Identification of predominant lactic acid bacteria and yeasts of Turkish sourdoughs and selection of starter cultures for liquid sourdough production using different flours and dough yields

Abstract

Eight samples of mature sourdough were collected from fi ve provinces of Turkey. Lactic acid bacteria and yeasts were isolated and identifi ed and used in different combinations to produce liquid sourdoughs. Microbiological and physicochemical characteristics of the experimental sourdoughs made with different fl our types and dough yields were studied. The main lactic acid bacteria species identifi ed were Lactobacillus (L.) sanfranciscensis, Pediococcus pentosaceus, L. plantarum, L. namurencis, L. rossiae, Leuconostoc mesenteroides and L. zymae. L. spicheri, L. paralimentarius, L. mindensis, L. farciminis, L. acetotolerans, L. casei, Enterococcus faecium and Enterococcus durans were also found in sourdoughs at subdominant levels. Among yeasts, mainly Saccharomyces cerevisiae, but also Pichia guiliermondii and Torulaspora delbrueckii were the predominant species of yeasts identifi ed in sourdoughs. Lactic acid bacteria and yeasts of liquid sourdoughs after fermentation were in the range of 9.61–9.89 log cfu/g and 6.55–7.36 log cfu/g, respectively. Various chemical parameters such as pH, total titratable acidity, lactic and acetic acids, ethanol and sugars were determined for liquid sourdoughs. Acidifi cation and metabolite contents of these products were different, depending on the starter culture, fl our type and dough yield. Total titratable acidity was more pronounced in the sourdoughs produced with whole wheat fl our (14.08 mL NaOH) and rye fl our (13.56 mL NaOH), dough yield 250 (13.93 mL NaOH) and control sample (13.12 mL NaOH) which were produced without inoculum.