The origin of the methoxypyrazines remains unclear and their importance as key odorants may be grossly underrated. They have very low odour thresholds and are typically present below the limit of detection of most analytical techniques without pre-concentration and the use of mass spectrometry. A total of six methoxypyrazines were tentatively identified during an earlier study of baked potatoes but, unlike alkyl pyrazines, did not appear to be generated during the cooking process (Duckham et al. unpublished data). Gallois and Grimont (1985) identified several methoxypyrazines apparently responsible for the characteristic potato odour produced by some members of the Enterobacteriaceae family, namely Serratia and Cedecea strains. Improvements in the sensitivity of mass spectrometers over the past 10 years will ensure more reliable detection and identification of these key compounds. Current studies are likely to more reliably identify them in foodstuffs and from environmental sources hopefully leading to a clearer understanding of their biochemical origins. Watch this space.
Several methoxypyrazines have been associated with off-flavours and taints in foodstuffs and this will form the subject of a future posting.
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