Fat crystal-stabilised double emulsions

Frasch-Melnik, Sarah (2011). Fat crystal-stabilised double emulsions. University of Birmingham. Ph.D.

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Abstract

This work investigates the effect of fat crystal-stabilised interfaces on the transport of solutes between the two aqueous phases in W1/O/W2 emulsions. The aim is to separate solutes (NaCl or KCl) between the two aqueous phases.

Fat crystals are used to stabilise the primary emulsion interface. Fat crystals are seeded at the interface during emulsion production using monoglycerides. Subsequently they sinter to form “shells” around the water droplets. It is shown that these “shells” are capable of retaining salt encapsulated within the aqueous phase despite the application of osmotic pressure gradients.

The W1/O primary emulsions are incorporated into a double structure. It is shown that primary emulsion droplets retain their structure during the secondary emulsification step, although the shear may cause some damage to their protective “shells”. Salt is retained within W1 as long as the primary interface is crystalline.

The choice of secondary emulsifier is important to double emulsion stability. The double structure is not stable if small molecule surfactants are used to stabilise the secondary interface. Protruding fat crystals from primary emulsion droplets cause coalescence of double globules and lead to phase separation. The double emulsions are stable if proteins or particles are placed at the secondary interface.

Type of Work:

Thesis (Doctorates > Ph.D.)

Award Type:

Doctorates > Ph.D.

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