Effect of brine composition on yeast biota associated with naturally fermented Nocellara messinese table olives

Abstract

Abstract The study aims to assess the yeast biota associated with table olives of the cultivar Nocellara messinese naturally fermented using different brines. Microbial counts, physico-chemical parameters, and yeast consortia was evaluated at days 0, 3, 7, 15, 30, 60, 90, 180, and 240. Yeasts were identified by PCR-RFLP of the 5.8S ITS rRNA region and sequencing of D1/D2 domain of the 26S rRNA gene. At the fermentation end, the yeast population was assessed by PCR-DGGE analysis. Throughout the eight months of fermentation, the brine modification determined different evolution of the yeast species. The salt concentration shift from 5% to 8% delayed the growth of some species at the end of the fermentation. The experimental brine acidification determined a growth of Pichia mexicana and Saccharomyces cerevisiae that were not found in the other brine formulations. Pichia kudriavzevii was the most isolated species followed by Wickeramomyces anomalus, Zygoascus hellenicus, Candida boidinii, Saccharomyces cerevisiae, Candida aaseri, Candida tropicalis, Candida diddensiae, Zygoascus meyerae, and Pichia mexicana. P. kudriavzevii and W. anomalus species were present in all the processed olives. Some of the strains exhibited suitable technological properties so they could be good candidates as starter in table olive fermentations.