Emulsions preparation based on ternary phase diagrams: comparative study using two oils (Miglyol and sweet almond) with two distinct surfactants (Tween 80 and Saponin)

An emulsion is a colloidal dispersion composed by a mixture of two immiscible liquids, being one the dispersed phase, as droplets, and the other one the continuous phase. In this work, a comparative study comprising the surfactants Tween 80 (synthetic surfactant) and Saponin (natural surfactant) and the oils Miglyol 812 and Sweet Almond was performed. The development of emulsions based on ternary phase diagrams showed that different phases can be formed giving rise to different formulations: microemulsions, gels, and mixtures with 1, 2 and 3 phases. The application of the HPH technique produced stable nanoemulsions with narrow distributions. Considering Tween 80, and comparing the two oils, Miglyol 812 gave rise to emulsions with lower particle size (0.023μm), comparatively to Sweet Almond Oil (1.009μm). This difference can be related with the oil viscosity, which is lower for Miglyol 812. Comparing the two surfactants, natural Saponin was very effective in the o/w composition range.info:eu-repo/semantics/publishedVersio

Saponins as natural emulsifiers for nanoemulsions

The awareness of sustainability approaches has focused attention on replacing synthetic emulsifiers with natural alternatives when formulating nanoemulsions. In this context, a comprehensive review of the different types of saponins being successfully used to form and stabilize nanoemulsions is presented, highlighting the most common natural sources and biosynthetic routes. Processes for their extraction and purification are also reviewed altogether with the recent advances for their characterization. Concerning the preparation of the nanoemulsions containing saponins, the focus has been initially given to screening methods, lipid phase used, and production procedures, but their characterization and delivery systems explored are also discussed. Most experimental outcomes showed that the saponins present high performance, but the challenges associated with the saponins’ broader application, mainly the standardization for industrial use, are identified. Future perspectives report, among others, the emerging biotechnological processes and the use of byproducts in a circular economy context.This work was financially supported by Base Funding − UIDB/00690/2020 of CIMO − Centro de Investigação de Montanha funded by national funds through FCT/MCTES (PIDDAC), Funding UIDB/50020/2020 and UIDP/50020/2020 of LSRE-LCM funded by national funds through FCT/ MCTES (PIDDAC), and project AIProc-Mat@N2020 − NORTE-01-0145-FEDER 000006 supported by NORTE 2020 under the Portugal 2020 Partnership Agreement, through ERDF. T.B.S. thanks FCT and European Social Fund (ESF) for the Ph.D. grant (2020.05564.BD).info:eu-repo/semantics/publishedVersio

Formulation and optimization of nanoemulsions using the natural surfactant saponin from Quillaja bark

Replacing synthetic surfactants by natural alternatives when formulating nanoemulsions has gained attention as a sustainable approach. In this context, nanoemulsions based on sweet almond oil and stabilized by saponin from Quillaja bark with glycerol as cosurfactant were prepared by the high-pressure homogenization method. The e ects of oil/water (O/W) ratio, total surfactant amount, and saponin/glycerol ratio on their stability were analyzed. The formation and stabilization of the oil-in-water nanoemulsions were analyzed through the evaluation of stability over time, pH, zeta potential, and particle size distribution analysis. Moreover, a design of experiments was performed to assess the most suitable composition based on particle size and stability parameters. The prepared nanoemulsions are, in general, highly stable over time, showing zeta potential values lower than 40 mV, a slight acid behavior due to the character of the components, and particle size (in volume) in the range of 1.1 to 4.3 m. Response surface methodology revealed that formulations using an O/W ratio of 10/90 and 1.5 wt% surfactant resulted in lower particle sizes and zeta potential, presenting higher stability. The use of glycerol did not positively a ect the formulations, which reinforces the suitability of preparing highly stable nanoemulsions based on natural surfactants such as saponins.This research was funded by (1) AIProcMat@N2020-Advanced Industrial Processes and Materials for a Sustainable Northern Region of Portugal 2020, with the reference NORTE-01-0145-FEDER-000006, supported by Norte Portugal Regional Operational Programme (NORTE 2020), under the Portugal 2020 Partnership Agreement, through the European Regional Development Fund (ERDF); (2) Base Funding—UIDB/50020/2020 of the Associate Laboratory LSRE-LCM—funded by national funds through FCT/MCTES (PIDDAC); and (3) Base Funding—(UIDB/00690/2020) of CIMO—Centro de Investigação de Montanha—funded by national funds through FCT/MCTES (PIDDAC).info:eu-repo/semantics/publishedVersio

Evaluation of saponin-rich extracts as natural alternative emulsifiers: A comparative study with pure Quillaja Bark saponin

Due to synthetic surfactants' environmental impact, their replacement by natural alternatives has gained relevance, with saponins emerging as sustainable approaches. In this work, three saponin-rich extracts from different sources (Tribulus terrestris (TT), Trigonella foenum-graecum (FG), and Ruscus aculeatus (RA)) were tested as emulsifiers, and their performance compared with Quillaja Bark saponin (PS). Characterisation comprised FTIR, solubility studies, CMC assays, and emulsifying properties (emulsifying capacity (EC) and foaming capacity (FC)). For all samples, solubility assays indicated high solubility in water and low in apolar solvents (e.g., n-hexane), compatible with their O/W emulsifier character. In general, the saponin content ruled extracts' performance (PS > TT > FG > RA). EC values (without pH adjustment) were found to be 82.5, 55.0, 47.5, 36.3%, respectively. When pH changed for 7 and 9, a shift in FG and RA order was observed. The pseudo-ternary diagrams, constructed to map emulsion's composition zones, indicate the formation of single-phase systems in the region of low oil and high extract content. Except for RA extract, gel samples were formed, which are interesting technological solutions for several applications. Among the studied samples, and in alternative to PS, TT extract showed the best performance.This work was financially supported by: Base Funding – UIDB/00690/2020 of CIMO – Centro de Investigação de Montanha – funded by national funds through FCT/MCTES (PIDDAC), Base Funding – UIDB/50020/2020 of the Associate Laboratory LSRE-LCM – funded by national funds through FCT/MCTES (PIDDAC), and project AIProcMat@ N2020 – NORTE-01-0145-FEDER 000006 supported by NORTE 2020 under the Portugal 2020 Partnership Agreement, through ERDF. National funding by FCT, Foundation for Science and Technology, through the individual research Grant 2020.05564. BD of Tatiana La Banca Schreiner. FCT, PI, through the institutional scientific employment program-contract for I.P. Fernandes contract through the celebration of program-contract foreseen in No. 4, 5 and 6 of article 23º of Decree-Law No. 57/2016, of 29th August, amended by Law No. 57/ 2017, of 19th July.info:eu-repo/semantics/publishedVersio

Saponin-based natural nanoemulsions as alpha-tocopherol delivery systems for dermal applications

Nanoemulsions can be produced using simple methods and compounds from natural sources. They can increase water dispersibility and bioavailability and optimise active ingredient dispersion in particular skin layers. Lipophilic compounds of the vitamin E family (tocopherols and tocotrienols) are well-known for their high antioxidant activity and capacity to protect the skin from oxidative stress. In this context, oil-in-water (o/w) nanoemulsions with and without α-tocopherol (Vitamin E, VE) were formulated with two emulsifier alternatives, Quillaja saponin (QS), and a combination of QS with Tribulus terrestris (QSTT) (50/50, w/w). The emulsions were evaluated concerning stability, microstructure, droplet size, colour attributes, encapsulation efficiency, UV photostability, antioxidant activity, and in vitro permeation studies to assess the delivery potential. Results showed highly stable systems, with round-shape droplets of 80–121 nm size. QS and QSTT samples' colours were close to white and light brownish, respectively. The topical nano cream had the capacity to entrap VE, producing a protective effect from UV degradation, and very significant antioxidant activity, with IC50 values around 0.01 %wt. The skin permeation profiles showed the efficiency of the formulations in the delivery of VE, with permeabilities between 64 and 74 µg/cm2, while the control sample showed no VE permeation.info:eu-repo/semantics/publishedVersio

Optimization of nanoemulsion formulations using saponin from quillaja bark, a natural surfactant

Nanoemulsions are systems comprising three constituents, hydrophilic, lipophilic and amphiphilic compounds, forming a single macroscopic phase with reduced particle size. Nowadays, an important topic under study is the introduction of natural products as surfactants. This is partly motivated by consumer’s demands for more sustainable products, leading industry and researchers to search for alternatives with natural-friendly connotation, avoiding the large utilization of the synthetic forms. In this context, recent studies have focused the use of saponins, highlighting its physicochemical properties, and commercial potential for the development of natural-based emulsions [1,2]. Thus, the objective of this work is to optimize a nanoemulsion formulation incorporating saponin as surfactant, through response surface methodology (RSM). The systems were formed with the natural surfactant, pure saponin from Quillaja Bark, and glycerol as co-surfactant. Sweet almond oil was used as the lipophilic component. To produce the nanoemulsions, a high energy technique was chosen, namely high-pressure homogenization (HPH). The produced emulsions were characterized by measuring the zeta potential, droplet size (by laser diffraction) technique), pH and viscosity. In order to select the best formulation, a 2k full-factorial design with 3 factors and 3 replicates at the central point was implemented. The chosen parameters were oil/water ratio (10/90, 20/80, 30/70, w/w), surfactant content in the mixture (0.5, 1 and 1.5%, w/w) and the surfactant/co-surfactant ratio (50/50, 75/25, 100/0, w/w). The results obtained with the produced formulations showed zeta potential to vary between -40.3 and -46.0 (evidencing high stability) and a particle size in volume comprised in the range 111.9-431.4 nm. These two parameters were selected to perform the experimental design to find the most stable systems. Nanoemulsions with pure saponin were successfully produced, where the formulations with better long term stability were those prepared with the lower amount of oil, which is 10%. It is important to point out that taking into consideration final product applications, to have less than 10% of the lipophilic component it is not suitable. Regarding the amount of surfactant, smaller droplet sizes, and consequently lower zeta potentials, were achieved at its highest content. The co-surfactant glycerol showed to have no significant impact in zeta potential, even it showed to slightly increase droplet’s size.This work is financed by POCI-01-0145-FEDER-006984 (LA LSRE-LCM) and UID/AGR/00690/2013 (CIMO), funded by FEDER, through POCI-COMPETE2020 and FCT; Project NORTE-01-0145-FEDER-000006, funded by NORTE2020 under PT2020.info:eu-repo/semantics/publishedVersio

Study of binary mixtures of Tribulus terrestris extract and Quillaja bark saponin as oil‐in‐water nanoemulsion emulsifiers

Several industrial fields use emulsifiers in their products, with the ones of natural origin gaining increasing relevance. Identifying and using diversified sources for their extraction is a pertinent topic regarding sustainability principles, biodiversity preservation, or cost rationalization. This is the case of Quillaja bark saponin (QS), for which saponin-rich extracts, for example, Tribulus terrestris (TT), are being highlighted as viable alternatives, even though constraints like performance are still on the table. In this context, an experimental design using binary emulsifier mixtures of TT with pure QS was carried out by changing their composition (50–90%wt. TT), content (1.5–4.5%wt.), and high-pressure homogenization conditions (5–15 cycles). The emulsions were characterized by zeta potential, morphology, droplet size, and stability (expressed as the number of days without creaming formation). Moreover, the cream index for 30 days was determined to indicate the destabilization extent. The zeta potential showed stable emulsions (values below 41 mV); even still, creaming formed for samples using a low emulsifier and high TT contents. The emulsions’ mean droplet diameter (D [3, 2]) was between 78 and 921 nm, with smaller sizes agreeing with higher stability. The statistical analysis indicated an optimum composition range comprising an emulsifier content between 3.9 and 4.5%wt. and TT content between 50 and 56%wt. to reach stable products. Overall, TT can provide an effective solution when combined with QS, decreasing the dependence on Quillaja bark.The authors are grateful to the Foundation for Science and Technology (FCT, Portugal) for financial support through national funds FCT/MCTES (PIDDAC) to CIMO (UIDB/00690/2020 and UIDP/00690/2020), SusTEC (LA/P/0007/2021), LSRE-LCM (UIDB/50020/2020 and UIDP/00690/2020), and ALiCE (LA/P/0045/2020). FCT for the PhD research grant of T.B. Schreiner (2020.05564.BD). National funding by FCT, P.I., through the institutional scientific employment program contract of A. Santamaria-Echart.info:eu-repo/semantics/publishedVersio

Multi-strange baryon production in pp collisions at √s=7 TeV with ALICE

A measurement of the multi-strange Ξ− and Ω− baryons and their antiparticles by the ALICE experiment at the CERN Large Hadron Collider (LHC) is presented for inelastic proton–proton collisions at a centre-of-mass energy of 7 TeV. The transverse momentum (pT) distributions were studied at mid-rapidity (|y|6.0 GeV/c. We also illustrate the difference between the experimental data and model by comparing the corresponding ratios of (Ω−+Ω¯+)/(Ξ−+Ξ¯+) as a function of transverse mass

Ds+ meson production at central rapidity in proton–proton collisions at √s=7 TeV

The pT-differential inclusive production cross section of the prompt charm-strange meson Ds+ in the rapidity range |y|<0.5 was measured in proton–proton collisions at s=7 TeV at the LHC using the ALICE detector. The analysis was performed on a data sample of 2.98×108 events collected with a minimum-bias trigger. The corresponding integrated luminosity is Lint=4.8 nb−1. Reconstructing the decay Ds+→ϕπ+, with ϕ→K−K+, and its charge conjugate, about 480 Ds± mesons were counted, after selection cuts, in the transverse momentum range 2<pT<12 GeV/c. The results are compared with predictions from models based on perturbative QCD. The ratios of the cross sections of four D meson species (namely D0, D+, D⁎+ and Ds+) were determined both as a function of pT and integrated over pT after extrapolating to full pT range, together with the strangeness suppression factor in charm fragmentation. The obtained values are found to be compatible within uncertainties with those measured by other experiments in e+e−, ep and pp interactions at various centre-of-mass energies