Effects of gamma irradiation on aspects of milled rice (Oryza sativa) end-use quality

In China, breeding efforts to create Indica-type rice cultivars with textur al and functional properties similar to Japonica-type rice have not been su ccessful. An alternative strategy is to develop a processing method to modi fy the end-use quality of Indica-type rice. Milled rice samples with low, i ntermediate and high apparent amylose content (AAC) were treated with Co-60 gamma rays. AAC was impacted only by high doses of gamma rays while gel co nsistency was significantly increased. Increasing levels of gamma irradiati on (GIR) reduced rice flour viscosity and increased the temperature of gela tinization onset. Exposure to gamma rays caused the RVA setback (rice pasti ng properties) but not the instrumental texture properties of an Indica-typ e cultivar to become more like that of the Japonica-type rice. GIR of mille d rice for human consumption would be limited to between 2 and 4 kGy becaus e of its negative effects at higher doses on rice color and aroma. However, that level will destroy insects and some microorganism and change rice of unacceptable quality for some consumers closer to being acceptable and may also broaden the functionality of rice for industrial uses.