Abstract

This research study was aimed to develop nutritious and sensorial acceptable teff based expanded product through optimization of extrusion process parameters. The experimental study was performed using response surface methodology face centered central composite design. Teff, maize and decorticated lentil composite flour was extruded through twin screw food extruder at different barrel temperature (120, 140, 160°C), feed moisture content (14, 17, 20%) and blend ratio BR1 (70T:20M:10L), BR2 (60T:25M:15L) and BR3 (50T:30M:20L) at constant screw speed (340 rpm). The physical, functional, textural and sensory characteristics of extrudates were inspected and their responses were examined. Maximum expansion ratio (4.85), maximum water absorption index (7.80), minimum hardness (13.49 N/g) and minimum bulk density (0.108 g/cm3)were found at 140°C barrel temperature, 14% feed moisture content with blend ratio of 60% Teff, 25% Maize and 15% Lentil (60T:25M:15L). Acceptable extrudates with added vanilla powder additive were significantly (p<0.05) better in colour, flavor, crispiness and overall acceptability. The model developed could be used for designing of extrusion process parameters in order to get extrudates with desirable characteristics.

Keywords:

Blend ratio, expanded product, extrusion process parameters, gluten-free snacks, process optimization, teff,

References