Irri Test Tube Mill Operating Parameters

The objective of this study was to optimize the operating parameters of the International Rice Research Institute (IRRI) Test Tube rice mill. The goal was to minimize the milling duration required to attain a milling degree equivalent to a 12% brown rice kernel mass loss. Operating parameters including brown rice mass, milling duration, tube oscillation frequency, and test tube size were investigated with the brown rice kernel mass loss as the response variable. Two rice cultivars, Bengal (medium−grain) and Cypress (long−grain), at 12.5 and 12.1% MC, respectively, were used for the tests. Results indicated that milling with the IRRI Test Tube mill was significantly affected by brown rice mass, milling duration, tube oscillation frequency, and the tube head space. A strategy to set up a milling procedure for optimum parameter combination to attain a 12% brown rice mass loss percentage was proposed. The results provide a guide to users, particularly rice breeders and physiologists, in the selection of proper parameters for removing the bran from small brown rice samples.