Effect of co-fermentation on functional and pasting properties of maize (Zea mays) and soybean (Glycine max) complementary flours
Background: Cereal complementary foods are characterized by low nutrient density and high bulk, contributing to high prevalence of under-nutrition among children. Fermentation has been demonstrated to improve nutrient density. Separately fermented products utilize cereals in combination with legumes to improve quality. Separate fermentation prior to formulation is both time and cost constraining.
Objective: The objective of this study was to assess the effects of co-fermentation on functional and pasting properties of maize-soybean complementary flours.
Methods: Optimum fermentation period (48 h) and blend (70:30 maize : soybean) were selected through preliminary sensory evaluation. Separately-fermented and co-fermented blends along with a non-fermented control were assessed for pasting and functional properties.
Results: Co-fermentation led to significantly (p<0.05) higher protein dispersibility index (8.77%), emulsification capacity (6.70ml/g) and reconstitution index (9.40ml/g) compared to separate fermentation (2.52%, 2.77ml/g and 8.17ml/g, respectively). Separate fermentation led to significantly(p < 0.05)reduced peak (59.0cP), trough (54.0cP) and final (124.0cP) viscosities compared to co-fermentation (71.0cP, 64.0cP and 128.0cP respectively). Co-fermentation led to significantly(p < 0.05) reduced gelatinization temperature (82oC) and swelling capacity (2.9g/g) compared to separate fermentation (86.0oC and 3.7g/g, respectively). Fermented maize flour had 797.5cP final viscosity compared to non-fermented maize flour (1059.5cP), indicating that more flour would be needed to reach desired consistency, thereby achieving higher nutrient density.
Conclusion: Co-fermentation of maize and soybean can be employed as a time-saving processing method for cereal-legume complementary flours, as most quality attributes were not adversely affected.
Keywords: Co-fermentation, nutrient density, cereal-legume blends, viscosity