PROFILE OF LACTIC ACID BACTERIA IN RYE FLOUR AND SOURDOUGH

In order to examine the composition of the lactic acid bacteria community of rye flour and sourdough made of it, 41 strains were isolated and characterized. The phenotypic characterization of the isolates, carried out using a set of 34 tests, allowed the identification of 11 clusters at the 80 % similarity level by hierarchical cluster analysis. All lactic acid bacteria isolates from rye flour were homofermentative cocci belonging to the genera Streptococcus (30 % of the lactic acid bacteria count) and Enterococcus (70 %). Homofermentative (Streptococcus sp. - 6 %, Enterococcus sp. - 26 %, and Pediococcus pentosaceus - 16 %) and heterofermentative (Leuconostoc mesenteroides - 13 %, and Weisella paramesenteroides - 7 %) cocci, as well as homo-fermentative bacilli (Lactobacillus sp. - 32 %) were isolated from sourdough.
The lactic acid bacteria were not the predominant microorganisms in the rye flour (comprising one-third of the entire bacterial population) but their acid resistance enabled them to continue growing during natural sourdough fermentation and to become the major bacterial population of sourdough.