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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: Effect of Cooling Methods and Milling Procedures on the Appraisal of Rice Milling Quality

Authors
item Pan, Zhongli
item Thompson, James - UC DAVIS, DAVIS, CA
item Amaratunga, K.S.P. - UC DAVIS, DAVIS, CA
item Anderson, Tom - UC DAVIS, DAVIS, CA
item Zheng, Xianzhe - NORTHEAST AG. UNIV., CHIN

Submitted to: Transactions of the ASAE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 21, 2005
Publication Date: December 1, 2005
Citation: Pan, Z., Thompson, J.F., Amaratunga, K., Anderson, T., Zheng, X. 2005. Effect of Cooling Methods and Milling Procedures on the Appraisal of Rice Milling Quality. Transactions of the ASAE. 48(5):1865-1871.

Interpretive Summary: It is important to accurately measure milling quality through milling a small rice sample. However, the temperature of current rice sample milling equipment changes during the milling process. In order to reduce the effect of the milling temperature on milling quality of rice samples, two different heat exchangers were developed and used for stabilizing the milling temperature. The results showed that the cooling devices improved the accuracy and consistency of rice sample milling.

Technical Abstract: The objective of this research was to appraise the quality of medium-grain rice as affected by cooling and two different Federal Grain Inspection Service (FGIS) milling procedures. Milled rice quality was measured in terms of total rice yield (TRY), head rice yield (HRY) and whiteness. The cooling study used an internal and an external heat exchanger developed for the McGill No. 3 mill with room-temperature water and ice-cooled water as cooling media. Californian M202 rough rice samples of three different qualities were milled using the McGill No. 3 mill with and without cooling following the standard FGIS Western rice milling procedure. The cooling methods increased the TRY and HRY, but decreased whiteness. Every 10°C reduction in the milled rice temperature due to cooling corresponded to an increase of 0.9 percentage points in TRY and 1.7 percentage points in HRY. The rice samples of M202 from California and Bengal from the Southern region milled with the Western milling procedure had lower TRY (1.0 to 1.4 percentage points) and HRY (2.3 percentage points) compared with the Southern milling procedure. Similar quality results obtained using the Southern milling procedure might be produced using the Western milling procedure with heat exchanger cooling.

Last Modified: 7/30/2014
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