The effects extrusion conditions on physical properties and flour dispersion viscosity of an extruded maize/Vigna unguiculata (85/15) mixture were studied A Brabender 20 DN extruder, with 4:1 screw compresion ratio, a 3 mmm die and 150 rpm, was used to obtain expanded samples from mixture. Surface response methodology was used to analyze the effects of grits moisture content and extrusion temperature on product characteristics. Factors levels were: 15%-17%-19 % and 150 ºC-165 ºC-180 ºC. The following characteristics were selected as responses: specific mechanical energy consumption, expansion; density, texture, water solubility and flour dispersion viscosity. Texture was evaluated, objectively by a compression test and subjectively, using a trained panel. Flour dispersion containing 10, 13 and 15% solids were prepared, and viscosity was determined using a Haake Rotovisco RV3 viscosmeter. As a way of comparison, samples of extruded maize grits and a commercial formula for pea cream soup were also used.The highest hardness values corresponded to the sample obtained at 150ºC and 19% and the lowest one to that obtained at 180ªc and 15%.Flour dispersion corresponding to extruded samples had viscosity values significantly lower that those of pea commercial sample. The highest viscosity corresponded to sample obtained at 150ºC and 19%, while the lowet one to that obtained at 180ºC and 15%, At 165 ºC and 15%, extrudate with good physical properties was obtained and also precooked flour having a high degree of cooking could be used to prepare cream soup type products with nutritional advantages.
The effects extrusion conditions on physical properties and flour dispersion viscosity of an extruded maize/Vigna unguiculata (85/15) mixture were studied A Brabender 20 DN extruder, with 4:1 screw compresion ratio, a 3 mmm die and 150 rpm, was used to obtain expanded samples from mixture. Surface response methodology was used to analyze the effects of grits moisture content and extrusion temperature on product characteristics. Factors levels were: 15%-17%-19 % and 150 ºC-165 ºC-180 ºC. The following characteristics were selected as responses: specific mechanical energy consumption, expansion; density, texture, water solubility and flour dispersion viscosity. Texture was evaluated, objectively by a compression test and subjectively, using a trained panel. Flour dispersion containing 10, 13 and 15% solids were prepared, and viscosity was determined using a Haake Rotovisco RV3 viscosmeter. As a way of comparison, samples of extruded maize grits and a commercial formula for pea cream soup were also used.The highest hardness values corresponded to the sample obtained at 150ºC and 19% and the lowest one to that obtained at 180ªc and 15%.Flour dispersion corresponding to extruded samples had viscosity values significantly lower that those of pea commercial sample. The highest viscosity corresponded to sample obtained at 150ºC and 19%, while the lowet one to that obtained at 180ºC and 15%, At 165 ºC and 15%, extrudate with good physical properties was obtained and also precooked flour having a high degree of cooking could be used to prepare cream soup type products with nutritional advantages.
