Chemicals with sweet aroma descriptors found in Portuguese wines from the Douro region: 2,6,6-trimethylcyclohex-2-ene-1,4-dione and diacetyl

J Agric Food Chem. 2001 Jan;49(1):263-9. doi: 10.1021/jf000948c.

Abstract

2,6,6-Trimethylcyclohex-2-ene-1,4-dione (TMCHD), a norisoprenoid with a sweet honey aroma descriptor, is reported for the first time as a minor constituent of single-varietal table and fortified wines from the demarcated Douro region. Olfactory gas chromatography (GC-O) of a volatile wine extract, previously isolated by preparative gas chromatography, indicated the presence of a zone containing an intense honey descriptor. The targeted odor compound was identified by GC-MS, GC-O, and Kovats index. Quantitative analysis using a selected characteristic ion (m/z 96) indicated that young Douro fortified wines from the 1997 vintage contained up to 4 microg/L TMCHD. The sweet honey sensory threshold limit for TMCHD in a model Port wine solution was found to be 25 microg/L. TMCHD is therefore only likely to contribute as a collective element to Port wine aroma. The wine volatile diacetyl was identified as a strong contributor to the sweet caramel aroma descriptor often associated with Port.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Chromatography, Gas / methods
  • Cyclohexanes / analysis*
  • Diacetyl / analysis*
  • Gas Chromatography-Mass Spectrometry
  • Odorants*
  • Portugal
  • Smell
  • Wine / analysis*

Substances

  • Cyclohexanes
  • 2,6,6-trimethylcyclohex-2-ene-1,4-dione
  • Diacetyl