Fabrication and characterization of W/O/W emulsions with crystalline lipid phase

Anthocyanin-loaded W/O/W emulsions were fabricated using polyglycerol polyricinoleate (PGPR) as a hydrophobic emulsifier, quillaja saponin as a hydrophilic emulsifier, and gum arabic as an additional biopolymer-based stabilizer. Hydrogenated soybean oil (HSO) was used to create a crystalline lipid phase. The impact of emulsifier, stabilizer, and lipid phase crystallization on emulsion formation, stability, and rheology was investigated. W/O droplets with a solidified oil phase aggregated, leading to an increase in emulsion viscosity. Gum arabic inhibited droplet aggregation and emulsion thickening, presumably by forming a protective coating around the W/O droplets. Conversely, PGPR promoted droplet aggregation, possibly by adsorbing to the fat crystal surfaces and changing their location or interactions. Optimized W/O/W emulsions (2.5% gum arabic, 5% PGPR, and 1% saponin) had a relatively low initial anthocyanin encapsulation efficiency (<55%) and were prone to anthocyanin leakage during storage, which was attributed to the fact anthocyanin had some solubility in the oil phase.