trans-2-hexenal

green aldehyde Key food odorant

Found in 107 ingredients across the CompKitchen flavor graph.

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

2D Lewis Structure

Formula: C6H10O
Molecular weight: 98.14 g/mol
PubChem CID: 5281168 — full record on PubChem

Key food odorant (individualist)

Dunkel et al. 2014

Identified in the meta-analysis of 227 food samples as one of 151 individualist odorants — appears in <5% of foods, carries the diagnostic signature of specific ingredients. Characteristic odor: green, apple-like.

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

Properties

Odor description: green, leafy, apple, fatty, aldehydic
Odor threshold — orthonasal, in clean water: 17.0 ppb – 110 ppb median 63.5 ppb · 2 published values · see all 5 with sources
Volatility: high
CAS number: 6728-26-3
Retention index: 850

Regulatory · United States

FEMA GRAS — Generally Recognized As Safe for flavoring use

✓ Exact match

FEMA number: 2560
GRAS publication: GRAS 3
FEMA primary name: 2-HEXENAL

Use-level matrix not extracted for this substance — check the source publication for current ppm guidance.

Source: FEMA GRAS publications 1-33.

How this molecule is described

Sources disagree about odour more often than they disagree about chemistry. Rather than show one answer, here is every description on file with how many ingredient records carry it.

Also filed as

(e)-2-hexenal e-2-hexenal

Same molecule, unified here — previously counted and displayed as separate compounds.

Descriptions on file

Ordered by how many independent descriptor streams give each wording, then by how often it appears. The bar is still replication — one source copied onto many ingredients scores high there — so the two can disagree.

green, apple, grassy Flavornet Cas, Flavornet Name, FlavorDB 2.0, Flavordb Odor Column 4 sources agree

aldehydic, almond, apple, banana, cheesy, fat, fatty, fruity, green, leafy, plum, rancid, sweet, vegetable FlavorDB 2.0

green, leafy, apple, fatty, aldehydic shown above Llm Adjudicated

—

Bars are the share of ingredient records carrying each description. High agreement means the sources replicate each other — not necessarily that they are right.

Published thresholds

5 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

17.0 ppb – 110 ppb

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

Threshold	Matrix	Source	Paper
17.0 ppb	water_odor	Leffingwell	—
110 ppb SIDA	water	Dunkel 2014	—

In a food matrix

27.0 ppb – 22628 ppb

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

Threshold	Matrix	Source	Paper
27.0 ppb	water (food: melon)	Literature corpus	—
1216 ppb	water (food: olive oil)	Literature corpus	—
22628 ppb	water (food: unknown)	Literature corpus	—

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.

Where you'd actually smell it

Odor Activity Value = measured concentration ÷ odor threshold (110.0 ppb, the engine's canonical value — see the 5 published values). OAV ≥ 1 = perceptible.

Food	Concentration (ppb)	OAV	Source
vinegar	20000.0	182 ⚡	Corpus paper
olive	20000.0	182 ⚡	DOI
extra virgin olive oil	11000.0	100 ⚡	Corpus paper
mango	84.0	0.76	DOI
olive oil	40.6	0.37	Corpus paper
strawberry	7.5	0.07	Corpus paper
melon	0.7	0.01	Corpus paper

Concentrations from PubMed Central Open Access papers (free literature corpus, MIT-style licensed). Copper = OAV ≥ 10 (strongly perceptible). Green = OAV ≥ 1 (perceptible).

Found in

Measured impact first, then profile share

Every ingredient known to contain trans-2-hexenal. 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 trans-2-hexenal in it. Full concentrations are in the OAV table above.

olive

measured · OAV 181.82

370 cmpds

410 cmpds

479 cmpds

426 cmpds