Isolation of Exopolysaccharide-Producing Yeast and Lactic Acid Bacteria from Quinoa (Chenopodium Quinoa) Sourdough Fermentation

Abstract

Quinoa, a nutritional grain, can be used as an ingredient in gluten-free sourdoughs. This study characterizes quinoa flour spontaneous fermentation with emphasis in the isolation of exopolysaccharide (EPS) producer bacteria. Real, red and black grains were studied. Dough yield, microbiota composition and fermentation biochemistry were determined for a total of 36 quinoa flour fermentations. The fermentation biochemistry was monitored by high-performance liquid chromatography (HPLC) analysis, pH measurement and titratable acidity. Changes in the microbiota were monitored by plating on deMann Rogosa and Sharp 5 agar (MRS5) and yeast and mold agar (YMA) plates and with metagenetic analysis. The ability to produce exopolysaccharides was screened in selected lactic acid bacteria (LAB) isolates. Production of organic acids in the spontaneous fermentation dropped the pH to 4.0 ± 0.3. The community of presumptive LAB reached 8.37 ± 0.01 log colony forming units (CFU)/mL by day 8 of back-slopped fermentations. The microbiota was composed of Lactobacillus, Enterococcus, Leuconostoc, Lactococcus, Pediococcus and Weissella. P. pentosaceous, L. citreum and W. cibaria were able to produce EPS in a starch-rich medium. P. pentosaceous showed higher exopolysaccharide yield, rapid acidifying kinetics and was able to drop the dough broth pH to values below 4.0 and a positive fermentation quotient after 24 h of incubation. Therefore, the bacterium might be a potential candidate for quinoa sourdough production.

A Novel Weissella cibaria Strain UTNGt21O Isolated from Wild Solanum quitoense Fruit: Genome Sequence and Characterization of a Peptide with Highly Inhibitory Potential toward Gram-Negative Bacteria

“…Nonetheless, further studies regarding the cytotoxicity of the peptide as well as its effect on other food spoilage microorganisms are required. In addition, in agreement with other authors, the effect of the peptides produced by lactic acid bacteria during food fermentation and their potential to improve safety of the consumer should be investigated [41][42][43].…”

Quinoa Flour, the Germinated Grain Flour, and Sourdough as Alternative Sources for Gluten-Free Bread Formulation: Impact on Chemical, Textural and Sensorial Characteristics

“…Pediococcus pentosaceus QB17, an exopolysaccharide-producing LAB recently isolated from quinoa spontaneous sourdough [10], was used as single starter culture. Thus, cells were harvested from MRS overnight activated cultures at 30 ± 2 • C [15], and then centrifuged at 12,000× g for 10 min at 5 • C (Centrifuge 5810; Eppendorf, Hamburg, Germany).…”

“…However, the mentioned effect is dependent on the starter culture strain used. The P. pentosaceous QB17 starter culture used in this study was isolated from spontaneous quinoa flour fermentation and chosen for its ability to produce exopolysaccharides [10]. These molecules are natural hydrocolloids that aid in the formation of a protein network and thus improve the texture of breads [35].…”

“…Sourdough fermentations are characterized by the conversion of sugars to organic acids and/or ethanol, primarily by lactic acid bacteria (LAB). Recently, we isolated and fully characterized an exopolysaccharide-producer LAB from quinoa dough through spontaneous fermentation [10] This compound has been associated with the improvement of textural attributes due to its hydrocolloidal effect [11][12][13][14]. The use of autochthonous LAB as a starter culture enabled uniform fermentations capable of sustaining maximum growth rates, resulting in complete fermentations.…”

Sourdough Biotechnology Applied to Gluten-Free Baked Goods: Rescuing the Tradition

“…The conditions of EPS production by sourdough lactobacilli depend on several factors, such as sourdough composition (available carbon sources, mainly sugars, and their concentration, nitrogen sources, content of other nutrients), fermentation conditions (time, temperature, oxygen, pH), Lactobacillus species, and the type of flour used, among others [ 100 , 101 , 107 , 108 , 109 ]. The concentration of fermentable sugars present in the dough affects the EPS microbial synthesis [ 110 ].…”