Preparation of high internal phase Pickering emulsion by centrifugation for 3D printing and astaxanthin delivery

Oil in water high internal phase Pickering emulsion (HIPEs) stabilized by edible colloid particles have attracted considerable attention for three-dimensional (3D) printing and delivery of a hydrophobic bioactive. In this paper, a facile route for preparing oil in water HIPEs was demonstrated, only requiring centrifuging gliadin/gelatinized starch nanocomposites (G/SNPs) stabilized pre-emulsions. The surface properties of G/SNPs were engineered which helped prevent oil coalescence during centrifugation, while obtaining HIPEs with oil phase fractions up to 77.3%, simultaneously. The resultant HIPEs exhibited shear-thinning behavior with high solid viscoelasticity. Furthermore, HIPEs with internal phase fraction above 80% were successfully prepared simply by adjusting the ionic strength. The HIPEs with suitable rheology properties for 3D printing were obtained, and the enhanced viscoelasticity and thixotropic recovery could be attributed to the electrostatic shielding under higher ionic strength. In addition, the light stability and bioaccessibility of astaxanthin were significantly improved by HIPEs, and more than 90% astaxanthin was retained after heating at 95 °C for 30 min. These results proved a new route for producing HIPEs with improved performance, opening new possibilities for manufacturing future food and delivery of hydrophobic bioactive molecules.