PERSONAL DE APOYO
MATURANO Ramona Del Carmen
congresos y reuniones científicas
Título:
POSITIVE CONTRIBUTION TO WINES AROMA BY THE CONTROLLED ADDITION OF Oenococcus oeni
Autor/es:
MATURANO CARMEN; RODRIGUEZ VAQUERO MARIA JOSÉ; RIVERO LUCIANA; GOLDNER M. C.; SAGUIR FABIANA M.
Lugar:
Mar del Plata, Argentina
Reunión:
Congreso; X CONGRESO ARGENTINO DE MICROBIOLOGÍA; 2014
Institución organizadora:
Sociedad de Microbiología General
Resumen:
Lactic acid bacteria (LAB), preferably Oenococcus oeni, play an important role in winemaking by undertaking the malolactic fermentation (MLF). As a consequence of this reaction, the total acidity decreases and the organoleptic properties and biological stability of wines are generally improved. Difficulties in triggering MLF and/or the presence of inadequate strains because they either exhibit low fermentative efficient or produce undesirable compounds could be avoided by the inoculation with selected LAB. In a previous research, we selected O. oeni MS46 by its high malolactic potential, ability to produce B-glucosidase enzyme and low diacetyl concentration in  laboratory media. The aim of this study was to investigate the malolactic potential of O. oeni MS46 and its influence on the aromatic profile of wine in microvinification assay. Bottles with 2000 ml of wine sterilized by filtration obtained by alcoholic fermentation of musts from red grapes belonging to the same region as the strain to be tested with a pH 3.7, were inoculated with O. oeni MS46 at an average initial cell density of 6.15 ± 0.18 log cfu/ml and incubated at 26±2ºC during 8 days (end of MLF). Wine samples were taken at the beginning and the end of MLF, sterilized as before and analyzed for sugars and organic acids contents by enzymatic tests, volatile compounds by gaseous chromatography coupled to mass spectroscopy (GC/MS) and sensorial profile. In inoculated wine, O. oeni MS46 grew by 1.58 log units and efficiently conduced MLF. At this time, the inoculated strain completely consumed L-malic (2 g/l) and citric acids (1.13 g/l) and only 9% of initial residual sugars, even though its concentration was 31 g/l, producing adequate concentrations of D-lactic and acetic acids. Total acidity slightly decreased from 5.63±0.42 to 5.25±0.32 g/l, while the volatile acidity remained almost unchanged. In addition, O. oeni MS46 produced significant qualitative and quantitative changes in the composition of volatiles aroma compounds, increasing total concentrations of esters, alcohols and terpenes among 20 and 60% as compared to wine without MLF. For instance, 2- phenylethylacetate and 2-phenyletanol concentrations increased by 38 and 36%, which could contribute to the fruity aromas of wine being 2-phenyletanol one of the most relevant aromarelated alcohols. On the other hand new compounds such as octanol or trans-nerolidol were synthesized. Sensorial analysis of wine samples obtained by microvinification by entreated panel correlated with the modifications in the volatile composition, especially by changes in higher alcohols and fatty acids ethyl esters and acetate. The results obtained in microvinification assay with O. oeni MS46, confirmed the importance of inducing the MLF in red wines with selected strains of LAB that can offer a positive contribution to the final aroma in wines