Spontaneous Fermentation-Induced Changes in Selected Ghanaian Plant-Based Flours: Physico-Functional and Biochemical Insights for Complementary Food Use.

Abstract

This study investigated the effects of spontaneous fermentation (SF) on the physicochemical and biochemical properties of seven Ghanaian staples: maize, millet, sorghum, sweetpotato, cassava, plantain, and soybeans. The cereals were soaked (12 h), ground, and fermented for 48 h. Cassava, plantain, and sweetpotato were peeled, grated, and fermented similarly. All samples were dried (3 days), milled into flour, and compared with unfermented controls. SF significantly enhanced water absorption in soybean flour and oil absorption in cassava, plantain, and sweetpotato flours. The foaming capacity generally declined, except for stable foams in millet and sweetpotato. The peak viscosity increased in most flours, except for cassava (-14%) and sorghum (-18%), following SF. There was an almost 3.6-fold and 2.2-fold increase in the trough viscosity of plantain and sweetpotato flours, respectively, after SF. Meanwhile, the final viscosity decreased in plantain (-72.6%) and sorghum (-20.6%) post-SF. The crude protein content increased significantly in sorghum (11.3% vs. 10.5%) and soybean (41.2% vs. 39.6%) after SF treatment. After SF, the total polyphenolic content increased in maize (3.92 vs. 3.26 mgGAE/100 g), millet (5.05 vs 4.04), plantain (5.22 vs 4.91), and sweetpotato (29.7 vs 4.8), but declined in cassava (-18.5%), sorghum (-20.4%), and soybean (-13.8%). Phytic acid levels were generally reduced across all matrices, ranging from 23% to 69% after SF. These findings support the potential of SF to improve the nutrient density and functional properties of local staple foods. However, elevated polyphenol levels and final viscosity in some flours may affect nutrient levels and digestibility, necessitating careful formulation when developing complementary foods for infants and young children.