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Ability of lactic acid bacteria to produce N‐heterocycles causing mousy off‐flavour in wine
Author(s) -
COSTELLO PETER J.,
LEE TERRY H.,
HENSCHKE PAULA.
Publication year - 2001
Publication title -
australian journal of grape and wine research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.65
H-Index - 77
eISSN - 1755-0238
pISSN - 1322-7130
DOI - 10.1111/j.1755-0238.2001.tb00205.x
Subject(s) - oenococcus oeni , pediococcus , malolactic fermentation , food science , lactobacillus brevis , chemistry , lactic acid , lactobacillus , lactobacillus plantarum , wine , bacteria , flavour , biology , fermentation , genetics
Thirty‐four strains of the genera and species representative of the wine lactic acid bacteria (LAB) were screened in an ethanolic grape juice medium for the production of mousy off‐flavour as determined by an alkaline test strip sensory method. Most Lactobacillus spp., Oenococcus oeni and Leuconostoc mesenteroides produced mousy off‐flavour, whereas Pediococcus spp. were generally incapable of detectable off‐flavour formation. To verify these results, selected LAB were tested for the ability to produce the three sensorially potent N‐heterocycles, 2‐ethyltetrahydropyridine (ETPY), 2‐acetyltetrahydropyridine (ACTPY) and 2‐acetyl‐1‐pyrroline (ACPY), which are associated with the mousy off‐flavour in wine. N‐heterocycle formation was determined by incubating a high density of bacterial cells in a chemically defined N‐heterocycle assay medium, and quantifying the ‘mousy’ compounds by gas chromatography‐mass spectrometry. Most strains produced each of the three N‐heterocycles, with the general order for this capability being Lactobacillus (heterofermentative) > Oenococcus > Pediococcus . Strains of Lactobacillus hilgardii and Lactobacillus brevis were characterised as producing the highest concentration of ACTPY (328–580 μg/L, sensory threshold in water =1.6 μg/L), whereas ACPY and ETPY were produced at a moderate concentration (< 50 and < 10 μg/L, respectively). In addition to the formation of ACPY and ACTPY, three of five strains of the commercially important wine malolactic bacterium, O. oeni , produced the highest concentration of ETPY (87–162 μg/L). Strains of the homofermentative LAB, Pediococcus sp. and Lactobacillus plantarum L11a, however, produced only a relatively low concentration of each mousy N‐heterocycle (≤ 37 μg/L), suggesting that the ability of LAB to produce mousy N‐heterocycles is linked to the pathway of sugar catabolism. The importance of selecting LAB for induction of malolactic fermentation which have limited ability to produce mousy N‐heterocycles is emphasised.