Issue 48, 2023

Long term water trapping in Pickering emulsions undergoing compositional ripening

Abstract

One approach to achieving low-calorie foods is to substitute regions of high-calorie content with water droplets, forming water-in-oil emulsions. However, in complex food systems consisting of multiple species of dispersed phases, compositional ripening may occur in which the emulsified water undergoes mass transfer to droplets filled with a species that is less soluble in the continuous phase, for example sugar. Here we present two model systems and use them to study compositional ripening for water-in-oil Pickering emulsions. Water-in-dodecane and water-in-tributyrin emulsions stabilised by PMMA particles were prepared and combined with similar emulsions that included sugar in the water. We use confocal microscopy as a function of time combined with particle tracking to explore how these systems evolve in time. For dodecane, as the system evolves, the pure water droplets appear to crumple due to the loss of water; in extreme cases, they eventually ‘explode’. Simultaneously, the sugar-filled droplets expand and slowly coalesce. Evidently, our interfacial coating of particles is unable to suppress compositional ripening. In contrast, pure water droplets in tributyrin crumple into small stable structures, potentially retaining water. We show that decreasing the concentration of the sugar solution also decreases the rate of change of water droplet size for both oils. Observations of droplet ‘explosions’ confirm that the driving force can overcome the trapping of the particles at the interface, in contrast to the case of Ostwald ripening. However the crumpled states in the tributyrin system provide some indication that this effect can be overcome.

Graphical abstract: Long term water trapping in Pickering emulsions undergoing compositional ripening

Supplementary files

Article information

Article type
Paper
Submitted
29 iyn 2023
Accepted
07 noy 2023
First published
09 noy 2023
This article is Open Access
Creative Commons BY license

Soft Matter, 2023,19, 9428-9434

Long term water trapping in Pickering emulsions undergoing compositional ripening

R. Tadi, B. Green, T. Curwen and P. S. Clegg, Soft Matter, 2023, 19, 9428 DOI: 10.1039/D3SM00856H

This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. You can use material from this article in other publications without requesting further permissions from the RSC, provided that the correct acknowledgement is given.

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