Fig 1.
Schematic representation of the spectral clustering applied to the vibrational spectra of odorant compounds.
Table 1.
Odor description and relative content (%) of aroma-active compounds in the Orchidaceae and Apocynaceae families.
The plant names are abbreviated as follows: D. lin. (Dendrophylax lindenii), M. ten. (Maxillaria tenuifolia), C. ari. (Catasetum arietinum), H. ken. (Huernia keniensis), P. cub. (Pseudolithos cubiformis), and O. var. (Orbea variegata).
Fig 2.
Classification of odorant compounds based on their infrared spectra.
Each spectrum is labeled according to the compound numbers listed in Tables I and II. The spectra are color-coded by group to enhance visual distinction. Group A: 6-Methylhept-5-en-2-one, Benzoic acid, 3-Methyl-2-pentanone, Benzaldehyde. Group B: (E,E)-α-farnesene, (E)-β-ocimene, linalool, (-)-β-Caryophyllene, (-)-α-Copaene, Caryophylladienol II, β-Bisabolene, (E)-α-Bergamotene, (E)-Geranyl geraniol, Eucalyptol, d-Limonene. Group C: Dimethyl disulfide, Dimethyl trisulfide. Group D: methyl salicylate, acetophenone, indole. Group E: Octanal, Heptanal, Decanoic acid. Group F: (Z)-Methyl-p-methoxycinnamate, (E)-Methyl-p-methoxycinnamate.
Fig 3.
Classification of odorant compounds based on their Raman spectra.
Each spectrum is labeled according to the compound numbers listed in Tables I and II. The spectra are color-coded by group to enhance visual distinction. Group A’: methyl salicylate, (Z)-Methyl-p-methoxycinnamate, Benzoic acid, Acetophenone, Benzaldehyde. Group B’: (-)-α-Copaene, Eucalyptol, Octanal, 3-Methyl-2-pentanone, Heptanal, Decanoic acid. Group C’: Dimethyl disulfide, Dimethyl trisulfide. Group D’: (E,E)-α-farnesene, (E)-β-ocimene, Caryophylladienol II, (E)-Methyl-p-methoxycinnamate. Group E’: Indole. Group F’: linalool, (-)-β-Caryophyllene, β-Bisabolene, (E)-α-Bergamotene, 6-Methylhept-5-en-2-one, (E)-Geranyl geraniol, d-Limonene.
Fig 4.
Classification of odorant compounds based on their Vibrational Density of States (VDOS).
Each spectrum is labeled according to the compound numbers listed in Tables I and II. The spectra are color-coded by group to enhance visual distinction. Group A”: Benzoic acid, Acetophenone, Benzaldehyde. Group B”: methyl salicylate, (Z)-Methyl-p-methoxycinnamate, (E)-Methyl-p-methoxycinnamate. Group C”: Dimethyl disulfide, Dimethyl trisulfide. Group D”: (E,E)-α-farnesene, (E)-β-ocimene, linalool, (-)-β-Caryophyllene, (-)-α-Copaene, Caryophylladienol II, β-Bisabolene, (E)-α-Bergamotene, 6-Methylhept-5-en-2-one, (E)-Geranyl geraniol, Eucalyptol, Octanal, 3-Methyl-2-pentanone, Heptanal, Decanoic acid, d-Limonene. Group E”: Indole.