Study of the inoculation time of Lactobacillus plantarum in combination with Saccharomyces cerevisiae and Hanseniaspora uvarum

In the last years, the interactions among different microbial populations have been studied by the scientific community in the aim of understanding their impact on the quality of wines. The main interactions during the vinification process occur among the yeast Saccharomyces cerevisiae, non-Saccharomyces yeasts species and lactic acid bacteria (LAB). A special interest has been dedicated to investigate the role non-Saccharomyces yeasts as they are responsible for much of the aromatic complexity and its presence improves the final organoleptic characteristics of the wine. Concerning LABS, selected strains belonging to Lactobacillus plantarum species have been recently investigated to produce starter cultures for malolactic fermentation in wine. The aim of the present study is to design mixed starter culture to simultaneously carry out Alcoholic fermentation (AF) and malolactic fermentation (MLF), thus obtaining wine denoted by complex organoleptic properties in a shorter period of time. We report the evaluation of the best inoculation time of L. plantarum strains in combination with autochthonous S. cerevisiae strains and non-Saccharomyces (Hanseniaspora sp.). Microvinifications were performed using must derived from Apulian autochthonous grape varieties. Both, yeasts S. cerevisiae and non-Saccharomyces strains were simultaneously or sequentially co-inoculated during the AF with the L. plantarum strains. The sequential co-inoculation was carried out at different point, when the concentration of the produced ethanol was 2%, 4%, 6%, 8%, 10% or 12% (v/v). Ethanol formation, malic acid consumption and cell viability were monitored during the vinifications. The obtained results demonstrated that L. plantarum cell viability after AF was strain-dependent. L. plantarum strains showed the highest viability when they were co-inoculated with S. cerevisiae and H. uvarum strains. This research was supported by the Apulian Region Project "Sviluppo di approcci microbiologici innovativi per il miglioramento della qualità di vini tipici regionali (NEWine)".