Relationship of moisture content and temperature to discoloration of rice during storage.

Samples of 2 varieties of paddy, ADT 27 and SLO 13, with an initial moisture content (MC) of 10%, were adjusted to 12.0, 13.0, 14.0, 15.0, 16.5 and 18.0% MC by addition of distilled water. The samples were stored in seeled glass jars at room temp. (22-33 degree C), 37 degree or 45 degree C for periods of 0.5, 1, 2, 4 and 18 months. Visual examination showed that no discoloration accurred in samples stored at room temp., although mould growth was observed in the high MC samples. At 37 degree C there was light discoloration in samples with 14% MC stored for 4 months, whereas at 45 degree C some discoloration was apparent after only 2 wk. There was a marked increase in browning with increasing storage temp. and increasing MC. Variety ADT 27 was more susceptible to discoloration than SLO 13. All kernells in a sample were equally discolored.