Protein content and amino acid profile of wild mushrooms depend on environmental conditions

Wild mushrooms can be an important source of protein and essential amino acids, however very little is known about the environmental factors affecting the content of these compounds. In our study, we investigated the influence of soil properties (soil type, C/N ratio, pH) and tree stand characteristics (tree diversity, canopy cover, understory cover, and the proportion of deciduous trees) on total protein and essential amino acids (Valine, Leucine, Isoleucine, Phenylalanine, Lysine, Methionine, Arginine, Histidine) contents in seven wild-growing mushroom species (Macrolepiota procera, Rhodocolybia butyracea, Russula cyanoxantha, R.heterophylla, Lactifluus vellereus, Armillaria mellea s.l., and Xerocomellus chrysenteron). Our study showed that the identity of mushroom species determines, to a large extent, the protein content and the amino acid profile of the mushrooms. The highest protein content was revealed in X. chrysenteron, M. procera and R. butyracea. Effects of environmental factors were weaker and species specific. The protein content in X. chrysenteron was mainly influenced by soil type (Cambisols vs. Luvisols) and soil characteristics (positively by C/N ratio and negatively by soil pH). In L. vellereus the protein content was negatively influenced by stand characteristics (canopy cover, understory cover, and tree diversity). In M. procera the protein content decreased with decreasing understory cover, while for all the other studied species, the effects of environmental factors were negligible. Similarly, the amino acid profiles were not affected by any environmental factors, however, they seem to be consistent with ecological roles of the species (ectomycorrhizal, saprotrophic, parasitic fungi). This last result requires further investigation.