Extrusion-based 3D printing of starch/PVA composite films: Structure-property relationships and application in fruit...

This study developed starch/polyvinyl alcohol (PVA) composite films via extrusion-based 3D printing using glutinous rice starch (GRS), tapioca starch (TS) and pea starch (PS). The effects of starch type and concentration on rheology, film properties, and performance were investigated. Rheological analysis indicated that starch structure influenced viscoelasticity of printing inks. The TS2 gel exhibited optimal printability, combining moderate viscosity with an 89% recovery rate, ensuring uniform extrusion and structural retention. TS2 film showed a tensile strength of 27.6 MPa, with water vapor and oxygen permeability reduced by about 35-40% compared with GRS films. FTIR, DSC, and SEM confirmed a dense hydrogen-bonded starch-PVA network. TS2 film extended fruit shelf life from 2 to 5 days and maintained higher firmness and soluble solids. Overall, this work demonstrates that starch molecular structure significantly affects the printability and functionality of starch/PVA composites, providing a strategy for designing sustainable and high-performance 3D-printed food packaging films.