Characterization of Aroma-Active Compounds in Italian Tomatoes with Emphasis on New Odorants

Johanna Kreissl, Peter Schieberle

Research output: Contribution to journalArticlepeer-review

34 Scopus citations

Abstract

An aroma distillate was prepared by solvent extraction and subsequent SAFE distillation from Italian vine-ripe tomatoes eliciting an intense overall aroma. Application of gc/olfactometry and the aroma extract dilution analysis revealed 44 odor-active compounds, 42 of which could be identified. The highest odor activity value of 2048 was established for the green, grassy (Z)-3-hexenal, the metallic smelling trans-4,5-epoxy-(E)-2-decenal, the potato-like 3-(methylthio)propanal, and the caramel-like 4-hydroxy-2,5-dimethyl-3(2H)-furanone. Of the further odorants, 13 compounds have previously not been reported as tomato odorants. Although most of these showed lower FD-factors, in particular, the coconut/dill-like smelling wine lactone ((3S,3aS,7aR)-3a,4,5,7a-tetrahydro-3,6-dimethylbenzofuran-2(3H)-one) appeared with a quite high FD factor. In addition, a fruity, almond-like odorant (6) with an FD factor of 1024 was detected. By application of high resolution mass spectrometry and polarity considerations, the structure of a methyl-2-ethoxytetrahydropyran isomer was suggested for 6. Four of the five possible isomers, the 3-methyl-, 4-methyl-, 5-methyl-, and 6-methyl-2-ethoxytetrahydropyran were synthesized and showed similar mass spectrometric patterns. However, these were excluded by their different retention indices. Although the synthesis of the remaining 2-methyl-2-ethoxytetrahydropyran resulted in only small yields, which were not sufficient for NMR measurements, this structure is very likely for 6. This compound was never reported as a food constituent before. Finally, quantitation of 23 odorants by stable isotope dilution assays allowed for the preparation of an aroma recombinate resembling the overall aroma of the tomatoes.

Original languageEnglish
Pages (from-to)5198-5208
Number of pages11
JournalJournal of agricultural and food chemistry
Volume65
Issue number25
DOIs
StatePublished - 28 Jun 2017
Externally publishedYes

Keywords

  • 2-methyl-2-ethoxytetrahydropyran
  • 3-methyl-2-ethoxytetrahydropyran
  • 5-methyl-2-ethoxytetrahydropyran
  • 6-methyl-2-ethoxytetrahydropyran
  • stable isotope dilution assay
  • wine lactone

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