Malfeito Ferreira, ManuelPais, Alda Sofia Aires Rebelo Monteiro2010-11-112010-11-112010http://hdl.handle.net/10400.5/2457Mestrado em Engenharia Alimentar - Qualidade e Segurança Alimentar - Instituto Superior de AgronomiaIn this study we evaluated the use of grapes with sour rot on the wine fermentation and the consequent final quality of wine. For that, microvinification of healthy grapes belonging to the variety of Trincadeira Preta and Cabernet Sauvignon were performed to which were added grapes affected by sour rot. The musts and wines, corresponding to 30 and 50% (w/w) of rotten grapes, showed an increase in the parameters color intensity, total anthocyanins and total phenols in function to the proportion of rotten grapes. This increase also reflected in a higher sugar concentration of grape must and therefore an increase in the alcohol content of wines produced. The higher volatile acidity in wines made from rotten grapes was due to its higher initial content in musts. It was possible to stabilize microbiologically wines with sour rot in order to avoid introducing potentially harmful microorganisms, although they possessed higher levels of residual sugars. The results of sensory evaluation by an untrained panel, before malolactic fermentation and after six months of probation, showed no statistically significant differences exist between different types of wines. In conclusion, it was possible to vinify grapes with high levels of sour rot without the quality of the wines being distinctly affected by the tasting panel.porgrapessour rotswine qualityalcoholic fermentationsensorial analysisyeast contaminationuvaspodridão ácidaqualidade do vinhofermentação vináriaanalise sensorialleveduras de contaminaçãomaster thesis