, compared to 203.89±10.18min for TSB (p<0.05). Interestingly, the presence of high amount of oil did not offer protective effect during thermal inactivation. We hypothesize that oleic acid in Tween 80 and lower hydrophobicity value of Triton X-100 help maintain membrane integrity and improve the resistance of bacteria to heat inactivation.

Cinnamon essential oil Pickering emulsions: Stabilization by bacterial cellulose nanofibrils and applications for active packaging films

Pickering emulsions are emulsions stabilized by solid particles with a wide range of potential applications as they typically provide more stable systems than surface-stabilized emulsions. Among the various solid stabilizers, bacterial cellulose (BC) may open up new opportunities for future Pickering emulsions due to its unique nano-size, amphiphilicity and other excellent properties. In this study, BC, TEMPO-oxidized BC (TOBC) and dialdehyde cellulose (DAC) were used as emulsifiers to stabilize cinnamon essential oil (CEO) Pickering emulsions. The microstructure, oil droplet size distribution, storage and loss moduli of the Pickering emulsions were affected by the type of emulsifier used. Compared to BC and DAC nanofibers, TOBC nanofibers exhibited better emulsifying capacity. TOBC (1%)-stabilized Pickering emulsion showed smaller droplet size, narrower size distributions, better stability and sustained release ability. Moreover, the Pickering emulsions showed high antibacterial activities against Gram-positive bacteria S. aureus and Gram-negative bacteria E. coli. Active gelatin composite films containing TOBC (1%)-stabilized CEO Pickering emulsions were successfully fabricated and showed good antibacterial and antioxidant properties, which make them suitable for food packaging application.