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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: Simultaneous Rough Rice Drying and Disinfestations with Infrared Radiation

Authors
item Pan, Zhongli
item Khir, Ragab - UC DAVIS, DAVIS, CA
item Lewis, Richard - UC DAVIS, DAVIS, CA
item Godfrey, Larry - UC DAVIS, DAVIS, CA
item Salim, Adel - SUEZ CANAL UNIV., EGYPT
item Thompson, James - UC DAVIS, DAVIS, CA

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: December 1, 2005
Publication Date: N/A

Interpretive Summary: The goal of this research was to develop rapid, non-chemical, safe alternative methods to eliminate insect pests from freshly-harvested paddy rice while retaining high rice quality. Alternatives are needed to replace the planned decommissioning of currently licensed pesticides. Infrared radiation was evaluated for its effectiveness in simultaneous drying and infestations, and retaining the milling quality of freshly-harvested rice. The results showed that the infrared radiation can be used for simultaneous rice drying and disinfestations with high rice milling quality.

Technical Abstract: The objective of this study was to investigate the processing performance of infrared heating for simultaneous drying and disinfestations. Freshly harvested medium grain rice samples, M202, with 20.6% and 25.0% moisture were used for this study. Before the drying, each 250 g rice sample was infested with 100 adult lesser grain borers (Rhizopertha dominica), and 50 adult angoumois grain moths (Sitotroga cerealella). The infested rice samples were dried as single-layer bed using a catalytic infrared dryer with the radiation intensity of 5348 W/m2 and four exposure times (25, 40, 60, and 90 sec). After heating, the tempering treatment was studied by placing the samples into incubators with different temperatures for four hours and the treatment results were compared with those of non-tempering treatment. The heating results showed that the obtained grain temperature ranged from 49 ºC and 68ºC under the tested heating conditions resulting in moisture removal from 0.8 % to 3.1 %. During natural and forced air cooling with ambient air, additional 0.4% to 2.0% moistures were removed. When the grain temperature was higher than 60ºC, all adult insects had been killed regardless of with or without tempering. The minimum grain temperature was 58ºC (40 sec heating) for killing all the insects with tempering. The 58°C treatment did not affect the milling quality of the rice samples.

Last Modified: 4/20/2014