Influence of Geographical Origin and Flour Type on Diversity of Lactic Acid Bacteria in Traditional Belgian Sourdoughs

Abstract

A culture-based approach was used to investigate the diversity of lactic acid bacteria (LAB) in Belgian traditional sourdoughs and to assess the influence of flour type, bakery environment, geographical origin, and technological characteristics on the taxonomic composition of these LAB communities. For this purpose, a total of 714 LAB from 21 sourdoughs sampled at 11 artisan bakeries throughout Belgium were subjected to a polyphasic identification approach. The microbial composition of the traditional sourdoughs was characterized by bacteriological culture in combination with genotypic identification methods, including repetitive element sequence-based PCR fingerprinting and phenylalanyl-tRNA synthase (pheS) gene sequence analysis. LAB from Belgian sourdoughs belonged to the genera Lactobacillus, Pediococcus, Leuconostoc, Weissella, and Enterococcus, with the heterofermentative species Lactobacillus paralimentarius, Lactobacillus sanfranciscensis, Lactobacillus plantarum, and Lactobacillus pontis as the most frequently isolated taxa. Statistical analysis of the identification data indicated that the microbial composition of the sourdoughs is mainly affected by the bakery environment rather than the flour type (wheat, rye, spelt, or a mixture of these) used. In conclusion, the polyphasic approach, based on rapid genotypic screening and high-resolution, sequence-dependent identification, proved to be a powerful tool for studying the LAB diversity in traditional fermented foods such as sourdough.Sourdough represents a natural food ecosystem in which the fermentation activities of lactic acid bacteria (LAB) and yeasts largely determine the typical characteristics of the resulting baked goods (26). Based on the production technology, sourdough fermentations can be divided into three types (2, 38): type I, or traditional, sourdoughs are characterized by continuous propagation of the dough at ambient temperatures (20 to 30°C); type II, or industrial, sourdoughs are incubated at high temperatures (Ͼ30°C), with longer fermentation times and a higher water content; and type III sourdoughs are dried preparations of industrial doughs. Traditional Belgian sourdoughs belong to type I sourdoughs. The use of sourdough improves the overall characteristics of bakery products, such as the dough properties, texture, and flavor (16). LAB contribute significantly to these properties, e.g., by acidification of the dough (17), proteolysis of the gluten (10), hydrolysis of the starch (5), and the production of taste and aromatic compounds (15). Moreover, several sourdough LAB inhibit the development of pathogens due to the production of acids and bacteriocins (22). During spontaneous sourdough maturation, LAB occur as the predominant microorganisms, at numbers of Ͼ10 8 CFU/g sourdough. The genera Lactobacillus, Pediococcus, Leuconostoc, and Weissella predominate in this ecosystem, whereas lactococci, enterococci, and streptococci are rarely found. Sourdough LAB may originate from natural contamination of the flour or may be introduced i...

Lactic Acid Bacterium and Yeast Microbiotas of 19 Sourdoughs Used for Traditional/Typical Italian Breads: Interactions between Ingredients and Microbial Species Diversity

“…In particular, W. cibaria and W. confusa were the dominant species found in Pane di Altamura PDO sourdough. These differences may be related to the following factors: (i) bakeries and methodologies of analysis (e.g., numbers of samples and isolates, temperature, pH, and culture media) (35,36), (ii) contamination by bakery environment (36), and especially, (iii) instability of the sourdough microbiotas during daily back slopping as affected by the type of flour and related autochthonous LAB (29,38). Indeed, a stable microbiota over a long period of time has been described only in a few sourdoughs that are used as the sole leavening agent (4,18,37).…”

Codominance of Lactobacillus plantarum and obligate heterofermentative lactic acid bacteria during sourdough fermentation

“…namely L. rossiae, is being frequently isolated at high numbers from sourdoughs produced in Italy (Valmorri et al, 2006;Di Cagno et al, 2007) and it has been also detected in Belgian sourdoughs (Scheirlinck et al, 2007(Scheirlinck et al, , 2008. The majority of LAB screened and selected to act as starters in sourdough production belong to OHe species (Minervini et al, 2012;Settanni et al, 2013).…”

Diversity and dynamics of bacterial populations during spontaneous sorghum fermentations used to produce ting, a South African food

“…For this purpose, 16S rRNA and pheS gene sequence alignments were generated using multiple sequence alignment based on Fast Fourier Transform (MAFFT v. 6) [37]. These alignments also included the sequence information for the relevant type strains of species in the genera Lactobacillus, Weissella, Lactococcus and Enterococcus, which were obtained from GenBank or from a taxonomic reference framework of pheS consisting of sequences for Lactobacillus, Enterococcus, Lactococcus, Leuconostoc, Pediococcus and Weissella strains [70]. To determine the best-fit evolutionary models for the datasets, PAUP* v. 4.0b1 [72], together with Modeltest v. 3.7 [63], were used.…”