Abstract
1(3)-palmitoyl-2-oleoyl-3(1)-stearoyl-(POS)-glycerol-enriched reaction products were synthesized from camellia oil, palmitic ethyl ester, and stearic ethyl ester via lipase-catalyzed interesterification. Response surface methodology (RSM) was employed to optimize the production of the POS-enriched reaction product (Y1, %) and the stearicand palmitic-acid contents at the sn-2 position due to acyl migration (Y2, %). The reaction factors were the enzyme amount (X1, 2-6%), reaction time (X2, 60-360 min), and substrate molar ratio of camellia oil to palmitic ethyl ester and stearic ethyl ester (X3, 1-3 mol). The predictive models for Y1 and Y2 were adequate and reproducible as no lack of fit was signified (0.128 and 0.237) and as there were satisfactory levels of R2 (0.968 and 0.990, respectively). The optimal conditions for the reaction product for maximizing Y1 while minimizing Y2 were predicted at the reaction combination of 5.86% enzyme amount, 60 min reaction time, and 1:3 substrate molar ratio (3 moles of palmitic ethyl ester and 3 moles of stearic ethyl ester). Actual reaction was performed under the same conditions as above, and the resulting product contained 20.19% TAG-P/O/S and 12.71% saturated fatty acids at the sn-2 position.
Camellia oil과 palmitic, 그리고 stearic ethyl ester를 기질로 하고 Lipozyme TLIM을 촉매로 이용하여 interesterification을 통한 POS를 많이 함유한 반응물을 합성하고자 하였다. 반응 조건(반응효소비율, 반응시간, 기질의 비율)을 독립변수로 하여 중심 합성 계획에 의한 반응 표면 분석을 통하여 POS의 함량은 높이고, sn-2 position의 acyl migration을 낮추어 합성하는 최적화 조건을 얻었다. POS를 많이 함유한 반응물의 합성 최적화 조건은 반응 효소양($X_1$)= 5.9%, 반응시간($X_2$)= 60 min, 그리고 기질비율($X_3$)= 1:3(1 mole의 camellia oil: 3 mole의 palmitic ethyl ester + 3 mole의 stearic ethyl ester)이었다. 이와 같은 조건으로 획득된 실재 효소반응 합성물의 TAG-P/O/S(palmitic, stearic과 oleic 지방산을 각각 1 분자씩 어느 위치이던지 함유한 TAG, 즉 POS 및 PSO/OSP/OPS/SPO)의 합성율($Y_1$)은 20.19%이었고, 이때 acyl migration 등에 의하여 sn-2 위치에 결합(이동)한 palmitic과 stearic acid의 양(P/S-sn-2)인 $Y_2$는 12.71% 이었다.
