A. Benichou et al., Polyols, high pressure, and refractive indices equalization for improved stability of W/O emulsions for food applications, J DISP SCI, 22(2-3), 2001, pp. 269-280
Mixtures of polyols (glycerol, propylene glycol, glucose) and water were em
ulsified in oil (isopropyl myristate (IPM), medium chain triglycerides (MCT
), long chain triglycerides (LCT), and d-limonene) under elevated pressures
and homogenization, in the presence of polyglycerol polyricinoleate (PGPR)
, glycerol monooleate (GMO), and their mixture as emulsifiers to form water
-in-oil emulsions. High pressures was applied to: a) the emulsion, b) the a
queous phase and c) the oil phase in the presence of the emulsifiers (PGPR
and GMO). Under optimal pressure (2000 atms) applied to the ready-made emul
sion or to the aqueous phase prior to its emulsification, and with optimal
composition (30wt% polyol in the aqueous phase and MCT as the oil phase), t
he aqueous droplets were stable for months and submicron in size (0.1 mum).
Moreover, due to equalization of the oil and the aqueous phases refractive
indices, the emulsions were almost transparent. Pressure and polyols have
synergistic effects on the emulsions stability. During preparation, surface
tensions and interfacial tensions were dramatically reduced until an optim
al water/polyols ratio was achieved, which allows rupturing of the droplets
to submicronal size (0.1 mum) without recoalescence and fast diffusion to
the interface. These unique W/O emulsions are suitable for preparing W/O/W
double emulsions for sustained release of active materials for food applica
tions.