Resumen de Effects of sterilising filtration on microbiological stability, chemical composition and sensory properties of red wine

Sara Canas, Baoshan Sun, Luis Coimbra, Joao Barroca

• It was studied the effects of the sterilising fi ltration on the microbiological stability, chemical composition and sensory properties of a red wine that has not undergone malolactic fermentation and that needed to be bottled. The fi ltration was performed in a pilot-scale system composed by a set of membranes in series: a prefi ltration membrane of 5 m (fi berglass), followed by the sterilising membranes of 1 m (fi berglass), 0.6 m (fi berglass) and 0.45 m (polyethersulfone). The results obtained showed that the levels of microorganisms decreased considerably after the sterilising fi ltration, without detection of microorganisms at the wines fi ltered with the membranes of 0.6 m and 0.45 m. The total phenolic content and the chromatic characteristics of the fi ltered wines were affected by the procedure under study, varying over the time of storage. After two months of storage, the fi ltered wine cannot be distinguished from the non-fi ltered wine by their phenolic content, being the wine fi ltered with the 0.6 m membrane more similar to the control group. Except for lightness, there was a remarkable positive evolution of the chromatic characteristics of the wine, especially in the wine fi ltered with 0.45 m. This suggests that two months after fi ltration the wines have actually reached its balance, along with the required microbiological stability. From the sensory point of view, there were no signifi cant effects on the colour intensity, aroma quality, fl avour quality and overall quality of the fi ltered wines after one month of storage. After two months of storage, there was a signifi cant increment on colour intensity, which is in agreement with the effects observed in the chromatic characteristics. Although there were no signifi cant differences among wines in the other sensory properties, there was a preference, corresponding to high quality, for the wine fi ltered with 1 m membrane, followed by the wine fi ltered with 0.6 m membrane.