Soybean (Glycine Max) Processing and Performance in Fermented Maize Dough System

Abstract

The effect of addition of processed soybean flour on the physicochemical characteristics of fermented maize dough was studied. Soybean flours; Full-fat, Extruded, and Defatted soy-flours were processed and added to maize dough before and after fermentation of the dough. The soy were added to the dough at 0,10,and 20 percent concentrations. The dough samples were also fermented at 0,6,24 and 4 8 hours respectively. Two traditional food products; Ga kenkey and Akasa (Porridge) were also prepared from the soymaize dough samples and subjected to sensory evaluation to assess product performance. Physicochemical analysis indicated that pH of the soy-fortified, dough was affected significantly by the method of addition of the soy flour, soy-flour concentration, and the fermentation time. Total titratable acidity of the soy-maize doughs were dependent on these factors. Generally pH of the dough decreased and total titratable acidity increased with increase fermentation time. Addition of Full fat soy flour to the maize dough before fermentation was found to promote fermentation resulting in higher acidity of dough. Hence increase in sourness of the dough. Regression models for pH and total titratable acidity were developed to predict various indices in the soymaize dough systems. Water absorption characteristics of the samples were observed to be dependent' on the temperature and fermentation time. Water absorption at 70°C were generally higher than at 29°C. Amylograph pasting properties indicate that addition of soyflour to maize dough caused a reduction in viscosity. Viscosity characteristics generally increased with increase in fermentation time. The soy fortified maize dough showed lower viscosity characteristics compared to the maize dough(no soy) sample. Sensory analysis indicated the Ga-kenkey and Akasa prepared from soy-fortified maize dough generally showed lower mean scores hence lower consumer preference for colour, taste, flavour and texture compared with samples containing no soy flour. General acceptability scores indicated no significant difference between samples containing no soy flour and that containing Full fat soy flour in which soy was added after fermentation of the maize dough. The two samples were also most acceptable to the consumers. The incorporation of Full-fat soy flour to Ga-kenkey and Ak'asa is therefore promising. Difference test (Triangle test) also revealed significant differences in colour, taste, texture and flavour between the maize dough (no-soy) samples and the soyfortified maize dough samples indicating the influence, of soyflours addition on sensory characteristics.