Physicochemical Characteristics of Rice Flour Gelatinized by Drum-Drying

드럼건조에 의한 알파미분의 물리화학적 특성

Gelatinized rice flours were prepared by drum drying at different moisture contents of slurry made from dry milled and wet milled rice flours. Milled rice samples were prepared from the Chuchung and the Samgang varieties. Degree of gelatinization of drum-dried rice flours revealed over 92% at 60% moisture content of wet milled rice flours and 80% moisture content of dry milled ones. With regards to amylogram and rheological properties, drum-dried rice flours prepared from wet milled raw materials showed higher viscosity than from dry milled ones. Increasing water contents in the slurry increased water absorption index(WAI) and decreased water solubility index(WSI). Hunter's color values of drum-dried rice flour at high moisture contents showed higher L values and lower b values. For the preparation of gelatinized rice flours by drum drying process, the higher water content caused more gelatinized network structure of rice starch in scanning electron micrographs. With regards to farinogram properties of dough with drum-dried rice flours and wheat flours in mixing ratio of 1 to 9 by weight, drum-dried rice flours made from wet milled raw rice flours revealed higher MTI than from dry milled ones.

드럼건조시 습식제분한 것은 슬러리 수분함량 60%이상, 건식제분한 것은 슬러리 수분함량 80%이상이 적정 하였으며 이 때의 호화도는 92% 이상이었다. 아밀로그램이나 리올로지 특성은 건식제분보다는 습식제분하여 제조된 알파미분이 우수하였으며 슬러리 수분함량이 높을수록 WAI값은 증가하고 WSI값은 강소하였다. 색도에서는 건식제분보다는 습식 제분 처리구에서 백색도가 높았으며 슬러리 수분함량이 증가할수록 알파미분의 백색도가 증가하였고 황색도는 감소하였다. 미세구조 관찰에서는 슬러리 수분함량이 높을수록 망상구조를 많이 형성하였다. 또한 반죽기능성은 건식 제분보다 습식제분 처리구에서 MTI가 높게 나타났다.