Yeast dynamics in the black table olives processing using fermented brine as starter

Abstract

Spontaneous fermentation with autochthonous yeasts is the most traditional method used for the production of black table olives, which requires minimal intervention. The aim of this study was to evaluate the effects of adding a brine starter, developed from one-year spontaneously fermented black table olives, on the microbiological, chemical, and sensory characteristics of naturally fermented Taggiasca table olives. The olives were fermented in brine containing 12% (w/v) NaCl with 0.6% (w/v) citric acid and inoculated with a selected brine starter containing primarily Pichia manshurica (87% predominance) and Saccharomyces cerevisiae (10% predominance). Brine and olives samples were analysed at the start of the experiment and after 3, 6, 9, and 12 months of fermentation. The P. manshurica and S. cerevisiae present in the brine starter drove the entire fermentation process, along with other autochthonous species that were not included in the starter, including Zygosaccharomyces mrakii. Spoilage microorganisms and undesired off-odours and off-flavours were not present at the end of fermentation. When compared to the control, the use of the brine starter increased the total yeast population in the brine during the first 6 months of fermentation, thus shortening the debittering time of the fruits and improving the taste complexity of the final product.