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United States Department of Agriculture

Agricultural Research Service

Research Project: NEW TECHNOLOGIES TO PROCESS VALUE-ADDED, HEALTHY FOODS FROM FRUITS AND VEGETABLES

Location: Healthy Processed Foods Research

Title: Influence of Milling Procedures on Milling Quality of Rough Rice with Varying Quality

Authors
item Pan, Zhongli
item Khir, Ragab - UC DAVIS, DAVIS, CA
item Thompson, James - UC DAVIS, DAVIS, CA

Submitted to: Proceedings for CIGR World Congress Meetings
Publication Type: Abstract Only
Publication Acceptance Date: February 15, 2007
Publication Date: N/A

Interpretive Summary: Rice milling quality is one of the major factors determining the economic value of rough rice in trade. It is normally appraised by milling a rice sample with various bench-scale milling methods. However, there is still lack of knowledge about how the sample milling procedures and methods affect the milling quality results if rough rice samples have varying quality. The research determined that milling temperature is a very important factor affecting the milling quality in rice sample milling.

Technical Abstract: Rice milling quality is one of the major factors determining the economic value of rough rice in trade. It is normally appraised by milling a rice sample with various bench-scale milling methods. However there is still lack of knowledge about how the sample milling procedures and methods affect the milling quality results if rough rice samples have varying quality. This research investigated the influence of three milling procedures using a McGill No. 3 mill on the milling quality of rough rice with varying quality. The milling procedures tested were the standard U.S. Western and Southern milling procedures and low temperature milling modification of the Western milling procedure. Low temperature milling was achieved by using a heat exchanger installed on the mill. To create rough rice with varying quality, each of the three lots of medium grain M202 rough rice with moisture of 24.8%, 22.7% and 20.2% was dried to 14% using heated air with four different temperatures, 23, 36, 43 and 53°C. Milling quality was compared based on: total rice yield, head rice yield, whiteness and lipid content. In general, the Western milling procedure produced rice with lower TRY and HRY with whiter color than the Southern milling procedure. However, the low temperature milling of the Western milling procedure produced similar or higher TRY and significantly higher HRY than the Southern milling procedure. HRY reduction caused by a high drying temperature was reduced by the low temperature milling compared to the standard Western milling procedure. It has been concluded that milling temperature is a very important factor affecting the milling quality in rice sample milling.

Last Modified: 7/30/2014
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