A study of the effect of different conditions on the growth of yeasts isolated from green table olives

Yeasts are present throughout the spontaneous fermentation of table olives, and can have a great influence on the final product. For this reason, yeasts could be used as starter cultures in order to improve the quality of table olives. The aim of the present work was to study the effect of the growth conditions on the behaviour of yeast isolated from table olives. In this study, 17 yeast strains obtained from table olives, and belonging to various species of the Candida, Debaryomyces, Kluyveromyces, Pichia and Saccharomyces genera, were characterized by their behaviour in different culture conditions (NaCl and pH). Moreover, the flocculation capacity was studied, and interactions between yeasts and lactic acid bacteria were analyzed. Significant differences were found when yeasts were grown in culture media with salt concentrations between 7% and 12%, and pH between 3.5 and 7. Most of the yeasts analyzed could be useful as starter cultures to enhance the control of table olive fermentation, and hence obtain a high quality final product.