Extraction and purification of flavonoids from apple pomace using pressurized liquids coupled online with solid phase extraction

Apple pomace is rich in bioactive compounds, such as flavonoids. This work aimed to develop a method to extract and purify phenolic compounds from apple pomace by extraction with pressurized liquids coupled online with extraction in solid phase. The amount of water in 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) were the variables evaluated. The Sepra adsorbent showed the best results. Temperature showed little effect on recovery, with significant differences for florizine and a derivative of quercetin. As an alternative to methanol, ethanol can be used as an activation, extraction / elution solvent. The developed method produced better or similar yields of acids (2.85 ± 0.19 mg / g) and flavonoids (0.97 ± 0.11 mg / g) when compared to conventional methods.