Document Type : Research Paper
Abstract
Decreasing crop loss is a way to achieve agriculture self-sufficiency. Many parameters affect the quality and quantity of rice loss, including the type of processing and grain moisture content. This study compared abrasive and blade (Engelberg) whitening systems for percentage of grain breakage and degree of milling. In addition, optimum milling moisture content was determined for both systems. The effect of two types of whiteners (abrasive and Engelberg) was investigated on rice quality for three rice cultivars (Sorkhe, Sazandegi and Tarom) at four moisture contents (14%, 12%, 10%, and 8%) using a factorial test based on a complete randomized block design with three replications. Percent of rice breakage, degree of milling, work capacity, and power consumption were measured for each treatment. The results showed that the effect of rice cultivar, whitener type, moisture content and their interactions caused significant differences at the 1% level. Sorkhe and Tarom rice cultivars had minimum and maximum rice breakage percentages, respectively. Rice breakage and degree of milling were lower for the abrasive whitener than for the Engelberg whitener. The sample with 14% moisture content had the minimum degree of milling and maximum rate of breakage. The optimum moisture contents for milling for Sorkhe, Sazandegi and Tarom rice cultivars by abrasive were 10%, 12%, and 10%, respectively. For the Engelberg whitener it was 10%, 12%, and 12%, respectively. Work capacity and power consumption were 1.7 and 3.43 times higher, respectively, for the abrasive system than for the blade system.
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