Effect of particle size of naked oat flours on physicochemical and antioxidant property

This study was carried out to investigate the effect of particle size of naked oat flour (NOF) on physicochemical property and antioxidant activity. The NOF was passed through 250 μm and 160 μm size sieves to obtain three fractions (fraction A: 250 μm or more, fraction B: 160-250 μm, and fraction C: 160 μm or less). Moisture, crude protein, crude fat, and crude ash contents of NOF were 8.4, 15.7, 10.0, and 1.8%, respectively, and these contents were increased as the particle size of NOF decreased. The mineral and free amino acid contents of NOF also had a similar tendency. The contents of total starch, amylose, starch damage, total dietary fiber, β-glucan, total phenolics, and flavonoids in NOF were 56.4%, 21.4%, 11.7%, 11.0%, 4.7%, 237.8 μg/g and 90.9 μg/g, respectively. As the particle size of NOF decreased, total starch, amylose, and starch damage contents increased, whereas total dietary fiber, β-glucan, total phenolic and flavonoid contents decreased. Also, three antioxidant activities of NOF were closely correlated with their total phenolics and flavonoids contents, showing high correlation coefficient values (R²=0.87 and 0.81, respectively).