Development of stable high internal phase emulsions by pickering stabilization: Utilization of zein-propylene glycol alginate-rhamnolipid complex particles as colloidal emulsifiers

In this study, zein-propylene glycol alginate-rhamnolipid complex particles were prepared with suitable three-phase contact angles (θ) for stabilizing oil-in-water Pickering high internal phase emulsions (HIPEs). At a fixed oil phase volume (φ = 0.75), particle concentration influenced the stability, physical properties, and rheology of HIPEs. Confocal laser scanning microscopy showed that complex particles formed a densely packed particle layer around the oil droplets and a three-dimensional network in the continuous phase, highlighting the potential for the complex particles to act as effective HIPE stabilizers. The storage modulus (G′) was higher than loss modulus (G″) over the entire angular frequency range, suggesting HIPEs had an elastic gel-like structure. The HIPEs had good stability across a range of environmental conditions (pH, temperatures and salt concentrations). These findings may extend the application of zein in foods and the HIPEs formed may be used as novel delivery system for bioactives.