Browsing by Subject "exopolysaccharide (EPS)"

Sorghum (Sorghum bicolor) and amaranth (Amaranthus spp.) are gluten-free cultivated crops native to Africa, and thanks to their drought-tolerating capabilities and adaptive nature, they provide an energy source in areas where cultivation of wheat is not possible. There is a need to exploit these indigenous crops and develop food products with better technological and nutritional properties to battle malnutrition on the continent. Exopolysaccharides (EPS) produced by lactic acid bacteria (LAB) have shown promising properties in improving the technological quality of gluten-free foods. The aim of this project was to identify naturally occurring LAB and yeasts from red sorghum grain, amaranth grain and amaranth leaf flour and from spontaneously fermented sourdoughs made from these flours. Possible EPS-producing LAB were of special interest. The sourdough pH and total titratable acidity were recorded daily, and microbial densities were calculated on selective media. Isolates were selected for sequencing based on morphology and biochemical properties. Twenty seven bacterial isolates, twelve of which produced EPS, were identified by partial 16S rRNA and pheS gene sequencing, and seven yeast isolates were identified by sequencing the variable D1/D2 region of the large subunit rDNA. The identified LAB belonged to five genera: Enterococcus, Lactiplantibacillus, Leuconostoc, Pediococcus and Weissella. The yeasts belonged to the genera Meyerozyma, Pichia and Rhodotorula. In general, many studies focusing on sourdough microbial communities usually concentrate on LAB, with little information on the yeasts currently being available. To the best of the author’s knowledge, this is the first report on sourdough made from amaranth leaves and its native microbial content, with 9/12 isolates producing EPS. This provides an excellent starting point for further study of the technological side of creating a gluten-free baked product using starter bacteria native to the flour itself.