Physicochemical Properties and Hydration of Rice on Various Polishing Degrees

도정도에 따른 쌀의 수화와 이화학적 특성

The physicochemical and gelatinization properties of rice flours, which were prepared by polishing nonwaxy brown rice (Dongjin byeo), depending on polishing degrees were investigated. The contents of protein, ash, lipid and fiber decreased significantly as the degrees of polishing increased and water uptake of rice grains decreased during hydration. When the surface of the soaked rice grains was examined by the SEM, extensive crack formation was observed. The water binding capacities, swelling power and solubility of rice flour increased as the polishing degree increased. By the amylogram, the initial gelatinization temperatures of rice flour decreased as the polishing degree increased and the peak viscosities, the breakdown and consistency of rice flour increased as the polishing degree increased.

동진 품종의 현미를 2분도미, 5분도미, 7분도미로 도정하여, 도정도에 따른 쌀의 수화와 쌀가루의 이화학적 성질 및 호화 특성을 조사하였다. 쌀의 도정도가 증가하면 일반성분 중에서 단백질, 회분, 지방질, 섬유소의 함량이 감소되고, 쌀의 수분 증가량은 감소되고 SEM으로 관찰하였을 때 틈이 점점 현저하였다. 도정도가 증가할수록 쌀가루의 물결합능력, 팽윤력과 용해도는 증가하였다. 아밀로그람에서의 초기 호화온도는 도정도가 증가할수록 낮아졌고 최고점도, breakdown과 consistency는 높아졌다.