Biodiversity and technological potential of lactic acid bacteria isolated from spontaneously fermented amaranth sourdough.
Spontaneous fermented sourdoughs prepared from amaranth flour were investigated for the presence of autochthonous lactic acid bacteria (LAB) predominating microbiota. The doughs were fermented with daily backslopping on a laboratory scale at 30°C for 10 days. LAB counts ranged from 2·60 to 8·54 log CFU g(-1) with a pH declined from 6·2 to 3·8 throughout fermentation. The combined use of randomly amplified polymorphic DNA (RAPD)-PCR analysis and sequence analysis of 16S rRNA was applied for LAB intraspecies differentiation and taxonomic identification, respectively. Enterococcus, Pediococcus and Lactobacillus species were present in amaranth sourdoughs (AS). After the first refreshment step, Lactobacillus plantarum dominated AS until the end of fermentation. In coincidence, when DGGE analysis was performed, the occurrence of a progressive change in bacterial communities allowed the selection of Lact. plantarum as a dominant species. Moreover, technological, functional and safety characteristics of representative RAPD-biotypes were investigated. Lact. plantarum CRL1898 was selected as a potential candidate for gluten-free amaranth sourdough starter.


CONCLUSIONS
Nowadays, there is an increasing interest in ancient noncereal gluten-free (GF) crops such as amaranth, due to their reported nutritional and health benefits. However, the use of these grains is still limited to traditional foods and bread making processes that are not yet well standardized. Results on the dynamics of autochthonous lactic acid bacteria (LAB) microbiota during laboratory spontaneous amaranth sourdoughs (AS) fermentation will contribute to overcome challenges for GF-fermented products development. In addition, knowledge about LAB diversity involving Enterococcus, Pediococcus and Lactobacillus species, with Lactobacillus plantarum predominating during AS fermentation, and their technological and functional properties provides the basis for the selection of autochthonous strains as starters cultures for novel gluten-free bakery products with enhanced nutritional, sensory and/or safety quality.
Centro de Referencia para Lactobacilos (CERELA), CONICET, Tucumán, Argentina.
L
L
Ruiz Rodríguez
Centro de Referencia para Lactobacilos (CERELA), CONICET, Tucumán, Argentina.
E
E
Vera Pingitore
Centro de Referencia para Lactobacilos (CERELA), CONICET, Tucumán, Argentina.
G
G
Rollan
Centro de Referencia para Lactobacilos (CERELA), CONICET, Tucumán, Argentina.
G
G
Martos
Centro de Referencia para Lactobacilos (CERELA), CONICET, Tucumán, Argentina.
L
L
Saavedra
Istituto di Microbiologia-Centro Ricerche Biotecnologiche, Università Cattolica del Sacro Cuore, Piacenza-Cremona, Italy.
C
C
Fontana
Centro de Referencia para Lactobacilos (CERELA), CONICET, Tucumán, Argentina.
E M
EM
Hebert
Centro de Referencia para Lactobacilos (CERELA), CONICET, Tucumán, Argentina.
G
G
Vignolo
D027721:Amaranthus / Q000382:microbiology*; D015373:Bacterial Typing Techniques; D044822:Biodiversity; D019149:Bioreactors / Q000145:classification / Q000382:microbiology; D001939:Bread / Q000382:microbiology; D055050:Diet, Gluten-Free; D016983:Enterococcus / Q000145:classification* / Q000302:isolation & purification / Q000378:metabolism; D005285:Fermentation; D005433:Flour / Q000382:microbiology*; D005516:Food Microbiology; D019344:Lactic Acid / Q000378:metabolism; D048191:Lactiplantibacillus plantarum / Q000145:classification* / Q000302:isolation & purification / Q000378:metabolism; D064307:Microbiota / Q000235:genetics; D010376:Pediococcus / Q000145:classification* / Q000302:isolation & purification / Q000378:metabolism; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D019105:Random Amplified Polymorphic DNA Technique
D012336:RNA, Ribosomal, 16S; D019344:Lactic Acid
amaranth; functional foods; lactic acid bacteria; sourdough; starter culture