The machine is equipped with two air ducts. The first ducts as the main separator which serves to suck out husk of the paddy husker. The second ducts serves as a second separator. If there are brown rice that is carried along with the husk on the main separator or if there are husk that is carried along with paddy rice on the main separator, it will be separated again by the second separator.
The DOM is a quantification of the amount of bran that has been removed from kernels during the milling process. The DOM is influenced by the grain hardness, size and shape, depth of surface ridges, bran thickness and milling efficiency. Harder rice requires greater energy to obtain the same DOM. The energy consumption during milling is also depends on the grain thickness, hardness, shape and variety, and DOM. Lower surface hardness facilitates breakage during milling, resulting lower milled rice recovery and quality in the case of long grains compared to that of short grains. Mass loss and breakage are affected by cultivar, kernel shape, and thickness of aleurone layer. The flow ability of short grains is higher than that of long grains through the milling chamber of friction type milling machine results in lower degree of breakage during milling, leads to produce greater amount of head rice. Roy et al. reported that in the case of the milled rice option, PBR contains 3% broken grains and untreated rice contains 13% broken grains, would be acceptable to the local consumers. The overall energy consumption during dehusking and milling is reported to be greater in the case of PBR compared to the untreated rice.
Many types of rice are labeled "white" in the store. In reality, there are many shades of white, ranging to near brown. The lighter shades of white are produced by abrasive rice whitener that whiten the stock to various shades of the color.