Simultaneous inoculation of yeasts and lactic acid bacteria: effects on fermentation dynamics and chemical composition of Negroamaro wine

Traditional vinification process is undertaken with the inoculation of the lactic acid bacteria (LAB) at the end of alcoholic fermentation (AF) to induce malolactic fermentation (MLF). MLF is an important phase during winemaking and the LAB co-inoculation with yeast starter represents a promising approach to enhance the quality and safety of wine. In this investigation we have studied: i) the effect of timing of LAB inoculation on the vinification dynamics and chemical features of Negroamaro wines; ii) the interactions between two commercial yeast and two commercial Oenococcus oeni strains. The fermentations dynamics were monitored by microbial counts, quantifying L-malic acid concentration and analyzing the volatile compounds contents in the obtained wines. Our results indicate that simultaneous yeasts/bacteria inoculation at the beginning of vinification reduces the processes duration and simultaneously lowers of volatile acidity. Wine obtained after co-inoculum showed a profile dominated by red and ripe fruits notes associated to esters and to buttery and creamy notes linked to diethyl succinate and ethyl lactate. Furthermore, compatibility specification between commercial yeasts and LAB strains were observed, suggesting the importance of the assessment of microbial-compatibility before their utilization in large-scale vinification.