Generation of magnesium enriched water-in-oil-in-water food emulsions by stirred cell membrane emulsification

This study has for the first time shown that complex food emulsifiers such as starch and protein can be applied to produce stable w/o/w emulsions with the membrane emulsification technology. Using a microporous metal membrane with a 20 μm pore size, 2% of polyoxyethylene (20) sorbitan monolaurate (Tween 20), 4% of octenyl succinic anhydride (OSA) starch or 1.5% of pea protein isolate (PPI) in the external water phase respectively was the minimum concentration necessary to stabilise the w/o/w droplets. Uniform with a span as low as 0.45 and for at least 13-day stable w/o/w emulsions of droplets between 35 and 320 μm were obtained. The release of a magnesium tracer from the internal water phase of xanthan gum-thickened w/o/w emulsions, when OSA starch and PPI were used, was found to be limited to around 3% after 13-day storage. However, w/o/w emulsions stabilised with Tween 20 were less stable with magnesium showing a release of 27% on day 13.