The a* value indicating redness of red-beetroot-coloured extrudates value ranged from 6.19 to 14.70 (Table 1). The increased a* value with respect to increase in MC may be due to the entrapment of the pigments in the dense matrix of the extruded product. The residence time of raw material decreased with an increase in screw speed, thus minimising the thermal action and consequently more retention of the colour. Minimum retention of red beetroot colour (36.63%;Table1) was found at highest temperature (180 °C), lowest MC (14%) and slowest screw speed (150 rpm) used in present extrusion processing. The colour retention also increased by increasing the MC of feed material, and screw speed confirming the sensitivity of red beetroot colour/betalains to temperature. Henry (1992) explained the betanin degradation, as mediated by temperature and/or base, presumably involves nucleophilic attack (e.g. by water) at the C-11 position yielding cyclodopa-5-O-glycoside and betalaminic acid which changes the colour from red to yellow. This study showed the retention of red beetroot colour/betacyanins under extrusion conditions to be better than other food systems such as pitaya juice (Herbach et al.2004b). The b* value of the coloured Moisture content extrudates was not significantly affected by extrusion processing parameters.