Certain mushrooms, when bruised, cut, or handled, develop a distinct blue discoloration. This transformation is not random but a specific chemical reaction. The blueing process prompts curiosity about the underlying scientific reasons for this change, highlighting the complex chemistry within these organisms.
The Chemical Process Behind the Blue
The blue color in these mushrooms results from an oxidative reaction. This process involves psilocybin and psilocin compounds present within the mushroom’s tissues. When the mushroom’s cellular structure is damaged, these compounds are exposed to oxygen.
Upon exposure, enzymes like psilocybin oxidase or polyphenol oxidase act on psilocybin and psilocin. Psilocybin first converts into psilocin by an enzyme called phosphatase (PsiP). Psilocin, which is less stable, then oxidizes, transforming into blue-colored products. This chemical change involves the formation of quinoid compounds that polymerize to create the blue pigment. Research suggests the blue color stems from the oxidation and dimerization of psilocin, forming oligomers.
Mushrooms Known for This Bluing
The bluing reaction is a characteristic of several mushroom genera, particularly those containing psilocybin and psilocin. The Psilocybe genus, including species like Psilocybe cubensis and Psilocybe cyanescens, is well-known for this phenomenon. Other genera exhibiting this bluing include Panaeolus, with species like Panaeolus cyanescens (often called “Blue Meanie”), and Gymnopilus, such as Gymnopilus aeruginosus.
These mushrooms can be found in various habitats, including wood, grass, and even dung, depending on the specific species. Not all mushrooms that exhibit a blue color or bruise a different shade contain these compounds. For example, some boletes, like Gyroporus cyanescens, turn blue upon damage due to the oxidation of a different compound called gyrocyanin, which is not psychoactive.
What the Blue Color Signifies
For mushrooms that undergo this chemical process, the blue coloration serves as an indicator of the presence of psilocybin and psilocin. This reaction is triggered by cellular disruption, signifying damage or stress to the mushroom tissue. The more a mushroom is handled or bruised, the more pronounced this blueing can become.
While bluing can be a useful characteristic for identifying certain types of mushrooms that contain these compounds, it does not universally indicate edibility or toxicity for all mushrooms. It specifically points to the chemical reaction occurring within those particular species. Therefore, expert identification is always necessary for any mushroom found in the wild, as relying solely on bluing can be misleading due to other non-psychoactive mushrooms also bruising blue from different chemical processes.