Effect of the natural winemaking process applied at industrial level on the microbiological and chemical characteristics of wine.

The composition of yeast and lactic acid bacteria (LAB) communities and the chemical evolution of the large-scalecommercial vinification of Catarratto IGT Sicilia, carried out under the biological regime, was followed from grapeharvest until bottling. Simultaneously to the maximumgrowth of yeasts, LAB counts reached high level of concentration(6e7 log CFU mLL1) during the first steps of the alcoholic fermentation. Yeast identification was determined applyingdifferent molecular methods. The highest species biodiversity was observed on grape and must samples taken soon afterpressing. Saccharomyces cerevisiae was detected at dominant concentrations during the entire winemaking process. LABcultures were grouped and identified by a combined phenotypic and genotypic approach. Leuconostoc mesenteroides,Lactobacillus hilgardii and Lactobacillus plantarum species were identified; the last was the main LAB recognized duringvinification. The winemaking process was also chemically monitored. The alcoholic content was approximately 12.67%(v vL1) at bottling; pH, volatile acidity and total acidity showed a moderate increase during vinification. Tartaric, citricand malic acids decreased until bottling, while lactic acid showed a rapid increase at the end of maceration and bottling.Trans-caffeil tartaric acid was the most abundant phenolic compound and volatile organic compounds (VOC) weremainly represented by isoamylic alcohol, isobutanol, ethyl acetate and octanoic acid.