Vapour pressure of a fragrance ingredient during evaporation in a simple emulsion

The phase diagram water, phenethyl alcohol and laureth 4 was determined and the variation of the vapour pressure of the alcohol was determined during evaporation using gas chromatographic head-space analysis. The phase changes during evaporation were estimated from the phase diagram and compared to the appearance of the emulsion using optical microscopy. The transfer of the fragrance ingredient between different phases during the process was estimated and its measured vapour pressures compared to those calculated from values of earlier determination in different phases in the system. The agreement was good.     

Non-invasive ‘through-package’ assessment of the microstructural quality of a model food emulsion by the NMR MOUSE

Recently, NMR has been demonstrated in a truly non-invasive through-package ‘sensor’ mode, also denoted as the MObile Universal Surface Explorer (MOUSE). In this feasibility study, we present a first example where we use the MOUSE sensor for assessment of the microstructural quality of a food material. We have taken model systems consisting of protein-stabilized oil-in-water emulsions, where an important microstructural quality parameter is water exudation (WE). In order to establish a sound relation between MOUSE signals and WE, it was necessary to deploy multivariate calibration techniques. It was found that the performance of the MOUSE is comparable to that of conventional benchtop NMR. Thus it was demonstrated that the NMR MOUSE presents a good option for non-invasive assessment of microstructural quality parameters, e.g. in manufacturing and in the supply chain.     

Buttermilk Properties in Emulsions with Soybean Oil as Affected by Fat Globule Membrane-Derived Proteins

The potential utilization of buttermilk from an industrial source was studied in this research, focusing primarily on its composition and use as ingredient in oil-in-water emulsions. Buttermilk contained not only large amounts of caseins and whey proteins, but also material derived from the natural milk fat globule membrane (MFGM). Emulsions made with soybean oil (10% w/w) and buttermilk were stable with a low concentration (about 1% w/w) of buttermilk solids. MFGM-proteins and skim milk proteins did not seem to compete for adsorption at the emulsion interface. The protein adsorbed at the interface was present in an aggregated form and gave a maximum surface coverage of about 8 mg/m².     

Transparent macroemulsions for cosmetic applications

This study proposes a method for preparation of transparent emulsions for cosmetic applications. The continuous phase in oil-in-water emulsions consisted of both water and several polyols in order to equalize the refractive indices of the two phases. Sorbitol , glycerol and mannitol were the main polyols used in the adequate concentration and isopropyl myristate was the oil phase. Stabilities of a few days in 60°C incubation and a few months on the shelf were obtained.
Combinations of triethanolamine oleate together with sorbitan esters and ethoxylated sorbitan esters were found to improve the emulsion stability.
The optimal water concentration was checked by spectrophotometer measurements at 660 nm in order to achieve best transparency.
In conclusion, it was demonstrated that relatively stable transparent macroemulsions can be prepared by equalizing the refractive indices of the two phases composing the emulsion.
Application des macroémulsions transparentes a la cosmétique     

Oil‐in‐Water Emulsion Exhibits Bitterness‐Suppressing Effects in a Sensory Threshold Study

Little is known about how emulsion characteristics affect saltiness/bitterness perception. Sensory detection and recognition thresholds of NaCl, caffeine, and KCl in aqueous solution compared with oil‐in‐water emulsion systems were evaluated. For emulsions, NaCl, KCl, or caffeine were dissolved in water + emulsifier and mixed with canola oil (20% by weight). Two emulsions were prepared: emulsion 1 (viscosity = 257 cP) and emulsion 2 (viscosity = 59 cP). The forced‐choice ascending concentration series method of limits (ASTM E‐679‐04) was used to determine detection and/or recognition thresholds at 25 °C. Group best estimate threshold (GBET) geometric means were expressed as g/100 mL. Comparing NaCl with KCl, there were no significant differences in detection GBET values for all systems (0.0197 ‐ 0.0354). For saltiness recognition thresholds, KCl GBET values were higher compared with NaCl GBET (0.0822 ‐ 0.1070 compared with 0.0471 ‐ 0.0501). For NaCl and KCl, emulsion 1 and/or emulsion 2 did not significantly affect the saltiness recognition threshold compared with that of the aqueous solution. However, the bitterness recognition thresholds of caffeine and KCl in solution were significantly lower than in the emulsions (0.0242 ‐ 0.0586 compared with 0.0754 ‐ 0.1025). Gender generally had a marginal effect on threshold values. This study showed that, compared with the aqueous solutions, emulsions did not significantly affect the saltiness recognition threshold of NaCl and KCl, but exhibited bitterness‐suppressing effects on KCl and/or caffeine.     

Emulsification, drying and film formation of alkyd emulsions

A method was developed and optimised for the emulsification of a conventional short oil alkyd resin which was solid at room temperature. The method was based on the emulsion inversion point (EIP) method whereby hot water (90°C) was added to molten alkyd resin (90°C) containing the emulsifier. Under slow mixing and addition of water, a point was reached where the emulsion instantaneously phase inverted from a water in oil emulsion (W/O) to an oil in water emulsion (O/W). Using optimum conditions, emulsions with droplet of diameters less than 0.8 μm were obtained. The drying and film formation of long oil alkyd emulsions were investigated with emphasis on loss of dry upon storage. The main reason for loss of dry was adsorption of the cobalt (drier) on pigment surfaces as a precipitated hydroxide. Titanium dioxides with alumina surface treatment and organic pigments were most detrimental to drying. Acrylate- and phosphate-based dispersants also deactivated cobalt presumably due to complexation and precipitation of cobalt. Emulsions prepared with an emulsifiable cobalt drier containing 2,2′-bipyridyl (complexing agent for cobalt) showed the best resistance to loss of dry. Films formed from the emulsions showed that surfactant migrated to the film surface which when washed with water leaves holes or pits in film. The pits were arranged in a hexagonal pattern, characteristic of Bénard cells which form due to interfacial tension gradients generated in the film during evaporation of water.     

Electronic properties of chemically produced silver clusters: grain morphology studies

Abstract

The electronic properties of silver clusters formed on the surface of reduction- sensitized octahedral and cubic AgBr emulsions were studied. Prior to sensitization with dimethylamineborane, SnCl₂ or high pH, these emulsions had the same efficiency. The results suggest that the octahedral emulsion has more potential to achieve a higher maximum speed increase. This difference may be due to fewer available sites for silver cluster formation on cubic surfaces. Gelatin concentration studies showed that the gelatin and/or impurities do play a role in silver cluster formation by high pH treatment. The precise role of OH^? is uncertain.     

Interaction of Commercial Dairy Proteins and Chicken Breast Myosin in an Emulsion System

The compatibility of commercial dairy proteins with chicken breast myosin in an emulsion system was examined. SDS-PAGE of the solution remaining after emulsion formation indicated that myosin incorporation into the cream layer was much more limited with the flexible additives such as sodium-caseinate and milk protein isolate resulting in decreased emulsion stability. However, myosin incorporation and emulsion stability were maintained with whey protein concentrate or whey protein isolate at all additive levels. No hydrophobicity changes were found in myosin with additive mixtures except for heated myosin and WPC (P=0.04). The stability of an emulsion was primarily determined by the amount of myosin incorporated.