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Lookup NU author(s): Dr Jie ZhangORCiD
This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).
© 2026 by the authors. The valorization of agro-industrial by-products is a sustainable approach to recovering high-value bioactive compounds. In this study, Opuntia ficus-indica (L.) Mill. seed press residues were investigated as a source of phenolic and flavonoid compounds using microwave-assisted extraction (MAE). A multi-step optimization strategy was implemented, combining preliminary single-factor experiments (OVAT), response surface methodology based on a Box–Behnken design (BBD), and machine learning modeling using K-nearest neighbors coupled with the dragonfly algorithm (KNN_DA), followed by desirability-based validation. The effects of ethanol concentration (50–100%), microwave power (400–800 W), extraction time (2–4 min), and liquid-to-solid ratio (30–50 mL/g) were evaluated on Folin–Ciocalteu reducing capacity (FCRC), AlCl3 complexation response, and antioxidant activity assessed by DPPH radical scavenging and reducing power assays. Optimal conditions were identified at 50% ethanol, 800 W microwave power, 4 min extraction time, and a liquid-to-solid ratio of 47.28 mL/g. Under these conditions, FCRC reached 376.85 ± 0.23 mg GAE/100 g DW and 49.16 ± 0.33 mg QE/100 g DW for AlCl3 complexation response, with prediction errors of 2.80% and 0.82%, respectively. The optimized extracts exhibited enhanced antioxidant activity. These findings confirm MAE as a rapid and environmentally friendly technique and highlight the predictive performance of the KNN_DA model for process optimization.
Author(s): Khaled S, Mahdeb A, Dahmoune F, Amrane-Abider M, Hamimeche M, Terki L, Moussa H, Tahraoui H, Kadri N, Remini H, Rahman MH, Khezami L, Fadhillah F, Ali FAA, Assadi AA, Zhang J, Amrane A, Madani K
Publication type: Article
Publication status: Published
Journal: Molecules
Year: 2026
Volume: 31
Issue: 6
Online publication date: 16/03/2026
Acceptance date: 12/03/2026
Date deposited: 15/04/2026
ISSN (electronic): 1420-3049
Publisher: MDPI
URL: https://doi.org/10.3390/molecules31060998
DOI: 10.3390/molecules31060998
Data Access Statement: It will be available after acceptance and publishing in this journal.
PubMed id: 41900097
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