β-glucan Contents and Their Characteristics of Winter Cereals According to Particle Sizes and Milling Recoveries

This study was conducted to investigate the β-glucan contents and their characteristics of winter cereals according to particle sizes and milling recoveries. Sieved fractions differed in their average contents of β-glucans, and the coarse fraction had higher contents of β-glucan than finely milled fractions. In all winter cereals, the β-glucan contents of raw flours were higher than those of their brans, and the highest β-glucan contents of every cereals were observed at 100 mesh ＞ or 100-140 mesh fractions except the Chalssalbori fractions which showed the higest β-glucan contents (12.9%) at 140-200 mesh fraction. As compared with the β-glucan content of Chalbori among the various milling recoveries, the β-glucan was distributed more evenly throughout the endosperm but β-glucan content in bran of Chalbori was only 1.5%. However, β-glucan content of Chalssalbori (hull-less waxy barley) was the highest in the subaleurone region (8.2 %) and declined slightly toward inner layers of grain. This results suggest that β-glucan distribution between high (Chalbori) and low β-glucan barley (Chalssalbori) may explain the difference in milling performance of barley. On the other hand, β-glucan contents of two rye varieties (Chilbohomil, Chunchoohomil) were lower than those of two waxy barley varieties, and the higest β-glucan contents were observed at the 60% milling recoveries. In all winter cereals, the L-values (lightness) of raw flours were higher than those of brans. And the L-values of barley varieties were higher than those of oat and rye varieties. As the particle sizes and milling recovery ratios were decreased, the L-value were increased. The a-values (redness) in brans of every winter cereals were higher than those of every particle size flours and every milling ratio fractions, and this tendency was observed in the b-values (yellowness) of every particle size of cereal flours. The L and b-value of barley, the b-value of oat, and L, a, b-value of rye have the significant relationship with the β-glucan contents, respectively. This results represent the fact that β-glucans affected the color of the flours and pounded grains of winter cereals.