OAT GUM AND BETA-GLUCAN EXTRACTION FROM OAT BRAN AND ROLLED OATS - TEMPERATURE AND PH EFFECTS

The extractability of oat pm from oat bran and rolled oats was studied using 12 treatment combinations in a factorial design (2x3x4x2) i.e. 2 oat products; 3 pH (8.0-10.5); 4 temperatures (50-70-degrees-C); 2 replications. The extraction procedure involved: (a) alkaline treatment of flour and removal of starch residue; (b) isoelectric precipitation of protein residue [namely, protein concentrates (PC)]; (c) and alcohol precipitation of oat gum/beta-glucan and collection of pm by centrifugation. Extracted oat pm ranged from 2.99-6.28% for oat bran and 1.82-5.24% for rolled oats whereas beta-glucan (in gum) ranged from 70-89% and 50-68%, respectively. Protein contents of the PC from oat bran was 69-91% and rolled oats 66-89%. Correspondingly, starch content of residues ranged from 30-63% and 61-87%. Oat gum/beta-glucan extracted at pH 9.2/50-degrees-C or pH 10.5/50/55-degrees-C showed little or no starch contamination.