Identification of lactic acid bacteria and yeasts from traditional sourdoughs and sourdough production by enrichment

The subject of this study was to investigate lactic acid bacteria (LAB) and yeasts microbiota of traditional sourdough (n = 36) and to indicate characteristics of enriched sourdough that is produced from combinations of isolates. A total of 60 LAB and 40 yeasts were identified from sourdough by matrix-assisted laser desorption ionisation-time-of-flightmass spectrometry (MALDI-TOF MS) analysis. The dominant LAB microflora was Lactobacillus brevis (43.33%), Pediococcus acidilactici (21.67%) and Lactobacillus plantarum (18.33%). The dominant yeasts microflora was Saccharomyces cerevisiae (27.5%), Pichia kudriavzevii (25.0%) and Kluyveromyces marxianus (12.5%). The sourdough prepared with the combination of L. brevis, Leuconostoc mesenteroides, P acidilactici and S. cerevisiae, K marxianus showed the best physicochemical and microbiological properties while that with L. plantarum, L. brevis and P kudriavzevii, Wickerhamomyces anumalus was the poorest. LAB and yeasts in the sourdoughs were ranged from 6.58 log CFU g(-1) to 9.12 log CFU g(-1) and from 6.12 log CFU g(-1) to 7.88 log CFU g(-1), respectively. Various chemical parameters such as pH, total titratable acidity (TTA), ethanol, and sourdough volume were differ depending on the type of microbial species. TTA was more pronounced in the sourdoughs produced with homofermentative LAB. Yeasts and LAB were dominated during continuous enriching of sourdough, supporting an important role during fermentation.

Automated summary

The study identified various LAB and yeast species in traditional sourdough and indicated that sourdough enriched with specific combinations of isolates exhibited different physicochemical and microbiological properties. The combination of L. brevis, L. mesenteroides, P. acidilactici, S. cerevisiae, and K. marxianus resulted in the best characteristics, while another combination led to the poorest properties. Yeasts and LAB played a dominant role during continuous enrichment of sourdough, impacting fermentation and chemical parameters such as pH and ethanol production.