Storage influence on the functional properties of malted and unmalted maize (Zea mays L ssp mays) and soybean (Glycine max L Merrill) flour blends

Abstract

The complementary blends of maize (Zea mays L ssp mays) and soybean (Glycine max L Merrill) were stored for a period of 12 weeks. The maize grains were malted by subjecting it to cleaning, washing, steeping, sprouting, drying, desprouting, milling and packaging. A portion of the maize flour was blended with soybean flour at the ratio of 70:30 (malted maize flour: soybean flour; unmalted maize flour: soybean flour). The resulting products were stored in polyethylene and plastic containers. The functional properties (Bulk density, viscosity, water and oil absorption capacity, swelling capacity, peroxide value and least gelation concentration) of the products were determined. The result showed that the bulk density and the peroxide value of both malted and unmalted maize flour reduced significantly (P>0.05) when blended with soybean. The swelling capacities of the malted products were lower than those of the unmalted blends and it also decreased though not significantly (P>0.05) with the period of storage. The malting process reduced the viscosity of the products, however; inclusion of soybean flour increased the viscosity. The viscosity and the peroxide value increased significantly (P>0.05) in the two storage containers as the storage period increased. The result revealed that the packaging materials had no significant effects on the parameters assessed. Key words: Unmalted maize, malted maize, soybean blends, bulk density, swelling capacity, water absorption capacity.