Isolation and separation of tocopherols from olive by-products with supercritical fluids

Supercritical fluid extraction of olive pomace, the semisolid residue obtai ned using two-phase olive oil production systems, and supercritical fluid c hromatographic separation of the extracts were performed to study the conte nt of tocopherols, a group of compounds of interest for the food industry o wing to their antioxidant activity. The developed method consists of superc ritical CO2 extraction at pilot plant scale and subsequent fractionation by two successive depressurizations. Enrichment of alpha-, beta-, and gamma-t ocopherol was achieved in separator 2 when working at low densities in the first separator. Fractions obtained using high densities in separator 1 con tained major proportions of triglycerides, waxes, and sterols. Tocopherols from olive by-products were separated and quantified in an environmentally friendly way by using supercritical fluid chromatography with packed capill ary columns coated with polyethylene glycol and neat CO2 according to a met hod previously optimized in our laboratory. The studied olive by-products c an be considered a natural source of antioxidants because substantial conce ntration of tocopherols have been obtained in the extracts. The isolation a nd separation of tocopherols from olive pomace by applying supercritical fl uid technology provides an interesting approach to exploit such by-products in an environmentally friendly way.