SOLUBILITY OF TOCOPHEROL AND TOCOTRIENOLS FROM PALM OIL IN SUPERCRITICAL CARBON DIOXIDE

ABSTRACT

The supercritical fluid extraction of tocols (tocopherol and tocotrienols) from palm oil was carried out in a dynamic (flow-through) system. The experiments were carried out in a 3 × 3 factorial design with three equally spaced pressures (14, 22 and 30 MPa) and three equally spaced temperatures (40, 60 and 80C). The tocols obtained were quantified using off-line high-performance liquid chromatography with fluorescent detection. The effects of operating pressure and temperature on the extraction and solubility of tocols in supercritical carbon dioxide were investigated. The results showed that tocols have solubility in the range of 0.94 × 10⁻³ to 0.018 mg/g CO₂ for the conditions investigated in this study. The concentration of tocols was optimized at 22 MPa and 40C for palm oil. The selectivity of tocols follows the preference of δ-tocotrienol > γ-tocotrienol > α-tocotrienol > α-tocopherol .

PRACTICAL APPLICATIONS

Crude palm oil (CPO) is unique among the common vegetable oils because of its high content of tocotrienols. Tocotrienols are more powerful antioxidants than tocopherols. Thus, CPO provides a good source for the production of tocols (tocopherol and tocotrienols) from a natural plant source. The solubility data obtained in the present study are important for the design and optimization of the supercritical fluid extraction of tocols because complex mixtures can lead to changes in solubility and mass transfer behavior. This study demonstrated that individual tocols have different maximum solubility and thus provide an alternative method for selective extraction of individual tocols.