A pioneering study on the recovery of valuable functional compounds from olive pomace by using supercritical carbon dioxide extraction: Comparison of perlite addition and drying

Abstract

In this study, supercritical carbon dioxide (SC-CO2) extraction was applied to the mixture of two-phase olive pomace (OP) with perlite and to the dried OP in order to prevent the environmental hazards that may arise from the leachate. Chemical oxygen demand (COD) and electrical conductivity (EC) of the leaching black water were detected as 131200 ± 21024 mg/L and 12300 ± 500 µS/cm, respectively, leading to toxicity. Total phenolic content (TPC) was determined in the raw OP and in the extracts as 8.9 ± 3.6 mg GAE/g and 2–14 mg GAE/g, respectively. Antioxidant capacity increased from 715 µM TE in the raw OP to 11000 µM TE in the extracts. The maximum extraction yield and TPC recovery values were obtained as 5.7 % and 3 %, respectively. Promising results were obtained on the recovery of phenolic substances and fatty acids (FAs). Main groups of the valuable compounds such as secoiridoids, flavonoids and phenolic alcohols were detected in the pomace as 400, 290 and 100 mg/kg, respectively, while their concentrations increased up to 16430, 7370 and 3280 mg/kg in the extracts. © 2022 Elsevier B.V.