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)]

A review describes new emerging improvements involving the stability and the control issues of double emulsions, discusses mechanistic considerations, and evaluates alternative ways to deal with the double emulsion concerns related to food applications. [on SciFinder(R)]

A review. Double emulsions are complex dispersed liq. systems known also as "emulsion of emulsion" or "emulsions with emulsions", in which the droplets of one dispersed liq. are further dispersed in another liq. Double emulsions can be of water-in-oil-in-water or oil-in-water-in-oil. The most common and the most studied double emulsions are of water-in-oil-in-water since they have higher potential to become com. products in food, cosmetics and pharmaceutical systems. Double emulsions are considered extremely promising formulations for slow and controlled release of entrapped active matter form the inner phase to the outer continuous phase. Recent studies and the different approaches that have been recently introduced to make double emulsions are discussed. One of the most promising techniques for making double emulsions is using the concept of emulsified microemulsion or emulsified mesophases. [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)]

Winsor IV water-dilutable food-grade microemulsions based on ethoxylated sorbitan esters, water, (R)-(+)-limonene, ethanol, and propylene glycol have been prepd. Tocopherols and lycopene, two active lipophilic antioxidants, have been solubilized in the water-in-oil, bicontinuous, and oil-in-water microemulsions several times more than the oil (R)-(+)-limonene dissoln. capacity. Diln. of the aq. phase and decrease of the surfactant content strongly affect the solubilization capacity and solubilization efficiency of the microemulsion. Self-diffusion coeffs. of the water and the oil in the presence of the solubilizates were correlated to the solubilization capacity, and are indicative of the locus of solubilization of the lycopene in the different microstructures. [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)]

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 present invention discloses the use of a lycopene coated with a water non-sol. thin film comprising amphiphilic protein polymer for coloring with red color, foods, pharmaceuticals or cosmetics having fat and/or oil contents higher than 5 %. The invention further discloses a process for the prepn. of stable lycopene formulation comprising: (a) treating an isolated protein to form a protein in a mol. form; (b) dispersing lycopene in an aq. soln. comprising an isolated protein in a mol. form; (c) grinding said dispersion to form lycopene particle size of 1 to 10 $μ$m forming an homogenized mixt. comprising fine particles; and optionally (d) drying the homogenized mixt. [on SciFinder(R)]

The artificial sweetener, aspartame, is a dipeptide, consisting of a hydrophobic phenylalanine methyl ester entity and a hydrophilic aspartyl residue. In this work, its solubilization in five different types of water in oil (w/o) microemulsions (MEs) was investigated. The stabilizing surfactants and cosurfactants of the MEs were ME1, sodium di-2-ethylhexyl sulfosuccinate (ACT) and no cosurfactant; ME2, maleic anhydride alpha-olefin copolymer and dimethyl amino ethanol; ME 3, sucrose ester monostearate and n-butanol; ME 4, L-alpha-phosphatidylcholine and n-butanol; and ME 5, mono- and diglycerides of fatty acids and L-alpha-phosphatidylcholine. The maximum amount that could be dissolved (boundary concentration) was determined by adding powdered aspartame to a heated ME and cooling to a specified temperature under controlled conditions. The solutions that remained clear for at least 4 days were regarded as stable, and those of the stable solutions with the highest aspartame concentrations were taken as having the boundary concentrations. From the solubility data, the distribution of the aspartame molecules between the w/o interface and the water pools was calculated, and the results were correlated with the molecular structure and ionic state of the surfactant. The results show that aspartame can be solubilized in all the investigated MEs to an extent, exceeding by far its solubility in pure water, and that overall solubilization is most efficient in water/isooctane MEs stabilized with ACT (ME1). While the aspartame solubility in the water pools was comparable in all the investigated MEs, the aspartame/surfactant molar ratio at the w/o interface was found to decrease with decreasing polarity of the stabilizing surfactant at the interface. In addition to the solubilization studies, the effect of aspartame on some properties of ME1 was investigated. It was found that aspartame lowers the interfacial tension at the water/isooctane/AOT interface and, under certain conditions, stabilizes unstable mixtures of water, isooctane, and ACT. The results of small-angle X-ray scattering measurements show that the ME droplet sizes increase in the presence of aspartame molecules and their shapes change from near spherical to ellipsoidal. It was concluded that aspartame acts as a cosurfactant in water/isooctane MEs stabilized with ACT.

Alcs. and polyols are essential components (in addn. to the surfactant, H2O, and oil) in the formation of U-type self-assembled nano-structures, (sometimes called L-phases or U-type microemulsions). These microemulsions are characterized by large isotropic regions ranging from the oil side of the phase diagram up to the aq. corner. The isotropic oily solns. of reverse micelles (the concs.) can be dild. along some diln. lines with aq. phase to the direct micelles corner via a bicontinuous mesophases (i.e., 2 structural transitions). This diln. takes place with no phase sepns. or occurrence of liq. cryst. phases. The structural transitions were detd. by viscosity, cond., and pulsed gradient spin echo NMR (PGSE NMR), and are not visible to the eye. Two guest nutraceutical mols. (lutein and phytosterols) were solubilized, at their max. solubilization capacity, in the reversed micellar solns. (L2 phase) and were further dild. with the aq. phase to the aq. micellar corner (L1 phase). Structural transitions (for the 2 types of mol.) from H2O-in-oil to bicontinuous microstructures were induced by the guest mols. The transitions occurred at an earlier stage of diln., at a lower H2O content (20% aq. phase), than in the empty (blank) microemulsions (transitions at 30% aq. phase). The transitions from the bicontinuous microstructure to the oil-in-H2O microemulsions were retarded by the solubilizates and occurred at later diln. stage at higher aq. phase contents (50% aq. region for empty microemulsion and \textgreater60% for solubilized microemulsion). As a result, the bicontinuous isotropic region, in the presence of the guest mols., becomes much broader. It seems that the main reason for such guest-induced structural transitions is related to a significant flattening and enhanced rigidity of the interface. The guest mols. of the high mol. vol. are occupying high vol. fraction of the interface (when the solubilization is maximal). [on SciFinder(R)]

A review. Structured self-assembled liqs. have been considered as efficient microreactors for org. and enzymic reactions. Only recently scientists learned to use food-grade cosolvents and coemulsifiers together with hydrophilic non-ionic surfactants and to construct U-type phase diagrams with large isotropic regions ranging continuously from the oil-rich corner to the water-rich corner without any phase sepn. The U-type microemulsions facilitate triggering and control of certain reactions by changing water activities. Maillard thermal degrdn. between sugars and amino acids is the main, and almost the only, chem. reaction that was studied in food-grade microemulsions. Some examples of recent studies include: Maillard processes in binary structured fluids composed of monoglycerides of fatty acids and water forming microemulsions and lyotropic liq. cryst. structures; pseudoternary and pseudoquaternary W/O microemulsions; U-type microemulsions (W/O, O/W and bicontinuous microemulsions); enzymic reactions aimed to prep. other surfactants such as sugar esters, monoglycerides and lysolecithins or triglycerides. Reactions in microreactors lead to unique new products. The reaction products and rates are controlled by the hydrophilicity/lipophilicity of the reagents (guest mols.), their molar ratios, type of oil phase, nature of surfactants and oil/surfactant ratios, nature of curvature and its elasticity (adjusted by cosolvent and coemulsifier) and by the water activity. The field is in its infancy and will need work of many more model reactions before it will be used in industrial food applications. Enzymic reactions in non-food microemulsions are common practice but only few examples of food microemulsions as enzymic microreactors were extensively studied. [on SciFinder(R)]

The microstructure of an unusual Winsor IV isotropic region of five-component microemulsions based on nonionic surfactants was studied. The microemulsions are composed of R(+)-limonene, water, propylene glycol (PG), ethanol (EtOH), and polyoxyethylene sorbitan monostearate (Tween 60) with a 1:1:3 R(+)-limonene/ethanol/surfactant wt. ratio. The phase diagrams of the system are characterized by an extended single continuous isotropic region starting from an oil-rich soln. contg. no aq. phase (reverse micelles) to the water/propylene glycol (1/1) corner (swollen direct micelles). The microemulsions seem to be attractive for food applications. The microstructure changes gradually, smoothly, and continuously upon increasing the aq. phase content. The microemulsion transforms from a water-in-oil (W/O) microemulsion to a bicontinuous phase and to an oil-in-water (O/W) microemulsion. The microstructure of the microemulsion along a selected diln. line, is probed using pulsed gradient spin-echo NMR, cond., and viscosity. The results are compared with a corresponding non-food-grade system based on C18:1E10 (Brij 96v). The hydrodynamic radius (RH) of O/W microemulsion samples based on Brij 96v and Tween 60, at 90% aq. phase, was detd. to be 5.4 ± 0.2 and 5.2 ± 0.2 nm, resp., and the calcd. values of the area of the polar headgroup (a) are 87 for Brij 96v and 160 \AA2 for Tween 60-based microemulsions. The ratio of the water self-diffusion coeff., DW, to the PG self-diffusion coeff. (DPG) (termed the L ratio) was found to be sensitive to the aq. phase content. In the O/W microemulsions, the water/PG mixt. diffuses as hydrogen bonded entity (mol. diffusion controlled), while in the W/O microemulsions, the PG partitions, in part, at the interface and the dominant diffusion process is neither aggregate nor mol. controlled. [on SciFinder(R)]

Anal. of the phenolic constituents of shea (Vitellaria paradoxa) kernels by LC-MS revealed 8 catechin compds.-gallic acid, catechin, epicatechin, epicatechin gallate, gallocatechin, epigallocatechin, gallocatechin gallate, and epigallocatechin gallate-as well as quercetin and trans-cinnamic acid. The mean kernel content of the 8 catechin compds. was 4000 ppm (0.4% of kernel dry wt.), with a 2100-9500 ppm range. Comparison of the profiles of the 6 major catechins from 40 Vitellaria provenances from 10 African countries showed that the relative proportions of these compds. varied from region to region. Gallic acid was the major phenolic compd., comprising an av. of 27% of the measured total phenols and exceeding 70% in some populations. Colorimetric anal. (101 samples) of total polyphenols extd. from shea butter into hexane gave an av. of 97 ppm, with the values for different provenances varying between 62 and 135 ppm of total polyphenols. [on SciFinder(R)]

A review. An outline is given on the use of microemulsions and other microcompartmentalized systems as media for chem. reactions. Examples are presented to illustrate the principles of different possible reactions and the used microheterogeneous media. Treated is the prepn. of nanosized inorg. particles from microemulsions, the prepn. of mesoporous inorg. materials from surfactant liq. crystals, and the use of solid foams prepd. from highly concd. emulsions to make meso/macroporous inorg. oxide materials. The use of microheterogeneous systems as media for the prepn. of org. polymers and of microemulsions for bioorg. synthesis is also described. [on SciFinder(R)]

Microemulsions are of growing interest to the food industry as vehicles for delivering and enhancing solubilization of natural food supplements with nutritional and health benefits. The incorporation of mol. phytosterols, cholesterol-lowering agents, in food products is of great interest to the food industry. The use is demonstrated of water-dilutable food-grade microemulsions consisting of ethoxylated sorbitan ester (Tween 60), water, R-(+)-limonene, ethanol, and propylene glycol as vehicles for enhancing the phytosterols solubilization. Phytosterols were solubilized up to 12 times more than the dissoln. capacity of the oil [R-(+)-limonene] for the same compds. The solubilization capacity of phytosterols and cholesterol along a diln. line in a pseudo-ternary phase diagram [wt. ratio of R-(+)-limonene/ethanol/Tween 60 const. at 1p1:3] was correlated to the microstructure transitions along the diln. line. Structural aspects were studied by self-diffusion NMR spectroscopy. The ability of phytosterols to compete with cholesterol for penetration into bile salt micelles in the gut may be limited to rich aq. systems (O/W microemulsion). [on SciFinder(R)]

Various industries including food and pharmaceuticals are sharing increasing interest in microemulsions. Also, one can demonstrate that solubilization of active materials within the core or interface of microemulsions may have environmental benefits. In this work, the authors report three examples of new microemulsion formulations specially designed to be capable of solubilizing active materials and protecting the environment from the emission of hazardous matter or protecting sensitive mols. from the detrimental effects of the environment. In the first example, fire-resistant ingredients were incorporated in hydraulic fluids based on water-in-oil (W/O) microemulsions and their typical characteristics were described. In the second example, five-component oil-in-water (O/W) microemulsions were designed to solubilize lycopene and protect it from exposure to light. In the third example, a friendly solvent (Bu lactate) was microemulsified to form nanosized liq. droplets capable of solubilizing bromine-based bactericide formulations of sophisticated wood preservatives. The new vehicles exhibit a very significant solubilization capacity and can be applied in aq. media. In the last example, the active matter may be triggered when demanded and the release will be followed by film formation. [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)]

An interfacial Maillard reaction between furfural and cysteine in two different food-grade nano-sized self-assembled solns. with two oppositely curved interfaces (W/O and O/W microemulsions) have been studied and compared. These microemulsions are selective microreactors strongly enhancing the generation of sulfur-contg. flavors. The Maillard reactions occur at lower temps. than in water and are much faster. The interfaces of both W/O and O/W microemulsions are capable of enhancing the Maillard reactions in which the selectivity and reactivity are controlled by the compn. of the interface and its curvature. In the W/O microemulsions the Maillard reaction was controlled and enhanced by the interfacial concn. of a co-emulsifier such as butanol and are restricted by the concn. of the core water reservoir. On the other hand, in the O/W microemulsions, where water is the continuous phase, the reaction rates are enhanced by increase in the water content and the microemulsion curvature. The Maillard product internal compn. (regioselectivity and type of products) is dictated by temp., time, pH and mainly by the nature of the interface, and by the surfactant nature and its interfacial compn. [on SciFinder(R)]