COMPOSITION OF OAT BRAN AND FLOUR PREPARED BY 3 DIFFERENT MECHANISMS OF DRY MILLING

Three mechanisms of oat milling were tested for laboratory-scale oat b ran production. Oat bran consistent with AACC definition and commercia lly obtained product was generated with either roller-milling or impac t-milling of greats, followed by sieving to retain larger particles. T hese bran preparations were enriched approximate to 1.7-fold in beta-g lucan and ash, 1.4-fold in protein, and 1.1-fold in lipid. Bran finish ing made further enrichments in protein, beta-glucan, and ash. Temperi ng oat (to 12% moisture for 20 min) improved bran yield from roller-mi lling 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 m ill isolated the outer layers of the great directly, but because of it s low beta-glucan composition it did not meet the AACC definition of o at bran, indicating a relatively uniform distribution of beta-glucan i n the great.