Effect of flour particle size on beta-glucan and polyphenol content of three Moroccan oat varieties

Food industries have been increasingly interested on oat grain thanks to its bioactive compounds dense with confirmed functional properties. The study aims to explore the effect of flour particle size of 425 µm, 560 µm, 670 µm, 1000 µm, whole flour and bran of oat on beta-glucan and polyphenol content. The six flour fractions from three Moroccan oat varieties, of which one is naked grain, were investigated. The three oat varieties have beta-glucan contents of (4.08%, 3.42% and 2.49%) and polyphenols contents of (351.0, 360.7 and 560.1 µgEAG/g) respectively. The results showed a high contents of these two compounds in the bran fraction and the fraction with a particle size smaller than 1000 µm and greater than 670 µm. The beta-glucan content showed the largest variation, from 6% in both fractions to 1.3% in the fraction with particles smaller than 425µm. Mastering the process of oat flour fractionation will be able to generate quality dense fractions adapted to the manufacturers' demand, investigating other fractionation protocols will be highly recommended.  Keywords: oat, fractionation, particle size, beta-glucan, polyphenols