Submitted to: The Third South American Oat Conference Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 10/25/1997
Publication Date: N/A
Interpretive Summary: Groat breakage, which may occur during the removal of the oat hull, reduces the value of the milled oat product. Oat bran is an important value-added product derived from milling the dehulled groats. Both groat breakage and bran yield are affected by groat hardness, which we have measured using methods developed for wheat and maize quality analysis. Groat hardness differed in different oat cultivars, and harder groats had less breakage. Increased moisture content of grain decreased groat breakage, increased bran yield, and increased bran yield. Structural characteristics, including groat size and beta-glucan content of groats also appeared to contribute to groat hardness. The results suggest strategies that oat breeders may use to improve groat hardness.
Technical Abstract: Both groat breakage during dehulling and oat bran yield appear to be influenced by groat hardness. Groat hardness, as measured by an automated kernel hardness tester or by the particle size index, was correlated with groat breakage. Correlations of groat hardness with groat beta-glucan suggest a structural basis for hardness. By definition, the particle size index, a measure of hardness, is equivalent to bran yield. Increased grain moisture reduced groat breakage and increased bran yields, presumably by affecting hardness. Oat bran produced by roller-milling or hammer-milling groats, and sieving to isolate larger particles, was enriched in protein and beta-glucan. A product isolated by pearling away the outer layers of the groat was not enriched in beta-glucan, indicating that oat bran is not primarily derived from the outer layers of the groat, but is derived from cell wall distributed throughout the groat.