Methoxypyrazines are a class of chemical compounds that produce odors. The odors tend to be undesirable, as in the case of certain wines,
/ref> or as defensive chemicals used by insects such as ''Harmonia axyridis
''Harmonia axyridis'' is a large lady beetle or ladybug species that is most commonly known as the harlequin, multicoloured Asian, or Asian lady beetle. This is one of the most variable species in the world, with an exceptionally wide range of col ...
'' which produces isopropyl methoxy pyrazine
Isopropyl methoxypyrazine (IPMP) is a methoxypyrazine, a class of chemical compounds that produce odors. The odor is rather undesirable and is produced by the Asian lady beetle or by the actinomycete '' Streptomyces'' sp. It can be detected by ...
(IPMP). They have also been identified as additives in cigarette manufacture. Detection thresholds are very low, typically near 2 parts per trillion (1 ng/L).
Examples of methoxypyrazines in wine grapes
Cabernet Sauvignon has high levels of methoxypyrazines.[Oz Clarke ''Encyclopedia of Grapes'' pg 223 Harcourt Books 2001 ] Two methoxypyrazine compounds, 3-isobutyl-2-methoxypyrazine (IBMP) and 3-isopropyl-2-methoxypyrazine (IPMP), are considered to be important determinants of green flavours in Sauvignon blanc wines.[Marais, J., Hunter, J.J., & Haasbroek, P.D. (1999). Effect of microclimate, season and region on Sauvignon blanc grape composition and wine quality. South African Journal of Enology and Viticulture, 20, 19-30.]
See also
* Alkylpyrazine Alkylpyrazines are chemical compounds based on pyrazine with different substitution patterns. Some alkylpyrazines are naturally occurring highly aromatic substances which often have a very low odor threshold and contribute to the taste and aroma ...
s
References
{{reflist
Pyrazines
Ethers
Wine chemistry