It means that the amount of
sulphur dioxide released from the packaging was too high and the cells of the mushrooms absorbed the excess. Therefore, the concentration
of citric acid was reduced to 0.06 g/m2, what resulted in
maintaining the samples white during 8 days without yellowish. In
the case of test pouches with green tea (6 g/m2), the mushroom
slices were white after 11 days, although orange blots were
observed in parts of the mushroom that had touched the paper
with antioxidant. Hereafter, only one slice of mushroom was placed
into the Petri dish to avoid direct contact between mushrooms and
packaging. Cinnamon essential oil (3.6 g/m2) caused the dark
brown on the entire surface of the mushroom slice, leaving the
smell of cinnamon. The pictures also showed that anthocyanins
(purple carrot liquid extract) did not keep the mushrooms fresh
longer than the blank test pouches, probably because its insufficient
antioxidant capacity.