Acetylated rice starches films with different levels of amylose: Mechanical, water vapor barrier, thermal, and biodegradability properties
Rosana Colussi, Vania Zanella Pinto, Shanise Lisie Mello El Halal, Bárbara Biduski, Luciana Prietto, Danilo Dufech Castilhos, Elessandra da Rosa Zavareze, Alvaro Renato Guerra Dias
Departamento de Ciência e Tecnologia Agroindustrial, Universidade Federal de Pelotas, Rio Grande do Sul, Pelotas, RS 96010-900, Brazil
Abstract: Biodegradable films from native or acetylated starches with different amylose levels were prepared. The films were characterized according to the mechanical, water vapor barrier, thermal, and biodegradability properties. The films from acetylated high amylose starches had higher moisture content and water solubility than the native high amylose starch film. However, the acetylation did not affect acid solubility of the films, regardless of the amylose content. Films made from high and medium amylose rice starches were obtained; however low amylose rice starches, whether native or acetylated, did not form films with desirable characteristics. The acetylation decreased the tensile strength and increased the elongation of the films. The acetylated starch-based films had a lower decomposition temperature and higher thermal stability than native starch films. Acetylated starches films exhibited more rapid degradation as compared with the native starches films.
Keywords: Rice starch; Amylose content; Acetylation; Biodegradable films; Tensile strength; Thermal stability