Study on content of cyanide in basidiomycetes and the effect of cooking

Abstract

The present study was carried out to examine the content of cyanide in basidiomycetes on the market and those in their natural habitat, and to investigate the chemical form of cyanide in basidiomycetes and the effect of cooking. The chemical form of cyanide in basidiomycetes was suggested to be free, because there was no significant difference in the quantities of cyanide found upon distillation of basidiomycetes immediately and after incubation with two kinds of β-glucosidase for 16 hours. The content of cyanide was examined in a total of 85 samples of 54 kinds of basidiomycetes on the market and those in their natural habitat, and cyanide was detected in 44 samples of 18 kinds. The content of cyanide in basidiomycetes on the market was the highest in Tricholoma giganteum at the level of 86-283 μg/g (n = 11), and was high in Grifola frondosa at 1.8-46 μg/g (n =6), and in Pleurotus eryngii at 1.1-26 μg/g (n =7). The contents in sample in the natural habitat were less than 1.0 μg/g. The remaining percentage of the cyanide in T. giganteum after grilling for 6 minutes was 65%, while that after boiling for 3 minutes was 46% (27% in basidiomycetes and 19% in broth). The level of residual cyanide in T. giganteum after cooking might be sufficient to cause poisoning with symptoms such as vomiting.