The composition of oat husk and its variation due to genetic and other factors

Abstract

Abstract The composition of oat husk has been determined in (i) 11 diverse oat genotypes, (ii) current high‐yielding spring and winter varieties from trials in various regions of Britain, and (iii) samples obtained from two British oat mills. Husks were comprised mainly of cell wall (>83%) with about equal quantities of cellulose and hemicellulose (∼30‐35%). Lignin and ash contents were 2–10% and 3.5–9% respectively. Protein and oil contents were low (1.6–5% and 1–2.2%) and only a proportion of the protein (40–60%) and total oil (5–30%) were of apparent nutritional significance. Starch and water‐soluble carbohydrates were very low (<2% and <1%). Pepsin‐cellulase digestibility was low (7–14%) and it was negatively correlated with lignin content in the 11 genotypes. There were significant genetic differences in composition within both the 11 genotypes and the trial varieties; however, the range was small and there were significant differences due to location among the trial varieties. Husk, which was hand‐separated from oat mill samples, was generally inferior in quality to the genotypes and varieties. However, due to groat contamination, industrially separated samples from the oat mills were similar in composition to those from other sources. It is confirmed that oat husk is a poor quality feedstuff and the most significant improvement in grain quality could be made by breeding for reduced husk content.