Simultaneous extraction and separation of bioactive compounds from apple pomace using pressurized liquids coupled on-line with solid-phase extraction

Abstract

The objective of this work was the development of an on-line extraction/fractionation method based on the coupling of pressurized liquid extraction and solid-phase extraction for the separation of phenolic compounds from apple pomace. Several variables of the process were evaluated, including the amount of water of the first stage (0-120 mL), temperature (60-80 °C), solid-phase extraction adsorbent (Sepra, Isolute, Strata X and Oasis) and activation/elution solvent (methanol and ethanol). The best results were observed with the adsorbent Sepra. The temperature had a small effect on recovery, but significant differences were observed for phlorizin and a quercetin derivative. Results indicate that ethanol can be used to replace methanol as an activation, extraction/elution solvent. While using mostly green solvents (water, ethanol, and a small amount of methanol that could be reused), the developed method produced higher or similar yields of acids (2.85 ± 0.19 mg/g) and flavonoids (0.97 ± 0.11 mg/g) than conventional methods.

Keywords: Apple pomace; Chlorogenic acid (PubChem CID: 1794427); Epicatechin (PubChem CID: 72276); Flavonoids; Gallic acid (PubChem CID: 370); Hyperoside (PubChem CID: 5281643); Phenolics; Phloretin xylosil glucoside; Phlorizin (PubChem CID: 6072); Pressurized liquid extraction; Quercetin rhamnoside (PubChem CID: 5353915); Rutin (PubChem CID: 5280805); Solid-phase extraction.