Microbial ecology and metabolite dynamics of backslopped triticale sourdough productions and the impact of scale
Triticale (X Triticosecale Wittmack) is the first man-made cereal crop species, resulting from the hybridization of wheat (Triticum aestivum L.) and rye (Secale cereale L.), to combine the positive attributes of both cereals. However, it has not been exploited for sourdough production yet. Further, the effect of scale on sourdough production has not been investigated systematically up to now. The aims of the present study were to assess the microbial ecology and metabolomic output of eleven spontaneously fermented, backslopped sourdough productions made with triticale flour in four different sizes between 100 and 1000 g. Therefore, the acidification profile [pH and total titratable acidity (TTA)], microbial diversity (culture-dependent and culture-independent), and metabolite dynamics were determined. After ten fermentation steps, different species of Lactobacillaceae were prevalent in the sourdoughs, in particular Limosilactobacillus fermentum, Pediococcus pentosaceus, and Latilactobacillus curvatus. The microbial diversity could be traced back to the grains and the milling fractions (flour, bran, and shorts). Furthermore, thanks to the use of Illumina-based high-throughput sequencing amplicon sequencing variant (ASV) approach, the presence of undesirable bacterial groups (clostridia, bacilli, enterobacteria) during the initial steps of the backslopping cycle was revealed. Small sourdough productions (100 and 200 g) selected for a lower species diversity and reached a stable consortium faster than large ones (500 and 1000 g). Although a comparable pH of 3.6-4.0 was obtained, the TTA of small sourdoughs was generally lower than that of large ones. However, the latter were less reproducible. Regarding the metabolic output, the simultaneous production of mannitol and erythritol, on top of ethanol and glycerol, could be linked to sourdoughs in which Liml. fermentum was the sole lactic acid bacteria species present. Besides, Pearson correlation suggested the use of the arginine deiminase pathway (ADI) by P. pentosaceus and Liml. fermentum.