University of Arkansas, Fayetteville Division of Agriculture


The objective of this research was to determine the influence on drying characteristics of storing high-moisture content (MC) rough rice under various conditions and durations before drying. Two cultivars of rice, 'Bengal', a medium-grain cultivar, and 'Cypress', a long-grain cultivar, were used. The MC of 'Bengal' was 24.8%1 and that of 'Cypress' was 20.4% at harvest. Immediately after harvest, drying runs were performed with samples of both cultivars under two drying air conditions: one at 51.7°C (125°F) and 25% relative humidity (RH), and the other at 60°C (140°F) and 17% RH. Storage treatments using the high MC rice were also initiated immediately after harvest. Both cultivars of rough rice were stored for one month (i.e., 27 d) and three months (i.e., 76 d) in either a walkin freezer at –9°C (15°F), a household refrigerator at 3.5°C (38.3°F) or a walk-in cooler at 4°C (38.5°F). After one month and three months of storage, all samples were dried under the same two drying air conditions as at harvest. The head rice yield (HRY) was determined for all the dried samples. There were no differences in the HRYs of samples that were stored for one or three months and then dried and in those HRYs of samples dried immediately after harvest; this finding was consistent across the three storage temperatures for both cultivars. The trends in HRY reduction were similar to previously reported drying trials using these drying air conditions. This research indicates that it is possible to store rough rice at high MCs for up to three months under storage temperatures varying from –9°C to 4°C without affecting HRY.