Effect of Select Parameters of the Sourdough Rye Fermentation on the Activity of Some Mixed Starter Cultures

The effect of select parameters (i.e., rye flour ash content, temperature, and dough yield) of the sourdough fermentation on the fermentation activity of different starter cultures (lactic acid bacteria Lactococcus lactis ssp. Lactis, Weissella confusa, Lactobacillus plantarum, Lactobacillus brevis, Lactobacillus helveticus, and yeast Kluyveromyces marxianus subsp. Marxianus) was determined. The major metabolic end products of fermentation (D, L-lactic acid, acetic acid, ethanol and glycerol) and the evolution of total phenolic content and folic acid during bread making were measured. Lactobacillus helveticus and Kluyveromyces marxianus allowed obtaining sourdoughs with the highest lactic acid/acetic acid ratios. The mixed starter culture with Lactococcus lactis and Saccharomyces cerevisiae generated the most important quantities of D/L lactic acid. The maximum values of ethanol concentration were obtained in case of the sourdoughs from whole rye flour fermented at lower temperature (30°C) with mixed starter cultures containing Sacchomyces cerevisiae. The fermentation process and type of starter culture are also tools to increase the bioactive compounds, enabling the increase of the phenolic content of the sourdough.