Effect of size reduction by freeze-milling on processing properties of beta-glucan oat bran

•Freeze-milling efficiently reduces oat bran particle size enabling higher yield of beta-glucan recovery.•Freeze-milling can efficiently reduce molecular-weight of beta-glucan preparation.•Particle size reduction form 250–200 μm to 80–50 μm leads to 30% improvement of lipid extraction.

An effect of freeze-milling on processing properties of beta-glucan oat bran has been evaluated. A comparison with existing, patented methods of high molecular weight oat beta-glucan has been carried out. The new method employs raw material pre-treatment with freezing and milling in a hammer mill, resulting in significant reduction of particle size – 89% was between 80 and 50 μm in comparison with initial material when 79% were between 250 and 200 μm. Reduction of particle size also improved some process parameters of extraction technology – 30% improvement in fat removal during first stage of beta-glucan recovery was observed. The achieved pilot plant yield of product containing beta-glucan extraction was 64,03%, purity (ie. beta-glucan content), of achieved product was 84,4% and average molecular weight was about 69,500 g/mol.