Supercritical Carbon Dioxide Extraction of Squalene from Amaranthus paniculatus: Experiments and Process Characterization

Separation of squalene from Amaranthus paniculatus using supercritical carbon dioxide extraction (SC-CO2) technology and optimization of its process parameters such as temperature, pressure, time of extraction, flow rate of carbon dioxide, and batch size have been conducted. The optimized conditions that provided the best yield of squalene were a sample size of 40 g of amaranth grains of particle diameter of 0.75 mm at a temperature of 100 degrees C and pressure of 550 bar for 1.5 h extracting time at a flow rate of 0.2 Lmin(-1) of carbon dioxide. Solubility of squalene in SC-CO2 under different operating conditions has also been evaluated using Chrastil equation which showed good agreement with the experimentally obtained yields. Various statistical analyses (regression equations, t test, and analysis of variance) conducted on the extraction parameters concluded that extraction pressure, time and sample batch size have significant effect on the yield of the squalene whereas extraction temperature and particle diameter do not. The results obtained are in accordance to the basic principle of supercritical fluid-phase equilibrium behavior and the solubility isobar and isotherm obtained showed similar trends with those reported for squalene. Using dimensionless numbers, an empirical correlation was also deduced for characterization of the extraction process of squalene in SC-CO2.