Polymeric films based on onion (Allium cepa L.): a new generation of materials for aplication as edible package

Abstract

The great need to replace the traditional food package by their sustainable and environmentally friendly counterparts has been endorsed mainly due to the severe damages caused to the environment. Most of the issues are the result of both indiscriminate use of non-renewable raw materials as well as the improper disposal of non-biodegradable materials. In general, edible packages must ensure food protection against microbial contamination and moisture and oxygen permeation, for example. Edible packages represent a promising concept once allow their consumption along the packaged food or facilitated biodegradation. In this context, the production of biodegradable films based on materials from renewable sources has been exhaustively pursued by researchers throughout the world. Edible packages show strongly innovative character and high potential for industrialization. In this project, different methods to obtain freestanding films using solvent casting techniques from the onion pulp processing (Allium cepa L.) are presented. It is worth to highlight that the onion is harvested in the entire Brazilian territory, whose production was estimated at 1.4 million tons in 2012. In this sense, we propose different processing protocols of in natura onion pulp, including mechanical and hydrothermal treatments in order to obtain free-standing films. The final products will be characterized according with their physicochemical (chemical composition of moisture, volatile compounds, ash and fixed carbon, elemental analysis: C, H, O, N and S, and crystallinity index), mechanical (tensile strength, modulus of elasticity and extensibility), barrier, thermal, and morphological properties (microscopic images of the surface and cross-section, porosity and topography). (AU)