Selection and technological potential of Lactobacillus plantarum bacteria suitable for wine malolactic fermentation and grape aroma release

Lactobacillus plantarum strains have resistance mechanisms that enable them to survive and proliferate in wine, which makes them potential malolactic fermentation (MLF) starter cultures. This work focused on the technological characterization of 11 L. plantarum strains isolated from Southern Italian wines that undergo spontaneous MLF, and proposes a selection of new L. plantarum malolactic starters. These strains were characterized according to their oenological characteristics, their ability to produce biogenic amines and bacteriocins, their response to the presence of phenolic compounds, their enzymatic activities and their ability to produce wine odorant aglycones from odourless grape glycosidic aroma precursors. Finally, the malolactic activity of one selected strain was assessed in Cabernet Sauvignon wine, using two inoculation methods. L. plantarum strains tested were not producers of biogenic amines. In particular, the M10 strain showed a good resistance to high levels of ethanol and low pH, it has a good malolactic performance and β-glucosidase activity, this last one demonstrated both directly through the measurement of this enzymatic activity and indirectly by following the release of volatile aglycones from commercial and natural grape glycosidic odourless precursors. These results demonstrated the potential applicability of M10 as a new MLF starter culture, especially for high-ethanol wines.