Physico-Chemical, Rheological, Structural, Thermal, Mechanical and Barrier Properties of Hybrid Powder and Films from Cassava Starch Crosslinked with Xanthan Gum

Abstract

Starch and xanthan are viscosifying, film-forming polysaccharides obtained from renewable sources.� The main objective of this work was to assess the effects of the cassava starch/deacetylated xanthan� proportion and reaction time in the crosslinking performed with sodium trimetaphosphate on the Physico-chemical, rheological, structural, thermal, mechanical and barrier properties of resulting� hybrid polymeric powder and films. Xanthan deacetylation, performed to improve crosslinking,� increased xanthan viscosity and pseudoplasticity. For further crosslinking, the crosslinking agent� (SMTP) and the alkalizing agent sodium sulfate (SS) concentration was set at 5% and 3% respectively� relative to the total polymeric mass (5%m/v); and according to the Central Composite Rotatable Design� (DCCR 22) the starch/deacetylated xanthan proportion and reaction time was varied, totalizing 11� treatments with 3 repetitions at the central point. Physical and chemical features of the crosslinked� polymers were checked, as well as films based on the crosslinked hybrid polymers were prepared and� tested. Treatments that showed best results were T1 (s/x: 4.5/0.5; 52 min.) and T4 (s/x: 3.5/1.5; 127� min). These resulted in low solubility, thickness and permeability to water vapor, with high tensile� strength.