Technical and economical Comparison of different rice milling methods in Fars province and evaluating the milling methods on the rice nutritional value.

In this study, technical and economical performance of different rice milling methods and their effects on rice nutritional value was evaluated and compared in Fars province. A completely randomized experimental design with three replications was used to analyze the collected data and Duncan , s multiple range test was used to compare the treatments mean. The evaluated treatments were as follows: 1- Using rubber roll husker, compartment type paddy separator, horizontal abrasive whitener and Polisher. 2- Using rubber roll husker, compartment type paddy separator, horizontal abrasive whitener and friction type whitner. 3- Using rubber roll husker, compartment type paddy separator and vertical abrasive whitener. 4- Using rubber roll husker, compartment type paddy separator, vertical abrasive whitener and polisher. 5- Using rubber roll husker, compartment type paddy separator, vertical abrasive whitener and friction type whitener. 6- Using rubber roll husker, compartment type paddy separator and friction type whitener. 7- Using rubber roll husker, tray type paddy separator, vertical abrasive whitener and Polisher ( Imported system from china). Tests were performed at milling factories of Fars province in two years. Two varieties of paddy, champa and shamim ( mid size kernel and long size kernel prevalent in the province) with the same moisture content ( 8 to 10 % wet basis ) were used in the first and second year, respectively. In each treatment 300 kg paddy ( for three replications ) was used. Parameters such as system power requirement, current consumption, electrical energy consumption, system capacity, milling yield, rice breakage percentage, rice cracking percentage, milling loss, kernel protein, kernel ashe, kernel fat, and amount of kernel calcium and iron were measured. Benefit to cost ratio was used to compare the treatments from the economic stand point. Results of the first year showed that the most proper milling method for champa variety ( mid size kernel) was the treatment including horizontal abrasive whitener and polisher ( treatment one ). There was a significant difference between the treatments from the viewpoint of calcium and iron so that the highest amount of calcium and iron was found in treatments one and four. Results of economical evaluation also showed that treatment one was the most economic treatment and treatments, 5, 2, 7, 6, and 4 took the next places, respectively. Results of the second year showed that the best milling method for shamim Variety ( Long kernel) was the method containing horizontal abrasive whitener and friction type whitener ( treatment two ). This treatment also showed the lowest consumption of electrical energy, and the highest system capacity, and milling yield compared to other treatments. There was also a significant difference between the treatments from the view point of fat, protein and iron so that the highest amount of fat, protein, and iron was found in treatments four, seven, and six, respectively. Results of economical evaluation showed that treatment seven was the most economic treatment compared to the other treatment, and treatments, 4,2,5,1, and 6 took the next places, respectively.