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Title: DEVELOPMENT OF STANDARD PROCEDURES FOR A SIMPLE, RAPID TEST TO DETERMINE WHEAT COLOR CLASS

Author
item RAM, M - KSU, MANHATTAN, KS
item Dowell, Floyd
item Seitz, Larry
item Lookhart, George

Submitted to: Cereal Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/27/2001
Publication Date: 3/1/2002
Citation: Ram, M.S., Dowell, F.E., Seitz, L.M., Lookhart, G.L. 2002. Development of standard procedures for a simple, rapid test to determine wheat color class. Cereal Chemistry. 79(2):230-237.

Interpretive Summary: Growing conditions, kernel characteristics, and genetics affect wheat kernel color. As a result, red and white wheats sometimes cannot be differentiated by visual examination. Red and white wheats must be kept segregated, because they have different end uses. Soaking wheat kernels in a sodium hydroxide (NaOH) solution causes the difference in color to be enhanced; red wheat turns a darker red, and white wheat turns straw-yellow. Previously, when NaOH was used for wheat determination of color class, only a visual assessment was made under arbitrarily chosen conditions, many times not suitable for field work. In this research, we optimized the soak time, concentration, and temperature. The optimal procedure will enable users who are not laboratory trained to utilize inexpensive, safe procedures to definitively assign wheat color class in the shortest time in field locations. The test differentiated even rain-bleached wheat and varieties that were difficult to classify visually. Rapid identification of wheat color class will allow the US wheat industry to keep wheat properly segregated and enhance our ability to compete in potential white wheat export markets.

Technical Abstract: Growing conditions, kernel characteristics, and genetics affect wheat kernel color. As a result, red and white wheats sometimes cannot be differentiated by visual examination. Soaking wheat kernels in a sodium hydroxide solution causes the difference in color to be enhanced; red wheat turns a darker red, and white wheat turns straw-yellow. Previously, when NaOH was used for wheat determination of color class, only a visual assessment was made under arbitrarily chosen conditions, many times not suitable for field work. In the present work, visible reflectance spectroscopy and visual assessment were used to optimize NaOH soak time, concentration, and temperature. The optimal procedure will enable users who are not laboratory trained to utilize inexpensive, safe procedures to definitely assign wheat color class in the shortest time in field locations. Calibration and prediction of several wheat varieties, using partial least square regression, were used to validate the optimal test procedure. The test differentiated even rain-bleached wheat and varieties that were difficult to classify visually. No distinct correlation occurred between predicted color value and the number of red genes.