The influence of barrel temperature (75-150 degrees C) and screw speed (100-300 rpm) on the retention Of L-ascorbic acid in a rice based extrudate were studied. At all screw speeds used greater losses of L-ascorbic acid occurred as barrel temperature increased. As screw speed increased from 100 rpm to 200 rpm at each temperature, an increase in L-ascorbie acid loss was observed. However, screw speeds above 200 rpm did not appear to have any further affect on L-ascorbic acid loss at all temperatures studied. Retention of the L-ascorbic acid varied between 56.4% and 79.2% with the highest retentions being associated with low screw speed and low temperature. (c) 2006 Elsevier Ltd. All rights reserved.