3-(methylthio)propanal (methional)

aldehyde Key food odorant

Found in 1 ingredient across the CompKitchen flavor graph.

Look up another compound — search by name, CAS number, PubChem CID, or FEMA #.

Key food odorant (generalist)

Dunkel et al. 2014

Identified in the meta-analysis of 227 food samples as one of 16 generalist odorants — appears in >25% of foods, typically from generic Maillard, lipid-oxidation, or fermentation pathways. Characteristic odor: cooked potato.

Source: Angew. Chem. Int. Ed. 2014, 53, 7124–7143

Properties

Odor description: cooked potato-like, cooked potato
Odor threshold — orthonasal, in clean water: 0.200 ppb – 1.0 ppb median 0.400 ppb · 3 published values · see all 29 with sources
CAS number: 3268-49-3
Retention index: 910

Not in FEMA GRAS publications 1-33. Of 3,367 listed flavoring substances, none match this compound name. May still be food-safe under other regulatory routes (FDA 21 CFR 172, EFSA, JECFA) — check femaflavor.org for the authoritative current list.

Published thresholds

29 measured values from the literature. Grouped by what was actually measured — a threshold smelled in clean water, tasted in the mouth, or measured in a real food are three different quantities and are not pooled.

Orthonasal, in clean water

0.200 ppb – 1.0 ppb

The reference measurement — smelled in water. OAV is computed against this.

Threshold	Matrix	Source	Paper
0.200 ppb	water_odor	Leffingwell	—
0.400 ppb SIDA	water	Dunkel 2014	—
1.0 ppb SIDA	water	Rychlik 1998 · 2 studies	—

In a food matrix

0.090 ppb – 50.0 ppb

Measured in a real food, where the matrix shifts detection — not a clean-water value.

Threshold	Matrix	Source	Paper
0.090 ppb	water (food: rice)	Literature corpus	41675126
0.200 ppb SIDA	water (food: hungarian-type salami)	Literature corpus	33714268, 10552650, 19778056 +11
0.200 ppb SIDA	water (food: smoked cooked loin (pork))	Literature corpus	33714268, 10552650, 19778056 +11
0.200 ppb SIDA	water (food: extruded wheat flour)	Literature corpus	33714268, 10552650, 19778056 +11
0.310 ppb SIDA	water (food: soy sauce)	Literature corpus	33714268, 10552650, 19778056 +11
0.430 ppb SIDA	water (food: pink guava)	Literature corpus	33714268, 10552650, 19778056 +11
0.430 ppb SIDA	water (food: reference standard (water))	Literature corpus	33714268, 10552650, 19778056 +11
0.430 ppb SIDA	water (food: longjing green tea infusion)	Literature corpus	33714268, 10552650, 19778056 +11
0.430 ppb SIDA	water (food: coffee)	Literature corpus	33714268, 10552650, 19778056 +11
1.4 ppb SIDA	water (food: japanese soy sauce)	Literature corpus	33714268, 10552650, 19778056 +11
1.4 ppb SIDA	water (food: beef vegetable gravy)	Literature corpus	33714268, 10552650, 19778056 +11
1.4 ppb SIDA	water (food: pork vegetable gravy)	Literature corpus	33714268, 10552650, 19778056 +11
1.8 ppb SIDA	water (food: hand-squeezed grapefruit juice)	Literature corpus	33714268, 10552650, 19778056 +11
1.8 ppb SIDA	water (food: litsea pungens fruit)	Literature corpus	33714268, 10552650, 19778056 +11
5.2 ppb SIDA	water (food: coffee)	Literature corpus	33714268, 10552650, 19778056 +11
15.5 ppb	water (food: milk)	Literature corpus	10552650, 39479676
35.6 ppb SIDA	water (food: bread)	Literature corpus	33714268, 28274420, 28490062
50.0 ppb SIDA	water (food: unknown)	Literature corpus	33714268, 19778056, 33152860 +2
907 ppb	water (food: tea)	Literature corpus	39877541
Flagged: 648× from the median of this group. Excluded from the range above pending re-check against the source publication — shown rather than hidden.
908 ppb	water (food: lime)	Literature corpus	26213023
Flagged: 649× from the median of this group. Excluded from the range above pending re-check against the source publication — shown rather than hidden.

Retronasal / in-mouth

5.0 ppb

Tasted rather than smelled — a different sense, not comparable.

Threshold	Matrix	Source	Paper
0.050 ppb SIDA	oil_retronasal	Rychlik 1998 · 1 studies	—
Flagged: 100× from the median of this group. Excluded from the range above pending re-check against the source publication — shown rather than hidden.
5.0 ppb SIDA	water_retronasal	Rychlik 1998 · 2 studies	—
5.0 ppb	water_flavor	Leffingwell	—

Other matrix

0.050 ppb – 0.520 ppb

Measured in a non-aqueous medium (oil, starch, cellulose).

Threshold	Matrix	Source	Paper
0.050 ppb SIDA	oil_orthonasal	Rychlik 1998 · 1 studies	—
0.270 ppb SIDA	starch	Rychlik 1998 · 1 studies	—
0.520 ppb SIDA	wine matrix (12% ethanol) (food: red wine)	Literature corpus	33714268, 10552650, 19778056 +11

Only values we can attribute are listed. Where a compendium's licence does not permit public attribution its figures are omitted here, so every number on this page traces to a citable source.

Found in

Measured impact first, then profile share

Every ingredient known to contain 3-(methylthio)propanal (methional). Ingredients with a measured concentration come first, ranked by odour activity; the rest follow by how large a share of that ingredient's profile this molecule is. The figure beside each is how many different compounds that ingredient has in total — not the concentration of 3-(methylthio)propanal (methional) in it.

coffee

beverage caffeinated

507 cmpds

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