Hexamethyldisiloxane cold plasma treatment and amylose content determine the structural, barrier and mechanical properties of starch-based films

Abstract

In this study, the effect of amylose content and cold plasma treatment on starch films properties was investigated. Films from normal (30%) and high amylose (50 and 70%) starches were subjected to hexamethyldisiloxane (HMDSO) cold plasma treatment. Morphological, structural, mechanical and barrier properties of the films were evaluated. The amount of remnant starch granules (RSG) in the films depended on the amylose content and on the gelatinization extent of the starch. This behavior was corroborated on the films from starch with 50% amylose, where the loss of RSG resulted in poor barrier properties and high hydrophilicity. Moreover, HMDSO cold plasma treatment incorporated methyl groups improving the hydrophobic properties and favored the helix ordering of the starch components resulting in a limited water-film interaction. Furthermore, the simultaneous effect of HMDSO coating and the ordering of the structures reinforced the surface of the films, improving the mechanical properties.

Keywords: Amylose; HMDSO cold plasma; Starch.