Effects of processing methods on the nutritional, antinutritional and sensory properties of multigrain composite flours formulated from <i>Sorghum bicolor</i> (L.) Moench, <i>Zea mays</i> L. and <i>Glycine max</i> (L.) Merr

Antinutritional factors such as phytates and tannins are major constraints in cereal – legume-based flours because they reduce mineral bioavailability and protein digestibility. This study assessed the effects of soaking, germination, and fermentation on the proximate composition and antinutritional properties of multigrain composite flours formulated from Sorghum bicolor (L.) Moench, Zea mays L. and Glycine max (L.) Merr. Flour formulations were processed by soaking alone or by a combined soaking, germination, and fermentation (SGF) method, with an untreated flour serving as the control. Standard analytical procedures were used to determine proximate composition, energy value, phytate, and tannin contents. Processing significantly reduced antinutritional factors (p < .001). Compared with the control, phytate content decreased by 75.56–84.44%, with the highest reduction (84.44%) observed in FG1. Tannin content was reduced by 79.49–92.31%, with the greatest decrease achieved under combined treatments. Proximate composition was significantly affected by processing, with variations in lipid, carbohydrate, and energy values; the highest energy value was recorded in FG3 (469.0 kcal/100 g). Ash content was highest in flours subjected to SGF. Sensory evaluation of porridges revealed highly significant differences (p < .0001), with F3 showing the highest acceptability for taste and texture, while FG2 and FG4 scored lowest, particularly for aroma and taste. These results demonstrate that traditional processing techniques improve the nutritional quality of cereal – legume composite flours for complementary feeding. Future work should assess micronutrient bioavailability, in vivo safety, shelf-life stability, and pilot-scale production to support broader application.