Physical characteristics of extrudates from wheat semolina enriched with cocoa bean shells

Abstract

Response surface methodology was used to investigate the effect of cocoa bean shells content (5 % and 10 %), moisture content (14 % and 20 %) and temperature of the matrix (160 °C and 180 °C) on the physical characteristics of wheat semolina extrudates with cocoa bean shells. The extrusion was carried out on a single screw extruder Brabender 20 DN. A full factorial experiment 23 was used to evaluate the influence of above mentioned parameters on the water absorption index (WAI), water solubility index (WSI) and moisture content (W). The water absorption index varies between 7.13 g/g and 9.91 g/g, water solubility index between 9.34 % and 22.48 % and moisture content between 7.75 % and 11.31 % respectively. The data show that the increase of the moisture content from 14 % to 20 % increases the water absorption index and decreases the water solubility index while the increase of cocoa bean shells content from 5 % to 10 % results in lower water absorption index and higher water solubility index. Temperature of the matrix has no influence on the moisture content and water absorption index. The water solubility index decreases when the temperature of the matrix increases.