| Abstract
| - The purpose of this study was to create water-in-oil (W/O) and water-in-oil-in-water (W/O/W) emulsionscontaining gelled internal water droplets. Twenty weight percent W/O emulsions stabilized by a nonionicsurfactant (6.4 wt % polyglycerol polyricinoleate, PGPR) were prepared that contained either 0 or 15wt % whey protein isolate (WPI) in the aqueous phase, with the WPI-containing emulsions beingeither unheated or heated (80 °C for 20 min) to gel the protein. Optical microscopy and sedimentationtests did not indicate any significant changes in droplet characteristics of the W/O emulsions dependingon WPI content (0 or 15%), shearing (0−7 min at constant shear), thermal processing (30−90 °C for30 min), or storage at room temperature (up to 3 weeks). W/O/W emulsions were produced byhomogenizing the W/O emulsions with an aqueous Tween 20 solution using either a membranehomogenizer (MH) or a high-pressure valve homogenizer (HPVH). For the MH the mean oil dropletsize decreased with increasing number of passes, whereas for the HPVH it decreased with increasingnumber of passes and increasing homogenization pressure. The HPVH produced smaller dropletsthan the MH, but the MH produced a narrower particle size distribution. All W/O/W emulsions had ahigh retention of water droplets (>95%) within the larger oil droplets after homogenization. This studyshows that W/O/W emulsions containing oil droplets with gelled water droplets inside can be producedby using MH or HPVH. Keywords: Membrane homogenization; W/O emulsion; W/O/W emulsion; stability; gelled particles;multiple emulsion
|
