The influence of barrel temperature and screw speed on the retention of l-ascorbic acid in an extruded rice based snack product Original Research Article

The influence of barrel temperature (75–150 °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-ascorbic 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.