Comparison of Operational Parameters and Energy Consumption in Rice Milling Systems (Case Study in Mazandaran Province)

In this research, operational process and energy consumption of paddy milling factories in three categories: conventional system (Engelberg Machine for hulling and whitening), semi modern system (Rubber roll dehusker and Engelberg whitener), modern system (Rubber roll husker and abrasive whitener) were investigated in Mazandaran province of Iran. Besides, milling efficiency, Degree of hulling, breakage percent of brown rice and white rice, degree of whitening, and quality factors gelatinization index, percentage of elongation and amylose of cooked rice were studied. Analysis of results indicated that no significant difference exist in degree of milling among conventional, semi modern and modern systems. The changes in the milling efficiency ranged between 62.45 to 63.58 percents. The milling systems had significant difference in hulling operation. Using rubber roll de husker decreased grain breakage and adding gravity separator to dehulling process increased dehulling to 96 percent. Engelberg de husker and whitener had significant effect on brown rice breakage and whitening than Rubber roll dehusker respectively. Results showed yhat, modern rice milling system had less harmful effects on rice than other systems. Rice milling systems did not have significant effect on amylose and gelatinization index of white rice. The parameters and gelatinization index varied in treatments from 21 to 22 percent and 3.97 to 3.99 respectively. Using of conventional milling system has more effect on cooked rice elongation percent than other systems. Results showed that, drying and milling of paddy consume 683.8 and 158.4 MJ thermal and electrical energy per ton respectively.