Biodiversity of Sourdough Lactic Acid Bacteria.

Modern technology of baked goods largely uses sourdoughs because of the many advantages offered over baker’s yeast. Sourdough is characterized by a complex microbial ecosystem, mainly represented by lactic acid bacteria (LAB) and yeasts, whose fermentation confers to the resulting product its characteristic features such as palatability and high sensory quality. Raw materials used in baking are not heat-treated; thus, they bring their wild microorganisms to the production process. Investigation of the composition and evolution of microbial communities of sourdough and raw materials is relevant in order to determine the potential activities of sourdough microorganisms. LAB are the main factor responsible for flavor development, improvement of nutritional quality as well as stability over consecutive refreshments of sourdough. LAB also establish some durable microbial associations, and the cell-cell communication process is crucial in determining sourdough performance during fermentation. The central aim of this chapter is to report on the knowledge of LAB hosted in raw materials and sourdoughs, their biodiversity and evolution before and during fermentation, their useful properties, their quorum sensing mechanisms and the methods routinely applied to their detection and monitoring in sourdough ecosystems.