Physical characteristics of extrudates from corn semolina flavored with cocoa shells

Abstract

Extrusion of corn semolina milled with cocoa shells using a single screw extruder "BRABENDER 20 DN"was carried out. Full factorial experimental 22 was used to investigate the effects of the quantity of cocoa shells and moisture of the material on the water absorption index (WAI) and water solubility index (WSI). Working screw speed and feed screw speed were fixed at 200 and 40 rpm, respectively. Compression ratio of the screw was fixed at 4:1. Temperatures of the first, second and third zone were 150, 155 and 160°C. Water absorption index values range were between 6.71 and 7.6 g/g and the water solubility index between 25.38 and 35.33%. The increase in moisture content and quantity of cocoa shells leads to an increase in water absorption index and a decrease in water solubility index. Organoleptic characteristics of extrudates were also analysed. The increase in moisture content leads to more unsatisfactory organoleptic characteristics of the extrudates. Practical applications: Cocoa shells in an amount of up to 10% can be used in the production of extrudates by mixing with corn semolina. Water absorption index values range between 6.71 and 7.6 g/g and the water solubility index between 25.38 and 35.33%. Sensory characteristics of extrudates values range between 3.8 and 4.8. The resulting regression models can be used to optimize the process. The best sensory characteristics were obtained for extrudates with moisture content of 14% and a cocoa shells content of 5%. In general, results show that cocoa shells can be mixed with corn semolina for the production of extrudates, which allows us to recommend extrusion processing of cocoa shells as an alternative technology in utilization processing of raw cocoa materials.