Dehulling capacity and storability of naked oat

Abstract

Harvested naked oat is not completely hulless. Hull content of various cultivars ranged between one and six percent. Genotype and environment control expression of nakedness. Using different threshing settings at different grain moisture contents, it was investigated whether grain moisture at threshing and combine harvester settings affected hull content and its relationship to germination capacity. Naked groats were stored at room temperature and analysed for protein content and fatty acid composition to determine storability. Grain moisture content at threshing had contrary effects on hull content and degree of hull retention in different years. Small grains tended to retain hulls more tightly during threshing. Grain filling capacity appears to be the dominant factor determining degree of nakedness rather than stage of maturity. The postulated protective nature of hulls was confirmed only for cultivar Lisbeth. Highly viable samples of grain of cv. Lisbeth, threshed at normal settings, contained a higher percentage of hulls than those with low germination capacity, while for cv. Bullion, a protective effect of the hulls was not evident. Grain moisture content at threshing did not affect protein content of naked cultivars, but some differences in fatty acid composition were recorded. Changes in lipid composition and volatile oxidation products during storage of groats were relatively moderate, indicating no major problems related to storage when naked oat was dried well.