Valorization of Apple Pomace as a Sustainable Source of Bioactive Compounds: A Comparative Study of Microwave-Assisted and Soxhlet Extractions

This study aims to evaluate and compare the efficiency of microwave-assisted extraction (MAE) and conventional Soxhlet methods for the recovery of bioactive compounds from apple pomace. The total phenolic content (TPC) of extracts obtained under various temperature and time conditions was determined using the Folin-Ciocalteu reagent. The antioxidant activity was evaluated through the 1,1-Diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging assay to calculate IC50 values. The highest total phenolic content was obtained with Soxhlet (9.78 ± 0.18 mg GAE/g extract) and MAE-5 (9.7 ± 0.18 mg GAE/g extract) methods (P>0.05). The IC50 values of MAE extracts ranged from 17.8 ± 1.2 to 33.3 ± 0.9 µg/mL, with the highest antioxidant activities observed in MAE-4 (17.8 ± 1.2 µg/mL) and MAE-2 (18.8 ± 1.3 µg/mL) samples. Notably, no significant statistical difference was observed between MAE-4 and MAE-2 (P>0.05), indicating that short-duration microwave treatment preserves antioxidant potency effectively across the tested temperature range. The Soxhlet extract (25 ± 1.2 µg/mL) showed significantly lower antioxidant activity compared to most MAE samples P