Isolation and fast pre-selection of yeasts from spontaneous fermentation of Calabrian table olives.

Calabria is a table olive-producing area in the South Italy and natural table olive processing is an old tradition. The aim of this research was to study the yeast microbiota in order to pre-select strains able to improve Calabrian table olives. In details, the main traits of interest are: (1) the quality improvement by interaction with natural phenolic compounds possessing positive sensorial characteristics; (2) the shelf-life extension by production/preservation of natural antioxidant compounds. Eighteen samples of Calabrian table olives produced by spontaneous fermentation were used. The olive cultivars were: Carolea, Geracese, Nocellara, Nocellara Messinese, and Ottobratica. Using Yeast Extract-Peptone-Dextrose (YPD) Agar a total of 54 yeast strains were isolated from the 18 table olive samples and their brines. The new strains were collected in Microbank at -80°C and their main phenotypic characteristics were detected. To perform a fast pre-selection from a great number of yeast strains, a simple phenotypic-based methodology was employed to allow many different strains to be simultaneously tested. This way, only the best strains remaining at the end of this pre-selection will be finally selected using Oxitester CDR with a great saving of money.