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United States Department of Agriculture

Agricultural Research Service

Title: Influence of Kernel Size and Shriveling on Soft Wheat Milling and Baking Quality

Authors
item Gaines, Charles
item Finney, Patrick
item Andrews, Lonnie

Submitted to: Cereal Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 14, 1997
Publication Date: N/A

Interpretive Summary: Some millers and grain quality evaluators believe that small kernels of soft wheat have inferior milling and baking qualities compared to larger kernels. Small kernels are also considered by some to be harder than larger kernels. A large percentage of the eastern U.S. soft wheat crop has some shriveled kernels and those shriveled kernels tend to be smaller than nonshriveled kernels. Likely, that relationship has led some to equate the quality of small kernels with the quality of shriveled kernels. Individual cultivars were separated into large, medium, and small kernels that had no shriveling. Other cultivars were separated into sound, moderate, and severely shriveled kernels, which decreased in size as shriveling progressed. Shriveling greatly decreased the amount of flour produced during milling, as well as other milling quality characteristics. Shriveled kernels were much softer in texture than nonshriveled kernels. Shriveled kernels produced flour that had inferior soft wheat baking qualities. On the other hand, kernels that were small and not shriveled had relatively few differences with larger nonshriveled kernels. Small nonshriveled kernels were softer than larger nonshriveled kernels. Small nonshriveled kernels also had slightly better baking quality than larger kernels. These findings show the miller that there is potential for greater flour yield if small sound kernels can be isolated from shriveled kernels during cleaning. The very poor quality of shriveled kernels, suggest that federal standards for measuring dockage percentage in soft wheat may need to be revised as not all shriveling is included in the dockage estimate.

Technical Abstract: Small kernels of soft wheat are often considered to be harder than larger kernels and to have inferior milling and baking characteristics. A distinction was made between kernel size and kernel shriveling. Nine cultivars were separated into large, medium, and small kernels that had no shriveling. Fourteen cultivars were separated into sound, moderate, and severely shriveled kernels, which decreased in size as shriveling progressed. Shriveling greatly decreased the amount of flour produced during milling, as well as other milling quality characteristics (endosperm separation index and friability). Shriveled kernels were much softer in texture than nonshriveled kernels (measured by break flour yield, particle size index, and flour particle size). Shriveled kernels produced flour that had inferior soft wheat baking qualities (smaller cookie diameter and higher alkaline water retention capacity). However, kernels that were small and not shriveled had relatively few differences with larger nonshriveled kernels. They had relatively similar test weight, were not diminished in milling quality, and they were softer in kernel texture and had slightly better baking quality (larger cookie diameter) than larger nonshriveled kernels. Smaller nonshriveled kernels did not have diminished total flour yield potential, diminished break flour, or diminished reduction flour milling characteristics. Those observations suggest a possibility of separating small sound kernels from small shriveled kernels to improve flour yield and the need to improve dockage testing estimation techniques to distinguish between small shriveled and small nonshriveled kernels.

Last Modified: 4/17/2014
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