Biodegradable Composite Materials based on Cassava Starch and Reinforced with Topinambur (Helianthus tuberosus) Aerial Part Fiber

Abstract

The cultivation of topinambur (Helianthus tuberosus) has aroused the interest of producers since it is a source of inulin and can be used for biofuel production. During tuber processing, the aerial part of the crop remains as a by-product with no practical application. This work aimed to characterize the fibers obtained from the aerial part of topinambur and to evaluate their reinforcing potential in cassava starch-based films. Starch-based films with topinambur fiber (0, 5, and 10%) were prepared by extrusion followed by thermocompression. Topinambur residue contains 88,6% of total fiber, 8,5% ash, and 0,68% lipid. Mechanical film properties evidenced the reinforcement action of topinambur fiber, 10% content was able to increase up to 70% the Young’s modulus. SEM micrographs evidenced the good fiber-matrix interaction. UV-visible capacity, opacity, and chromaticity parameters of TPS films increased with fiber content in the formulation. Fiber incorporation improved the hydrophobicity of the biocomposite materials by increasing the contact angle. Starch-based films biodegraded more than 55% after 110 days, showing a similar trend to that of microcrystalline cellulose. Thus, topinambur residue can be effectively used as a reinforcing agent for TPS materials, being an innovative and non-toxic additive within the circular economy premises.