Fat-crystal stabilised w/o emulsions for controlled salt release

Abstract

The potential of fat-crystal stabilised w/o emulsions to control the release of salt contained within their aqueous phase has been investigated. A mixture of mono- and triglyceride crystals was used to obtain Pickering-stabilised 60:40 w/o emulsions. Salt release was monitored by placing small amounts of these emulsions into a bulk aqueous phase (this was either pure water or glucose aqueous solutions in order to vary osmotic pressure gradients) and measuring changes in conductivity over time. Less than 5% of total salt was released after 1 month in emulsions containing a mixture of mono- and triglycerides. Emulsions containing only monoglycerides released more than 40% salt in this period. SEM pictures showed that crystals have sintered at the interface to give total surface coverage with no or very few defects. Stability measurements at varying temperatures and Differential Scanning Calorimetry (DSC) indicate that any release is the result of partial melting of the crystals. Finally, varying the osmotic pressure gradient has no impact on salt release.