JOURNAL OF SENSORY STUDIES, Issue 5 2010
MARÍA EMMA PARENTE
ABSTRACT The sensory characteristics of cosmetic products are commonly used for attracting consumers' attention in advertising campaigns and packaging. Thus, in order to appropriately satisfy consumers' sensory expectations, it is important to gather information about their perception of the sensory characteristics. In this context, the aim of the present work was to apply two consumer methodologies (intensity scales and a check-all-that-apply [CATA] question) to gather information about the sensory profile of cosmetic emulsions. Six cosmetic emulsions with different formulation, widely differing in their sensory characteristics, were evaluated by two groups of 50 female consumers. One group used intensity scales to evaluate eight attributes of the emulsions and the other completed a CATA question comprising 20 terms related to sensory characteristics of the emulsions, cosmetic applications and effects on the skin. Both intensity scales and CATA question were able to detect differences in consumers' perception of the sensory characteristics of the evaluated emulsions. These differences could be explained considering the samples' formulation, which suggests their validity and indicates that they could consist on interesting alternatives to traditional sensory profiles obtained with trained assessors' panels. PRACTICAL APPLICATIONS The application of intensity scales or a CATA question consisted of an interesting approach to gather information about consumers' perception of cosmetic products. Despite both methodologies provided similar results, the application of CATA questions could be regarded as more natural for consumers and easier to use. Besides, CATA questions could enable the identification of consumers' perception of the sensory characteristics of cosmetic products, but also their effects on the skin and the cosmetic applications for which they are considered appropriate. An interesting application of this methodology could be the development of a line of cosmetic products with different applications or the selection of sensory and efficacy claims during the design of marketing strategies or labels of cosmetic products. [source]

RHEOLOGY OF DOUBLE (W/O/W) EMULSIONS PREPARED WITH SOYBEAN MILK AND FORTIFIED WITH CALCIUM

JOURNAL OF TEXTURE STUDIES, Issue 5 2010
ANDRÉS L. MÁRQUEZ
ABSTRACT The objective of this work was to study the rheological behavior of water-in-oil-in-water (w/o/w) emulsions prepared with soybean milk and sunflower oil, with different calcium solutions as the internal aqueous phase, in order to evaluate them as a vegetable substitute of whipped dairy cream. The obtained systems exhibited a creamy texture, which was attributed to the swelling of w/o droplets because of the osmotic gradient generated by the inclusion of soluble salts in the internal aqueous phase. A secondary factor could be the flocculation of w/o droplets due to the interaction of released calcium with soybean proteins at the interface. Consequently, the increase of calcium chloride content produced emulsions with higher consistency. A pasteurization produced flocculation and coalescence of w/o droplets only at high calcium chloride content. These double emulsions could be a potential alternative to the whipped dairy cream, because of their texture, reduced fat content and calcium contribution. PRACTICAL APPLICATIONS This article deals with the formulation of novel calcium-fortified food emulsions prepared with soybean milk and sunflower oil. Because calcium needs to be isolated from soybean milk components (proteins and phospholipids), we proposed to include calcium salts in the internal aqueous phase of a water-in-oil-in-water (w/o/w) emulsion. The practical applications of this research could include the formulation of low lipid content emulsions and the isolation of a component which is incompatible with the continuous aqueous phase. Particularly, this work leads to the understanding of how the inclusion of calcium salts in the internal aqueous phase of a w/o/w emulsion prepared with soybean milk affects the rheology and microstructure of the system. The results led to the conclusion that these emulsions can work as a whipped dairy cream substitute with vegetal components, low lipid content and important calcium contribution. [source]

MICROSTRUCTURAL AND RHEOLOGICAL PROPERTIES OF LOW-FAT STIRRED YOGHURTS MADE WITH SKIM MILK AND MULTIPLE EMULSIONS

JOURNAL OF TEXTURE STUDIES, Issue 6 2009
C. LOBATO-CALLEROS
ABSTRACT This article focuses on the study of the dynamic rheological and structural properties developed in low-fat stirred yoghurts made with skim milk and multiple emulsions stabilized with carboxymethylcellulose (SYCMC) or amidated low methoxy pectin (SYALMP), in comparison with a full milk-fat stirred yoghurt control (SYMF). The SYALMP yoghurt exhibited greatest Tan,after 14 days of storage than the SYMF and SYCMC yoghurts. The SYALMP yoghurt presented the highest lacunarity value and was characterized by a structure composed of highly clusterized casein aggregates. In contrast, the SYCMC and SYMF yoghurts displayed lower lacunarity values and structures characterized by smaller casein clusters. Lower Tan,values were associated with lower lacunarity values. PRACTICAL APPLICATIONS Limited work has been done on stirred and set-style yoghurts, cheeses and, in general, dairy products, where milk-fat globules are substituted by skim milk combined with multiple emulsions containing polyunsaturated vegetable oils. As a result of this, multicomponent gels formation occurs (made up by milk proteins, polyunsaturated vegetable oils, emulsifiers, hydrocolloids and many possible other ingredients), which give rise to completely different structural arrangements that may display comparable mechanical-sensory properties with those exhibited by their full milk-fat counterparts, paving the way for the development of new healthier foods sensory and texturally acceptable to consumers. [source]

Development of emulsion from rhizobial fermented starch industry wastewater for application as Medicago sativa seed coat

ENGINEERING IN LIFE SCIENCES (ELECTRONIC), Issue 3 2010
Rojan Pappy John
Abstract Starch industry wastewater was efficiently employed for the production of Sinorhizobium meliloti and the concentrated culture was used for the development of a biofertilizer formulation. Tween-80 (0.02,g/L) acted as the best emulsifier for a Sinorhizobium,canola oil emulsion. The stability of the emulsion and survival of the organism was enhanced by supplementation of xanthan gum at pH 8. The refrigerated condition was most favorable for stability and survival of the microorganism. The survival of microorganism at 4±1°C was 2.78×1010 and 2.01×1010,CFU (colony forming unit)/mL on storage for 1 and 2 months, respectively. The values were higher than the prescribed cell count (×103,CFU/mL) for field application. At 40°C, the survival of bacteria reduced from 3×1010,CFU/mL to 8.1×109 and 8.8×106,CFU/mL in 1 and 2 months, respectively. Emulsion-coated seed was incubated at different temperatures and a cell count of 105,CFU/seed was observed after 2 months of storage at 4°C, which was equal to the highest level of the described requirement (103,105,CFU/seed). Emulsion supplemented with xanthan gum improved the shelf-life under optimized conditions (Sinorhizobium concentrate,,,canola oil (1:1) emulsion with 0.02,g/L Tween-80; storage at pH 8 and temperature 4±1°C) and this emulsion with the required cell count and prolonged viability was used for the pre-inoculation of seed or for in situ soil application. [source]

Emulsion as a Means of Controlling Electrospinning of Polymers

ADVANCED MATERIALS, Issue 18 2009
Jay C. Sy
A generalized approach to attain spinnability in polymer solutions in electrospinning using emulsions is described. By using emulsions, low-molecular weight (MW) polymer solutions that tend to electrospray can be spun into nanofibers. Additionally, control over fiber properties independent of polymer solution viscosity and MW is achieved, with an order of magnitude reduction in fiber diameter upon emulsification. Nanofibrous sheets obtained demonstrate excellent cellular biocompatibility and are suitable for tissue contacting applications. [source]

Comparative Structural, Emulsifying, and Biological Properties of 2 Major Canola Proteins, Cruciferin and Napin

JOURNAL OF FOOD SCIENCE, Issue 3 2008
J. Wu
ABSTRACT:, Canola is an economically important farm-gate crop in Canada. To further explore the potential of canola protein as value-added food and nutraceutical ingredients, a better understanding of fundamental properties of 2 major canola proteins is necessary. Two major protein components, cruciferin and napin, were isolated from defatted canola meal by Sephacryl S-300 gel filtration chromatography. SDS-PAGE showed that cruciferin consists of more than 10 polypeptides, and noncovalent links are more important than disulphide bonds in stabilizing the structural conformation. Napin consists of 2 polypeptides and is stabilized primarily by disulphide bonds. Purified cruciferin showed 1 major endothermic peak at 91 °C compared with that of 110 °C for napin. Emulsion prepared by cruciferin showed significant higher specific surface area and lower particle size than that of napin. The study indicated that the presence of napin could detrimentally affect the emulsion stability of canola protein isolates. Hydrolysates from cruciferin and napin showed potent angiotensin I-converting enzyme inhibitory activity (IC50: 0.035 and 0.029 mg/mL, respectively), but weaker than that of canola protein isolate hydrolysate (IC50: 0.015 mg/mL). [source]

Emulsion-Based Delivery Systems for Lipophilic Bioactive Components

JOURNAL OF FOOD SCIENCE, Issue 8 2007
D.J. McClements
ABSTRACT:, There is a pressing need for edible delivery systems to encapsulate, protect, and release bioactive lipids within the food, medical, and pharmaceutical industries. The fact that these delivery systems must be edible puts constraints on the type of ingredients and processing operations that can be used to create them. Emulsion technology is particularly suited for the design and fabrication of delivery systems for encapsulating bioactive lipids. This review provides a brief overview of the major bioactive lipids that need to be delivered within the food industry (for example, ,-3 fatty acids, carotenoids, and phytosterols), highlighting the main challenges to their current incorporation into foods. We then provide an overview of a number of emulsion-based technologies that could be used as edible delivery systems by the food and other industries, including conventional emulsions, multiple emulsions, multilayer emulsions, solid lipid particles, and filled hydrogel particles. Each of these delivery systems could be produced from food-grade (GRAS) ingredients (for example, lipids, proteins, polysaccharides, surfactants, and minerals) using simple processing operations (for example, mixing, homogenizing, and thermal processing). For each type of delivery system, we describe its structure, preparation, advantages, limitations, and potential applications. This knowledge can be used to facilitate the selection of the most appropriate emulsion-based delivery system for specific applications. [source]

Preparation of Nanometer-Sized ,-Alumina Powders by Calcining an Emulsion of Boehmite and Oleic Acid

JOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 1 2002
Chih-Peng Lin
This study proposes a method to form ultrafine ,-Al2O3 powders. Oleic acid is mixed with Al(OH)3 gel. The gel is the precursor of the Al2O3. After it is mixed and aged, the mixture is calcined in a depleted oxygen atmosphere between 25° and 1100°C. Oleic acid evaporates and decomposes into carbon during the thermal process. Residual carbon prevents the growth of agglomerates during the formation of ,-Al2O3. The phase transformation in this process is as follows: emulsion ,,-Al2O3,,-Al2O3,,-Al2O3,,-Al2O3. This process has no clear , phase. Aging the mixed sample lowers the formation temperature of ,-Al2O3 from 1100° to 1000°C. The average crystallite diameter is 60 nm, measured using Scherrer's equation, which is consistent with TEM observations. [source]

Empirical Modeling of Butyl Acrylate/Vinyl Acetate/Acrylic Acid Emulsion-Based Pressure-Sensitive Adhesives

MACROMOLECULAR MATERIALS & ENGINEERING, Issue 5 2004
Renata Jovanovic
Abstract Summary: Butyl acrylate/vinyl acetate/acrylic acid (BA/VAc/AA) emulsion latexes were produced in a semi-batch mode. The objective was to generate polymers with properties favoring their application as pressure-sensitive adhesives. The influence of the individual monomer concentrations on final properties such as glass transition temperature (Tg), peel strength, shear strength and tack was investigated. To obtain the maximum amount of information in a reasonable number of runs, a constrained three-component mixture design was used to define the experimental conditions. Latexes were coated onto a polyethylene terephthalate carrier and dried. Different empirical models (e.g. linear, quadratic and cubic mixture models) governing the individual properties (i.e. Tg, peel adhesion, shear resistance and tack) were developed and evaluated. In the given experimental region, no single model was found to fit all of the responses (i.e. the final properties). However, in all models the most significant factor affecting the final properties was the AA concentration, followed by the VAc concentration. Shear strength contour lines over the investigated region. [source]

Stable Free Radical Polymerization in Emulsion: Modeling the Thermodynamics of Monomer Transfer between Droplets and Particles

MACROMOLECULAR THEORY AND SIMULATIONS, Issue 2-3 2008
Jordan Pohn
Abstract A mathematical model is developed from polymer solution thermodynamics and stable free radical polymerization kinetics to predict the monomer swelling behavior of large droplets and small particles that coexist during the seeded polymerization of styrene in emulsion. This model is used to predict the sensitivity of polymerized latex stability (based on the persistence of large particles) to changes in seed particle size and final latex target molecular weight. Simulation results show that the use of small seed particles (diameter,,,50 nm) in recipe formulation will lead to polymerization occurring preferentially in the large droplets, and offers theoretical evidence that TEMPO-mediated ab initio emulsion polymerizations will not be feasible. Our predictions are consistent with experimental evidence suggesting that the presence of large particles leads to the formation of undesirable coagulum in the final product. [source]

Novel Sample Preparation Method of Polymer Emulsion for SEM Observation

MICROSCOPY RESEARCH AND TECHNIQUE, Issue 10 2007
Jing Xu
Abstract The aim of this study was to design a simple and reliable method for obtaining the detailed information about the average size, size distribution, and the surface morphology of particles with variation of the sample preparation of a polymer emulsion. In this work, the characteristic features of the particles of rosin size with high viscosity were first described by scanning electron microscopy (SEM). The morphologies of polymer emulsion of solid lipid nanoparticles and of the microspheres were observed. The advantage of the method is that not only the true size and shape of emulsion particles can be shown, but the problem of high-viscosity emulsion that prevents there study with SEM is solved. Using this new method, the micromorphology and size distribution of the emulsion particles with different viscosities have been clearly observed. Microsc. Res. Tech., 2007. © 2007 Wiley-Liss, Inc. [source]

Fluorous Biphase Synthesis of a Poly(p -phenyleneethynylene) and its Fluorescent Aqueous Fluorous-Phase Emulsion,

ANGEWANDTE CHEMIE, Issue 41 2010
Jeewoo Lim
Eine hochfluorierte Verbindung mit starrer 3D-Gestalt wurde als Monomer für Poly(p -phenylenethinylene) (PPEs) synthetisiert. Anhand einer Zweiphasensynthese (fluoriges/organisches Lösungsmittel) wurde das PPE synthetisiert, welches eine selektive Löslichkeit in fluorigen Lösungsmitteln zeigt. Eine fluorige Lösung des Polymers konnte in eine wässrige Emulsion mit hoher Fluoreszenzquantenausbeute überführt werden (siehe Bild). [source]

Microfluidic Mass-Transfer Control for the Simple Formation of Complex Multiple Emulsions,

ANGEWANDTE CHEMIE, Issue 39 2009
Chun-Xia Zhao Dr.
Mehr als eine einfache Emulsion: Bei einer direkten Methode zur Umwandlung einer einfachen Emulsion in Mehrfachemulsionen in einem T-förmigen Mikrofluidiksystem wird Wasser als Cosolvens in Öl eingebracht. Am Kreuzungspunkt bildet sich zunächst eine einfache Emulsion, anschließend entsteht auf autokatalytischem Weg dann eine Mehrfachemulsion, indem das Cosolvens in die kontinuierliche Phase eindringt. [source]

Intravenous Lipid Emulsion as Antidote Beyond Local Anesthetic Toxicity: A Systematic Review

ACADEMIC EMERGENCY MEDICINE, Issue 9 2009
FACEM, Grant Cave MBChB
Abstract Objectives:, The objective was to asses the efficacy of lipid emulsion as antidotal therapy outside the accepted setting of local anesthetic toxicity. Methods:, Literature was accessed through PubMed, OVID (1966,February 2009), and EMBASE (1947,February 2009) using the search terms "intravenous" AND ["fat emulsion" OR "lipid emulsion" OR "Intralipid"] AND ["toxicity" OR "resuscitation" OR "rescue" OR "arrest" OR "antidote"]. Additional author and conference publication searches were undertaken. Publications describing the use of lipid emulsion as antidotal treatment in animals or humans were included. Results:, Fourteen animal studies, one human study, and four case reports were identified. In animal models, intravenous lipid emulsion (ILE) has resulted in amelioration of toxicity associated with cyclic antidepressants, verapamil, propranolol, and thiopentone. Administration in human cases has resulted in successful resuscitation from combined bupropion/lamotrigine-induced cardiac arrest, reversal of sertraline/quetiapine-induced coma, and amelioration of verapamil- and beta blocker,induced shock. Conclusions:, Management of overdose with highly lipophilic cardiotoxic medications should proceed in accord with established antidotal guidelines and early poisons center consultation. Data from animal experiments and human cases are limited, but suggestive that ILE may be helpful in potentially lethal cardiotoxicity or developed cardiac arrest attributable to such agents. Use of lipid emulsion as antidote remains a nascent field warranting further preclinical study and systematic reporting of human cases of use. [source]

Determining the Optimal Dose of Intravenous Fat Emulsion for the Treatment of Severe Verapamil Toxicity in a Rodent Model

ACADEMIC EMERGENCY MEDICINE, Issue 12 2008
Eric Perez MD
Abstract Objectives:, Recent animal studies have shown that intravenous fat emulsion (IFE) increases survival and hemodynamics in severe verapamil toxicity. However, the optimal dose of IFE is unknown. The primary objective was to determine the optimal dose of IFE based on survival in severe verapamil toxicity. Secondary objectives were to determine the effects on hemodynamic and metabolic parameters. The hypothesis was that there is a dose-dependent effect of IFE on survival until a maximum dose is reached. Methods:, This was a controlled dose-escalation study. Thirty male rats were anesthetized, ventilated, and instrumented to record mean arterial pressure (MAP) and heart rate (HR). Verapamil toxicity was achieved by a constant infusion of 15 mg/kg/hr. After 5 minutes, a bolus of 20% IFE was given. Animals were divided into six groups based on differing doses of IFE. Arterial base excess (ABE) was measured every 30 minutes. Data were analyzed with analysis of variance. Results:, The mean survival time for each dose of IFE was 0 mL/kg = 34 minutes, 6.2 mL/kg = 58 minutes, 12.4 mL/kg = 63 minutes, 18.6 mL/kg = 143.8 minutes, 24.8 mL/kg = 125.6 minutes, and 37.6 mL/kg = 130 minutes. Post hoc testing determined that the 18.6 mL/kg dose resulted in the greatest survival when compared to other doses. It increased survival 107.2 minutes (p = 0.004), 91.2 minutes (p = 0.001), and 80.8 minutes (p = 0.023) when compared to the lower doses of 0, 6.2, and 12.4 mL/kg, respectively. There was no added benefit to survival for doses greater than 18.6 mL/kg. The secondary outcomes of HR, MAP, and ABE showed the most benefit with 24.8 mL/kg of IFE at both 30 and 60 minutes. Conclusions:, The greatest benefit to survival occurs with 18.6 mL/kg IFE, while the greatest benefit to HR, MAP, and BE occurs at 24.8 mL/kg IFE. The optimal dose for the treatment of severe verapamil toxicity in this murine model was 18.6 mL/kg. [source]

Rhodium-Catalyzed Heck-Type Coupling of Boronic Acids with Activated Alkenes in an Aqueous Emulsion.

CHEMINFORM, Issue 51 2004
Mark Lautens
Abstract For Abstract see ChemInform Abstract in Full Text. [source]

Hemodynamic Effects of Intravenous Fat Emulsion in an Animal Model of Severe Verapamil Toxicity Resuscitated with Atropine, Calcium, and Saline

ACADEMIC EMERGENCY MEDICINE, Issue 2 2007
Theodore C. Bania MD
Background Intravenous fat emulsion (IFE) decreases cardiotoxicity from several lipid-soluble drugs, including verapamil. Objectives To verify if the addition of IFE to the standard treatment of severe verapamil toxicity would improve hemodynamics and survival. Methods Fourteen dogs were instrumented to measure systolic blood pressure, diastolic blood pressure, mean arterial pressure (MAP), heart rate, cardiac output, central venous pressures, left ventricular pressure changes over time, mixed venous oxygen saturation, pH, and base excess. Verapamil toxicity, defined as a 50% decrease in MAP, was induced with verapamil at 6 mg/kg/hr and maintained for 30 minutes by titrating the verapamil infusion rate. Following verapamil toxicity, the verapamil infusion rate was changed to 2 mg/kg/hr and continued for 90 minutes. All dogs were resuscitated with atropine (0.04 mg/kg intravenously) and calcium chloride (15 mg/kg intravenously every 5 minutes for three doses) and then randomized to receive either IFE (7 mg/kg of 20%) intravenously or equivalent volumes of 0.9% normal saline over 30 minutes. Measurements were recorded for 120 minutes by investigators blinded to the treatment. Data were analyzed using analysis of variance, survival analysis, and log-rank test. Results Before the 30-minute IFE or normal saline infusion, there were no differences in hemodynamic parameters. After IFE or normal saline infusion, the IFE-treated group had higher MAP at 30 minutes (95% confidence interval [CI] = 5.6 to 44.7 mm Hg), 45 minutes (95% CI = 10.8 to 50.0 mm Hg), and 60 minutes (95% CI = 10.2 to 53.1 mm Hg). Kaplan,Meier 120-minute survival rate was 14% (95% CI = 0.5% to 53%) for the saline group as compared with 100% (95% CI = 59% to 100%) for the IFE group (p = 0.01). Conclusions Standard resuscitation and IFE increase MAP and survival in an animal model of severe verapamil toxicity compared with standard resuscitation alone. [source]

Development of spray- and freeze-dried high-concentration sesamol emulsions and antioxidant evaluation in fibroblasts and UV-exposed rat skin slices

DRUG DEVELOPMENT RESEARCH, Issue 5 2008
Juliana Alencar
Abstract Dry sesamol emulsions were synthesized from several combinations of saccharose with hydroxypropylmethylcellulose (HPMC) or sodium caseinate (SC) using spray-drying techniques at 120° to 180°C, or freeze-drying. On the basis of physical characteristics such as droplet size distribution, residual moisture, and microscopic structure, the best material was obtained when spray-drying was applied at either 150° or 180°C with SC or HPMC as excipients, respectively. The extent to which the antioxidant properties of free sesamol towards a set of free radicals (galvinoxyl, diphenylpicrylhydrazyl, superoxide, and hydroxyl) were altered in the starting and reconstituted liquid emulsions submitted to normal storage or pre-exposed to a flux hydroxyl radicals was investigated. Emulsions were further evaluated for their antioxidant properties in cultured 3T3 murine fibroblasts and in an ex vivo model of ultraviolet irradiated rat skin. It was found that, in the material having the best physical properties, encapsulation was decisive in: (1) improving the overall antioxidant behavior of reconstituted versus starting liquid emulsions: (2) sparing sesamol consumption due to free radical attack; and (3) significantly protecting cells and skin against free radical- or irradiation-induced enzymatic release and/or lipid peroxidation. Demonstrating a high activity at high dilutions where interactions of excipient become negligible, the new emulsions could be of great interest in sesamol-based pharmacology or topical applications. Drug Dev Res 69:251,266, 2008. © 2008 Wiley-Liss, Inc. [source]

Preparation of Titanium Foams by Slip Casting of Particle Stabilized Emulsions,

ADVANCED ENGINEERING MATERIALS, Issue 8 2009
Bram Neirinck
Bulk titanium foams were prepared by emulsion templating during slip casting. The emulsion template was stabilized using partially hydrophobized titanium particles while the continuous phase consisted of a titanium hydride powder suspension. Sintering was performed in inert atmosphere. The use of titanium hydride resulted in lower sintering temperatures and denser, stronger struts. Both homogeneous foams with high compressive strength and structures with a gradient in pore size were obtained. [source]

Liquid Crystal Emulsions as the Basis of Biological Sensors for the Optical Detection of Bacteria and Viruses

ADVANCED FUNCTIONAL MATERIALS, Issue 14 2009
Sri Sivakumar
Abstract A versatile sensing method based on monodisperse liquid crystal (LC) emulsion droplets detects and distinguishes between different types of bacteria (Gram +ve and ,ve) and viruses (enveloped and non-enveloped). LCs of 4-cyano-4'-pentylbiphenyl transition from a bipolar to radial configuration when in contact with Gram ,ve bacteria (E. coli) and lipid-enveloped viruses (A/NWS/Tokyo/67). This transition is consistent with the transfer of lipid from the organisms to the interfaces of the micrometer-sized LC droplets. In contrast, a transition to the radial configuration is not observed in the presence of Gram +ve bacteria (Bacillus subtilis and Micrococcus luteus) and non-enveloped viruses (M13 helper phage). The LC droplets can detect small numbers of E. coli bacteria (1,5) and low concentrations (104,pfu mL,1) of A/NWS/Tokyo/67 virus. Monodisperse LC emulsions incubated with phosholipid liposomes (similar to the E. coli cell wall lipid) reveal that the orientational change is triggered at an area per lipid molecule of ,46,Å2 on an LC droplet (,1.6,×,108 lipid molecules per droplet). This approach represents a novel means to sense and differentiate between types of bacteria and viruses based on their cell-wall/envelope structure, paving the way for the development of a new class of LC microdroplet-based biological sensors. [source]

A Stack of Functional Nanolayers for Simultaneous Emulsion Separation and Sensing

ADVANCED MATERIALS, Issue 35 2009
Pagra Truman
A novel lab-on-a-chip device based on a stack of four nanolayers for emulsion separation and simultaneous detection is introduced. Emulsions are separated on top of chemically patterned surfaces while the process is monitored using semiconductor sensors. [source]

Degradable, Surfactant-Free, Monodisperse Polymer-Encapsulated Emulsions as Anticancer Drug Carriers

ADVANCED MATERIALS, Issue 18 2009
Sri Sivakumar
Anticancer emulsions: Degradable, surfactant- free, micrometer- to sub-micrometer-sized polymer-encapsulated emulsions loaded with lipophilic drugs (doxorubicin and 5-fluorouracil) are prepared. In vitro drug-release studies demonstrate controlled release under redox conditions and incubation with human colorectal cancer cells triggers cell death with greater efficiency (,106 fold) than the free drug. [source]

Formation of Lipid Emulsions and Clear Gels by Liquid Crystal Emulsification

INTERNATIONAL JOURNAL OF COSMETIC SCIENCE, Issue 1 2007
T. Suzuki
Recently developed emulsion technologies for the formation of fine emulsions, lipid emulsions and clear gels by liquid crystal emulsification were reviewed. As a basic information on liquid crystal emulsification, the structures and characteristic behaviours of lyotropic liquid crystals were summarized. Formation of a liquid crystalline phase was often seen in emulsions and biological systems. The significance of liquid crystal formation during emulsification was analysed by comparing the states and stabilities of emulsions prepared by different processes. Then uses of liquid crystals for formation of the characteristic emulsions and gels were also discussed. In liquid crystal emulsification, an oil phase is dispersed directly into the lamellar liquid-crystalline phase composed of surfactant, glycerol and water to prepare a gel-like oil-in-liquid crystal emulsion. This is followed by dilution with the remaining water to produce an emulsion. From the phase behaviour during emulsification and analysis of the local motion of the liquid crystal membrane by fluorometry, it was confirmed that the interaction between surfactant and a polyol molecule such as glycerol promotes hydrogen bonding and enhances the strength of the lamellar liquid crystal membranes, which results in the formation of oil-in-liquid crystal emulsions. The interaction between the liquid crystal and oil was analysed from the changes in molecular motion of the membrane at the oil-liquid crystal interface using the spin label technique of electron spin resonance (ESR). The fluidity of the liquid crystal membrane did not change when oil was added, and therefore oil-in-liquid crystal emulsions of various oils were prepared by the identical process. This lack of dependence of the liquid crystal membrane on oil results in the unique properties of liquid crystal emulsification, which can be used for oils of various polarity and different molecular constituents. When a self-organizing artificial stratum corneum lipid containing pseudo-ceramide was used as a principal component of the oil, a multilamellar emulsion of concentric lamellar structure was formed. The multilamellar emulsion supplements the physiological function of stratum corneum by the identical mechanism as natural intercellular lipids. High-pressure treatment of the lipid emulsion produced a gel-like emulsion crystal, in which the homogeneous nanoemulsion droplets were arranged in a hexagonal array. This review paper was presented at the Conference of the Asian Societies of Cosmetic Scientists 2005 in Bangkok. [source]

Effect of oil content and processing conditions on the thermal behaviour and physicochemical stability of oil-in-water emulsions

INTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 1 2009
Megan Tippetts
Summary The destabilisation mechanism of oil-in-water (o/w) emulsions was studied as a function of oil content (20% and 40% o/w), homogenisation conditions and crystallisation temperatures (10, 5, 0, ,5 and ,10 °C). A mixture of anhydrous milk fat and soya bean oil was used as the lipid phase and whey protein isolate (2 wt%) as emulsifier. Crystallisation and melting behaviours were analysed using differential scanning calorimetry. Physicochemical stability was measured with a vertical scan macroscopic analyser. Emulsions with 20% oil were found to be less stable than those with 40% oil. For 20% o/w emulsions, the crystallisation was delayed and inhibited in emulsions with smaller droplets and promoted in emulsions with larger droplets when compared with 40% o/w emulsions. Depending on the droplet sizes in the emulsion, the formation of lipid crystals (in combination with the emulsifier) either stabilises (small droplets) or destabilises (big droplets) the emulsion. [source]

The emulsifying properties of a polysaccharide isolated from the fruit of Cordia abyssinica

INTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 5 2004
Mudadi Albert Nhamoiesu Benhura
Summary Polysaccharide was isolated from Cordia abyssinica and its effect, at differing concentrations, on its emulsifying ability was determined. Emulsions of vegetable oil containing up to 1% of the polysaccharide in phosphate pH 7.4 buffer, were prepared by using a hand piston homogenizer. Emulsification was assessed by diluting samples of the emulsions in sodium dodecyl sulphate and measuring absorbance at 500 nm. Addition of increasing concentrations of the polysaccharide up to 1% enhanced emulsification and emulsion stability. Above 1% concentration the polysaccharide solutions were too viscous for making emulsions conveniently. At a constant concentration of the polysaccharide, addition of up to a 1% concentration of salt enhanced emulsion formation. Further addition of salt above 1% resulted in no further changes in emulsifying ability, but the stability of the emulsions formed decreased on increasing the concentration of salt above 1%. The effect of pH on emulsifying ability was investigated by preparing emulsions using buffers of different pH, from pH 3 to pH 13. The polysaccharide had poor emulsifying ability below pH 7. Emulsifying ability increased with pH between pH 7 and 11. At pH above 11 there was a decrease in emulsifying ability. [source]

Physical and Mechanical Properties of Pea Starch Edible Films Containing Beeswax Emulsions

JOURNAL OF FOOD SCIENCE, Issue 6 2006
J.H. Han
ABSTRACT:, Hydrophobic beeswax emulsions were incorporated into hydrophilic starch films to modify physical, mechanical, and thermal properties of the films. Beeswax was added in the film-forming solution of high-amylose pea starch (35% to 40% amylose w/w) at the level of 0%, 10%, 20%, 30%, and 40% w/w of starch with glycerol as a plasticizer (40/60 of glycerol/starch). Addition of beeswax affected mechanical properties, significantly reducing tensile strength and elongation and increasing elastic modulus. Beeswax addition decreased water vapor permeability and increased oxygen permeability. However, the addition of hydrophobic wax particles in starch films marginally affected these physical properties below 30% beeswax in the films. Beeswax addition at the 40% concentration formed amylose,lipid complex that caused the dramatic changes of physical and thermal properties of the films. [source]

Protein Stabilization of Emulsions and Foams

JOURNAL OF FOOD SCIENCE, Issue 3 2005
Srinivasan Damodaran
ABSTRACT: Proteins play an important role as macromolecular surfactants in foam and emulsion-type food products. The functioning of proteins in these applications is determined by their structure and properties in the adsorbed layers at air-water and oil-water interfaces. In addition, because typical food proteins are mixtures of several protein components, interaction between these components in the adsorbed layer also impacts their ability as surfactants to stabilize dispersed systems. In this paper, recent progress in our understanding of the molecular mechanisms involved in the formation and stability of protein-stabilized foams and emulsions has been reviewed. [source]

Effect of Ultra-high-pressure Homogenization on Structure and on Rheological Properties of Soy Protein-stabilized Emulsions

JOURNAL OF FOOD SCIENCE, Issue 9 2002
J. Floury
ABSTRACT: An ultra high-pressure homogenizer (20 to 350 MPa) was used to realize fine food emulsions stabilized by soy proteins. The first aim of the work was to understand how dynamic high-pressure processing affects soybean globulin conformation. Then, the effect of homogenizing pressure on the emulsions structure and rheology was investigated. High-pressure homogenization caused denaturation of proteins due to strong mechanical forces and high temperatures encountered in the valve. Droplet sizes of emulsions were greatly reduced with high-pressure homogenization and Newtonian liquid emulsions were converted into shear-thinning emulsion gels by homogenization at pressures above 250 MPa. Hydrophobic interactions between proteins were supposed to cause the gel-like network structure of emulsions. [source]

Influence of Flocculation on Optical Properties of Emulsions

JOURNAL OF FOOD SCIENCE, Issue 3 2001
W. Chantrapornchai
ABSTRACT: The influence of droplet flocculation on the optical properties of 1 and 10 wt% oil-in-water emulsions with and without dye was investigated. Flocculation was induced by addition of SDS micelles to the aqueous phase of emulsions to increase the depletion attraction between droplets. Droplet flocculation caused the spectral reflectance and L -value (lightness) of emulsions to decrease, and the magnitude of the a - and b - values to increase, but the changes were rather small. Similar trends were observed for emulsions with and without dye. Overall, emulsion optical properties were dominated by light scattering from droplets rather than flocs. [source]

The Emulsifying Properties of Commercial Milk Protein Products in Simple Oil-in-Water Emulsions and in a Model Food System

JOURNAL OF FOOD SCIENCE, Issue 6 2000
S.R. Euston
ABSTRACT: The emulsifying properties of six commercial milk protein products were studied. The products were separated into one of two groups depending on whether they contained aggregated (micellar) casein or disordered protein (casein or whey protein). Disordered proteins had a greater emulsifying ability than aggregated proteins. Dispersion of aggregated protein in dissociating buffer improved the emulsifying ability. Comparison of emulsion properties in simple oil-in-water emulsions with those in a model coffee whitener formulation showed that the lower emulsifying ability of aggregated protein could be partially compensated by other ingredients. [source]