This study was conducted to investigate the effect of dietary total mixed ration (TMR) supplementation and dry-aging period on the physico-chemical and sensory quality of striploin (longissimus lumborum) from multiparous Hanwoo cows. The experimental cows were divided into two treatments (n=3/treatment) according to the type of feed: in one treatment (slaughter age: 87±6 months old, parity: 5±1) the cows were fed on TMR for 7 months before slaughter, while in the other treatment (slaughter age: 83±9 months old, parity: 5±2) the cows were fed on concentrate and rice straw (CRS) for the whole rearing period. After slaughtering, the striploins were dry-aged for 20 or 40 days at 2±1℃, 85% relative humidity and 2 m/sec air flow velocity and then utilized for quality measurements. The pH value, cooking loss, and hypoxanthine content were higher (p<0.05) for the striploins dry-aged for 40 days than for those dry-aged for 20 days. Notably, the inosine 5’-monophosphate content was decreased (p<0.05) by increasing the dry-aging time. With regard to microbiological quality, the striploins dry-aged for 40 days exhibited lower (p<0.05) lactic acid bacteria counts and higher (p<0.05) coliform counts than those dry-aged for 20 days. Moreover, the tenderness and overall liking scores based on sensory evaluation were higher (p<0.05) for the dry-aged striploins of the TMR treatment and those dry-aged for 40 days than for the CRS treatment and those dry-aged 20 days, respectively. These findings suggest that dietary TMR supplementation leads to an increase in the sensory preference of dry-aged striploins from multiparous Hanwoo cows, and alteration of the CRS into the TMR may improve the quality of dry-aged Hanwoo beef.
Curcumin, the major yellow-colored pigment in turmeric(Curcuma longa L.), was extracted by using supercritical carbon dioxide. Optimum extraction conditions were determined. Overall experiments were planned by central composite design and results were analyzed by response surface methodology to find effects of three independent variables, temperature(X1), co-solvent flow rate(X2) and pressure(X3) on the yield of curcumin extract(Y). Regression model optimized by response surface analysis was as follows Y = -8.581270 + 0.220770X1 + 1.176731X2 + 0.036873X3 + -0.0026816X12 - 0.013010X2X1 - 0.103353X22 + 0.000198X3X1 - 0.0000825X3X2 - 0.000096554X32. Optimum temperature, pressure and co-solvent flow rate for extracting curcumin from turmeric were 40.31oC, 3.07 ml/min and 231.59bar, respectively, and statistical maximum yield of curcumin was 1.922%.
이 논문은 불규칙 가진력을 받는 회전-고정보의 비선형 응답특성을 나타낸다. 불규칙 가진력은 두 번째 고유모드의 절점과 최대변위점에 가했다. 비선형 편미분 방정식과 경계조건으로 표현되는 이 문제를 Galerkin의 방법을 이용하여 연립 비선형 상미분방정식으로 변환하였다. 이 상미분방정식으로부터 Fokker-Planck방정식과 모멘트 방정식을 얻은 후 Gaussian closure 방법 및 non-Gaussian closure 방법을 이용하여 3 모드 근사시 각각 27개 및 209개의 자율 상미분방정식을 구하였다. Gaussian closure 방법과 non-Gaussian closure 방법으로 2 모드 및 3 모드 근사해석을 수행하였고 해석적 결과들은 Monte Carlo 시뮬레이션 결과와 비교되었다. 해석결과 2 모드 근사해와 3 모드 근사해가 거의 일치하였고 2 모드 내부공진만 고려하여도 해석결과에 별 영향을 주지 않는다는 것을 알 수 있다.