Microbial inactivation and MLF performances of Tempranillo Rioja wines treated with PEF after alcoholic fermentation

This study was performed with the aim of reducing the microbial communities of wines after alcoholic fermentation to improve the establishment of commercial Oenococcus oeni inoculum for developing the malolactic fermentation. Microbial community reduction was accomplished by applying Pulsed Electric Field (PEF) technology to four different wines. Overall, significant reductions in yeast population were observed. To a lesser extent, lactic acid bacteria were reduced while acetic acid bacteria were completely eliminated after the PEF treatment. In three out of the four tested wines, a decrease in the competitive pressure between microorganisms due to the detected reduction led to a general but slight shortening of the malolactic fermentation duration. In the wine with the most adverse conditions to commercial starter establishment, the shortest malolactic fermentation was reached after PEF treatment. Finally, the sensorial quality of three out of the four treated wines was considered better after the PEF treatment. Therefore, PEF technology meant an important tool for improving the malolactic fermentation performance.
This work was supported by funding and pre-doctoral grant (B.O.E. 12th May 2012) of the Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria project RTA2011-00070-00-00 and the Navarra Government project IIQ14037.RI1.