Novel Three-Dimensional-Printed ι-Carrageenan–Carnauba Wax Bigel Formulation for Codelivery Applications

Abstract

This research aimed to develop a bigel (BG) from ι-carrageenan (hydrogel; HG) and carnauba wax (oleogel; OG) with rice bran oil base and optimize its extrusion 3D printing conditions. Different combinations of OG and HG were experimented for the BG formation and the impact on texture, rheology, structural, and functional properties were investigated. These parameters were correlated with the printability of the gel formulations. BG (BG3 in this research), with 40% OG and 60% HG, exhibited the desired properties for 3D printing. Particularly, the thixotropic assessment revealed ideal shear-thinning characteristics, elevated storage modulus, and favorable recoverability. This was evidenced by a flow behavior index (n) of 0.13, and a recovery index and percentage of 0.32 and 27.38%, respectively. BG3 demonstrated seamless extrusion and displayed enhanced mechanical and structural stability post-printing. Results indicated that BG formulated from 60% of ι-carrageenan and 40% carnauba wax was printable and supported high print precisions when extruded using a 0.60 mm nozzle diameter at a 1000 mm/min printing speed, with an air pressure of 0.2–0.4 bar, extrusion motor speed of 6–8 rpm, and infill of 25%. In the future, such 3D-printed BG systems can be used for the customized/personalized codelivery of bioactive flavors or colors with dissimilar polarities/functionalities.