AI Article Synopsis
- High-quality oak wood contains volatile compounds that give pleasant aromas like coconut, vanilla, and caramel, but a new rancid butter off-flavor has been discovered.
- Using advanced techniques such as gas chromatography and mass spectrometry, researchers identified six nitrogen-containing compounds linked to a family of chemicals called 2,5-disubstituted pyrazines.
- These compounds were created in the lab from amino acids and led to hypotheses about a bacterial source for the rancid off-flavors.
Article Abstract
Volatile extractive compounds from high-quality oak wood ( sp.) are responsible for important pleasant olfactory notes, such as coconut, wood, vanilla, caramel, and spice. Recently, a new off-flavor reminiscent of rancid butter has been detected in oak wood. Using gas chromatography-olfactometry (GC-O) coupled to several detection modes, such as nitrogen-phosphorus detection (GC-O-NPD) or mass spectrometry (GC-O-MS) and multidimensional GC-O coupled to time-of-flight mass spectrometry, six compounds containing nitrogen atoms were identified. The volatiles were suggested to belong to 2,5-disubstituted pyrazines family, which was confirmed by comparison with synthetic reference compounds. For this purpose, symmetric and dissymmetric 2,5-dialkylpyrazines were prepared from methyl esters of corresponding aliphatic amino acids (Val, Leu, and Ile) by a three-step, one-pot reaction under mild reducing conditions. Organoleptic descriptors and odor detection thresholds were also determined, whereas a bacterial origin explaining these off-flavors was hypothesized.
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| http://dx.doi.org/10.1021/acs.jafc.9b03185 | DOI Listing |
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