Solubilization and structural transformations in nonionic food microemulsions, characterized by large continuous isotropic region, contg. solubilized lutein, and lutein ester were studied. The prepns. are of oil-based concs. composed of solubilized lutein or lutein ester in reverse micelles constructed from hydrophilic surfactant, alc. and R(+)-limonene. The reverse micelles are dild. along a 60/40 surfactant/oil diln. line with aq. phase (contg. water and glycerol) up to the opposite corner of the diagram where o/w microemulsions are formed passing through a bicontinuous phase, without any visual phase sepn. The diln. goes through two structural transitions that were detd. in empty (ref.) and solubilized systems. The solubilization capacity of both free lutein (FL) and lutein ester (LE) is considerably higher (as expected) in the reverse micelles (no aq. phase), and in the W/O microemulsions than in the O/W microemulsions, but the highest solubilization was obtained within the bicontinuous phase. The solubilization was found to be affected by the lipophilicity of the surfactant and is also concn.-dependent throughout all the microemulsions structures, but the most pronounced surfactant effect was shown to be in the bicontinuous region. Structural transitions w/o → bicontinuous occurred at 30% aq. phase in empty (ref.) microemulsions as well as in microemulsions contg. solubilized free and esterified lutein (at the max. solubilization levels). However, the transitions bicontinuous → o/w occurred at higher aq. phase contents of 50 and 60% aq. phase for FL and LE, resp., in comparison to a transition at 40% for the empty microemulsion. As a result, the bicontinuous region in the presence of the guest mols. becomes much broader. The results indicate that in the reverse swollen micelles the guest mols., being practically lipophilic will be easily accommodated at the concaved water interfaces (in the w/o region), which will enable high solubilization capacities, and without significant modifications of the interface. It becomes also evident that at zero curvature interfaces (bicontinuous) and in convex interfaces (oil/water) the lutein ester (the more lipophilic mol.) penetrates into the interface and swells both the bicontinuous interface and the droplets, similarly to most guest mols. However, free lutein is poorly accommodated at the interface and interferes with the interfacial organization and modifies the flattened curvature, affecting the transformation from bicontinuous to o/w droplets. [on SciFinder(R)]

Fine boron powd. particles with diam. of ≤1 $μ$m were encapsulated in poly(Me methacrylate-Et acrylate) using water/oil/water (W/O/W) double emulsion. The microencapsulation process, factors affecting microcapsule (MIC) formation and dimensions, and flocculation phenomena of the encapsulated powders, were studied to optimize the product. Optical and SEM observations indicate that the double emulsion technique yielded microcapsules with diam. of 30 to 250 $μ$m, depending on the process parameters. Two encapsulation mechanisms are proposed. The first, prevailing at low vol. fraction of the primary emulsion (ϕ2 ≤ 0.01), leads to the formation of MICs derived from discrete secondary emulsion droplets. The second, which is more significant with the increase of ϕ2, at boron-to-polymer ratio (n) of 0.7, is derived from the coalescence of the secondary emulsion drops, leading to sepn. of polymer-boron aggregates. The most problematic step of microencapsulation is the drying process of MICs. At n = 0.7, hypo-osmotic drying leads to partial water withdrawal from the drop interior upon heating and solvent evapn.; the boron particles do not form a solid core. Water diln. of the double emulsion results in addnl. osmotic water withdrawal from the MIC interior. MICs from discrete liq. drops or from sepd. aggregates have similar (30-50 $μ$m) dimensions detd. by the d. matching law. Microgranulated powders prepd. at n = 0.7, may result in flocs due to the agglomeration of polymer-boron aggregates during the drying process. The dimensions of the flocs depend on the drying regime that can be controlled to form particles of desired dimensions. At n = 1 and ϕ2 = 0.01, when water is completely eliminated from MICs simultaneously with solvent evapn., fast drop solidification leads to the formation of solid core. The diam. of the resulting MICs is 200-250 $μ$m. Powd. boron is a component of propellants, and encapsulation provides for coarsening of particles and surface protection, both of which are required for the application. [on SciFinder(R)]

Some parts of the review were taken from an article by Schmitt et al. entitled "Structure and Technofunctional Properties of Protein-Polysaccharide Complexes. A Review" (C. Schmitt, C. Sanchez, S. Desobry-Banan, and J. Hardy, Crit. Reviews in Food Science and Nutrition, 38 (8), 689-753, 1998). Much of the section on Industrial applications of Protein-Polysaccharide Complexes on pages 114-115 were paraphrased or taken directly from Section V-Industrial Utilization of Protein-Polysaccharide complexes on page 730-736 of Schmitt et al. The material borrowed so directly should have been set off in quotes and had more direct attribution and the table should have indicated its source. Table 3 on page 117 was reproduced from Table 8 of Schmitt et al. and the table should have indicated its source. The caption to Figure 10 is incorrect. The figure was extd. from a ref. which should be added to the ref. list as Ref. 36b: C. Schmitt, C. Sanchez, A. Lamprecht, D. Renard, C.-M. Lehr, C. G. de Kruif and J. Hardy. "Study of beta-Lactoglobulin-Acacia Gum Complex Coacervation Using Diffusing Wave Spectroscopy and Confocal Laser Scanning Microscopy." Colloids and Surfaces B: Biointerfaces, 20 (3), 267-280, 2001. [on SciFinder(R)]

A review. The main focus and efforts for the next few years in the area of emulsion technol. will be to improve stability and control the release of active matter in double emulsions (3rd World Congress on Emulsions, Lyon, France, Sept. 2002). Almost any possible blends of low-mol. wt. emulsifiers, oils, cosolvents and coemulsifiers were already tested. Biopolymers, synthetic graft and comb co-polymers and polymerizable emulsifiers that impart steric or mech. stabilization with improved stability and better controlled release were explored. Amphiphilic macromols., natural occurring or synthetic, that increase the viscosity of each of the phases, complex with the oil or the emulsifiers and form systems that will behave much like microcapsules, microspheres and/or mesophasic liq. crystals were mentioned as possible new technologies for improved stability. This review will conc. only on the most recent findings that can enhance stability of the double emulsions and/or will reduce droplets sizes for potential food applications. The attempts and achievements include: selection of food-grade blends of emulsifiers to enhance emulsion stability at both inner and outer interfaces and use of new polymeric amphiphiles (carriers, complexing agents, natural polymeric emulsifiers) to control and reduce the reverse micellar transport phenomena and to control the addenda transport. [on SciFinder(R)]

In this paper we present the structural characterization of a five-component food-grade microemulsion contg. Tween 80, R(+)-limonene, ethanol, glycerol, and water. Our main approach to investigating the microstructure of dense microemulsions, and how it can be influenced by the various components, was to employ small-angle neutron scattering and the new evaluation technique for dense, interacting systems, the Generalized Indirect Fourier Transformation. We started our investigation with the impact of glycerol and ethanol on Tween 80 micelles in water. We found that glycerol increases the aggregation no. and withdraws the hydrating agents from the headgroup region of the surfactant, resulting in a higher packing d. of mols. in a micelle at slightly increasing size. The same trend holds when the micelles are oil swollen and/or ethanol is present. Ethanol, on the other hand, redistributes mainly between water and the interface-headgroup region of the surfactant. Part of it replaces surfactant mols. in the micelles, which increases the available interface and results in a higher no. of micelles with shrinking size. The same trend holds when the micelles are oil swollen and/or glycerol is present in the aq. phase. We also investigated samples along the diln. of a mixt. of surfactant and oil phase (R(+)-limonene and ethanol), which can be dild. with aq. phase (mixt. of water and glycerol) without the occurrence of phase sepn. In some samples of this diln. most probably bicontinuous structures are present. To elucidate this point, we also employed dynamic light scattering, viscosity, and cond. measurements. [on SciFinder(R)]

Crystal growth of calcium hydrogenphosphate dihydrate (DCPD), in the presence of polyaspartic acid or calcium phytate (system A), as well as nucleation and growth of octacalcium phosphate (OCP), in the presence of poly-L-lysine, poly-L-glutamic acid or polystyrene sulfonate (system B) were investigated. In system A crystn. of DCPD was inhibited and the crystal growth morphol. was specifically modified by preferential interaction of the resp. additive with the dominant (010) crystal face. In system B crystals were formed via precursor phase(s) and polyelectrolytes exhibited dual action, at low concns. inducing and at high concns. inhibiting nucleation of the cryst. phase. Crystal/additive interactions controlling growth were nonspecific and resulted in smaller crystals with rounded edges, but with the same basic orientation as in the controls. [on SciFinder(R)]

Crystal growth of calcium hydrogenphosphate dihydrate (DCPD), in the presence of polyaspartic acid or calcium phytate (system A), as well as nucleation and growth of octacalcium phosphate (OCP), in the presence of poly-l-lysine, poly-l-glutamic acid or polystyrene sulfonate (system B) have been investigated. In system A crystallization of DCPD was inhibited and the crystal growth morphology was specifically modified by preferential interaction of the respective additive with the dominant (010) crystal face. In system B crystals were formed via precursor phase(s) and polyelectrolytes exhibited dual action, at low concentrations inducing and at high concentrations inhibiting nucleation of the crystalline phase. Crystal/additive interactions controlling growth were nonspecific and resulted in smaller crystals with rounded edges, but with the same basic orientation as in the controls.

U-type microemulsions based on five food-grade ingredients, water, R(+)-limonene, ethanol, propylene glycol, (or glycerol) and ethoxylated sorbitan esters (Tween 60 or Tween 80) were studied. The U-type phase diagram is characterized by a unique compn., fully dilutable with the aq. phase that inverts progressively from an L2 phase to an L1 phase via a bicontinuous structure without phase sepn. The oil conc.' (surfactant, oil, alc.) is loaded with water-insol. solubilizates (phytosterols, lutein and lycopene) a few times more than the soly. capacity of the oil phase (without the surfactant). The max. solubilization capacity ($μ$-value) was obtained for phytosterols and the min. solubilization capacity was for lycopene. All solubilization values decrease with aq. phase diln. If solubilization is calcd. on the basis of the oil content ($\alpha$-value) or the oil + surfactant ($\gamma$-value) it is obvious that the interface plays a key role in the solubilization.The lipophilic solubilizates (by SD-NMR) are tightly packed and well accommodated at interfaces that convex (hydrophobic-in-nature) toward the water (water-in-oil microemulsions). Solubilization at the bicontinuous interface is lower and the solubilizates are loose packed. Once phase inversion occurs, and the interface becomes more hydrophilic and transforms into oil-in-water microemulsion, the solubilization becomes minimal, and most of the solubilizate desorbs. Phytosterols and lycopene induce the transition from W/O to bicontinuous and it occurs at lower water content (ca. 25 wt% aq. phase in the presence of solubilizate vs. 35 wt% in its absence). The transition from bicontinuous to O/W is mostly unaffected (or undetected) since the interface flattens out and the solubilizate does not affect the curvature much. Lutein displays different behavior, the transition, from bicontinuous phase to O/W, occurs at higher water contents because its adsorption and packing are significantly tighter. Solubilization capacities of each of the nutraceuticals were detd. for all diln. compns. [on SciFinder(R)]

The unique properties of jojoba oil make it an essential raw material in the manuf. of cosmetics. New, totally dilutable U-type microemulsions of water, jojoba oil, alcs., and the nonionic surfactant polyoxyethylene-10EO-oleyl alc. (Brij 96V) were formulated recently. Here, these microemulsions are shown to be capable of solubilizing lycopene, a nutraceutical insol. in water and/or oil, much more effectively than the solvent (or a solvent and surfactant blend) can dissolve them. In water-in-oil (W/O) and oil-in-water (O/W) microemulsions with 10 and 90 wt% water, resp., the normalized maximal solubilization efficiency $\alpha$ is ca. 20-fold larger than its soly. The solubilization capacity of the system is mainly surfactant-concn. dependent. The lycopene resides at the interfaces of the W/O and O/W microemulsions and engenders significant structural changes in the organization of the microemulsion droplets. In the absence of lycopene, the droplets are spherical; when lycopene is added, compaction of the droplets and formation of threadlike droplets are obsd. On further addn. of lycopene, the bridging effect wanes and the droplets revert to a spherical shape. The enhanced solubilization demonstrated for lycopene opens up new options for formulators interested in making liq. and transparent products for cosmetic or pharmaceutical uses. [on SciFinder(R)]

A promising route to the fabrication of biomimetic coatings for artificial implants is the deposition of org./inorg. composite materials consisting of polyelectrolyte multilayers alternating with layers of "in situ" grown calcium phosphate crystals. To facilitate understanding of the underlying mechanisms, in this paper we discuss the influence of polyelectrolytes (PEs), polystyrene sulfonate (PSS), poly-L-lysine (PLL), and poly-L-glutamic acid (PGA) on the formation and properties of amorphous calcium phosphate (ACP) and on the nucleation and growth morphol. of the cryst. phase. PH vs. time curves revealed three distinct pptn. events, i.e., (I) pptn. of ACP, (II) secondary pptn. of a cryst. phase upon the amorphous precursor, and (III) soln.-mediated phase transformation and crystal growth. Finally, cryst. mixts. with low Ca/P molar ratios (1.39), consisting of octacalcium phosphate crystals and small amts. of apatite, were obtained. From the pH vs. time curves, the induction time, ti, preceding crystal nucleation was detd. All PEs at low concns. induced and at high concns. inhibited nucleation. The efficiency of induction increased in the order: LMw PGA equiv. HMw PGA \textless LMw PLL \textless HMw PLL \textless PSS, while the inhibition efficiency increased as LMw PLL equiv. HMw PLL \textless PSS \textless LMw PGA \textless HMw PGA. ACP particles formed in the presence of PE were smaller and less aggregated and had a higher surface charge than in the controls. All investigated PEs also inhibited growth of the cryst. phase in a nonspecific way. [on SciFinder(R)]

The properties of jojoba oil make it uniquely suited as a raw material for the cosmetics industry. Water-based, thermodynamically stable prepns. of jojoba oil are essential in many formulations. New microemulsions were prepd. based on jojoba oil and different nonionic surfactants, namely polyoxyethylene-(ethylene oxide)10-oleyl alc. (brij 96V) and ethoxylated sorbitan esters (Tweens). The effects of the surfactants and of primary alcs. as cosurfactants on the isotropic regions of the phase diagram were elucidated. It was found that, up to a certain cosurfactant chain length, the isotropic region expanded considerably as chain length increased. The size of the isotropic region also increased as a function of the ethylene glycol content of the aq. phase in microemulsions based on ethoxylated alc. but shrank when ethylene glycol was included in microemulsions prepd. with ethoxylated sorbitan esters. Secondary structural phase transitions from water-in-oil to bicontinuous and to oil-in-water structures (as detd. by measuring cond. and viscosity) were found to be related to jojoba oil content. Dynamic light scattering and small angle X-ray scattering studies established that incorporation of jojoba oil into Brij 96V micelles caused micellar transformation from elongated to spherical droplets and a decrease in the aggregation no. [on SciFinder(R)]

The microstructure of a multi-component oil-in-water (O/W) microemulsion, to serve as a microreactor or a solubilization vehicle for food applications, has been studied using small angle scattering X-rays (SAXS) and neutron (SANS) techniques. Significant structural changes along selected aq. diln. lines in the O/W microemulsions were detd. It was found that the droplets' size is affected by increasing the water content, the oleic phase concn. and content (mixt. of R(+)-limonene and ethanol), and the nature of the surfactant (Brij 96v and Tween 60). The micellar size increases with increasing the aq. phase content in both, Brij 96v-based and Tween 60-based systems. Replacing Brij 96v by Tween 60 at const. wt. leads to larger microemulsion droplets. The increase in the surfactant concn. of these systems, as expected, leads to smaller interaction radii and to higher values of the no. particle d. Increasing ethanol content in the oleic phase (R(+)-limonene plus ethanol) decreases the effective vol. fraction, and causes redn. in the micellar size at decreasing surfactant aggregation no. as a result of its redistribution between the interfacial film and the continuous aq. phase. The SANS investigations allowed a focus on the main effects of propylene glycol (PG) and ethanol (EtOH). Both hydrophilic mols. have similar tuning properties on the microstructure. Both decrease the droplet size, render them more globular, and increase the no. of micelles. It was concluded from these results that both alcs. are partially incorporated into the interface (most of it stays in the aq. phase). The only obsd. difference in the investigated samples was that upon replacing the aq. phase partially with PG, the effective vol. fractions of the dispersed phase was decreased, while it remained unchanged when it was partially replaced by EtOH. PG and EtOH seem to influence the microstructure independently. [on SciFinder(R)]

To improve its soly. and bioavailability, lutein was solubilized in U-type food grade microemulsions based on ethoxylated sorbitan fatty acid esters, glycerol, R-(+)-limonene, and ethanol. Reverse micellar and W/O compns. solubilized both lutein and lutein ester better than an O/W microemulsion, and max. solubilization was obtained within the bicontinuous phase. Free lutein was solubilized better than the esterified lutein in the W/O microemulsions, whereas the esterified lutein was better accommodated within the O/W microemulsion. Vegetable oils decreased the solubilization of free lutein. Glycerol and alc. enhanced the solubilization of both luteins. Solubilization was surfactant-dependent in all mesophase structures, but its strongest effect was in the bicontinuous phase. [on SciFinder(R)]

The present invention is directed to a 3-dimensional optical memory comprising as an active medium a compd. capable of interconverting from one isomeric form to another by interaction of light. The compds. comprise stilbene derivs. bound to, e.g., PMMA. The compd. is bound to a polymer for achieving a uniform memory unit. [on SciFinder(R)]
Patent application expired