天然叶黄素转化的虾青素的热异构化研究

Study on thermal isomerization of astaxanthin transformed from natural lutein

为了给天然叶黄素转化的虾青素微胶囊制备工艺的乳化过程提供基础数据和技术依据,研究了由天然叶黄素转化而来的顺式虾青素向反式虾青素的热异构化转变过程。通过将虾青素置于甲醇和乙醇溶液中加热回流,HPLC跟踪分析,建立了由天然叶黄素转化的虾青素在乙醇中的一级可逆反应动力学模型,采用matlab进行了参数估值。顺反异构体的转化取决于加热的时间和温度,乙醇比甲醇适合用于本异构化转变实验。在顺反异构化的过程中,反式与13-顺之间的正逆反应速率比反式与9-顺之间的要快,且两个顺反异构化反应的逆反应速率要比正反应速率快,基本上不发生反式向9-顺的转化。顺式异构体向反式异构体的转化过程在一定时间后会达到一个平衡,顺式异构体并未能完全转化成反式异构体。

In order to provide basic data and technical basis for the emulsification process of preparation of astaxanthin microcapsules transformed from natural lutein,the isomerization of cis-astaxanthin to trans-astaxanthin which transformed from natural lutein was investigated. Astaxanthin in methanol and ethanol solution reflux combined with HPLC tracking analysis were used to established the first order reversible kinetic model of astaxanthin transformed from natural lutein,and matlab was applied in paramters estimation. The isomerization transformation was dependent on the heating time and temperature;ethanol is more suitable for the transformation than methanol. In the process of thermal isomerization,the positive and reverse reaction rate between the trans-and 13-cis is faster than that between the trans and 9-cis,and the reverse reaction rates of the two isomerization reactions are faster than the positive reaction rates,the conversion of trans to 9-cis rarely occurs. The isomerization of cis-astaxanthin to trans-astaxanthin will reach an equilibrium eventually rather than fully to cis-isomer.