Effects of heat and mechanical processing on release of ibotenic acid from Amanita muscaria in traditional preparations used for catching flies in Slovenia

We investigated the traditional use of Amanita muscaria in Slovenia and analyzed the effects of heat processing (HP) and mechanical processing (MP) on the release of ibotenic acid (IBO) from A. muscaria in different preparations for catching flies. From October 2013 to September 2014 we interviewed 59 people and 16 respondents described the preparations used for catching flies, which they remembered from their parents or neighbors. However, there were no reports about the present use. The methods for preparing the cap of A. muscaria included soaking in milk or water and combinations of HP or MP with soaking. Three caps of A. muscaria were harvested in October 2014 in Črni Vrh, Slovenia, and sliced into 9 equal pieces, 2 were used for the analysis of IBO content and 7 were prepared following the traditional methods in 50 ml of milk or water. Preparations were: soaking in milk or water, cooking in milk or water and toasting on a hot plate, tapping or slicing before soaking in milk. Preparations were sampled at 5 time points (0.5, 1, 2, 3, 24h) and the concentration of IBO was analyzed with HPLC. Our results suggest that the release of IBO from the fungal material did not depend on the solvent used in the experiment, but was time dependent with the proportion of released IBO gradually increasing over time. HP and MP led to faster extraction of IBO into milk or water. In the first 30 min the soaked fungal material released up to 10% of IBO content, the mechanically processed from 10 to 25% and the heat processed at least 60%. HP also weakly influenced the yield of extraction. After 24h the heat processed fungal material released at least 85% of IBO content, but when prepared with other methods the proportion approached but not exceeded 80%. In conclusion, soaking the fungal material in milk or water resulted in the lowest proportion of the released IBO; on the other hand, HP and MP of fungal material led to faster release of IBO into milk or water.