Solubility and stability of lycopene are the main problems in
extracting lycopene from tomato by-products. Lycopene is insoluble
in water but soluble in highly toxic organic solvents such as benzene,
chloroform, and dichloromethane; it also decomposes easily during
storage. Development of the supercritical fluid extraction (SFE)
method is one way scientists have worked to circumvent these
problems.
Separation for food products and medicine are limited by the
requirement of low temperatures since the product usually has
poor stability at high temperatures. Also, solvents must be nontoxic
and not remain as residue in the product. SFE is an extraction
method which operates above the solvent’s critical pressure and
temperature, enhancing the solvating power of the solvent. Carbon
dioxide is a solvent frequently used in the SFE method due to its
low critical temperature, it being neither toxic nor flammable,
and its availability at low cost and high purity (Brunner, 1994).