Softening and milling of brown rice in solvent was carried out by a milling machine having 3mm-dia. holes and a large number of pores in the horizontal stone.
Unsteady and steady state experiments were performed at room temperatures variables were flow rates and oil concentrations of the miscella, and the experiment scheme was consisted of solvent extractive milling and dry milling with two different feed materials of brown rice.
Dependent variables observed were the degree of polish, breakage of rice, and leaching efficiency of the system.
The conclusions from the experiment were as follows:
1. Increase in the inlet oil concentraction of the miscella showed that the viscosity of the miscella increased linearly, but the degree of polish, leaching efficiency and breakage of rice decreased exponentially. The following correlations were obtained by the experimental data.
$\beta/(r.f) = 0.390 e^{-0.035x_0}$
$E/(y_0T) = 0.013 e^{-0.020x_0}$
2. With increase in the degree of polish it showed the trend of linear increase in the outlet concentration of the oil-free inlet miscella, and also showed the trend of exponential increase in breakage of the rice.
3. The degree of breakage by the solvent extractive milling became 14 percent and 19 percent lower than that by the dry milling for 8 and 5.6 percent-milled rice, respectively.
4. The optimum inlet oil concentration in the miscella was about 12 percent for making the 5.6 percent-milled rice.
Hole을 가진 rotor의 수평 삭찰식 도정기를 제작하여 통일 현미를 용매 추출 가공함에 있어서 연화 및 가공 공정이 실험 검토되었다. 실온에서 unsteady state 실험 및 miscella의 유량과 oil농도를 변수로 한 steady state 의 실험을 하였다.
steady state 에서의 실험은 재현성 확인 실험 및 건식 도정까지 포함되었으며 도정도, 쇄미율, 추출 효율 및 miscella의 oil농도와의 상호 관계를 고찰하였다. 그 결과, 도정도가 증가함에 따라 oil-free miscella의 출구 지질 농도는 직선적인 증가 추세를 나타내었으며, 쇄미율은 exponential 하게 증가함을 알았다. miscella 의 입구 oil농도가 증가함에 따라 그 점도는 직선적으로 증가하였으며 도정도, 추출 효율 및 쇄미율은 exponential하게 감소하였으며 이들 사이에 다음의 실험식을 얻었다.
$\beta/(r.f) = 0.390 e^{-0.035x_0}$
$E/(y_0T) = 0.013 e^{-0.013x_0}$
현미를 10분도미로 가공하는 경우 용매 추출법으로 도정하면 건식법으로 도정하는 것보다 쇄미율이 14% 감소되었으며, 7분도미로 가공하는 경우에는 19%이상 감소되었다.
7분도미로 가공할 대의 miscella내의 최적 입구 oil 농도는 약 12%이었다.
