Isopropyl methoxypyrazine (IPMP) is a
methoxypyrazine
Methoxypyrazines are a class of chemical compounds that produce odors. The odors tend to be undesirable, as in the case of certain wines, or as defensive chemicals used by insects such as ''Harmonia axyridis'' which produces isopropyl methoxy pyra ...
, a class of chemical compounds that produce odors. The odor is rather undesirable and is produced by the
Asian lady beetle
''Harmonia axyridis'' is a large Coccinellidae, 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 wi ...
or by the actinomycete ''
Streptomyces
''Streptomyces'' is the largest genus of Actinomycetota and the type genus of the family Streptomycetaceae. Over 500 species of ''Streptomyces'' bacteria have been described. As with the other Actinomycetota, streptomycetes are gram-positive, ...
'' sp. It can be detected by human taste at concentrations of as low as 2
nanogram
To help compare different orders of magnitude, the following lists describe various mass levels between 10−59 kg and 1052 kg. The least massive thing listed here is a graviton, and the most massive thing is the observable universe. ...
s per litre.
Presence in wine grapes
The odor of IPMP tends to be undesirable in the case of certain wines.
[Trace flavour components of grapes](_blank)
/ref>
Cabernet Sauvignon
Cabernet Sauvignon () is one of the world's most widely recognized red wine grape varieties. It is grown in nearly every major wine producing country among a diverse spectrum of climates from Australia and British Columbia, Canada to Lebanon' ...
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, are considered to be important determinants of green flavours in Sauvignon blanc
is a green-skinned grape variety that originates from the Bordeaux region of France. The grape most likely gets its name from the French words ''sauvage'' ("wild") and ''blanc'' ("white") due to its early origins as an indigenous grape in ...
wines.
Presence in coffee
IPMP is also an important flavour compound in coffee and is responsible for causing an off-taste called "potato taste" in East African coffee.Antestiopsis
''Antestiopsis'' is a genus of shield bug, commonly known as antestia and the variegated coffee bug. Several species in eastern Africa are pests of coffee plants, giving the coffee beans a distinctive 'potato taste', which is thought to be ca ...
'' are also implicated in causing the taste.
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 o ...
s
References
{{reflist
Pyrazines
Isopropyl compounds
Foul-smelling chemicals