Mushroom slices (one or two, depending on the experiment) were placed in a plastic Petri dish. The Petri dish was then introduced into a plastic bag with dimension 11 x 11 cm, made of thermosealable polypropylene film provided by the Food Innovation and Technology Centre from La Rioja (Spain). The film was manufactured to be used in conventional trays of fresh mushrooms. The thickness of the film was 40 μm, and it contained 7-8 longitudinal microperforations per tray of 100 μm ± 10% every 15 mm. A piece of filter paper or active film with dimensions 6.0 x 6.0 cm was placed on the inner surface of the upper side of the bag, in such a way that there was no direct contact between the active agent and the mushroom. Blank samples without antioxidant were also prepared. Twenty replicates of each type were prepared.