Community dynamics and metabolite target analysis of spontaneous, backslopped barley sourdough fermentations under laboratory and bakery conditions

Barley flour is not commonly used for baking because of its negative effects on bread dough rheology and loaf volume.
However, barley sourdoughs are promising ingredients to produce improved barley-based breads. Spontaneous
barley sourdough fermentations were performed through backslopping (every 24 h, 10 days) under
laboratory (fermentors, controlled temperature of 30 °C, high dough yield of 400) and bakery conditions (open
vessels, ambient temperature of 17–22 °C, low dough yield of 200), making use of the same batch of flour.
They differed in pH evolution, microbial community dynamics, and lactic acid bacteria (LAB) species composition.
After ten backsloppings, the barley sourdoughs were characterized by the presence of the LAB species Lactobacillus
fermentum, Lactobacillus plantarum, and Lactobacillus brevis in the case of the laboratory productions
(fast pH decrease, pH b 4.0 after two backslopping steps), and of Leuconostoc citreum, Leuconostoc mesenteroides,
Weissella confusa and Weissella cibaria in the case of the bakery productions (slowpH decrease, pH 4.0 after eight
backslopping steps). In both sourdough productions, Saccharomyces cerevisiae was the sole yeast species. Breads
made with wheat flour supplemented with 20% (on flour basis) barley sourdough displayed a firmer texture, a
smaller volume, and an acceptable flavour compared with all wheat-based reference breads. Hence, representative
strains of the LAB species mentioned above, adapted to the environmental conditions they will be confronted
with, may be selected as starter cultures for the production of stable barley sourdoughs and flavourful breads.