The suitability of anthocyanin as a pre-extrusion colour nutraceutical of rice flour was evaluated as a function
of extrusion parameters viz. moisture content, screw speed and temperature of extrusion. The retention of
anthocyanin increased with an increase in the moisture content of feed material and screw speed, but
decreased with an increase in the die temperature. The effect of citric acid and sodium bicarbonate on colour
stability of extrudates during processing, and that of light and packaging materials during storage at ambient
conditions (30± 2 °C) were evaluated. Addition of 1% citric acid increased the retention of anthocyanin up to
18.2% which could reduce the requirement of pre-extrusion colouring by almost 25%. Metallized polyethylene
was found to be a better packaging material than low density polyethylene and protected the extrudates from
light as well as losses during storage.
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