Material guide: furaneol — the strawberry makes it, then attaches a sugar and puts it away

CAS 3658-77-3, 101 suppliers, FEMA 3174. Its synonym field reads 'furaneol (Firmenich)' — a trademark that became the common name. The odour field is sweet, cotton candy, caramellic, strawberry, brown sugar, burnt, savory, and its descriptions differ between 0.10% and 1.00%. It is a white to pale yellow solid melting at 78–81 °C, and its substantivity is recorded as 320 hours at 20% in dipropylene glycol — because it is not a liquid and cannot be evaluated neat. Raab and colleagues identified the strawberry enzyme that makes it, FaQR, in The Plant Cell in 2006, and Yamada and colleagues found in 2018 that the plant uses a dedicated glucosyltransferase to attach glucose and store it. It is also one of the sixteen same-type materials in my last article's clique.

About a 5 minute read.

The short version

Name: strawberry furanone, HDMF, better known as Furaneol (a Firmenich trademark), CAS 3658-77-3, FEMA 3174
It is a solid: white to pale yellow, melting at 78–81 °C
Odour type: caramellic; odour: sweet, cotton candy, caramellic, strawberry, brown sugar, burnt, savory
Strength: high (evaluate at 1% or less), rank 3
Substantivity: 320 hours at 20% in dipropylene glycol — note that 20%
Suppliers: 101; storage: under nitrogen, 12 months

The synonym field holds a trademark

head_synonym reads: "furaneol (Firmenich)."

Furaneol is a Firmenich trademark, and it has become the name of the molecule — academic papers use it. This happens in fragrance (I wrote about leerall and lyral being two trade spellings of one material), but here the trademark won outright.

Its chemical name is 4-hydroxy-2,5-dimethyl-3(2H)-furanone, abbreviated HDMF in the literature.

About that "20%" in the substantivity field

odor_substantivity:

320 hours at 20.00% in dipropylene glycol

This is the first substantivity record I have seen in this series stated at anything other than 100%. Most read "N hours at 100%."

The reason is that it is not a liquid. Melting at 78–81 °C means it is solid at room temperature, so there is no neat material to put on a blotter. The evaluation has to happen in solution, and that concentration has to be stated or the number means nothing.

It is also why most of what you can buy is a solution. (The database carries a separate strawberry furanone solution record with 73 suppliers, sharing FEMA 3174 with this one — the one-number-many-records pattern I measured.)

It is a different thing at different concentrations

odor_descriptions holds several entries at different dilutions:

Concentration	Description
1.00% (in propylene glycol)	sweet, cotton candy, caramel, strawberry, sugar (Luebke 1995)
0.10%	sweet, slightly burnt brown caramellic, cotton candy with a savory nuance (Mosciano, P&F 21(5):49, 1996)
—	strongly fruity, on dilution strawberry and pineapple

That last line is the point: "on dilution strawberry and pineapple."

Concentrated it is caramel and candyfloss; only diluted does it become fruit. One molecule, two identities, and the boundary is a dilution factor.

(Last time I measured the database's ladder of evaluation concentrations — this record demonstrates exactly why that number matters: without aligning concentrations you cannot compare two descriptions.)

And taste_descriptions at 0.10–1.00 ppm reads: sweet, caramellic, cooked, meaty and fruity nuances.

Caramel and meat in one sentence. Which explains why it is used both in berry flavours and in savoury applications — the field's own words are "a chemical with a sweet, caramel taste used extensively in both berry flavours and in savoury applications."

How the strawberry makes it

Raab and colleagues open their 2006 Plant Cell paper:

The flavor of strawberry (Fragaria × ananassa) fruit is dominated by an uncommon group of aroma compounds with a 2,5-dimethyl-3(H)-furanone structure.

They partially purified the enzyme responsible for HDMF and found it corresponded to a "strongly ripening-induced, auxin-dependent putative quinone oxidoreductase," which they named FaQR — a 322-amino-acid protein of 34.3 kD. Laser capture microdissection showed its mRNA in the fruit's parenchyma tissue, and they expressed the active protein in E. coli.

"Strongly ripening-induced" means the enzyme appears in quantity as the strawberry turns red. Which is exactly when a strawberry starts to taste of anything.

And then the strawberry puts it away

Yamada and colleagues, in Bioscience, Biotechnology, and Biochemistry in 2018, took up the next step:

A considerable amount of HDMF is converted into HDMF β-D-glucoside and accumulated in mature strawberry fruits.

They isolated a novel glucosyltransferase, UGT85K16, which preferentially glucosylates HDMF's hydroxyl group. Once the sugar is on, the molecule stops being volatile — it turns from a smell into an inventory.

This is the third time this series has met the same theme. Birch tar is heat turning bark into something else. Allyl isothiocyanate is a plant keeping a weapon in two halves and assembling it when bitten. And the strawberry makes its aroma and then locks it to a sugar.

Three plants, three strategies, one thing in common: the molecule you smell is not what the plant left sitting out for you.

It is in last article's clique

Last time I searched the official blending suggestions for the largest complete cluster and found sixteen materials all recommending each other — every one caramellic, and strawberry furanone among them (with maltol, ethyl maltol, cyclotene, maple furanone, immortelle absolute, fenugreek absolute and the rest).

What that clique tells you is not "use these sixteen together" but "these sixteen are the same thing." They overlap heavily in a formula — so that suggestion list is no help in choosing a kit, but it is very useful for understanding which family a molecule belongs to.

How to use it

Evaluate at 1% or less. Rank 3.
Buying a solution is more practical. It is a solid, and suppliers sell it pre-diluted.
Store under nitrogen. It is one of the 92 records told to.
Dilute for strawberry, concentrate for caramel. That is not a metaphor; it is in the field.
It is also a savoury material. At 0.1–1 ppm it brings cooked and meaty notes.
Oral LD50 in mouse 1608 mg/kg (1988); cosmetic_uses reads fragrance and tonic.

What this doesn't establish

I have not smelled it. This is fields, whole-database statistics, and two papers.
Both papers are plant biochemistry, not fragrance research. I cite their account of synthesis and storage.
Raab 2006 establishes FaQR's involvement in the synthesis; I did not verify the whole pathway or follow later corrections to it.
"On dilution strawberry and pineapple" is an unsigned entry in the field, and I could not trace its source.
"A trademark that became the common name" is my observation; I did not check Firmenich's trademark status.
The paper gives no precise figure for the glucoside fraction ("a considerable amount"), and I did not chase one.
I did not check the IFRA text.