Extrusion Cooking and its Impact on the Overall Acceptability of Snacks Produced from Aerial Yam and Soybean Composite Flour

This study evaluated the impact of extrusion cooking on the overall acceptability of snacks produced from aerial yam and soybean composite flour. Design Expert (version 11.0.1) was used in the experimental design, with a three-factor experimental set-up at five levels each. The aerial yam and soybean composite flour was formulated in the ratio of 1:3 and extruded using laboratory scale single-screw extruder. Twenty runs were carried out to produce twenty samples for the sensory test. Response Surface Methodology was adopted in analyzing the effect of the independent variables on the dependent factors. Results of sensory evaluation showed that the overall acceptability scores ranged from 4.20 to 7.10. The least score of 4.20 for overall acceptability was recorded for snacks produced at 100 barrel temperature, 100 rpm screw speed and 33% feed moisture, while the highest score (7.10) for overall acceptability was obtained from snacks produced at 110 barrel temperature, 100 rpm screw speed and 37% feed moisture. Response surface analysis revealed that an increase in barrel temperature, screw speed and feed moisture resulted in an increase in the overall acceptability. The overall acceptability of the snacks was significantly (p < 0.05) affected by barrel temperature and feed moisture, while the screw speed had no significant (p > 0.05) effect on the overall acceptability. The interaction of the extrusion cooking parameters had a significant (p < 0.05) effect on the overall acceptability of the snacks. The acceptability scores ranged from 4.20 to 7.10, indicating moderate to high acceptance by sensory panelists.