ABSTRACT
Understanding the quality of products containing a substantial amount of soy protein is essential to meet the demand for soy foods that are acceptable to American consumers. In this study, the effects of sugar and feed moisture contents on the sensory characteristics of extruded corn-soy breakfast cereals were investigated, and the relationships among the product sensory and physical properties and extruder system responses were characterized by generalized procrustes analysis (GPA). Corn meal-soy protein isolate mixes were extruded at feed moistures of 21, 23, and 25% and sugar levels of 0, 5, and 10%. Descriptive sensory attributes, physical properties, and extruder responses were measured. GPA results showed that the breakfast cereal sensory attributes were primarily affected by the sugar-addition level. Products with sugar added at the 5% level were associated with soy and off-flavors, but increasing sugar to 10% yielded an association with crunchiness and hardness. Feed moisture content had a dramatic effect within the 5% added sugar products in determining sensory characteristics. Reverse relationships between mechanical system responses and sensory texture attributes were revealed by GPA results. Increased heat and mechanical forces in the extruder barrel were responsible for higher sensory residual soy flavor and off-flavor intensities.
