The nitrogenous constituents of the dehydrated mushroom, Boletus edulis, and their relation to flavour

Steam distillation of dehydrated Boletus edulis gave a ‘flavour essence’ which contained only the off‐flavour components of the sample and was reminiscent of town gas and/or rubber. The true mushroom flavour was found to be non‐volatile, the residue after distillation being of undiminished flavour intensity. About half of the sample was water soluble and this extract contained all of the flavour components. These were concentrated into the basic fraction by an ion‐exchange technique, and further separated into fractions containing amino‐acids of progressively increasing basicity by a displacement development ion‐exchange chromatographic technique. The most basic compounds tasted most characteristically of mushrooms, but it was clear that all the nitrogenous constituents contributed something to the overall flavour profile. The contribution of the highly basic amino‐acids is considered to be especially important as it was found that their flavours lingered in the mouth and were therefore savoured more strongly than would be expected simply from a consideration of their taste intensity as measured by threshold dilution technique.