Feasibility of Agaricus bisporus waste biomass to develop biodegradable food packaging materials*

This work aimed to valorise Agaricus bisporus biomass residues to produce bio-based and biodegradable films. To this end, two of the most widely consumed varieties, Agaricus bisporus brunnescens (Abb) and Agaricus bisporus hortensis (Abh), were compositionally characterised and then, films were formed by extrusion and compressionmoulding. Proteins and 8-glucans were the major components in both varieties. Abb showed a higher protein content, whereas the amount of polysaccharides and lipids was higher in Abh. Thermally-processed Abh-films showed better mechanical and barrier performance than their counterparts prepared with Abb, mainly ascribed to the higher carbohydrate and lipid content. Thus, Abh was selected to optimize the processing conditions in terms of energy consumption (from 100 to 130 degrees C) and barrier properties. As a result, 110 degrees C was selected as the optimum processing temperature for Abh-films since the mechanical properties in terms of strength were not significantly modified and barrier properties were significantly improved. The resulting film was coated with a beeswax layer to reduce its hydrophilic nature. The coated films showed similar mechanical properties than their counterparts prepared without the beeswax coating but displayed significantly better water vapour barrier performance. Furthermore, both films were easily disintegrated under composting conditions according to ISO 20200.