Abstract
Whilst literature describing edible Pickering emulsions is becoming increasingly available, current understanding of these systems still suffers from a lack of consistency in terms of the (processing and formulation) conditions within which these structures have been studied. The current study aims to provide a comparative analysis of the behaviour of different edible Pickering candidates and their ability to stabilise emulsion droplets, under well-controlled and uniform experimental conditions, in order to clearly identify the particle properties necessary for successful Pickering functionality.More specifically, an extensive investigation into the suitability of various food-grade material to act as Pickering particles and provide stable oil-in-water (O/W) and water-in-oil (W/O) emulsions was carried out. Polysaccharide and flavonoid particles were characterised in terms of their size, ζ-potential, interfacial activity and wettability, under equivalent conditions. Particles were subsequently used to stabilise 20% w/w O/W and W/O emulsions, in the absence of added surfactant or other known emulsifying agents, through different processing routes.All formed Pickering emulsions were shown to resist significant droplet size variation and remain stable at particle concentrations between 2 and 3% w/w. The main particle prerequisites for successful Pickering stabilisation were: particle size (200nm – 1μm); an affinity for the emulsion continuous phase and a sufficient particle charge to extend stability. Depending upon the employed emulsification process, the resulting emulsion formation and stability behaviour can be reasonably predicted a priori from the evaluation of specific particle characteristics.
Highlights
Pickering stabilisation [1,2] has long been recognised as a very useful method for producing emulsions with superior stability to conventional surfactant-stabilised emulsions
Particles used as emulsifying agents were rutin hydrate, naringin, colloidal microcrystalline cellulose (CMCC), ethylcellulose (EC) andmethyl cellulose (HPMC) and all were obtained from Sigma, UK
Particle characteristics were analysed in an attempt to predict the droplet size, microstructure and stability of the simple stabilised emulsion characteristics prior to emulsion formulation, facilitating particle selection in food emulsion research and development efforts
Summary
Pickering stabilisation [1,2] has long been recognised as a very useful method for producing emulsions with superior stability to conventional surfactant-stabilised emulsions. Surfactants stabilise emulsions largely via an electrostatic mechanism: surfactants, comprised of a hydrophilic head group and a hydrophobic tail component, preferentially adsorb at the oil–water interface, reducing the free energy present when producing a high surface area during emulsification, and interfacial tension is reduced, allowing emulsions to form [3,4]. Several factors influencing Pickering emulsion stability have been identified These include parameters such as oil phase composition, particle characteristics, emulsification technique, and storage conditions. If how > 90°, the (largely lipophilic) particle will predominantly remain within the oil phase and facilitate formation of W/O emulsions. In those cases where how = 90°, there is no net curvature of the interface and no preference for forming a specific emulsion type [9]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
