Book

This study investigated the effects of 15-day traditional spontaneous steeping fermentation on the physicochemical, microbiological, nutritional, and sensory properties of Urwinike dehulled maize flour in Rwanda. Fermentation progressively reduced pH from 6.25 to 4.34 and increased titratable acidity and water-holding capacity from 1.03 to 1.53 g/g, indicating enhanced acidification and techno-functional properties. However, prolonged fermentation resulted in substantial nutritional losses, with crude protein decreasing from 7.65% to 5.4%, while zinc, copper, and riboflavin declined by 69%, 95%, and 80%, respectively. Aflatoxins remained below the detection limit throughout the process. Despite improved functional properties and microbiological safety, sensory acceptability decreased by day 15 due to excessive sourness and intense volatile compounds. The findings suggest that extending fermentation to 15 days may compromise nutritional value and consumer acceptance. Therefore, an optimized fermentation period of 7–10 days is recommended to balance functional improvements, nutrient retention, microbiological safety, and sensory acceptability.