Response Surface Methodology for the Optimization of Flavan-3-ols Extraction from Avocado By-Products via Sonotrode Ultrasound-Assisted Extraction Razola Díaz, María del Carmen Verardo, Vito Guerra Hernández, Eduardo Jesús García Villanova Ruiz, Belén Gómez Caravaca, Ana María Avocado seed Avocado peel Flavan-3-ols Sonotrode Procyanidins Avocado peel and seed are the main by-products of avocado processing and are considered as promising sources of phenolic compounds with biological activities. Thus, this research focuses on the establishment, for the first time, of ultrasound-assisted extraction of flavan-3-ols with high antioxidant activity from avocado peel and seed using a sonotrode. Indeed, 2 Box–Behnken designs were performed for 15 experiments, with each design having three independent factors (ratio ethanol/water (v/v), time (min) and amplitude (%)). In both models, the responses included total procyanidins (flavan-3-ols) measured via HPLC-FLD and antioxidant activity measured via DPPH, ABTS and FRAP. The results showed that applying the sonotrode extraction method could increase flavan-3-ols recovery by 54% and antioxidant activity by 62–76% compared to ultrasound bath technology. Therefore, this technology was demonstrated to be a non-thermal, low time-consuming and scalable method that allowed the recovery of flavan-3-ols from avocado by-products that could be used as functional ingredients 2023-09-22T08:40:00Z 2023-09-22T08:40:00Z 2023-07-11 journal article Razola-Díaz, M.d.C.; Verardo, V.; Guerra-Hernández, E.J.; García-Villanova Ruiz, B.; Gómez-Caravaca, A.M. Response Surface Methodology for the Optimization of Flavan-3-ols Extraction from Avocado By-Products via Sonotrode Ultrasound-Assisted Extraction. Antioxidants 2023, 12, 1409. [https://doi.org/10.3390/antiox12071409] https://hdl.handle.net/10481/84579 10.3390/ antiox12071409 eng info:eu-repo/grantAgreement/EC/H2020/817936 http://creativecommons.org/licenses/by/4.0/ open access Atribución 4.0 Internacional MDPI