Solubility of carotenoids in supercritical CO<inf>2</inf>

Carotenoids have been shown to provide a range of health benefits and to decrease the risk of disease. Although carotenoids are naturally present in plants advanced extraction technologies to remove carotenoids from plant materials are needed to prepare concentrated materials. Because carotenoids are sensitive to heat, oxygen, and light, large-scale supercritical fluid extraction (SFE) has drawn attention as a separation technology. SFE with solvents such as CO2 offers an organic-chemical-free process that yields quality end food products, compared to traditional extraction methods that organic solvents. In the SFE process for plant materials, an important step is to measure and predict the solubility of target components in the supercritical fluid at various pressure and temperature conditions to optimize the extraction process. The solubility of targeted carotenoids in supercritical fluids is related to its physical and chemical properties such as polarity, molecular structure, and nature of the material particles, and it is also related to the operating conditions such as temperature, pressure, density of solvent and co-solvents, and solvent flow rate in the supercritical region. The solubility of -carotene, -carotene, and other carotenoids under different extraction conditions has been reviewed. It would be interesting and useful for researchers and food industries to compare the data of the solubility of carotenoids to develop optimum extraction process and to get maximum yields.