微藻油微胶囊的释放动力学研究

微藻油经微胶囊化后对其在不同贮藏条件下的释放进行动力学研究。运用Avrami s 公式对其主要的功能活性成分DHA 在不同温度、湿度及光照强度条件下保留率的变化进行研究，并分析所得出的释放机理参数及释放速率常数。结果表明：在不同温度条件下藻油微胶囊释放速率常数均较低，在60℃条件下贮藏12d 后，DHA 的保留率为66.69%，表明微胶囊藻油有较好的耐温性。在高相对湿度条件下，藻油微胶囊释放速率常数显著增大，DHA 保留率明显下降，90% 相对湿度条件下贮藏12d 后，DHA 保留率仅有3.45%，证明藻油经过微胶囊化后也应该贮藏在低湿条件下。而微藻油微胶囊受光照强度影响不大，10000lx 光照强度下照射12d 后，DHA 的保留率仍有78.33%。随着温度、相对湿度及光照强度的升高，释放速率常数均上升，即低温、低湿、避光是藻油微胶囊化产品贮藏的最佳条件。

Evaluation of Release Kinetics of Micro-algal Oil Microcapsules

The release kinetics of microencapsulated micro-algal oil was investigated under different storage conditions. The Avrami equation was employed to analyze the release mechanism parameters and release rate constant (K) and measure the change in retention ratio of DHA, one of the major functional components of micro-algal oil, under different levels of light intensity, temperature and relative humidity. The results indicated that the K value of micro-algal oil microcapsules was smaller though stored at a higher storage temperature (60 ℃) and the DHA retention ratio was 66.69% after 12 days of storage at 60 ℃. DHA retention ratio, however, was very sensitive to humidity and the value was only 3.45% after 12 days of storage at 90% humidity, and K increased obviously. This indicates that micro-algal oil microcapsules should be stored at lower humidity. Light intensity had no remarkable effect on the stability of micro-algal oil microcapsules, and the DHA retention ratio was still 78.33% after 12 days of 10000 lx illumination. Higher storage temperature, relative humidity and light intensity all could result in an increase in K. It is obvious that microalgal oil microcapsules should be stored in light-avoiding, low-temperature and low-humidity environment.