Chemistry behind Quality—Emission of Volatile Enantiomers from Mentha spp. Plant Tissue in Relationship to Odor Sensory Quality

Abstract

The quality of food, considering increasing consumer demands and competition among producers, is a highly important issue. Quality concerns are also applicable to the odor quality of herbs and spices (HSs). Meanwhile, HSs commonly are graded based on their essential oils (EOs) content and analysis; but does the instrumental analysis really provide general information about the HSs sensory quality? Three chemotypes of Mentha spp. were used in the present study. From samples diversified by convective drying at different temperatures, EOs were hydrodistillated and analyzed by enantioselective GC-MS; moreover, the source plant material’s volatile profile was analyzed by the HS-SPME technique. The instrumental analysis was confronted with the results of the sensory panel. Changes in enantiomeric composition were observed during the drying process, although no clear correlations or trends could be found for individual chiral components. Furthermore, even with significant differences in particular volatiles’ contribution to plants’ EOs and their volatile profiles, judges were not able to match the sample EOs and plant samples with sufficient effectiveness (~40%). Based on those results, we suggest that volatile enantiomeric distribution does not have an actual influence on odor quality and that the sensory analysis should not be replaced with instrumental analysis, which cannot predict general sensory quality.