Traditional and Novel Applications of Sourdough Microbes in Northern Europe and the Baltic Countries

Traditional bread baking in Northern Europe and the Baltic countries has relied on, and still uses the grains that are locally available, i.e. the cool season cereals rye, barley, oat and wheat. Grain properties dictate the peculiarity of the technological processes as well as the types of breads that are produced which traditionally include unleavened, thin and dry crisp breads, or sourdough fermented loaves. A great diversity of local products has developed during the last centuries. Differences in process parameters and technologies greatly influence the composition of the sourdough microbiota with heterofermentative and homofermentative Lactobacillaceae and yeast (mainly Saccharomyces cerevisiae) dominating the sourdough microbiota in Northern Europe and the Baltic states. The fermentation of characteristic and widely consumed grains by sourdough microbes contributes to an extension of shelf life, improves technological and sensory properties of grain-based food in Northern Europe and the Baltics, and enhances their nutritional quality through reduction of antinutritional compounds, for e.g. phytate. Additional processes for e.g. in situ vitamin production have been proposed. Beside their application in bread production, souring microbes have been used in other cereal fermentation processes in Northern Europe and the Baltics. Examples are the development of oat-based yoghurt alternatives or the production of the rye-based fermented beverage kvass or sour beer, which have led to commercially available products. In addition, novel products based on side stream of cereal processing, or waste streams of bread production, have been developed during the last decades. Several of these products have been served in top rated restaurants within the New Nordic Cuisine gastronomic phenomenon. New application possibilities of established grains in combination with selective microorganisms developed in Scandinavia can contribute to the current transitions from animal protein to plant-based diets using fermentation as a tool to enhance preservation, organoleptic and nutritional properties.