Few citrus notes have appeared on more flavor trend lists over the past decade than yuzu. Given the popularity of the flavor profile, we dug back into the research to find out what makes its sensory profile tick. The answer is complicated.
Yuzunone (FEMA# 4691, JECFA# 2217, CAS# 1009814-14-5) has long been associated with yuzu’s distinctive aroma. Yet it may be less important to its overall sensory character than previously thought, according to research published in Food Chemistry in 2020.
The report, “Stereoselective synthesis of (6Z,8E)-undeca-6,8,10-trien-3-one (yuzunone) for its characterization in yuzu and various citrus essential oils,” by Ayaka Uehara and Nicolas Baldovini, investigated the presence and olfactory contribution of yuzunone, a compound previously identified as a key contributor to yuzu peel oil’s fruity, green and balsamic notes.
Using a stereoselective synthesis, the researchers produced a pure reference sample of yuzunone, enabling them to distinguish it from its geometric isomer and investigate its presence in five commercial yuzu and other citrus essential oil samples.
Surprisingly, yuzunone was not detected by gas chromatography-mass spectrometry (GC-MS) in any of the five samples. Gas chromatography-olfactometry (GC-O), combined with aroma extract dilution analysis (AEDA) and an eight-person sensory panel, detected the compound in one commercial yuzu oil, but only some panelists perceived it. Its overall olfactory contribution was found to be very limited.
The findings challenge earlier research that identified yuzunone, chemically known as (6Z,8E)-undeca-6,8,10-trien-3-one, as an important contributor to yuzu’s characteristic aroma. They also highlight the importance of using stereochemically pure reference compounds when investigating odorants, as earlier work used a mixture of yuzunone and its geometric isomer.
For flavor chemists, the results are a reminder that a compound’s reputation as a character-impact odorant does not necessarily translate into a consistent contribution across commercial oils. Yuzu’s distinctive sensory profile may depend on a more complex combination of volatile compounds, with their relative importance varying between samples.
Source: Uehara, A. and Baldovini, N., Food Chemistry, 338 (2021), article 128130. Read the research paper.
