Langmuir : the ACS journal of surfaces and colloids | 2019
The impact of Pickering intervention on the stability of W1/O/W2 double emulsions of relevance to foods.
Abstract
Although water-in-oil-in-water (W1/O/W2) double emulsions have been associated with a spectrum of potential applications in foods, their complex microstructure is significantly unstable. Pickering stabilisation, reputed for superior and longer-term interfacial stabilisation when compared to surfactant-stabilised systems, could provide the opportunity to enhance double emulsion stability. The current work presents a systematic study on the impact of progressively adopting such a Pickering intervention onto one or both interfaces of W1/O/W2 emulsions relevant to foods. A range of surfactants/emulsifiers and particles have been used at the W1/O or O/W2 interface of the W1/O/W2 microstructure and, where appropriate, cross-compared with the equivalent interfaces of simple emulsions (W/O and O/W, respectively). As the aqueous compartments of all investigated systems were not osmotically balanced, any advantages in terms of double emulsion stability enhancement can be directly attributed to the employed particle stabilisation. It is demonstrated that although partial Pickering intervention can encourage stability (particularly if that is introduced at the inner W1/O interface), only complete Pickering stabilisation of the double microstructure can ensure that oil globule size is maintained and internal water phase is retained unaltered over a storage period of one month.