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Influence of #-lactones on monolinolein/ water bulk and emulsified mesophases Aurélien Tidu, Fabienne Méducin, Anne Marie Faugère, and Samuel Guillot Langmuir, Just Accepted Manuscript • Publication Date (Web): 12 Oct 2018 Downloaded from http://pubs.acs.org on October 19, 2018

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Influence of γ-lactones on monolinolein/water bulk and emulsified mesophases

Aurélien Tidu, Fabienne Méducin, Anne-Marie Faugère, Samuel Guillot*

Interfaces, Confinement, Matériaux et Nanostructures (ICMN), Université d’Orléans, CNRS, UMR 7374, 1b rue de la Férollerie, CS 40059, 45071 Orléans Cedex 2, France.

*Corresponding author:

Tel: 00 33 2 38 25 53 74

Fax: 00 33 2 38 25 53 76

E-mail address: [email protected]

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ABSTRACT The emulsification of two flavor compounds of γ-lactone type with monolinolein liquid crystalline submicron particles is reported. The stabilization is ensured by the copolymer F127. γ-nonalactone can be loaded in bicontinuous cubic monolinolein particles at a larger level (up to 20 wt%) than γ-decalactone (less than 15 wt%). The phase behavior of the ternary monolinolein/water/γ-nonalactone system was studied. The large γ-nonalactone content solubilized into cubosomes was corroborated by the observation of a wide cubic V2 range in the ternary phase diagram. Surprisingly no inverted hexagonal phase was found in the system. On the contrary, the incorporation of γ-decalactone in the lipid particles gave rise to a dispersion of inverted hexagonal phase, which corresponds to a classical behavior of an oily additive. We finally determined the internal phase of particles including 10 wt% of γ-nonalactone upon increasing the F127 content. We thus found that γ-nonalactone restricts very significantly the interaction of the emulsifier with the cubosomes’interior.

KEYWORDS. Lyotropic liquid crystals; miniemulsions; monoglycerides; aromas; SAXS


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INTRODUCTION Perfumes are used in many industrial products in the food industry, in cosmetics or household goods. They are in general hydrophobic compounds that must be solubilized into surfactant carriers or emulsified in aqueous media in order to sustain the release and to increase the longevity of the fragrant sensation. Polymer-based capsules, inclusion complexes, micelles, zeolithes, or surfactant mesophases are examples of materials tested for fragrance encapsulation (1-3). Applications of colloids are easily understandable where functional molecules (drugs, foods, and aromas) have to be solubilized or protected. Internally structured lipid particles are promising colloidal systems since they can encapsulate actives with various hydrophobicities (4). They are an alternative carrier system to emulsions or solid lipid nanoparticles due to their higher loading capacity. Our first objective is to formulate lipid liquid crystalline mixtures including food-grade flavor ingredients and then disperse them as fragrancing nanostructured lipid miniemulsions. The long-term stability of those particles is an important study to conduct in a future work and is out of scope here. As an example, the evolution of the internal lipid mesophase was followed in the case of limonene in such particles (5). Lyotropic liquid crystalline phases can be formed in concentrated mixtures of monoglycerides with water. The lipid phases at the maximum water content may be dispersed in water as submicron particles keeping the initial internal nanostructuration considering that emulsifiers do not interact with the lipid mesophase (6). Bicontinuous cubic phases (cubosomes) (7), a hexagonal phase (hexosomes) (8), micellar cubic phases (micellar cubosomes) (9,10) and an L2 phase (emulsified micro emulsions, EME) (11,12) are normally reported. As a structuring lipid, monolinolein (see its structure in Fig.1) is able to form those phases with water (13), and the dispersed system is often found stabilized in the continuous aqueous phase by means of large amphiphilic molecules like the Pluronic® F127 triblock copolymer (6). Several works reported the nanostructure of dispersed liquid crystalline mesophases loading oily additives (12,14-21). Upon increasing the guest molecule content, successive transformations from cubosomes via hexosomes to EMEs (for some cases via micellar cubosomes in between hexosomes and 3 ACS Paragon Plus Environment

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EMEs) seem to represent a typical phase sequence in those systems. In this study we worked with γlactones as guest molecules in the lipid/water matrix. They are fat-soluble flavors forming part of many natural products aroma. We selected γ-nonalactone (-NL) used as the coconut fragrance and decalactone (-DL) which has an intense peach flavor. Those organic compounds contain the same γbutyrolactone head but differ in length by only one carbon in the hydrocarbon chain. The molecular structures of both flavors are presented in Fig. 1. As a first step of fragrance submicron delivery systems, the influence of flavors on the nanostructured reservoir must be determined. We then focused on the structural investigation by small angle X-ray scattering of liquid crystalline (LC) particles including up to 40 wt% of those flavors. Although those oily and very similar γ-lactones should give the same results, we established differences in phase behaviors. We confirmed those results with bulk states when needed. In addition, we pointed out the effect of solubilizing -NL in the particles on the structural modification occurring upon increasing the emulsifier content. EXPERIMENTAL SECTION Materials. The lipid, Dimodan® U/J (DU), was supplied by DANISCO A/S (Braband, Denmark). It is a commercial-grade form of monolinolein comprising 96 % distilled monoglycerides, of which 62 % are monolinoleate. -nonalactone (4-pentyl-4-butanolide) and -decalactone (4-hexyl-4-butalonide) were generously provided by Aromor (France). The emulsifier Pluronic® F127 is a triblock copolymer (PEO99PPO67-PEO99) and was provided by BASF. In this paper, all contents in % are weight percentages. Preparation of bulk samples and LC particles loading γ-lactones. DU/γL mixtures forming the LC phase with water were first prepared at the corresponding  mass ratio   100  DU DU  γL  . After weighting this mixture and ultrapure water (deionized water at 18.2 M cm from a Millipore MilliQ device) into Pyrex tubes, the bulk samples were heated using a Bunser burner (up to 100°C for a few seconds at a time) with intermittent vigorous mixing using a vortex for homogenization. They were then left for cooling at room temperature. Concerning the dispersions, the stabilization of the LC droplets was 4 ACS Paragon Plus Environment

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ensured by the incorporation of the copolymer F127, previously dissolved into ultrapure water before mixing with the DU/γL mixtures. The stabilizer/mesophase weight ratio was defined by

  100  Stab DU  γL  . The DU/γL content was mixed with water in order to form a 5 % emulsion. This raw mixture was emulsified by fragmentation using ultrasonic waves (Vibracell 75115 ultrasound tip) for 8 min at 160 W in a pulse mode (1s on /1s off). Mesophase determination by small angle X-ray scattering. Small angle X-ray scattering (SAXS) experiments were performed on a Xeuss SAXS/WAXS system of Xenocs. This in-house instrument is equipped with a GeniX3D Micro Spot source operating at 50 kV – 0.6 mA that provides an X-ray beam with a photon wavelength of λ = 0.1541 nm (Cu Kα radiation). The scattered intensity as a function of the wave vector q  4 sin  2   , with  the scattering angle, was recorded on a 2D detector Pilatus 300K (Dectris) having a sensitive area of 83.8 x 106.5 mm2 with a pixel size of 172 x 172 µm2. The sample-to-detector distance of 1.170 m allowed for covering a scattering q range from 0.09 to 4.29 nm-1. The SAXS profile of each emulsified sample was recorded during 9h, and 2h for the bulk phases. They were analyzed through the indexation of Bragg peak positions, which determined the lipid mesophases involved within the droplets, the space groups and the mean lattice parameter by

 

a  2 h 2  k 2  l 2 q and a  4 h 2  k 2 q 3

for cubic and 2D-hexagonal structures

respectively. The measurements were carried out at 22°C through cylindrical capillaries of 1 mm diameter (Hilgenberg) for liquid samples. Bulk samples were put in a two-part open cell equipped with flat walls. RESULTS AND DISCUSSION Impact of γ-nonalactone content on monolinolein/water mesophases. We start by presenting the characterization of the SAXS patterns observed in the DU/γ-nonalactone/water system at 22 °C. We thus explored the part of the ternary phase diagram corresponding to large DU/γ-nonalactone mass ratios and with water contents smaller than 50 % (Fig. 2). At low water content (5-15 %), a lamellar or the reversed microemulsion phase was formed. Upon increasing the water content a cubic phase of gyroid type (Ia3d 5 ACS Paragon Plus Environment

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symmetry) was created, which was followed by a cubic phase of diamond type (Pn3m symmetry) eventually fully hydrated. The latter bulk samples were visually white due to the coexistence of the mesophase with an excess of water. By increasing the solubilized amount of γ-NL up to 13 %, the bicontinuous cubic phases still existed for water contents between 20 and 50 %. Thus the V2 phase including γ-NL was found relatively large in the phase diagram. The structural determinations with increasing the aqueous contribution at several  allowed to deduce the water content in the LC particles for different DU/γ-NL ratios. We followed the evolution of the lattice parameter at fixed  upon increasing the water content. Above the lamellar or L2 phases, the lattice parameter in the cubic Ia3d regime increased, and the system was not at saturation yet (Fig. S1 in the Supporting Information). A further increase in the water content induced a modification in the symmetry of the V2 phase into Pn3m, and the lattice parameter reached a constant value above a certain water content. This maximal water content value corresponds to full hydration conditions of the ternary system, and that can be found in aqueous dispersions of the corresponding mesophase. Without γ-NL, the maximal water content is found around 37.5 %, in agreement with literature values (21). From SAXS studies at several , we deduced that upon increasing the γ-NL in the cubic phase region, the maximum water solubilization did not much vary and was again in the range of 35-40 % (see Table 1). The wideness of the cubic range in the DU/γ-nonalactone/water system underlines the ability to carry a large amount of γ-NL in a V2 phase in the emulsified state too. This will be studied in the second part of this contribution. Emulsified mesophases with γ-lactones. Previous bulk samples cannot often be used as such for applications. Dispersions of mesophases in excess of water are then formulated with an efficient stabilizer that should have less interaction with the lipid. This part of the study was carried out keeping the stabilizer F127/mesophase weight ratio  constant at 8. The emulsification of DU/γL mixtures leads to submicron particles with diameters in the range of 200-300 nm (see Table S1 in the Supporting Information); the


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particle size was measured by dynamic light scattering and the distribution size was found of lognormal type (Fig. S2 in the Supporting Information). The SAXS profiles of DU-based particles loading γ-NL for various  values are shown in Fig. 3. The sample of 5 % dispersed phase without the flavor compound ( 100) formed the inverse bicontinuous phase V2 of pure Im3m type (seven Bragg peaks were visible in Fig. 3 that are in relative positions 2:4:6:10:12:14:18). This symmetry is the consequence of the F127 incorporation within the lipid mesophase (22-24). At lower  value, the Pn3m symmetry should occur in the particles (22), as it is found in the non-dispersed phase. We further included up to 40 % of γ-NL relatively to the lipid content. As shown in Fig. 3, the cubic phase V2 was retained at γ-NL concentrations up to 20 % ( 80), however we observed a change in the symmetry that turned into a pure Pn3m space group at  90 (see the six Bragg peaks in relative positions 2:3:4:6:8:9). This result is consistent with the study of the non-dispersed γ-NL/DU/water mesophases where a V2 phase was found for such an extended area. At  95, a coexistence of the two types of cubosomes was observed. We calculated the ratio of the cubic lattice parameters at aIm3m a Pn3m  1.336 , above the theoretical value of 1.279 from the Bonnet transformation relation (25), which shows the emulsifier takes part to the mesophase. The variation in the symmetry suggested that F127 stayed out of the particles when γ-NL was included above 10 % relatively to the lipid. As the γ-NL content increased up to 20 %, the Bragg peak positions shifted to larger q-values. The cubic lattice parameter progressively decreased when γ-NL is added and thus incorporated to the lipid domain (see Fig. 4). Thus the DU/water cubic mesophase can solubilize a large amount of γ-NL in the emulsified state. Surprisingly a further increase in the γ-NL concentration led to the emulsification of the L2 phase characterized by a large peak in the SAXS profiles (EME). It is interesting to note that the classical sequence of phase for an oily additive is not found here. Even up to 40%, γ-NL had a strong effect on LC internal structure of DU-based miniemulsions. The smaller characteristic distance in the mesophase by increasing γ-NL suggested that γ-NL should favor negative curvatures of the lipid/water interfaces. A signature of a hexagonal phase is however observed mixed with the Pn3m cubic


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phase at only  80. Since the L2 phase already occurs at  77.5, this shows a hexagonal phase cannot stand alone or in a very narrow  range. The variation in the internal structure with increasing the γ-NL/DU ratio is in agreement with that of the phase diagram of the bulk ternary system shown in Fig. 2. As expected from the bulk phases’ study where no true hexagonal phase was found in the γ-NL/DU/water mesophases, we effectively observed a direct cubosomes-to-EME transformation at about 20 % of γ-NL. The usual sketch of the internal phase evolution when hydrophobic compounds are added to a lipid/water mesophase is the successive V2-H2-L2 transitions with a possible I2 between H2 and L2. Since the H2 phase is not produced, this suggests that when the V2-H2 transition should occur, the γ-NL content is so large that it induced a strong variation in the mean interfacial curvature so the structure directly shifted to an L2 phase instead of I2. On the other hand, the structural impact of γ-DL on DU-based LC particles was similar to many other hydrophobic materials. Like with γ-NL, the solubilization of γ-DL induced a Pn3m symmetry in the LC cubic mesophase (Fig. S3 in the Supporting Information). A first structural transformation from those bicontinuous cubosomes to hexosomes occurred above 10 % of γ-DL. The hexagonal phase is found in the

 range of at least 75-85. At  70 and above, EME are produced. Thus, this amphiphilic component seems to act as a guest hydrophobic agent. The most noticeable difference with the observations using γ-NL was the presence of the H2 phase. Furthermore lattice parameters and characteristic distances were systematically found larger in case of γ-NL. This point was already observed at one fixed content of flavors (26). SAXS experiments were then conducted at the same molar content and gave the same result; we concluded at a closer localization to the lipid chain in the case of -NL. Thus, this former discussion can be extended here at various γ-lactone contents. Although the theoretical critical packing parameter variation is negligible between -NL and -DL (only 0.43% with the same headgroup, as explained in reference 26), no V2-H2 phase transition was found with -NL. This main difference in phase behavior between those flavors having a similar steric bulk 8 ACS Paragon Plus Environment

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could be attributed to the different localization of -NL in the lipid/water nanostructure. Indeed, our previous results at the same molar contents for both -lactones, showing a larger cubic lattice constant for the smallest molecule, suggested that -DL would be localized closer to the lipid chain than -NL, which would be closer to the water/lipid interface. Although -NL is a smaller molecule, its lower affinity for the lipid aliphatic chains would induce larger lattice constants. At larger contents, -DL being closer to the lipid chains can manage with the packing frustration of the hexagonal phase. On the contrary due to its preferred localization, -NL cannot fill the void spaces for the relief of the frustration, thus forbidding the formation of a hexagonal phase. Thus this could be an explanation why the mesophase with the larger negative interfacial curvature, i.e. the EME, is promoted with -NL. Effect of γ-nonalactone on the influence of the emulsifier on the structure of cubosomes. In this last part, we focused on the emulsifier interaction with the dispersed phase when -NL is solubilized in the particles. As shown in Fig. 3, F127 at  8 modifies the cubic symmetry occurring in the DU/water bulk phase (Pn3m) to Im3m in the emulsified state ( 100). Adding -NL above 10 %, we observed another transition back to Pn3m (see Fig. 4). This was also observed with -DL already at 5 % ( 95, see Fig. S3 in the Supporting Information). An intermediate  range was observed with -NL where both symmetries were simultaneously obtained. Henceforth  is fixed at 90. Thus at  8, a pure Pn3m phase with -NL is produced. Then, the emulsifier content was increased up to four times, i.e. at  32 (see SAXS patterns in Fig. 5). From the study of non-dispersed DU/γ-NL/water samples, we found at  90 that the lattice parameter at water saturation was 8.44 nm (value at 50 % water content). Besides, in the dispersion state at  8, the lattice parameter from the Pn3m structure was 8.43 nm. We can conclude that, at  90, F127 does not participate to the internal structure of the cubosomes. Thus the addition of -NL above a certain content pushed the F127 away from the particle interior. This effect is found at least until  16, where we still observed a pure Pn3m cubic structure with the same lattice constant (8.43 nm). At  24, the presence of additional peaks 9 ACS Paragon Plus Environment

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from the Im3m symmetry revealed a mixture of both kinds of cubosomes, however mainly in the diamond type. At  32, peaks of both structures were still present but the intensity of those related to the Pn3m was strongly lower compared to the sample at  24. This reflects once again the incorporation of the F127 in the particles, however at very large amounts of the emulsifier. Cubosomes with only one type (Im3m) were still not obtained at  32, while this state was attained without -NL at a much lower content of F127. Using DU as the lipid we found the Im3m symmetry was already present at  8, while using a much pure monolinolein the transition between the two symmetries occurred between  8 and  16 (22). With DU, this transition for free-cubosomes should occur below  8. Consequently, the presence of -NL strongly restricts the interaction of F127 with the internal structure. CONCLUSIONS SAXS characterization studies were conducted on flavors/lipid/water bulk phases and related submicron particles. We aimed to investigate initial structures of fragrancing lipid miniemulsions with γlactones. The addition of γ-nonalactone to the monolinolein/water cubic V2 phase did not induce any structural instability until it was added up to 20 % relatively to the lipid. In this range the water content in the mesophase was found rather constant between 35 and 40 %. Above this flavor content a drastic loss of order was observed in the lipid liquid crystalline phase reflected by the emulsification of the L2 phase. The feature is different when solubilizing γ-decalactone due to the presence of an intermediate inverted hexagonal phase H2, which shifts the transition to L2 to a larger γ-lactone content. Although the chemical structure of those flavors is very similar, a clear difference in the phase behavior was identified. We discussed this missing hexagonal phase in terms of different localizations of the flavors in the mesophase. This difference should have an impact on their release characteristics. Finally, we showed that the structural modification of the lipid/water mesophase by increasing the F127 is shifted to higher values of the emulsifier content as γ-nonalactone is solubilized in the interiors of particles. 10 ACS Paragon Plus Environment

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The study of the entrapment of fragrances, here γ-lactones, in lipid-based emulsions of submicron size is a starting point for their increasing use especially in cosmetic products. The next step is to characterize and improve the retention of the volatile compounds in such carrier materials.

ACKNOWLEDGEMENTS This research was supported by Cosmetosciences, a global training and research program dedicated to the cosmetic industry. Located in the heart of the cosmetic valley, this program led by University of Orléans is funded by the Région Centre-Val de Loire.

Supporting Information

Evolution of the lattice parameter of DU/γ-nonalactone/water bulk phases with increasing water content for  90; example of the size distribution of DU/water particles loading γ-nonalactone; sizes and polydispersity indices from DU/γ-lactones/water dispersions; SAXS profiles of DUbased dispersions at various γ-decalactone contents


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FIGURES

Figure 1. Chemical structures of (a) monolinolein, (b) γ-nonalactone, (c) γ-decalactone.

Figure 2. Ternary phase diagram of the DU/γ-nonalactone/water system at 22°C.


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Figure 3. SAXS curves from DU-based dispersions with varying content of γ-nonalactone (emulsions at 5 %, stabilized with F127 at  8).

Figure 4. Lattice parameters and characteristic distances of emulsified DU/γ-lactones/water mesophases at 5 %, stabilized with F127 at  8. Please note that the value at  100 does not include nonalactone.


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Figure 5. SAXS curves from DU-based dispersions at 5 % with 10 % of γ-nonalactone ( 90) by varying the emulsifier content.

Table 1. Maximum solubilization content of water at different γ-nonalactone/DU ratios.


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REFERENCES (1) Uddin, Md. H.; Kanei, N.; Kunieda, H. Solubilization and emulsification of perfume in discontinuous cubic phase. Langmuir 2000, 16, 6891-6897. (2) Kaur, R.; Kukkar, D.; Bhardwaj, S.K.; Kim, K.-H., Deep, A. Potential use of polymers and their complexes as media for storage and delivery of fragrances. J. Control. Release 2018, 285, 81-95. (3) Conde-Petit, B.; Escher, F.; Nuessli, J. Structural features of starch-flavor complexation in food model systems. Trends Food Sci. Technol. 2006, 227-235. (4) Yaghmur, A.; Glatter, O. Characterization and potential applications of nanostructured aqueous dispersions. Adv. Colloid Interface Sci. 2009, 147-148, 333-342. (5) Serieye, S. Ph.D. Thesis, University of Orléans, France, January 2012. (6) de Campo, L.; Yaghmur, A.; Sagalowicz, L.; Leser, M. E.; Watzke, H.; Glatter, O. Reversible phase transitions in emulsified nanostructured lipid systems. Langmuir 2004, 20, 5254-5261. (7) Gustafsson, J.; Ljusberg-Wahren, H.; Almgren, M.; Larsson, K. Cubic lipid-water phase dispersed into submicron particles. Langmuir 1996, 12, 4611-4613. (8) Gustafsson, J.; Ljusberg-Wahren, H.; Almgren, M.; Larsson, K. Submicron Particles of Reversed Lipid Phases in Water Stabilized by a Nonionic Amphiphilic Polymer. Langmuir 1997, 13, 6964-6971. (9) Yaghmur, A.; de Campo, L.; Salentinig, S.; Sagalowicz, L.; Leser, M. E.; Glatter, O. Oil-loaded monolinolein-based particles with confined inverse discontinuous cubic structure (Fd3m). Langmuir 2006, 22, 517-521. (10) Martiel, I.; Handschin, S.; Fong, W.-K.; Sagalowicz, L.; Mezzenga, R. Oil transfer converts phosphatidylcholine vesicles into nonlamellar lyotropic liquid crystalline particles. Langmuir 2015, 31, 96-104. 15 ACS Paragon Plus Environment

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(11) Pilman, E.; Larsson, K.; Tornberg, E. Inverse micellar phases in ternary systems of polar lipids/fat/water and protein emulsification of such phases to w/o/w-microemulsion-emulsions. J. Disper. Sci. Technol. 1980, 1, 267-281. (12) Yaghmur, A.; de Campo, L; Sagalowicz, L.; Leser, M. E.; Glatter, O. Emulsified microemulsions and oil-containing liquid crystalline phases. Langmuir 2005, 21, 569-577. (13) Lutton, E.S. Phase behaviour of aqueous systems of monoglycerides. J. Am. Oil Chem. Soc. 1965, 42, 1068-1070. (14) Dong, Y.-D.; Larson, I.; Hanley, T.; Boyd, B.J. Bulk and dispersed aqueous phase behavior of phytantriol: effect of vitamin E acetate and F127 polymer on liquid crystal nanostructure. Langmuir 2006, 22, 9512-9518. (15) Guillot, S.; Moitzi, C.; Salentinig, S.; Sagalowicz, L.; Leser, M.E.; Glatter, O. Direct and indirect thermal transitions from hexosomes to emulsified micro-emulsions in oil-loaded monoglyceride-based particles. Colloids Surf., A. 2006, 291, 78-84. (16) Salentinig, S.; Sagalowicz, L.; Glatter, O. Self-assembled structures and pKa value of oleic acid in systems of biological relevance. Langmuir 2010, 26, 11670-11679. (17) Nilsson, C.; Edwards, K.; Eriksson, J.; Larsen, S.W., Østergaard, J.; Larsen, C.; Urtti, A.; Yaghmur, A. Characterization of oil-free and oil-loaded liquid-crystalline particles stabilized by negatively charged stabilizer citrem. Langmuir 2012, 28, 11755-11766. (18) Tran, N.; Mulet, X.; Hawley, A.M.; Hinton, T.M.; Mudie, S.T.; Muir, B.W.; Giakoumatos, E.C.; Waddington, L.J.; Kirby, N.M.; Drummond, C.J. Nanostructure and cytotoxicity of self-assembled monoolein-capric acid lyotropic liquid crystalline nanoparticles. RSC Adv. 2015, 5, 26785-26795. (19) Liu, Q.; Graham, B.; Hawley, A.; Dong, Y.-D.; Boyd, B.J. Novel agrochemical conjugates with selfassembling behavior. J. Colloid Interface Sci. 2018, 512, 369-378. 16 ACS Paragon Plus Environment

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(20) Tran, N.; Mulet, X.; Hawley, A.M.; Fong C.; Zhai, J.; Le, T.C.; Ratcliffe, J.; Drummond, C.J. Manipulating the ordered nanostructure of self-assembled monoolein and phytantriol nanoparticles with unsaturated fatty acids. Langmuir 2018, 34, 2764-2773. (21) Salonen, A.; Guillot, S.; Glatter, O. Determination of water content in internally self-assembled monoglyceride-based dispersions from the bulk phase. Langmuir 2007, 23, 9151-9154. (22) Guillot, S.; Salentinig, S.; Chemelli, A.; Sagalowicz, L.; Leser, M.E.; Glatter, O. Influence of the stabilizer concentration on the internal liquid crystalline order and the size of oil-loaded monolinoleinbased dispersions. Langmuir 2010, 26, 6222-6229. (23) Sagalowicz, L.; Michel, M.; Adrian, M.; Frossard, P.; Rouvet, M.; Watzke, H. J.; Yaghmur, A.; de Campo, L.; Glatter, O.; Leser, M. E. Crystallography of dispersed liquid crystalline phases studied by cryo-transmission electron microscopy. J. Microsc.-Oxf. 2006, 221, 110-121. (24) Abraham, T.; Hato, M.; Hirai, M. Polymer-dispersed bicontinuous cubic glycolipid nanoparticles. Biotechnol. Prog. 2005, 21, 255-262. (25) Hyde, S. T. Bicontinuous structures in lyotropic liquid crystals and crystalline hyperbolic surfaces. Curr. Opin. Solid State Mater. Sci. 1996, 1, 653-662. (26) Serieye, S.; Méducin, F.; Tidu, A.; Guillot, S. Incorporation of aromas in nanostructured monolinolein-based miniemulsions: A structural investigation. Colloids Surf., A. 2018, 555, 802-808.


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Graphical Abstract


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Chemical structures of (a) monolinolein, (b) γ-nonalactone, (c) γ-decalactone. 950x315mm (120 x 120 DPI)

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Ternary phase diagram of the DU/γ-nonalactone/water system at 22°C. 288x201mm (150 x 150 DPI)


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SAXS curves from DU-based dispersions with varying content of γ-nonalactone (emulsions at 5 %, stabilized with F127 at β 8). 288x201mm (150 x 150 DPI)


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Lattice parameters and characteristic distances of emulsified DU/γ-lactones/water mesophases at 5 %, stabilized with F127 at β 8. Please note that the value at δ 100 does not include nonalactone. 288x201mm (300 x 300 DPI)


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SAXS curves from DU-based dispersions at 5 % with 10 % of γ-nonalactone (δ 90) by varying the emulsifier content. 288x201mm (150 x 150 DPI)


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Maximum solubilization content of water at different γ-nonalactone/DU ratios. 975x159mm (120 x 120 DPI)


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water bulk and emulsified

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