Composition of oat bran and flour prepared by three different mechanisms of dry milling

Three mechanisms of oat milling were tested for laboratory-scale oat bran production. Oat bran consistent with AACC definition and commercially obtained product was generated with either roller-milling or impact-milling of greats, followed by sieving to retain larger particles. These bran preparations were enriched approximate to 1.7-fold in beta-glucan and ash, 1.4-fold in protein, and 1.1-fold in lipid. Bran finishing made further enrichments in protein, beta-glucan, and ash. Tempering oat (to 12% moisture for 20 min) improved bran yield from roller-milling nearly two-fold but had little effect on bran composition. Bran yield from the impact-type mill was significantly affected by grinding screen size. Oat bran obtained from a pearling mill was only slightly enriched in beta-glucan and protein, but it was more heavily enriched in ash and oil than brans from roller or impact mills. The pearling mill isolated the outer layers of the great directly, but because of its low beta-glucan composition it did not meet the AACC definition of oat bran, indicating a relatively uniform distribution of beta-glucan in the great.