Abstract The analysis of aroma volatiles of parsley revealed the presence of two novel oxygenated p-mentha-1, 3, 8triene derivatives, the amounts of which increase during processing of plant material and deteriorate the typical fresh aroma. The two derivatives, which could be synthesized by means of a dye sensitized photooxygenation reaction, were identified as 1-methyl-4-(methylethenyl)-2, 3-dioxabicyclo [2.2. 2] oct-5-ene and 4-methyl- ...