Effect of Some Mechanical Parameters of Blade Type Whitener on Broken and Fissured Milled Rice of Hashemi Rice Cultivar

Losses in paddy milling are a major concern in Iran. Thus research on the optimization of operating conditions for milling machines is a need. In this regard, an experiment was conducted at rice research institute of Iran in autumn 2007. The effects of two engineering factors of blade type whitener on rice breakage and kernel fissure of Hashemi paddy variety were studied. Three numbers of 22, 24 and 26 for grate magnitudes and three levels of 8, 10 and 12 mm for the distance between blade and hub were considered. Results showed that as the grate magnitudes decreased the percent of rice breakage, at first decreased and then was fixed. Percent of rice breakage decreased with increasing the distance between blade and hub. Maximum fissure in rice kernels was observed at grate No. 22. The effect of grate No. 24 was as the same as No. 26 on rice fissure. Results of statistical analysis of the data indicated that the best treatment for minimum rice breakage and minimum kernel fissure for milling of Hashemi paddy variety by blade type whitener was the combination of distance 12 mm and grate No. 26.