Sourdough-based microbiota, fermentations and the development of anti-microbial and anti-oxidant metabolites

Sourdough is a fermented product prepared by the combination of flour or flours, salt, and water in a certain ratio. Owing to the starter culture used in sourdough manufacturing, sourdough has unique properties and differs in its own kind. These end-products produced by yeasts and lactic acid bacteria are mainly responsible for the peculiar texture and flavor of the bread prepared from sourdough. Not only the type of starter culture but also the processing and sources of flours, along with the microbial progression during sourdough fermentation, play critical roles in shaping the final bread formation. Proteolysis, lipolysis, and carbohydrate metabolism occurring during sourdough fermentation result in the enhancement of the nutritive value of the bread and, at the same time, reduce the anti-nutritional factors that might interfere with protein and starch during digestion. Further, the nutritional value is augmented by the generation of certain anti-microbial and anti-oxidant metabolites. This review will cover the recent advances in the microbiota and metabolite composition of sourdough, which imparts the techno-functional attributes as well as health benefits.