Abstract
The oxidative stability of cholesterol in tallow heated at different frying temperatures (130$\^{C}$, 150$\^{C}$, and 180$\^{C}$) was studied by identifying cholesterol oxides by thin layer chromatography(TLC). And fatty acid compositions in tallow heated were also measured and compared with cholesterol oxides. Unsaturated fatty acid contents slightly decreased as the heating time increased, whereas saturated fatty acid contents increased This phenomenon became excessive especially by heating to higher temperature. It was found that RF value and spot color of the nonsaponifiable lipids from tallow heated on TLC analysis accorded with the synthetic cholesterol oxides in this experiment. Four kinds of cholesterol oxides were detected in tallow heated for 24 hours at three different temperatures. The oxides were identified as 7-$\alpha$-hydroxycholesterol, 7-$\beta$-hydroxycholesterol, 7-ketocholesterol and cholesterol epoxide. It was found that there was a little difference in oxidative pattern of cholesterol between several heating temperatures.
가열우지중 콜레스테롤 산화안정성을 연구하기 위하여 130, 150 및 18$0^{\circ}C$ 가열온도에서 일정시간 가열하였을 때 생성되는 각종 콜레스테롤 산화생성물을 TLC에 의하여 분리.확인하고, 지방산 조성의 변화를 측정하였다. 지방산 조성은 가열시간이 경과함에 따라 linoleic과 linolenic acid등의 불포화 지방산은 약간씩 감소한 반면 포화지방산의 함량은 다소 증가하는 경향이었고, 이러한 변화는 가열온도가 높을수록 심하였다. 추출한 비비누화물의 반점과 Rf값은 콜레스테롤 산화물의 표준품들과 일치함을 확인 할 수 있었다. 또한 TLC상으로 확인된 콜레스테롤 산화물은 7-$\alpha$-hydroxycholesterol, 7-$\beta$-hydroxycholesterol, 7-ketocholesterol 및 cholesterol epoxide의 4가지였으며, 이들 4가지 콜레스테롤 산화물은 가열 온도와 가열시간에 따라 생성되는 종류와 그 생성량이 상이함을 알 수 있었다.