탈지에 따른 아끼바레와 밀양30호쌀의 물리적 특성

Abstract

This study was conducted to investigate physical properties of Akibare (undefatted), Milyang 30 (undefatted), defatted Akibare and defatted Milyang 30. The properties examined in the study were hydration rate of rice kernels, X-ray diffraction of starch, amylographic characteristics of rice flour, alkali gelatinization of starch and Instron and Rheometer measurements of cooked rice. The results are summarized as follows: 1) The kernels of Milyang 30 were longer but thinner than those of Akibare. 2) The hydration rate of rice kernels was increased with the increase of soaking temperature. The rate of Milyang 30 was faster than that of Akibare and hydration rate was increased with defatting of rice. 3) Diffusion rate o f Milyang 30 was slightly more dependent on temperature than that of Akibare, but the effect of defatting was not marked. 4) X-ray diffraction patterns of starch belonged to "A" type. The peak obtained from Milyang 30 was larger and sharper than that from Akibare. Defatting resulted in decreased relative crystallinity of starch in both rices. The effect was more obvious in Milyang 30. 5) Amylographic viscosity of Milyang 30 was higher than that of Akibare and the effect of defatting was much greater in Milyang 30 than in Akibare. 6) In alkali gelatinization of rice starch, critical concentration was 3.4 meq NaOH/g starch in Akibare, Milyang 30 and defatted Akibare, while viscosity of defatted Milyang 30 was reached equilibrium at 3.2 meq NaOH/g starch in defatted Milyang 30. Although the critical concentrations of Akibare with and without defatting were the same, viscosity of defatted Akibare reached equilibrium state faster. 7) Instron measurement indicated that Milyang 30 was harder than Akibare. Hardness of defatted Milyang 30 was, however, markedly lower than that of Milyang 30 and defatting caused greater reduction of hardness in Milyang 30 than in Akibare. 8) On Rheometer measurements, hardness was not significantly different between two varieties with and without defatting.;본 연구는 국내산 쌀 품종인 아끼바레와 밀양30호를 시료로 선택하여 탈지 시킴으로써 지방에 의한 물리적 특성의 차이를 알아보고자 하였다. 아끼바레와 밀양30호를 그대로 또는 ethyl ether로써 유리 지방질을 제거시킨 시료에 대하여 쌀알의 수화속도, X선 회절양상, 아밀로그람에 의한 쌀가루의 호화양상 및 알칼리에 의해 전분의 호화양상, 취반에 따른 Instron 및 Rheometer에 의한 텍스쳐 측정등을 통하여 그들의 물리적 특성을 비교하였다. 그 결과를 요약하면 다음과 같다. 1) 시료 쌀의 형태는 밀양30호가 아끼바레보다 장반경은 길고, 단반경은 짧았다. 2) 수화속도는 침지온도가 올라갈수록 증가하였으며, 밀양 30호가 아끼바레보다 빨랐고, 탈지한 경우 모두 수화속도가 증가하였다. 3) 밀양30호의 수분 확산시 온도 의존성은 아끼바레에 비해 약간 높았다. 그러나 탈지에 의한 영향은 매우 적었다. 4) 전분의 X선 회절양상은 두 A형을 나타내었으며, 밀양30호에서 나타난 peak가 아끼바레의 것에 비해 크고 예리하였다. 탈지에 의한 상대적 결정도는 아끼바레에 비해 밀양30호가 더 크게 감소하였다. 5) 쌀가루의 아밀로그람에 나타난 호화양상은 밀양30호가 아끼바레보 (이후원문누락)