A polyphasic approach to study the dynamics of microbial population of an organic wheat sourdough during its conversion to gluten-free sourdough

Autors/ores

  • Emilie Lhomme ONIRIS, Laboratory of Food and Industrial Microbiology, Nantes.
  • Sandra Mezaize Biofournil, Le Puiset Doré.
  • Maren Bonnand Ducasse Biofournil, Le Puiset Doré.
  • Hubert Chiron INRA, UR1268 Biopolymers, Interactions & Assemblages, Nantes.
  • Marie-Christine Champomier-Vergès INRA, UMR1319 Micalis, Jouy-en-Josas.
  • Stéphane Chaillou INRA, UMR1319 Micalis, Jouy-en-Josas.
  • Monique Zagorec INRA, UMR 1014 Secalim.
  • Xavier Dousset INRA, UMR 1014 Secalim.
  • Bernard Onno ONIRIS, Laboratory of Food and Industrial Microbiology, Nantes.

Paraules clau:

Lactobacillus spp., Saccharomyces, Candida, sourdough, gluten-free food, organic, lactic acid bacteria, yeast

Resum

To develop a method for organic gluten-free (GF) sourdough bread production, a long-term and original wheat sourdough was refreshed with GF flours. The dynamics of the sourdough microbiota during five months of back-slopping were analyzed by classical enumeration and molecular methods, including PCR-temporal temperature gel electrophoresis (PCR-TTGE), multiplex PCR, and pulsed field gel electrophoresis (PFGE). The results showed that the yeast counts remained constant, although Saccharomyces cerevisiae, present in the initial wheat sourdough, was no longer detected in the GF sourdough, while lactic acid bacteria (LAB) counts increased consistently. In the first phase, which was aimed at obtaining a GF sourdough from wheat sourdough, Lactobacillus sanfranciscensis, L. plantarum, and L. spicheri were the main LAB species detected. During the second phase, aimed at maintaining the GF sourdough, the L. plantarum and L. spicheri populations decreased whereas L. sanfranciscensis persisted and L. sakei became the predominant species. Multiplex PCRs also revealed the presence of several L. sakei strains in the GF sourdough. In a search for the origin of the LAB species, PCR-TTGE was performed on the flour samples but only L. sanfranciscensis was detected, suggesting a flour origin for this typical sourdough species. Thus, while replacement of the wheat flour by GF flour influenced the sourdough microbiota, some of the original sourdough LAB and yeast species remained in the GF sourdough. [Int Microbiol 2014; 17(1):1-9]

Keywords: Lactobacillus spp. · Saccharomyces · Candida ·  sourdough · gluten-free food · organic · lactic acid bacteria · yeast

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