Exploitation of simultaneous alcoholic and malolactic fermentation of incrocio Manzoni, a traditional Italian white wine

Malolactic fermentation (MLF) is a key feature in the production of high-quality wines. Its evolution isnot always guaranteed, especially in white wine, due to certain limiting factors (low pH, sulphur dioxide,low temperature) acting against malolactic bacteria. The inoculation of grape must with bacteria is analternative approach to the management of oenological fermentation, favouring the survival of bacteriadue to the absence of ethanol or sulphur dioxide – toxic compounds made by yeasts in the first stages ofwinemaking. We compared the activity of two strains of Oenococcus oeni during MLF in wines madefrom an emerging white grape variety, native to north-eastern Italy, namely Incrocio Manzoni. Differentwinemaking protocols were assayed, comparing sequential or simultaneous inoculation of microbialstarters. The monitoring of bacterial viability through fermentations and a comprehensive characterisationof the volatile profile of the wines were achieved by advanced analytical approaches, flow cytometry andGC-MS respectively. According to the preliminary hypothesis, the chemical composition of the grapemust was characterised by high acidity, which represented a serious barrier to bacterial development.Simultaneous inoculation of the two O. oeni strains ensured a regular evolution of MLF. Some differenceswere highlighted, both in terms of fermentation kinetics and the aromatic profile of the wines obtained,in relation to the strain of lactic bacteria. The work provides an exhaustive overview of the opportunitiesand risks related to different wine fermentation approaches in order to enhance the quality of white winesmade from “new” or “local” wine grapes