Determination of dockage for accurate rough rice quality assessment.

摘要

Determination of dockage of freshly harvested rice is crucial for precise development of a universal rice shrink chart. The objectives of this research were to determine the effect of different factors, including rice variety, farm location, harvest moisture and time, drying, dropping, weather events such as wind and rainfall, and type of harvester, on dockage. The study was conducted during two consecutive rice harvesting seasons. The dockage of freshly harvested rice with moisture content (MC) ranging from 18% to 27% wet basis (w.b.) varied between 0.2% and 2.0% with averages of 0.92% and 0.79% in 2010 and 2011 harvest seasons, respectively. The corresponding averages of dockage of dried rice with MC of 14+or-1% (w.b.) were 0.78% and 0.65%, which were lower than those of freshly harvested rice. There were no significant differences (p>0.05) in dockage among the studied rice varieties. It was also observed that dockage was not significantly affected (p>0.05) by the harvest MC, geographical location and dropping from certain height. However, wind and rainfall events significantly (p<0.05) increased the dockage. The results also revealed that the type of harvester affected the dockage. The obtained dockage results for all tested factors were significantly (p<0.05) lower than 2% which is the value accepted in the rice industry at present.