Flavour and off-flavour compounds of Swiss Gruyere cheese. Evaluation of potent odorants

The flavour of atypical sample of Gruyere cheese and that of a Gruyere exhibiting a potato-like off flavour was examined by instrumental and sensory analyses. Based on the results of dynamic headspace gas chromatography-mass spectrometry (DHGC/ MS), aroma extract dilution analysis (AEDA) and gas chromatography-olfactometry of static headspace samples (GCO-H), 2-/3-methylbutanal, methional, dimethyltrisulphide, phenylacetaldehyde, 2-ethyl-3,5-dimethylpyrazine, 2,3-diethyl-5-methylpyrazine, methanethiol, as well as butyric, 2-/3-methylbutyric and phenylacetic acid form the typical flavour of Gruyere cheese. The potato-like character of the sample showing an aroma defect, however, could not be attributed definitively to one of these compounds. Considering the results of DHGC/MS and AEDA, 2-ethyl-3,5-dimethylpyrazine and 2,3-diethyl-5-methylpyrazine could be the possible causes of the off-flavour. (C) 2002 Elsevier Science Ltd. All rights reserved.