Experiments and statistical analysis of supercritical carbon dioxide extraction

In this study, experimental design was employed in order to investigate the effects of operating condition on supercritical carbon dioxide extraction of astaxanthin from Haematococcus pluvialis and essential oils from Amomum krevanh Pierre. The factors investigated for astaxanthin were operating temperature (40-80 degrees C), the operating pressure (300-500 bar), and the extraction time (1-4 hours). The results showed that the main effect of operating pressure, the main effect of extraction time, and the interaction effect between operating temperature and operating pressure were significant factors for the astaxanthin yields. From the response surface model of the experimental data, an optimal condition for astaxanthin content was found to be at the temperature of 90 degrees C, the pressure of 640 bar, and the extraction time of 2.9 hours. This condition yields the highest amount of astaxanthin extract of 22.66 mg/g dry algae. The factors investigated for essential oil were operating temperature (30-70 degrees C), the operating pressure (90-260 bar), and the extraction time (20-70 min).