No abstract

Nanotechnology has been crucial in the development of environmentally friendly and naturally based materials for food packaging. In this work, an inexpensive and scalable way to develop amylopectin-enriched nanocomposites with nano/micro particles of starch is investigated. Cassava starch nanocomposites with rich-amylopectin starch nano/micro particles (S AP ) are prepared by flat-die extrusion. S AP , obtained by applying shear stresses to an aqueous solution of native cassava starch using grinding, consists of (10.8 ± 0.9)% of nanofiller (< 200 nm) and (88 ± 1)% of micro-size particles (2-10 µm). After processing, great compatibility between S AP and the matrix is achieved. Nanocomposites with 15 wt.% of S AP show increases in Young's modulus (73%), tensile stress (30%), and tensile toughness (63%), and a decrease in water vapor permeability (34%) compared to the films without S AP (TPS). The use of 30 wt.% of S AP leads to a slight increase in crystallinity without significant changes in the overall properties, as a consequence of the combination of the effects produced by the presence of nanofiller and the enrichment of the matrix in amylopectin. This investigation provides a methodology for developing amylopectin-enriched starch nanocomposites with high compatibility between the nanofiller and the matrix as an attractive alternative for conventional starch-based packaging.