26 resultados para EMULSIONS

em Deakin Research Online - Australia


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Described herein are microcapsules and emulsions prepared from low Bloom gelatin and methods of making and using thereof.

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Disclosed are emulsions and microcapsules that comprise one or more substances with a low interfacial tension. Methods of making the emulsions and microcapsules as well as methods of using them are also disclosed. In some embodiments microbial oil is used. In some embodiments marine oil is used. In some embodiments the emulsion has a pH of greater than 6,0. In some embodiments the emulsion has a pH of less than 5,0.

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Herein, we report the phase inversion of ionomer-stabilized emulsions to form high internal phase emulsions (HIPEs) induced by salt concentration and pH changes. The ionomers are sulfonated polystyrenes (SPSs) with different sulfonation degrees. The emulsion types were determined by conductivity measurements, confocal microscopy and optical microscopy, and the formation of HIPE organogels was verified by the tube-inversion method and rheological measurements. SPSs with high sulfonation degrees (water-soluble) and low sulfonation degrees (water-insoluble) can stabilize oil-in-water emulsions; these emulsions were transformed into water-in-oil HIPEs by varying salt concentrations and/or changing the pH. SPS, with a sulfonation degree of 11.6%, is the most efficient, and as low as 0.2 (w/v)% of the organic phase is enough to stabilize the HIPEs. Phase inversion of the oil-in-water emulsions occurred to form water-in-oil HIPEs by increasing the salt concentration in the aqueous phase. Two phase inversion points from oil-in-water emulsions to water-in-oil HIPEs were observed at pH 1 and 13. Moreover, synergetic effects between the salt concentration and pH changes occurred upon the inversion of the emulsion type. The organic phase can be a variety of organic solvents, including toluene, xylene, chloroform, dichloroethane, dichloromethane and anisole, as well as monomers such as styrene, butyl acrylate, methyl methacrylate and ethylene glycol dimethacrylate. Poly(HIPEs) were successfully prepared by the polymerization of monomers as the continuous phase in the ionomer-stabilized HIPEs.

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The study used microchannel emulsification (MCE) to encapsulate quercetin in food grade oil-in-water (O/W) emulsions. A silicon microchannel plate (Model WMS 1-2) comprised of 10,300 discrete 10 × 104 μm microslots was connected to a circular microhole with an inner diameter of 10 μm. 1% (w/w) Tween 20 was used as optimized emulsifier in Milli-Q water, while 0.4 mg ml-1 quercetin in different oils served as a dispersed phase. The MCE was carried by injecting the dispersed phase at 2 ml h-1. Successful emulsification was conducted below the critical dispersed phase flux, with a Sauter mean diameter of 29 μm and relative span factor below 0.25. The O/W emulsions remained stable in terms of droplet coalescence at 4 and 25 °C for 30 days. The encapsulation efficiency of quercetin in the O/W emulsions was 80% at 4 °C and 70% at 25 °C during the evaluated storage period.

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Nutritional deficiencies of ergocalciferol (VD2) and cholecalciferol (VD3) cause skeletal deformations. The primary aim of this study was to encapsulate VD2 and VD3 in food-grade oil-in-water (O/W) emulsions by using microchannel emulsification (MCE). Silicon asymmetric straight-through microchannel (MC) array consisting of 10 313 channels, each having an 11 × 104 μm microslot connected to a 10 μm circular microholes. 1% (w/w) sodium cholate or Tween 20 in water was used as the continuous phase, while 0.5% (w/w) of each VD2 and VD3 in different oils served as the dispersed phase. Monodisperse O/W emulsions with Sauter mean diameters of 28 to 32 μm and relative span factor widths below 0.3 were formulated via an asymmetric straight-through MC array under appropriate operating conditions. The monodisperse O/W emulsions stabilised with Tween 20 remained stable for >30 days with encapsulation efficiencies (EEs) of VD2 and VD3 of above 70% at 4 and 25 °C. In contrast, those stabilised with sodium cholate had stability of >30 days with their EEs of over 70% only at 25 °C.

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Ergocalciferol is one important form of vitamin D that is needed for proper functioning of the human metabolic system. The study formulates monodisperse food grade ergocalciferol loaded oil-in-water (O/W) emulsions by microchannel emulsification (MCE). The primary characterization was performed with grooved MCE, while the storage stability and encapsulating efficiency (EE) were investigated with straight-through MCE. The grooved microchannel (MC) array plate has 5 × 18 μm MCs, while the asymmetric straight-through MC array plate consists of numerous 10 × 80 μm microslots each connected to a 10 μm diameter circular MC. Ergocalciferol at a concentration of 0.2-1.0% (w/w) was added to various oils and served as the dispersed phase, while the continuous phase constituted either of 1% (w/w) Tween 20, decaglycerol monolaurate (Sunsoft A-12) or β-lactoglobulin. The primary characterization indicated successful emulsification in the presence of 1% (w/w) Tween 20 or Sunsoft A-12. The average droplet diameter increased slowly with the increasing concentration of ergocalciferol and ranged from 28.3 to 30.0 μm with a coefficient of variation below 6.0%. Straight-through MCE was conducted with 0.5% (w/w) ergocalciferol in soybean oil together with 1% (w/w) Tween 20 in Milli-Q water as the optimum dispersed and continuous phases. Monodisperse O/W emulsions with a Sauter mean diameter (d3,2) of 34 μm with a relative span factor of less than 0.2 were successfully obtained from straight-through MCE. The resultant oil droplets were physically stable for 15 days (d) at 4 °C without any significant increase in d3,2. The monodisperse O/W emulsions exhibited an ergocalciferol EE of more than 75% during the storage period.

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The aim of this study was to investigate the effects of the emulsifying conditions and emulsifier type on production of water-in-oil (W/O) emulsions encapsulating ascorbic acid derivatives by microchannel (MC) emulsification. The ascorbic acid derivatives added in a dispersed aqueous phase are calcium ascorbate (AA-Ca) and ascorbic acid 2-glucoside (AA-2G). The continuous phase used was decane, soybean oil or their mixture, containing 5% (w/w) tetraglycerin monolaurate condensed ricinoleic acid ester or sorbitan trioleate. A hydrophobized silicon MC array plate (model: MS407) with a channel depth of 7μm was used for MC emulsification. The use of MC emulsification enabled successful encapsulation of AA-Ca and AA-2G in monodisperse W/O emulsion droplets with coefficients of variation (CV) less than 7%. Their average droplet diameter (dav) increased with increasing the continuous-phase viscosity that is similar or higher than the dispersed-phase viscosity. The dav and CV of the resultant monodisperse W/O emulsions were unaffected by the dispersed-phase flow rate below critical values of 1.2-1.6mLh-1 when using decane as the continuous-phase medium.

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Stabilizing l-ascorbic acid is a challenge for food industries. The present study aimed to formulate monodisperse food-grade water-in-oil-in-water (W/O/W) emulsions containing a high concentration of l-ascorbic acid in an inner aqueous phase using homogenization and subsequent microchannel emulsification (MCE). The microchannel (MC) array plate used here was a silicon asymmetric straight-through MC array that consists of numerous 10. μm. ×. 100. μm microslots with a 30. μm depth, each connected to a 10. μm-diameter circular MC with a 70. μm depth. Water-in-oil (W/O) emulsions contained a soybean oil solution with 4-8% (w/w) tetraglycerin condensed ricinoleic acid ester as a continuous phase and an aqueous solution with 10-30% (w/v) l-ascorbic acid, 1% (w/w) magnesium sulfate, and 1% (w/v) gelatin as an inner aqueous phase. The W/O emulsion droplets formulated using a rotor-starter homogenizer had average droplet diameters of 2.6-2.9. μm and coefficients of variation (CVs) of 13-17%. MCE was performed using a dispersed W/O emulsion phase and a 5. mM phosphate buffer containing 1% (w/w) decaglycerol monolaurate and 10-30% (w/v) D(+)-glucose as an outer aqueous phase. Monodisperse W/O/W emulsions containing W/O droplets with average diameters of 26.0-31.5. μm and CVs below 10% were successfully formulated via an asymmetric straight-through MC array at a low hydrophobic emulsifier concentration, regardless of l-ascorbic acid concentration. The W/O droplets dispersed in these monodisperse W/O/W emulsions were physically stable in variation of average diameter and CV for more than 10d of storage at 4. °C. The monodisperse W/O/W emulsions also exhibited l-ascorbic acid retention exceeding 80% during storage.

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This study sought to encapsulate a high concentration of L-ascorbic acid, up to 30% (w/v), in the inner aqueous phase of water-in-oil-water (W/O/W) emulsions with soybean oil as the oil phase. Two-step homogenization was conducted to prepare W/O/W emulsions stabilized by a hydrophobic emulsifier and 30% (v/v) of W/O droplets stabilized by a hydrophilic emulsifier. First-step homogenization prepared W/O emulsions with an average aqueous droplet diameter of 2.0 to 3.0 μm. Second-step homogenization prepared W/O/W emulsions with an average W/O droplet diameter of 14 to 18 μm and coefficients of variation (CVs) of 18% to 25%. The results indicated that stable W/O/W emulsions containing a high concentration of L-ascorbic acid were obtained by adding gelatin and magnesium sulfate in the inner aqueous phase and glucose in both aqueous phases. L-Ascorbic acid retention in the W/O/W emulsions was 40% on day 30 and followed first-order kinetics.

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The present study was conducted to encapsulate higher concentration of l-ascorbic acid up to (30 g 100 mL-1) in the dispersed phase of water-in-oil (W/O) emulsions. Their continuous phase contained refined soybean oil or Moringa oleifera oil and a food-grade hydrophobic emulsifier. The volume fraction of the dispersed phase was fixed as to 30%. W/O emulsions with l-ascorbic acid retention greater than 95% were prepared using rotor-stator homogenizer at 7000 rpm for 5 min. The prepared W/O emulsions under this operating conditions had average droplet diameter of 2.0-3.0 μm and coefficients of variation of 13%-22%. All the W/O emulsions were stable for more than 30 days at 4 °C or 25 °C with slight increase in average droplet diameter and without phase separation. Their l-ascorbic acid retentions were 50 g 100 g-1 at 4 °C and 30 g 100 g-1 at 25 °C after 30 days of storage. l-ascorbic acid retention ratio of the prepared W/O emulsions followed first-order kinetics with a good fit.

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Although conducting polymers have various potential applications, lack of solubility is an impediment in their direct application to material surfaces. Synthesis of alkyl pyrrole monomers and subsequent polymerization into soluble conducting polymers are aimed as alternatives to conventional methods of application of conducting polymers on substrates. Alkyl chains are attached to a pyrrole ring to produce solubility in the resulting conducting polypyrroles, which allow direct application of conductive polymer emulsions to any desired surface. Friedel-Crafts acylation of the tosyl-protected pyrrole provides high yields of the 3-acylated product. The conductivity values of poly-3- and 3, 4-substituted pyrroles are generally less than the unmodified polypyrrole. Increasingly bulkier groups attached to the pyrrole means lower conductivity of the resultant polymer. As the carbon chain length attached to the 3-position of pyrrole increases, the solubility also increases. However, the magnitude of change in conductivity of films and pellets of soluble conducting polypyrroles over the alkyl range is not significant.