Optimization of pressurized liquid extraction of zeaxanthin from Chlorella ellipsoidea

The total zeaxanthin level in Chlorella ellipsoidea, a green microalga, was more than nine times that of red pepper, a plant source of zeaxanthin. Additionally, the zeaxanthin in C. ellipsoidea consisted of the free form, while those in other plants exist as zeaxanthin mono- and diesters. Pressurized liquid extraction (PLE) was used to extract zeaxanthin from C. ellipsoidea. Both the extraction temperature and extraction time, the two main factors in PLE, were optimized with a central composite design to obtain the highest extraction efficiency of zeaxanthin. Hexane, ethanol, and isopropanol were used as PLE extraction solvents. Ethanol extracted zeaxanthin most efficiently from C. ellipsoidea. Temperature was the parameter with the strongest influence on the extraction of zeaxanthin. The optimum extraction temperature and time for zeaxanthin were 115.4A degrees C and 23.3 min, respectively. The maximum predicted value of 4.28 mg g(-1) agreed with the experimental value of 4.26 mg g(-1), supporting the quality of the fitted model. These results indicate that PLE using ethanol may be a useful method for extracting zeaxanthin from C. ellipsoidea.