Characterization of Ready-to-Eat Composite Porridge Flours Made by Soy-Maize-Sorghum-Wheat Extrusion Cooking Process

Abstract

The materials used included sorghum, maize, wheat and soybean and two composite flours were formulated Sorghum-Maize-Soy 1 (SMS1) and Sorghum-Maize-Soy 2 (SMS2). Nutritional and functional characteristics of the two products were determined after High Temperature Short Time (HTST) extrusion; SMS2 had higher content (p<0.05) of zinc, magnesium and phosphorus than SMS2. SMS1 and SMS2 had protein content of 23.87 and 17.95% wt (percent weight) respectively with energy value of 1 694.89 and 1 540.88 Kilojoule/100g (KJ/100g) respectively while In vitro Protein Digestibility (IVPD) was found at 72.32 and 68.85% wt respectively. Linoleic acid, linolenic acid and all the essential amino acids were found in both extrudates and lysine was well retained during HTST extrusion. In general, changes in proximate composition, minerals and amino acids content during HTST extrusion were significant in both flours while fatty acids content did not change significantly. SMS1 was characterized by a decrease in viscosity on cooling as indicated by setback viscosity value, 12.00 Brabender Unit (BU), a pointer towards low retrogradation property of the flour. SMS1 had the lowest (p<0.05) peak viscosity of 15.00 BU but showed the highest (p<0.05) paste stability with 2.0 BU of breakdown viscosity. Results showed that SMS1 flour would have better gelation characteristics than SMS2 at similar concentrations with a least gelation concentration of 16.66% (w/v).