Mousy Off-Flavor of Wine: Precursors and Biosynthesis of the Causative N-Heterocycles 2-Ethyltetrahydropyridine, 2-Acetyltetrahydropyridine, and 2-Acetyl-1-pyrroline by Lactobacillus hilgardii
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- 作者：Peter J. Costello and Paul A. Henschke
- 刊名：Journal of Agricultural and Food Chemistry
- 出版年：2002
- 出版时间：November 20, 2002
- 年：2002
- 卷：50
- 期：24
- 页码：7079 - 7087
- 全文大小：158K
- 年卷期：v.50,no.24(November 20, 2002)
- ISSN：1520-5118
文摘
The N-heterocyclic bases, 2-ethyltetrahydropyridine (1), 2-acetyl-1-pyrroline (2), and 2-acetyltetrahydropyridine (3) are associated with the occurrence of mousy off-flavor in wine. The biosynthesis ofthese N-heterocycles by the wine lactic acid bacterium, Lactobacillus hilgardii DSM 20176, was studiedby high-cell-density incubation in combination with a minimal chemically defined N-heterocycle assaymedium. The key components of the defined N-heterocycle assay medium included D-fructose, ethanol,L-lysine, L-ornithine, and mineral salts. N-heterocycle formation was quantitatively determined by gaschromatography-mass spectrometry. The formation of 2 and 3 required the concomitant availabilityof a fermentable carbohydrate (D-fructose), ethanol, and iron (Fe2+). In addition, L-ornithine stimulatedthe formation of 2 and repressed 3 formation, whereas L-lysine stimulated the formation of 3 andrepressed 2 formation. Incorporation of d6-ethanol into the acetyl side chain of 2 and 3, and of d4-acetaldehyde into the acetyl side chain of 3, confirmed that ethanol and acetaldehyde could serveas major side chain precursors. A pathway for the formation of 2 and 3 by heterofermentative lacticacid bacteria is proposed involving the interaction of accumulated C-2 intermediates from theheterolactic pathway and N-heterocyclic intermediates derived from the metabolism of L-ornithineand L-lysine.Keywords: Mousy off-flavor; 2-acetyltetrahydropyridine; 2-acetyl-1-pyrroline; 2-ethyltetrahydropyridine;N-heterocycles; Lactobacillus; wine; lactic acid bacteria; L-ornithine; L-lysine