Exploitation of Acha (Digitaria exiliis) and Iburu (Digitaria iburua) flours: Chemical characterization and their use for sourdough fermentation

This study aimed at characterizing the chemical and microbiological composition of Acha (Digitariaexiliis) and Iburu (Digitariaiburua) flours and at exploiting their potential for sourdoughfermentation. Both the flours had a gross composition similar to other cereals. As shown by two-dimensional electrophoresis analysis, Acha flour had a higher number of prolamins with respect to Iburu flour. The opposite was found for the number of glutelin spots. The concentration of total free amino acids of Iburu flour was higher than that of Acha flour (1348 ± 34 vs. 100 ± 20 mg/kg). Pediococcus pentosaceus was the dominant species in both the flours. Several isolates were used to ferment Acha or Iburu flours. After 8 h fermentation at 30 °C, pH ranged from 3.41 to 3.83 and from 4.20 to 4.66 for Acha and Iburusourdoughs, respectively. The highest values of TTA and concentration of lactic acid were found in almost all Iburusourdoughs. The synthesis of acetoin and γ-amino butyric acid (GABA) was only found in Iburusourdoughs. Data from the kinetics of acidification, synthesis of lactic and acetic acids, acetoin, and liberation of total free amino acids were elaborated by Principal Component Analysis. Sourdoughs from Acha and Iburu flour were clearly differentiated.