Selection of Yeasts as Starter Cultures for Table Olives

Abstract

Ninety-nine yeasts were isolated from Bella di Cerignola table olives; first, the strains were studied in relation to their ability to produce biogenic amines in a laboratory medium and 49 strains were positive to this assay and cut off from the research. The remaining 50 strains were characterized for their enzymatic traits (β-glucosidase, catalase, pectolytic, xylanolytic, and lipolytic activities) and for their ability to grow at different temperatures, pHs, with salt or lactic/acetic acids added. Data were used for the evaluation of growth index and submitted to cluster and principal component analyses to choose the most promising 4 strains. In the final step of the research, the strains were inoculated as a cocktail in a model brine, containing different amounts of salt (4% to 12%) and glucose (0% to 3%), and adjusted to different pHs (4.0 to 9.0). Data analysis through a multiple regression procedure highlighted that salt, glucose, and pH acted in a different way within the storage and NaCl affected yeast growth only for few days, and then glucose and pH played a major role.

Selection of yeasts with multifunctional features for application as starters in natural black table olive processing

“…Especially two strains, W. anomalus Y18 and P. guilliermondii Y16, showed desirable features and were clearly differentiated from the rest of isolates. In the last years, many researchers have also used this methodology for the selection of the most promising yeast starters related with table olive processing (Bevilacqua et al, 2009(Bevilacqua et al, , 2013Rodríguez-G omez et al, 2012).…”

“…For many years, the search for starters with application in olive fermentation has been practically focused on the activity of lactic acid bacteria. However, in the last years, diverse publications have emphasised the importance of selection of yeasts as starter cultures during table olive processing (Silva et al, 2011;Arroyo-L opez et al, 2012;Rodríguez-G omez et al, 2012;Bevilacqua et al, 2012Bevilacqua et al, , 2013Tofalo et al, 2013). Although these microorganisms can cause spoilage of the product due to the production of CO 2 , bad odours and flavours, clouding of brines or softening of fruits, which is especially harmful in olive packaging or storage, they also show some desirable activities with important potential technological and probiotic applications.…”

Yeast Ecology of Fermented Table Olives: A Tool for Biotechnological Applications

“…The first one is the selection of promising species, which should have some interesting properties. The second step is the validation of those microorganisms on laboratory scale and finally the third one, and the most important, is the demonstration at large scale [32].…”

“…Thus, the screening of those yeast strains is very important. Esterase and lipase enzymatic activities are desirable in yeasts because of their ability to improve the organoleptic characteristics of olives through the configuration of volatile compounds that can be produced by the catabolism of free fatty acids [9,[32][33][34].…”

“…For extensive information on selection of yeasts as starter cultures for table olives, Refs. [32,82] are thorough reviews with step by step procedures to follow.…”