Accurate Test for Determining
Wheat Color Class
By Linda McGraw
November 27, 2000
The ability to separate hard red
wheats from whites has been improved by Agricultural Research Service scientists.
Its an important advance for export markets because baking and milling
characteristics of hard red and white wheat varieties differ--and theyre
difficult to distinguish visually. Wet weather and other environmental factors
can add to the difficulty. For instance, red wheat thats been rained on
can look white. Red wheats are typically used for baking breads, but white
wheats are used to produce bright yellow noodles for Asian consumers.
The new test uses a dilute sodium hydroxide to accentuate color differences
between the reds and the whites. Perten
Instruments in Springfield, Illinois, has already turned the test into a
kit available to aid grain elevator operators.
The idea is not new, but until now the procedure has not been standardized
enough to serve as a reliable indicator. ARS postdoctoral chemist M.S. Ram and
agricultural engineer Floyd Dowell at the Grain Marketing and Production Research
Center in Manhattan, Kansas, optimized the procedure so that correct color
class can be determined in 10 minutes. Grain elevator operators can use the kit
at a cost of only pennies per sample.
Several grain elevator managers in Kansas used the kit during the 2000
winter wheat harvest season. USDAs
Inspection Service (FGIS) is considering adopting the kit as an alternative
to visual inspection now voluntarily performed by grain inspectors.
The kit includes a heater, test tubes, thermometer and enough sodium
hydroxide to last through harvest. It costs about $100 and is available from
Perten Instruments or from the
Kansas Grain and Feed
Association, Topeka, Kansas. This project was funded by the
Kansas Wheat Commission and administered
through the Grain Industry Alliance under a Cooperative Research and
Development Agreement (CRADA). The research may help expand export markets for
hard white wheat, which is becoming more popular with Great Plains wheat
ARS is the chief scientific research agency for the
U.S. Department of Agriculture.
Scientific contact: Floyd Dowell, ARS Grain Marketing and Production
Research Center, Manhattan, Kan., 66502, phone (785) 776-2753, fax (785)