Milling Small Samples of Rice

The International Rice Research Institute (IRRI) Test Tube Mill and the Kett ”Pearlest” Polisher were evaluated in terms of milling performance in comparison with a McGill No. 2 Mill. Degree of milling (DOM), evaluated in terms of percent bran removal (the percentage of weight lost during milling) from brown rice, and whole kernel yield (WKY) were compared using sample lots of medium– and long–grain rice at 12 and 15% m.c. (wet basis). The milling effect of each mill on the shape and size of kernels was compared and analyzed using a Satake image analysis system and a video microscope. Degree of milling and WKY versus milling duration curves were determined for the three mills. The removal of bran as the milling duration increased resulted in a linear reduction of WKY for each mill, although the relationship varied for each mill. The type of mill, moisture content of the samples, and milling duration affected WKY. The type of mill and milling duration affected the shape and dimensions of the milled rice kernels. Overall, the IRRI Test Tube Mill performed better than the Kett Polisher and was comparable to the McGill No. 2 Mill.