Improvement of extrudability and self-support of emulsion-filled starch gel for 3D printing: Increasing oil content

Abstract

This work investigated the mechanism of increasing oil content in synchronously enhancing extrudability and self-support of β-carotene loaded starch-based emulsion-filled gels (S-EFG) during 3D printing in terms of gel properties. Increasing emulsion oil content enhanced the storage modulus, relaxation modulus, and hardness of gels, which indicated sodium caseinate-stabilized emulsions were active fillers in the starch gel. Thus, printed products with high oil content were less prone to collapse when selecting models with higher height. In addition, lower yield stress, relaxation time, and higher frequency dependence were observed in S-EFG with higher oil content (30-50 %) due to the lubricating/plasticizing effect of oils, which corresponded to the smoother extruded filament. Furthermore, the retention of β-carotene in high oil content gel was higher after heat treatment due to denser microstructure. These results indicated that the extrudability and self-supporting of S-EFG were simultaneously improved by increasing oil content under the active filling effect and lubricating/plasticizing effect of emulsions.

Keywords: 3D printing; Emulsion-filled gel; Extrudability; Rheological properties; Self-support; Starch.