On the Temporary Storage of High-Moisture Rough Rice : II. Effect of harvesting dates on the quality of rough rice grains during the storage

Abstract

In the present investigation, the authors observed the changes caused during the storage in the quality of rough rice grains harvested at the different dates (i. e., August 4, September 5, and November 7). For this purpose, rough rice grains were conditioned at four moisture-content levels: approximately at 16, 18, 22 and 24 % and stored for 30 days at variable temperatures in a barn of wooden construction (room air temperatures: 30.0°C to 28.4°C on August 4; 25.8°C to 17.6°C on September 5; and 15.2°C to 7.5°C on November 7). The results are summarized as follows: 1. The occurrence of deteriorated grain during the storage for 30 days showed an increasing trend in proportion to the earlier harvesting date (higher storage temperature) and higher moisture-content. 2. Viability of embryos (TZ values) tended to decrease more rapidly with longer storage duration, earlier harvesting date and higher moisture-content. 3. In case of grains with less than 17 % moisture-content, grains, irrespective of harvesting dates, could be stored safely for as long as 30 days without any noticeable deterioration in the quality. In case of grains with 18.4∼18.7% moisture-content, grains harvested on August 4 could be stored safely for 20 days and on September 5 and November 7 for 30 days; grains with 20.0∼20.2% moisture-content harvested on August 4 could be stored safely for 7 days and grains harvested on September 5 and November 7 could be stored for 30 days; grains of 21.4∼22.0 % moisture-content could be stored safely for 3 days only in case of grains harvested on August 4, for 10 days in case of grains harvested on September 5, and for as long as 30 days in case of grains harvested on November 7. In case of grains containing 23.4∼24.6% moisture-content, grains harvested on August 4 were impossible to be stored even for one day, but grains harvested on September 5 and on November 7 could be stored safely for one day and for 10 days, respectively.