RESUMEN
Solvent extraction is the most efficient method for recovering residual oil from palm pressed fiber (PPFO), which may contain up to eight times the carotenoid content of that found in crude palm oil. The objective of the present study is the use of binary mixtures of hydrocarbons (HC), hexane (Hex), cyclohexane (CHex) or heptane (Hep), and alcohols (ALC), ethanol (Eth) or isopropanol (IPA), in order to promote the highest recovery of a carotenoid-rich PPFO, in which the compositions of the mixtures are defined based on the calculation of solute-solvent distance (Ra) considering ß-carotene as the solute. The extraction experiments were conducted in batch, at 60 ± 2 °C, or in a fixed-bed packed column, at 55 ± 3 °C. Hex and Hep:IPA provided 80% of batch PPFO extraction yield, while in column, the highest yields were obtained with Eth and Hex:IPA (66%). The total carotenoid content obtained was the same independent of the solvent and extraction configuration (from 1790 ± 230 up to 2539 ± 78 mg ß-carotene/kg PPFO). In terms of the carotenoid profile, ß-carotene was mostly extracted by Hex, Hex:Eth stood out in the extraction of α-carotene, and Eth extracted the highest content of lycopene. It is possible to infer that mixtures of HC and ALC with compositions defined based on Hansen Solubility Parameters (HSPs) demonstrated good ability to extract carotenoid-rich PPFO, maintaining their relatively stable fatty acids composition and free acidity, showing that partial substitution of HC by ALC is technically possible.
