Comparison of volatile compounds released during the consumption of Cheddar cheese with compounds extracted by vacuum distillation using gas chromatography–olfactometry

Buccal headspace analysis is an in vivo extraction technique capable of extracting volatile compounds released during consumption in concentration ratios that stimulate the olfactory receptors. Vacuum distillation is designed to measure the total volatile profile of a food and as a result pays little attention to conditions in the mouth that determine volatile release and aroma stimulation. Volatile extracts of mature Cheddar cheese were obtained using buccal headspace analysis and vacuum distillation. Cheddar cheese volatile extracts were compared using gas chromatography–olfactometry and gas chromatography–mass spectrometry. Estimation of odour intensity was carried out using a time–intensity gas chromatography–olfactometry technique similar to OSME. Odour-active volatile compounds identified in Cheddar cheese buccal headspace analysis extracts included dimethyl sulphide, 2,3-butanedione, 3-methylbutanal, toluene, ethyl butyrate, hexanal, 2-heptanone, heptanal, α-pinene, methional, ethyl hexanoate and dimethyl trisulphide. All of these volatile compounds have previously been associated with the volatile profile of Cheddar cheese. Vacuum distillation obtained a near-complete volatile extract of Cheddar cheese, which was distinguished from buccal headspace analysis extracts by the presence of low vapour pressure odour-active volatile compounds. Significant differences (p < 0.05) between extractions were determined for the quantities of ethyl butyrate, 2-heptanone and ethyl hexanoate, the odours of which were also identified in both extractions. Buccal headspace analysis and vacuum distillate principal aromagrams of mature Cheddar cheese were obtained using non-centred principal components analysis. Qualitative odour differences were observed between both extractions, in particular for odour intensity measurements of one odour, ‘raw mushroom’. Tentative relationships between gas chromatography–olfactometry odour intensity measurements and corresponding gas chromatography–mass spectrometry quantitative measurements were established. Copyright © 2001 John Wiley & Sons, Ltd.