Formulation engineering of water-in-oil-in-water emulsions for salt reduction with sucrose oleate as a PGPR-alternative lipophilic emulsifier

Abstract

Sucrose oleate was assessed as an alternative lipophilic emulsifier to polyglycerol polyricinoleate (PGPR) for the stabilisation of the internal aqueous phase of a water-in-oil-in-water emulsion formulation designed for salt release from the internal aqueous phase during oral processing. A water-in-oil emulsion (30 g water/100 g oil), containing an internalised salt solution (1.5 g salt/100 g), was successfully incorporated as droplets into a salt containing external aqueous phase (0.5 g salt/100 g) with in-situ gelatinised waxy rice starch (WRS) stabilising the oil droplet interface. The droplets of the sucrose ester stabilised water-in-oil emulsion were aggregated, and this microstructure carried over into the water-in-oil-in-water emulsion. The PGPR stabilised water-in-oil emulsion showed no evidence of aggregation, and the primary droplet size was smaller. Mean oil droplet size was comparable, slightly increasing for the sucrose ester containing formulation over a 3-months observation period. Nevertheless, salt encapsulation efficiency, reducing by around 10% over 3-months, as well as in vitro salt release, reducing by 20%, were comparable. This study demonstrated that sucrose ester SE O-170 is a viable alternative for PGPR in w/o/w emulsions designed for salt release during oral processing.