Effect of baking and freeze-drying on the direct and indirect mutagenicity of extracts from the edible mushroom Agaricus bisporus

The objectives of the study were to evaluate the effect of baking and freeze-drying on the direct and indirect mutagenicity in the Ames test of ethanolic extracts from the edible mushroom Agaricus bisporus. Direct mutagenicity was not influenced by baking for 10 min at 225°C, but more prolonged baking, for example 4 hr at 100°C reduced mutagenicity. Hepatic cytosol from Aroclor 1254-induced rats and mushroom tyrosinase potentiated the mutagenic response elicited by the mushroom extracts. Baking did not influence either of these processes. Finally, freeze-drying influenced neither the direct nor the indirect mutagenicity of the mushroom extracts. It is concluded that mutagenic and premutagenic compounds present in mushroom are generally not heat labile.