Establishment of the Metabolic Profiles of Lactic Acid Bacteria


Project Number
IWBT-B 08-10

Project title
Establishment of the metabolic profiles of lactic acid bacteria

Project leader
Nieuwoudt, H H

Institution
University of Stellenbosch. Faculty of AgriSciences. Institute for Wine Biotechnology

Team members
Nieuwoudt, H H
Du Toit, M
Tredoux, A
Roux, K
Malherbe, S

Project description
Malolactic fermentation is essential for the aging of red wines and some white wines. During this process an important reaction is the conversion of malic acid to lactic acid, catalyzed by lactic acid bacteria. This usually results in the acid stabilisation of wine, but the impact of the deacidification on sensory properties such as the flavour and texture of wine has been well researched (Liu, 2000; Matthews et al., 2004). Several reports in the literature also suggest a contribution of lactic acid bacteria to wine aroma composition, however information on the latter aspect is fragmented and studies are mostly limited to a few selected chemical compounds such as diacetyl and dicarbonyl compounds (Bartowsky et al., 2004). The nature and concentrations of aroma compounds formed as a result of lactic acid bacterial metabolism remain largely unknown.

Lactic acid bacteria have diverse genetic make-up and possess enzymes that can potentially covert pre-cursor compounds into aroma compounds including volatile phenols, esters, higher alcohols and acetic acid (Liu, 2002; Matthews et al., 2004). It is anticipated that the metabolism of lactic acid bacteria (and hence possible contribution) of lactic acid bacteria to wine aroma will be influenced by several factors including grape cultivar, concentrations of flavour precursors in grape juice, fermentation process technologies, maturation strategies and wine style. Although numerous studies have focused on the formation of grape- and yeast derived volatiles and the factors influencing their formation, the factors influencing lactic acid bacteria derived aroma compounds have not been studied in-depth. Based on the important impact that malolactic fermentation has on the sensory properties of wine, it is of high importance to investigate the contribution of industrial lactic acid bacteria starter cultures on the volatile composition of wine.

This project has two aims, namely the development of a portfolio of analytical methods suitable for the identification and quantification of mostly, but not exclusively, aroma compounds in wine and to apply these methods to evaluate the contribution of selected lactic acid bacteria starter cultures to wine aroma and flavour. The analytical method development will have a particular focus on rapid high-throughput analytical strategies suitable for detailed metabolic profiling. Experimental wines will be produced using various combinations of yeast and lactic acid bacteria starter cultures under different winemaking conditions. The optimised analytical methods will then be used to do wide-scale chemical analyses of the wines. Wines will also be subjected to sensory evaluation. Statistical correlations will be sought between chemical and sensory data with the ultimate aim to evaluate the contribution of malolactic fermentation to wine aroma and flavour. The information gained will be used to formulate a better understanding of the integrated yeast and or lactic acid bacteria contribution to the establishment of wine aroma.

Presentation(s)
Malherbe, S, Roux, K, Nieuwoudt, H H, Du Toit, M and Tredoux, A G J. 2008. Increasing sample throughput by analysing major volatile compounds in wine with fast GC-FID. Paper presented at the 31st National Congress of the South African Society for Enology and Viticulture. 11-14 November, Somerset West, South Africa.

Malherbe, S, Tredoux, A G J, Du Toit, M and Nieuwoudt, H H. 2008. Evaluating the impact of different MLF starter cultures on wine aroma and flavour: A holistic / multivariate approach. Paper presented at the 31st National Congress of the South African Society for Enology and Viticulture. 11-14 November, Somerset West, South Africa.

Malherbe, S, Nieuwoudt, H H, Du Toit, M and Tredoux, A G J. 2008. Determination of malolactic fermentation related carbonyl compounds with the use of headspace SPME GC-MS. Paper presented at the 31st National Congress of the South African Society for Enology and Viticulture. 11-14 November, Somerset West, South Africa.

Malherbe, S, Tredoux, A G J, Du Toit, M and Nieuwoudt, H H. 2008. Evaluating the impact of different malolactic fermentation starter cultures on wine aroma and flavour: A holistic / multivariate approach. Paper presented at the South African Chemometric Society Seminar. 1-5 December, Stellenbosch, South Africa.

Malherbe, S, Nieuwoudt, H H, Du Toit, M and Tredoux, A G J. 2009. Analysis of carbonyl compounds during malolactic fermentation in red wine: Application of SPME GC-MS. Paper present at In Vino Analytica Scientia. 2-4 July, Angers, France.

Malherbe, S, Nieuwoudt, H H, Du Toit, and Tredoux, A G J. 2009. A simple method for high throughput analysis of volatiles in wine. Paper presented at In Vino Analytica Scientia. 2-4 July, Angers, France.

Malherbe, S, Nieuwoudt, H H, Du Toit, M and Tredoux, A G J. 2009. A simple method for high throughput analysis of volatiles in wine. Paper presented at In Vino Analytica Scientia. 2-4 July, Angers, France.

Malherbe, S, Tredoux, A G J, Du Toit, M and Nieuwoudt, H H. 2010. Malolactic fermentation definitely makes a difference: the aroma facts. Paper presented at the 4th International Congress of the South African Society for Enology and Viticulture. 28-30 July, Cape Town, South Africa.

Malherbe, S, Nieuwoudt, H H, Du Toit, M and Tredoux, A G J. 2010. Making it faster: evaluation of a fast GC-FID method for wine volatile analysis. Paper presented at the 4th International Congress of the South African Society for Enology and Viticulture. 28-30 July, Cape Town, South Africa.

Malherbe, S, Nieuwoudt, H H, Du Toit, M and Tredoux, A G J. 2010. Analysis of carbonyl compounds during malolactic fermentation in red wine: Application of SPME GC-MS. Paper presented at the 4th International Congress of the South African Society for Enology and Viticulture. 28-30 July, Cape Town, South Africa.

Malherbe, S, Tredoux, A G J, Du Toit, M and Nieuwoudt, H H. 2010. Evaluation of the potential contribution of lactic acid bacteria to wine aroma and flavour. Malolactic Fermentation Workshop: Beyond De-acidification – Aroma possibilities and variations. Paper presented at the 4th International Congress of the South African Society for Enology and Viticulture. 28-30 July, Cape Town, South Africa.

Du Toit, M, Knoll, C, Malherbe, S, Lerm, E, Engelbrecht, L, Carstens, J, Mtshali, S and Rauhut, D. 2010. Impact of lactic acid bacteria on wine aroma. Paper presented at the Intervitis Interfructa Congress. Stuttgart, Germany.

Malherbe, S, Nieuwoudt, H H, Du Toit, M and Tredoux, A G J. 2010. Metabolic profiling of volatiles produced during malolactic fermentation: application of SPME GC-MS. Paper presented at the Cape Technology Forum. Somerset West, South Africa.

Malherbe, S, Nieuwoudt, H H, Du Toit, M and Tredoux, A G J. 2010. A simple method of high throughput analysis of volatiles in wine. Paper presented at the Cape Biotechnology Forum, Somerset West, South Africa.

Malherbe, S, Naes, T, Tredoux, A G J, Du Toit, M and Nieuwoudt, H H. 2010. Impact of malolactic fermentation starter cultures on red wine aroma compounds, sensory properties and consumer preference. Paper presented at the 32nd National Congress of the South African Society for Enology and Viticulture. 18-19 November, Somerset West, South Africa.

Du Toit, M. 2011. How does malolactic fermentation impact on aroma? Presentation to the Lallemande and IWBT Malolactic Fermentation Workshop. University of Stellenbosch, Stellenbosch, South Africa.

Article
Vestner, J, Malherbe, S, Du Toit, M, Nieuwoudt, H H, Mostafa, A, Gorecki, T, Tredoux, A G J, De Villiers, A J. 2011. Investigation of the volatile composition of Pinotage wines fermented with different malolactic starter cultures using comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry (GCxGC-TOF-MS) Journal of Agricultural and Food Chemistry, v. 59 (p. 12732-12744)

Malherbe, S, Tredoux, A G J, Nieuwoudt, H H, Du Toit, M. 2012. Comparative metabolic profiling to investigate the contribution of Oenococcus oeni malolactic fermentation starter cultures to red wine composition, Journal of Industrial Microbiology, v. 39 (p. 477-494)

FinalReport.pdf

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