Bacterial communities analysis of amaranth and quinoa sourdough fermentation by PCR-DGGE

VERA PINGITORE, E.; SAAVEDRA, L.; FONTANA, C.; COCCONCELLI, P.S.; REBECCHI, A.; BASSI, D.; PISACANE, V.; VIGNOLO, G.; HEBERT, E.M.

Simposio; 23rd International ICFMH Symposium. Food Micro 2012; 2012

Andean regions are center of origin and domestication of a large number of plant such as quinoa (Chenopodium quinoa) and amaranth (Amaranthus caudatus). Because their nutritional value (balanced composition of essential amino acids, mineral; vitamins) and the absence of gluten, new consumer demands have emerged for these cereals and their flours. Although the use of such alternative flours is restricted due to the low baking quality, fermentation may improve both the sensory and baking qualities. In this study, spontaneously sourdoughs prepared from commercial amaranth (Sturla®) as well as natural (Real Hornillos) and commercial (Yin Yang®) quinoa flours were monitored by DGGE to assess the microbial diversity. Doughs were prepared on a laboratory scale over a period of 10 days with daily back-slopping (10%) at 30°C and samples were withdrawn daily at refreshment steps (T0 to T10). Total DNA from dough samples were obtained using the FastDNA Spin Kit and the V3 variable region of 16S RNA ribosomal gene was amplified by PCR. The analysis of the bacterial community diversity and dynamics was performed by DGGE. The bands identification was carried out by comparison of the migration profiles with those of reference strains and by sequencing the re-amplified bands excised from the acrylamide gel. DGGE profiles showed at the beginning of the fermentation process the presence of multiple bands while a progressive change in the bacterial communities occurred from the third day of fermentation in the three assayed sourdoughs. Lactobacillus plantarum represents the dominant species during Quinoa Yin Yang and amaranth dough fermentation; being detected from time 1 to time 10. During Quinoa Real dough fermentation Enterococcus devriesei band was detected from time 0 to time 3 while Lactobacillus brevis band was detected during all fermentation period except time 0. An intense band originated by L. plantarum was detected at time 3, decreasing then its intensity and disappearing at time 10. The direct molecular techniques applied here were useful for the identification of the main bacteria developed in this novel fermented dough which can be exploited to improve functional quality and safety of traditional Andean foods.