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

Emilie Lhomme (1) , Sandra Mezaire (2) , Maren Bonnand Ducasse (2) , Hubert Chiron (3) , Marie-Christine Champomier-Verges (4) , Stephane Chaillou (4) , Monique Zagorec (5) , Xavier Dousset (5) , Bernard Onno (1, 6, 7)

1 Laboratoire de Sécurité Alimentaire et Microbiologie Industrielle
2 Biofournil
3 BIA - Unité de recherche sur les Biopolymères, Interactions Assemblages
4 MICALIS - MICrobiologie de l'ALImentation au Service de la Santé
5 SECALIM - SECurité des ALIments et Microbiologie
6 GEPEA - Laboratoire de génie des procédés - environnement - agroalimentaire
7 ONIRIS - École nationale vétérinaire, agroalimentaire et de l'alimentation Nantes-Atlantique

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]

Mots clés: Candida; Saccharomyces; Lactobacillus spp; sourdough; gluten-free food; organic; lactic acid bacteria; yeast

Domaines: Sciences du Vivant [q-bio]

Emilie Lhomme, Sandra Mezaire, Maren Bonnand Ducasse, Hubert Chiron, Marie-Christine Champomier-Verges, et al.. A polyphasic approach to study the dynamics of microbial population of an organic wheat sourdough during its conversion to gluten-free sourdough. International Microbiology, 2014, 17 (1), pp.1-9. ⟨10.2436/20.1501.01.202⟩. ⟨hal-01190027⟩