Diversity and interactions in a low-input « Wheat/Human/Sourdough » agro-food ecosystem : towards a better understanding of bakery sustainability – BAKERY

We have constructed a group of 30 French bakers and farmers/bakers who make sourdough breads, using flours resulting from agro ecological practices. Information on their bakerys’ practices as well as their consumers representation have been collected. Their wheat seeds’, flour, sourdough and bread were analyzed with classical microbiology, meta-barcoding and biochemstry technics. .

Simultaneaously taking advantage of previous works of the project partners on participative wheat breeding, we have developped a controlled experiments for analyzing the effect of terroir, of bread wheat varieties (ancient vs modern) and of bakers’ practices on the sourdough microbiome and bread quality. These experiments have been carried out in complete co-construction between farmers, bakers and scientists.

Furthermore, we have studied the sourdough microbial interaction by comparing population densities in co-culture and mono-culture. This approach allow the characterization of the nature of the LAB/Yeast interaction (ecological facilitation or competition) and their consequences on the sourdoughs functioning (acidification). In addition, we are currently developping a mathematical model to analyse how the compexity of the mechanisms underlying microbiel interaction impact the outcome of microbial interactions.

Our first results show that French organic bakery maintains a high diversity of bread-making processes, as well as a high microbial species diversity, compared to what was found elsewhere. New yeast species have been discovered. Several lactic acid bacteria species have been found for the first time in sourdoughs. Bakers, Farmers-bakers and Bakery Companies harbor different microbial diversity, showing the relevance of preserving socio-cultural diversity.

In addition to confirm and complete our results, we will now look at the link between bread-making practices, sourdough microbial diversity and bread quality. In addition we will study the consumer representation. Finally we will look at the origin of the microbial sourdough's diversity (terroir, wheat varieties, water, bakers' house).

PUBLICATIONS
Jacques N, Sarilar V, Urien C, Lopes MR , Morais CG, Uetanabaro APT, Tinsley CR, Rosa CA, Sicard D, and S Casaregola. 2016. Three novel ascomycetous yeast species of the Kazachstania clade, Kazachstania saulgeensis sp. nov., Kazachstania serrabonitensis sp. nov. and Kazachstania australis sp. nov. Reassignement of Candida humilis to Kazachastania humilis f. a. comb nov and Candida pseudohumilis to Kazachstania pseudohumilis f. a. comb. nov. International Journal of Systematic and Evolutionary Microbiology. doi: 10.1099/ijsem.0.001495
Michel E, Monfort C, Deffrasnes M, Guezenec S, Lhomme E, Barret M, Sicard D, Dousset X and B Onno. 2016 Characterization of relative abundance of lactic acid bacteria species in French organic sourdough by cultural, qPCR and MiSeq high-throughput sequencing methods, International Journal of Food Microbiology, dx.doi.org/10.1016/j.ijfoodmicro.2016.07.034
Lhomme E, Onno B, Chuat V, Durand K, Orain S, Valence F, Dousset X, and M-A Jacques. 2016. Genotypic diversity of Lactobacillus sanfranciscensis strains isolated from French organic sourdoughs. International Journal of Food Microbiology, Volume 226, Pages 13-19
Lhomme E, Urien C, Legrand J, Dousset X, Onno B and D Sicard. 2016. Sourdough microbial community dynamics: An analysis during French organic bread-making processes. Food Microbiology, Volume 53, Pages 41-50, dx.doi.org/10.1016/j.fm.2014.11.014
Lhomme E, Orain S, Courcoux P, Onno B and X Dousset 2015. The predominance of Lactobacillus sanfranciscensis in French organic sourdoughs and its impact on related bread characteristics. International Journal of Food Microbiology. Volume 213, Pages 40-48, dx.doi.org.gate1.inist.fr/10.1016/j.ijfoodmicro.2015.05.010

ARTICLES DE VULGARISATION

Ramsayer J et Sicard D, Explorer et conserver la diversité de la flore dans les levains, un potentiel en boulangerie, Innovation Agronomique, 44, 45-54.

Global change has a critical effect on biological and socio-cultural diversity leading to a strong demand for the development of sustainable food-agro-ecosystem. In this context, a better understanding of these diversities in the bakery food chain would facilitate development of more sustenance in this food chain. Hence, the objectives of BAKERY are to provide a detailed description of biological and socio-cultural diversity to enable a better understanding of the interactions and services in an organic or low input “Wheat/Human/Sourdough” food-agro-ecosystem.
The aim is to develop a pluridisciplinary and participatory research project aiming at (i) describing socio-cultural diversity of bakers’ practices and consumers’ representations, (ii) studying the effects of wheat varieties, terroir and bakers’ practices on the diversity of sourdough microbiome, sensorial and nutritional bread quality as well as consumers preferences, (iii) analyzing the nature of the sourdough microbial interaction (complementation or selection) and their consequence on the sourdough fermentation and bread quality, (iv) integrating all the data to find determinants of the biological and socio-cultural diversity in the bakery chain, and (v) propose strategies for the conservation of biological and socio-cultural diversity in bakery.
We will survey 30 French bakers and farmers/bakers who make sourdough breads, using flours resulting from agro ecological practices and distribute their production locally. Information on bakers’ practices as well as wheat seeds’ origin (for baker/farmers), flour, sourdough and bread samples will be collected. In addition we will interview thoroughly a total of thirty consumers of some of the surveyed bakers. The wheat seeds, flour and sourdough microbiome will be analyzed using metagenomic pyrosequencing and phylogeny analysis of rDNA loci. Biochemical characterization as well as sensorial analysis will be performed for sourdoughs and breads. This will delineate sourdough biodiversity, bread quality, and also the diversity of baker practices and consumer representation and implementing an integrated database.
Simultaneaously taking advantage of previous works of the project partners on participative wheat breeding, we will use control experiments for analyzing the effect of terroir, of bread wheat varieties (ancient vs modern) and bakers’ practices on the sourdough microbiome and bread quality. Furthermore, we will study the sourdough microbial interaction by analyzing fermentation and population dynamic in reconstituted communities composed of lactic acid bacteria and yeast species. This approach will allow the characterization of the nature of the microbial species interaction (ecological facilitation or selection) and their consequences on the sourdoughs services (dough characteristics and bread quality). Thus, the analysis of these controlled experiments will provide candidate determinants of the diversity in “Wheat/Human/Sourdough” food-agro-ecosystem.
The BAKERY project will allow us: (i) to increase our knowledge on the diversity of bakers’ and farmers/bakers’ practices and consumer representation of sourdough breads, (ii) to characterize and to conserve the microbial diversity of French sourdoughs, (iii) to better understand the impact of different determinants on the biodiversity and functioning of the “wheat/Human/Sourdough” food-agro-ecosystems, (iv) to think about the complementarity of ex situ and in situ conservation of wheat and microbial genetic resources and (v) to identify action promoting sustainable bread making practices.
This ambitious project is based on the integration of innovative approaches and advanced tools (participatory research, pluridisciplinary interactions, mathematical modeling, post-genomic data) and will benefit from the strong complementarity between partners.