2.4.2. Preparation of colourant powder using steaming-assisted solvent
extraction (CP-ST)
Steam heating was conducted by following the method developed
by Juliano (1985). A rice bran sample (180 g) was steamed in an
autoclave (ACV-3167 IWAKI) at 115 °C. When the inside temperature
of the bran reached 105 °C, it was held for a minute, removed from
the chamber and cooled at an ambient temperature. To obtain the CPST
and CP-RB (colourant from raw rice bran), the steamed and raw
bran samples were extracted, dried, stored and analysed using the
same conditions as the CP-OHM.
2.5. Chemical analysis
Moisture content, crude protein, ash, crude fat and total dietary fibre
of the raw rice bran samples were determined according to the official
methods of AOAC (2000) in triplicate. The water activity (aw) of the
colourant powder was measured with a digital aw meter (Aqualab®,
USA).