title: Degradation of free and sulfur-dioxide-bound acetaldehyde by malolactic lactic acid bacteria in white wine.
abstract: OBJECTIVE
  Acetaldehyde is the major carbonyl compound formed during winemaking and has implications for sensory and colour qualities of wines as well as for the use of the wine preservative SO(2). The current work investigated the degradation of acetaldehyde and SO(2)-bound acetaldehyde by two commercial Oenococcus oeni starters in white wine.
  
  
  RESULTS
  Wines were produced by alcoholic fermentation with commercial yeast and adjusted to pH 3.3 and 3.6. While acetaldehyde was degraded rapidly and concurrently with malic acid at both pH values, SO(2)-bound acetaldehyde caused sluggish bacterial growth. Strain differences were small.
  
  
  CONCLUSIONS
  Efficient degradation of acetaldehyde can be achieved by commercial starters of O. oeni. According to the results, the degradation of acetaldehyde could not be separated from malolactic conversion by oenococci. While this may be desirable in white winemaking, it may be necessary to delay malolactic fermentation (MLF) in order to allow for colour development in red wines. SO(2)-bound acetaldehyde itself maybe responsible for the sluggish or stuck MLF, and thus bound SO(2) should be considered next to free SO(2) in order to evaluate malolactic fermentability.
  
  
  CONCLUSIONS
  The current study provides new results regarding the metabolism of acetaldehyde and SO(2)-bound acetaldehyde during the MLF in white wine. The information is of significance to the wine industry and may contribute to reducing the concentration of wine preservative SO(2).
authors.affiliation: Department of Chemistry, The University of Auckland, Auckland, New Zealand.
authors.forename: J P
authors.initials: JP
authors.lastname: Osborne
authors.forename: A
authors.initials: A
authors.lastname: Dubé Morneau
authors.forename: R
authors.initials: R
authors.lastname: Mira de Orduña
mesh_terms: D000079:Acetaldehyde / Q000378:metabolism*; D001673:Biodegradation, Environmental; D003116:Color; D005285:Fermentation; D005516:Food Microbiology; D005524:Food Technology; D006863:Hydrogen-Ion Concentration; D007777:Lactobacillaceae / Q000378:metabolism*; D008293:Malates / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000378:metabolism; D013458:Sulfur Dioxide / Q000378:metabolism*; D014920:Wine
chemical_list: D008293:Malates; D013458:Sulfur Dioxide; C030298:malic acid; D000079:Acetaldehyde