| Title: | Comparative metabolic profiling to investigate the contribution of O. oeni MLF starter cultures to red wine composition |
| Author(s): | Malherbe S; Tredoux AG; Nieuwoudt HH; du Toit M; |
| Address: | "Institute for Wine Biotechnology, Stellenbosch University, Matieland, Stellenbosch, South Africa" |
| Journal Title: | J Ind Microbiol Biotechnol |
| DOI: | 10.1007/s10295-011-1050-4 |
| ISSN/ISBN: | 1476-5535 (Electronic) 1367-5435 (Linking) |
| Abstract: | "In this research work we investigated changes in volatile aroma composition associated with four commercial Oenococcus oeni malolactic fermentation (MLF) starter cultures in South African Shiraz and Pinotage red wines. A control wine in which MLF was suppressed was included. The MLF progress was monitored by use of infrared spectroscopy. Gas chromatographic analysis and capillary electrophoresis were used to evaluate the volatile aroma composition and organic acid profiles, respectively. Significant strain-specific variations were observed in the degradation of citric acid and production of lactic acid during MLF. Subsequently, compounds directly and indirectly resulting from citric acid metabolism, namely diacetyl, acetic acid, acetoin, and ethyl lactate, were also affected depending on the bacterial strain used for MLF. Bacterial metabolic activity increased concentrations of the higher alcohols, fatty acids, and total esters, with a larger increase in ethyl esters than in acetate esters. Ethyl lactate, diethyl succinate, ethyl octanoate, ethyl 2-methylpropanoate, and ethyl propionate concentrations were increased by MLF. In contrast, levels of hexyl acetate, isoamyl acetate, 2-phenylethyl acetate, and ethyl acetate were reduced or remained unchanged, depending on the strain and cultivar evaluated. Formation of ethyl butyrate, ethyl propionate, ethyl 2-methylbutryate, and ethyl isovalerate was related to specific bacterial strains used, indicating possible differences in esterase activity. A strain-specific tendency to reduce total aldehyde concentrations was found at the completion of MLF, although further investigation is needed in this regard. This study provided insight into metabolism in O. oeni starter cultures during MLF in red wine" |
| Keywords: | "Acetates/metabolism Animals Chromatography, Gas Esters/analysis/metabolism Fermentation Lactates/metabolism Lactic Acid/metabolism Metabolome/*physiology Oenococcus/*growth & development/physiology Phenylethyl Alcohol/analogs & derivatives/metabolism Prop;" |
| Notes: | "MedlineMalherbe, Sulette Tredoux, Andreas G J Nieuwoudt, Helene H du Toit, Maret eng Comparative Study Research Support, Non-U.S. Gov't Germany 2011/11/29 J Ind Microbiol Biotechnol. 2012 Mar; 39(3):477-94. doi: 10.1007/s10295-011-1050-4. Epub 2011 Nov 26" |
