Improving the nutritional quality of ben-saalga, a traditional fermented millet-based gruel, by co-fermenting millet with groundnut and modifying the processing method

To improve the nutritional value of ben-saalga, a traditional gruel from Burkina Faso, co-fermentation of millet and groundnut (MG) was monitored using either the traditional processing method (MG-T) or a modified processing method including precooking, addition of malt and inoculation by backslopping (MG-CMI). Fermentation kinetics and microbial composition in the two processing methods were characterized and compared to that of ben-saalga process used as control. The fermented pastes from control, MG-T and MG-CMI experiments had a low pH of around 3.9. Their microbiota were dominated by lactic acid bacteria (LAB) with amylolytic LAB:LAB ratios of respectively 12%, 4% and 15%. In MG-T paste, glucose and fructose were the main substrates for lactic acid fermentation and their concentration decreased during settling, whereas in MG-CMI paste, the main substrate was maltose and its concentration increased transiently. At a suitable consistency, the dry matter content of MG-CMI gruel was almost twice as high as that of ben-saalga. During the three processing methods, phytate content decreased of about 75%, 50% and 66%, respectively. Thanks to the incorporation of groundnut, the macronutrient balance of MG-T and MG-CMI met the requirements for complementary foods but only the MG-CMI gruel had sufficient energy density.