MLF performance by L. plantarum and its sensorial impact in malbec wines of argentina

LERENA M.C.; SARI S.; PEREZ M.D.; ROJO M.C.; MERCADO L.; KRIEGER, S.; COMBINA M.

Mendoza

Congreso; 37° Congreso Mundial de la Vid y el Vino; 2014

Organizacion Internacional de la Vid y el Vino (OIV)

The current market requirements to obtain wines with greater complexity and with its own character propose the finding of new microorganisms capable of providing new and distinctive characteristics in wine. During malolactic fermentation (MLF) malic acid naturally present in grape must is converted to lactic acid by a decarboxylation reaction carried out by lactic acid bacteria, mainly Oenococcus oeni. Recently, a new strain of Lactobacillus plantarum (V22) suitable for MLF in high pH wines has been selected. Furthermore, it has been shown that this microorganism has a larger number of genes encoding enzymes associated with flavor and aroma production, compared with O.oeni. Previous studies performed in our laboratory have shown that the feasibility of L. plantarum V22 to complete MLF in Malbec is associated with pH evolution during the fermentation process. The objective of this work was to evaluate MLF performed by L. plantarum V22 in Malbec musts at semi-industrial scale and the analysis of the sensory profile of the obtained wines. For that aim co-inoculation of two Malbec musts with S. cerevisiae D254 (Lallemand) and L. plantarum V22 (Lallemand) was performed, to conduct alcoholic fermentation (AF) and malolactic fementation respectively. We also used sequential inoculation with O. oeni VP41 (Lallemand) as control. AF, MLF and bacterial viability was monitored during the entire fermentation process. The obtained wines were stabilized, bottled and analyzed at sensory level by a trained panel of experts through Flash Profile FP in the Aroma and Flavor Center of Pontificia Catholic University of Chile. No alterations in AF kinetics attributable to the co-inoculation with V22 for any of the treatments were observed. The ability of L. plantarum to completely consume malic acid present in the must was higher in musts where the pH was above 3.5 during the entire fermentation. A gradual decrease in the population of V22 along fermentation was observed. However populations remained viable over 104 CFU/ml. At a sensory level the wines showed significant differences in 11 descriptors (ANOVA p ≤ 0.05). The wines fermented with L. plantarum showed higher intensity for herbaceus descriptors, tobacco, eucalyptus, floral, caramel and roasted. Furthermore wines fermented with O. oeni showed greater intensity descriptor for black berries.