Seven indigenous yeast strains of Saccharomyces paradoxus previously isolated and identified using molecular and physiological methods were tested for their fermentation abilities. Chemical analyses of produced wines showed differences compared with the Saccharomyces cerevisiae strain used as a control. The examined S. paradoxus strains showed good fermentation vigour, ethanol tolerance and difference in the fermentation rate. Four of seven analysed S. paradoxus strains (RO66, RO54, RO11 and RO134) metabolised sugar up to 1 g L-1. The total amount of higher alcohol was lower compared with S. cerevisiae wines. Strain RO83 was able to degrade up to 40% malic acid and can be used for biological deacidification. Sensory evaluation of dry and semidry wines underlined good enological properties and positive influence of tested wine strains on final wine quality. All these properties of S. paradoxus strains pointed out the possibility of their application in wine industry. © 2006 Institute of Food Science and Technology Trust Fund

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Two commercial enzyme preparations were used in the production of wine from the Croatian autochthonous red grape variety Plavac Mali in order to improve the extraction of polyphenolic components from grapes, chromatic parameters, and sensory quality. During two vintages, the conventional maceration without enzymes was compared with the maceration using products with different characteristics: pectinase with additional cellulase and hemicellulase activity and pectinase with inactive yeast cells. Both products affected polyphenolic extraction and colour parameters: intensity and hue, and ratio between the yellow, red, and blue colour in young wines (2 months after fermentation) and at the moment of bottling (9 months after fermentation). The correlation between anthocyanins and colour intensity was very strong. The expected reduction of quantitative chromatic parameters during aging was confirmed. Significantly better results were observed in wines produced with pectinase, in relation to all analysed physical and chemical parameters. The sensory analysis showed that wines produced with pure pectolytic enzymes were significantly better than those produced without the enzymes. A product of the combination of pectolytic enzymes and inactive yeast cells had a partial influence on the improvement of the phenolic and sensory quality. The overall quality was significantly more expressed in wines produced with pectolytic enzymes, especially in young wines.