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In order to get long time stability in Water-in- Soybean oil emulsion the impact of selfstructuring lipid, polyglycerol polyricinoleate (PGPR) has been investigated. The rheological and microstructural techniques were employed to characterize the stability and flow behavior of the material. Emulsions were prepared from 10- 40 wt.% water having 2-8 wt. % Polyglycerol polyricinoleate in phosphate buffer (pH 7, NaCl 100mM). It has been observed that an increase in water contents led to decrease in stability of emulsion while the impact of Polyglycerol polyricinoleate was other way round. The shear viscosity of the system was increased with the increase in water as well as polyglycerol polyricinoleate (PGPR) contents. The stated observations were also in accord with the optical micrographs and were helpful to explain the stability as well as the rheological results. [ABSTRACT FROM AUTHOR]

The study aims to investigate the stability of W/O emulsions with respect to coalescence time. The various concentrations of water were dispersed in oil phase (soybean oil). The compositions of organic and aqueous phases were varied by adding emulsifier (Monoglyceride), sodium chloride and thickening agent (mango's pulp). The technique employed for the mixing of two phases was homogenization. The Emulsion Stability Index (ESI), Viscosity changes, separation of organic and aqueous phases as a function of storage time have been studied. It has been found that monoglyceride increases the stability and decreases the emulsion stability index (ESI) and also decreases the viscosity changes with storage time while electrolytes and mango's pulp encourage the coalescence process and enhance the instability of the system. On the other hand the system that contained all the organic and aqueous ingredients showed high stability. [ABSTRACT FROM AUTHOR]

Abstract: The objective of this work was to prepare novel microstructures and textures by controlled osmotic swelling and gelation of multiple (W1/O/W2) emulsions. Initially, multiple emulsions were prepared: internal aqueous phase (W1) containing 20wt.% whey protein isolate (WPI) in buffer solution (pH7, 250mM NaCl); oil phase (O) containing 6wt.% polyglycerol polyricinoleate (PGPR) in soybean oil; and external aqueous phase (W2) containing 250mM NaCl and 1wt.% Tween 80. These W1/O/W2 emulsions were then subjected to different degrees of dilution (1:0 to 1:5 with salt-free buffer) and thermal treatment (30 to 90°C) to induce swelling and/or gelation of the internal aqueous phase. W1/O/W2 emulsions had appreciably higher viscosities than O/W emulsions with similar fat contents, which was attributed to the increase in effective particle volume associated with the water droplets trapped inside the fat droplets. Heat treatment increased the apparent shear viscosity of the emulsions, which was attributed to thermal denaturation and aggregation of the globular proteins altering the structure and interactions in the system. The strategies used to alter the microstructure and rheology of the multiple emulsions utilized in this study may be useful for the production of foods with novel textures or reduced-fat products. [Copyright &y& Elsevier]

Abstract: This study shows that controlled aggregation of acidic whey protein microspheres in water-in-oil (W/O) emulsions can be used to create semi-solid lipids. An acidic aqueous phase (10 g/100 g whey protein isolate, 100 mmol/L NaCl, pH 3.5) was homogenized with an oil phase (8 g/100 g polyglycerol polyricinoleate in soybean oil) to form a W/O emulsion. These emulsions were then heated (90 °C, 30 min) to induce thermal denaturation and gelation of the globular proteins in the internal aqueous phase, which promoted irreversible gelation of the overall W/O emulsion. Rheology measurements indicated that the resulting materials had paste-like properties: they were solid-like below a critical yield stress and fluid-like (shear-thinning) above this value. The apparent shear viscosity of the W/O emulsions increased with thermal treatment, aqueous phase content, and decreasing shear rate. W/O emulsion gels containing acidic aqueous phases were considerably weaker than those containing neutral aqueous phases due to the pH dependence of whey protein gelation. Controlled aggregation of whey protein microspheres within W/O emulsions may be a useful means of producing highly viscous or semi-solid lipids with low saturated and trans-fat contents for use in the food and other industries. [Copyright &y& Elsevier]