Orthonasal and retronasal but not oral-cavity-only discrimination of vapor-phase fatty acids.

Discrimination of vapor-phase linoleic, oleic, and stearic fatty acids was studied using triangle tests. For each trial, 2 of the 3 modified odorant delivery containers (MODCs) had the same content and 1 was different. Contents were either mineral oil-diluted linoleic or oleic acids, with mineral oil in the other MODC (blanks) or undiluted stearic acid with NaCl in the other MODC (blanks).

Metallic taste and retronasal smell.

A series of experiments investigated the nature of metallic taste reports and whether they can be attributed to the development of a retronasal smell. Two studies showed that the metallic sensation reports following oral stimulation with solutions of FeSO4 were reduced to baseline when the nose was occluded. No such reduction was seen for CuSO4 or ZnSO4, which were more bitter and astringent, respectively, and less metallic.