Nyons Table Olives
Microbio-R1-Nyons Table Olives
UMR STLO Unit
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Microbio-R1-Nyons Table Olives

Nyons Table Olives: a microbial diversity to be treasured !

Artisanal fermented foods constitute a significant part of the Mediterranean diet and represent a cultural heritage that needs to be preserved and protected. Nyons table black olives are produced in south-eastern France, and benefit from a PDO Label. They are produced according to a traditional process by a slow spontaneous fermentation in brine, i.e., without any starter adjunction. The manufacture and unique sensorial properties of these olives thus only relies on autochthonous complex microbiota, which we have deciphered.

We studied the fermentation of black olives during a yearlong spontaneous fermentations, from harvest of olives to fermented olives. The study was done in partnership with a local and artisanal producer. We studied the microbial ecology and dynamics of Nyons table olives, using complementary and innovative microbiological methods. The fresh olives fruits, the salt implemented for the brine as well as the environment were analysed to decipher the origin of the microbes and their role during fermentation.We found that:

  • - Unlike other fermented table olives, Nyons table olive fermentations mainly rely on yeasts but not on lactic acid bacteria. Lactic acid bacteria are only detected in fresh olive fruits in some fermentations.
  • At the start of fermentation, the microbial population is mainly constituted by yeasts, originated from soil and olive fresh fruits. Then this flora is replaced by different yeast species, which follow each other in a precise order: W. anomalus, C. nyonsensis, Z. mrakii, P. membranifaciens and C. boidinii.
  • These five yeast species constitute the core microbiota of Nyons olive fermentation, and are very resilient, as there were found in the fermentations made for 4 years.
  • For the first time, specific volatile compounds that are essential for the development of organoleptic properties of the fermented olives were identified as specific of some yeast species.
Graph showing microbial species and abundance in olives
Fungal diversity observed in brine during fermentation of table olive fermentation.

We deciphered for the first time the core microbiota of the famous Nyons table olives. This microbiota is mainly constituted by yeasts species. The role of each yeast remains to be precisely elucidated. Finally, as a result of this work, we isolated numerous yeast strains representative of the nyons table olive fermentations, that are conserved in microorganism collection, for further studies.

Collaboration

Monika Coton & Jérôme Mounier - Université de Bretagne Occidentale - LUBEM

Read More

Marine Penland & al. (2021). Use of metabarcoding and source tracking to identify desirable or spoilage autochthonous microorganism sources during black olive fermentations. Food Research International, https://hal.inrae.fr/hal-03205178

Marine Penland & al.  (2020). Deciphering Microbial Community Dynamics and Biochemical Changes During Nyons Black Olive Natural Fermentations. Frontiers in Microbiology, https://hal.inrae.fr/hal-02961412

Marine Penland & al. (2022) Brine salt concentration reduction and inoculation with autochthonous consortia: Impact on Protected Designation of Origin Nyons black table olive fermentations. Food Research International, https://hal.inra.fr/hal-03609442

Contacts

  • Stéphanie Deutsch, stephanie.deutsch@inrae.fr
  • Hélène Falentin, helene.falentin@inrae.fr

Financial support

PROMEDFOODS is a project funded through the ARIMNet2 2017 Call by the following funding agencies: ANR, ELGO-DEMETER, MESRS, MIPAF, INIA and MHESR. ARIMNet2 (2014-2017) has received funding from the European Union’s Seventh Framework Programme for research, technological development and demonstration under grant agreement n° 618127.

Modification date: 29 August 2023 | Publication date: 29 August 2023 | By: S Deutsch