The impact of lactic acid bacteria on sourdough fermentation

Abstract

The baking of sourdough breads represents one of the oldest biotechnological processes. Despite traditionality, sourdough bread has great potential because of its benefits. Sourdough is a mixture of flour and water that is dominated by a complex microflora composed of yeasts and lactic acid bacteria that are crucial in the preparation of bread dough. Lactic acid bacteria cause acidification by producing lactic acid that increases the shelf life of bread by preventing the growth of undesirable microorganisms and affects the nutritional value of bread by increasing the availability of minerals. In addition to these advantages, the use of sourdough fermentation also improves dough machinability, breadcrumb structure and the characteristic flavour of bread. Lactic acid bacteria in sourdough fermentation are well known representing both homofermentative and heterofermentative bacteria. They may originate from selected natural contaminants in the flour or from a starter culture containing one or more known species of lactic acid bacteria. Sourdough can be cultivated in bakeries or obtained from commercial suppliers. However, many bakeries in Europe still use spontaneously fermented sourdoughs, which have been kept metabolically active for decades by the addition of flour and water at regular intervals. The impact of lactic acid bacteria on sourdough fermentation and their influence on dough and bread quality was discussed on the basis of research and literature data.Iako predstavlja jedan od najstarijih biotehnoloskih postupaka, proizvodnja hleba od kiselih testa ima veliki potencijal zbog svojih mnogobrojnih prednosti. Kiselo testo se dobija fermentacijom testa, pri cemu slozena mikroflora sastavljena od kvasaca i bakterija mlecne kiseline ima sustinsku ulogu u formiranju osobina testa. U toku svog rasta, bakterije mlecne kiseline stvaraju mlecnu kiselinu i povecavaju kiselost testa, a sto sprecava umnozavanje nezeljenih mikroorganizama i povecava trajnost hleba. Pored toga, upotreba kiselih testa poboljsava tehnoloske karakteristike testa, strukturu, hranljivu vrednost (povecavajuci dostupnost minerala) i aromu hleba.