Nutritional Components and Physicochemical Properties of Hulled and Naked Oat Flours according to Particle Sizes

摘要

Hulled oat (Chohan) and naked oat (Choyang) flours were analyzed according to particle size to investigate nutritional components and physicochemical properties. Particle size of naked oat flours was larger than that of hulled oat flours. As the meshof the crushed ones decreased, particle sizes increased in value. The content of total p-glucan was highest in hulled oat flour (4.23%) with 60 mesh and in naked oat flour (4.26%) with 100 mesh. Most total P-glucan was soluble p-glucan in both flours (over 76%). Total starch of hulled oat flours (63.64—69.82%) was higher than that of naked oat flours (52.45 —63.71%)). Whereas amylose contents showed a negative correlation with total starch contents. Contents of free amino acids increased according toparticle size, and each component was dependent on each type of amino acid. Moreover, while fatty acid composition was not significant, the content of most naked oats was higher than that of hulled oats. Besides, the ratio of unsaturated fatty acids (oleic acid and linoleate) in both types of oat flours was relatively higher than that of other grains. The pasting properties of peak viscosity, trough, and breakdown showed the highest value in both oats with 100 mesh. Further, the values of final viscosity and the setback were higher with relatively larger particle size. In addition, peak time exhibited a lower value with larger particle size, whereas it showed the opposite value for pasting temperature. Starch digestibility did not show any specific trend according to particle size, whereas expected glycemic index of hulled oats was lower than that of naked oats. Moreover, lower values were investigated at larger particle sizes. The results of this study provide basic useful information for processingof oat products to improve consumption of oats grown in Korea.