Alkyl-methoxypyrazines (MPs) elicit green aroma and flavour in many wines, and are generally considered detrimental to wine quality. Grapes and select members of the Coccinellidae (ladybeetle) family contribute MPs to wine, however, relatively little is known about the relative contribution of each source or the prevalence of the recently identified 2,5-dimethyl-3-methoxypyrazine (DMMP) in commercial wines. Here, we determined the concentrations of DMMP, isopropyl methoxypyrazine (IPMP), secbutyl methoxypyrazine (SBMP) and isobutyl methoxypyrazine (IBMP) in 187 wines from 14 countries, nine vintages and seven wine varietals using Multi Dimensional Gas Chromatography coupled with Mass Spectrometry and headspace solid phase microextraction. Results generally confirm previous findings, including the range of IBMP and SBMP values, and the lack of a clear relationship between MP concentrations in wines and any one geographical, climatic, or vintage factor. DMMP was detected in a large number of wines for the first time, particularly reds, and at levels that indicate it may play an active role in wine aroma. IPMP concentrations in Chardonnay wines were higher than previously reported. A new parameter – Total Impact Factor (TIF) - is proposed as a metric of the combined sensorial impact of MPs on wine aroma. We also conclude that IPMP:IBMP ratios may be useful as a possible diagnostic of Coccinellidae contamination in some varietal wines, and thus potential for ladybug taint (LBT).
|Number of pages||6|
|Journal||Journal of Food, Agriculture and Environment|
|Publication status||Published - Jan 2016|