The Relation of Flour Color Degradation with the State of Bran Coat Alteration by Rainfall during the Ripening Period in Common Wheat (Triticum aestivum L.)

Exposure to rain during the ripening period not only degrades the quality of wheat grain, but also adversely deteriorates the color of flour. To investigate the relation between exposure to rain in the ripening period and the degradation of the flour color using 5 wheat varieties. We examined the effects of rain on grain quality, milling characteristics, and flour quality. Three expousures to rain reduced the grain test-weight by 1%, and resulted in a 7-point reduction in grain hardness according to the Single Karnel Classification Sysytem Hardness Index (SKCS-HI). The grain exposed to rain showed exfoliation between cell layers. These gaps between the barn coat layers may cause brittleness of the grain husk. Consequently, it was assumed that the flour could be contaminated with the grain husk during milling. And thus, the grain exposed to rain produced flour with inferior color characteristics.