Pre-extrusion aromatization of a soy protein isolate using volatile compounds and flavor enhancers: Effects on physical characteristics, volatile retention and sensory characteristics of extrudates

The effect of aromatization of a soy protein isolate, using volatile compounds (isovaleraidehyde, ethyl butyrate and butyric acid) and flavor enhancers, with extrusion under different conditions, on the physical characteristics, volatile retention and sensory characteristics of extrudates was investigated. With 30% feed moisture and 170 degrees C processing temperature, the extrudates had greater expansion ratio and lower density, cutting force and compression force when rehydrated. Under the same extrusion conditions, addition of flavor enhancers to the soy protein isolate resulted in greater retention of isovaleraldehyde and ethyl butyrate. The aroma intensity significantly decreased and sensory acceptability significantly increased as the feed moisture reduced and processing temperature increased. Based on principal component analysis, the soy protein isolate with added volatile compounds and flavor enhancers, which was extruded under 30% feed moisture and 170 degrees C temperature, resulted in extrudates with desirable physical characteristics, improved volatile retention and greater sensory acceptability. (C) 2014 Elsevier Ltd. All rights reserved.