Effects of controlled ambient aeration on rice quality during on-farm storage

Rice (Oryza sativa L., 'Cypress') quality is highly dependent on its handling; hence, new storage treatments must be analyzed for their impact on rice quality. Rough rice from the 2000 season was harvested, dried, and stored in six farm-scale bins. Three of the bins were aerated with a thermostatically activated controller, and three were aerated under traditional methods. Rice was sampled periodically over 12 weeks, and quality parameters were analyzed. The effects of bin sample position (spatial), bin sample depth, aeration treatment, and storage duration were investigated for their impact on rice quality factors: moisture content, head rice yield, pasting properties, and water absorption. For both aeration treatments at most sampling durations, rice sampled from the center of the bins had significantly lower head rice yield than that sampled from the north and south areas. Overall, moisture contents were not significantly affected by sampling position, although, in some specific sampling time and aeration treatment combinations, significant variation was noticed for moisture content as a function of sampling position. Sample depth within the bin did not cause any changes in the values of the rice properties. Throughout the storage duration, the physicochemical properties of the rice treated with controlled aeration were consistent with the trends of the rice treated with manual aeration. Storage duration significantly influenced (P < 0.05) water absorption, peak viscosity, head rice yield (HRY), and moisture content, with all but moisture content increasing over the storage duration. In contrast, the moisture content of the grain slightly decreased over the storage period.