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Yeasts involved in velum formation during biological ageing of sherry wine have to date been classified into four races of Saccharomyces cerevisiae (beticus, cheresiensis, montuliensis, rouxii) according to their abilities to ferment different sugars. It has been proposed that race succession during biological ageing is essential for the development of the organoleptical properties of sherry wines. In this work we studied the physiological characteristics, the molecular differentiation and the phylogenetic relationships of the four races employing type and reference strains from culture collections and natural environments. Using restriction analysis of the ribosomal region that includes the 5.8S rRNA gene and internal transcribed regions (5.8S-ITS) we were able to differentiate ‘flor’ and non-‘flor’S. cerevisiae yeast strains. However, no correlation between fermentation profile, mitochondrial DNA restriction analysis or chromosomal profiles and these races was found. Moreover, sequences of the D1/D2 domain of the 26S rRNA gene and the 5.8S-ITS region from these strains were analysed and no genetic differences were noted suggesting that ‘flor’ yeast cannot be grouped into four different races and the four races are identified as S. cerevisiae. Since the yeasts isolated from velum in sherry wine present a unique 5.8S rRNA pattern different from the rest of the Saccharomyces cerevisiae strains we propose that they should be included as a single race or variety inside the S. cerevisiae taxon. [ABSTRACT FROM AUTHOR]

The consumption of chili pepper fruits (CPF) is widespread throughout the world. However, countries without tropical climates can only consume few CPF varieties. The lactic fermentation (LF) of CPF is a good alternative for their preservation and consumption in those regions where they are not cultivated. The main objective of this research was to optimize the fermentation process conditions for a CPF variety (Capsicum frutescens) modifying the Sodium Chloride (NaCl) and glucose concentrations to increase the acidification rate. The Response Surface Methodology was used applying a Central Composite Design to integrate a desirability approach. The growth of the microorganisms responsible for the fermentation process was also evaluated. The addition of NaCl and glucose significantly affected the acidification rate for LF of CPF. The optimum fermentation parameters determined to maximize the acidification rate were 6.25% NaCl and 1.77% glucose concentrations with an acidification rate of 0.113% acidity/day. However, this value was slightly lower than predicted. Lactic acid bacteria and yeasts were the main microorganisms throughout the fermentations.