A Sustainable Approach for High-Recovery of Procyanidins from Coffee Pulp: Optimization of Microwave-Ultrasound Hybrid Extraction

Coffee pulp, which accounts for approximately 40% of the dry weight of coffee cherries, is one of the many byproducts produced by the world¿s most popular beverage, coffee. Such neglected waste represents an interesting source of bioactive compounds, such as procyanidins, which have antioxidant, anti-inflammatory, and neuroprotective properties. This study aims to develop an efficient method for procyanidins extraction from Coffea arabica pulp using a novel microwave¿ultrasound hybrid method of extraction. Microwave-assisted extraction (MAE), ultrasound-assisted extraction (UAE) and a novel hybrid method (MAE¿UAE) were comparatively analyzed. Using Box¿Behnken design, the hybrid extraction method was optimized, giving a procyanidin yield of 60.88 mg/g (under these conditions: ~60 °C, ~21 min, ~1:13 solid-to-liquid ratio). The purification was carried out through a Sephadex LH-20 packed column chromatography, and the identified procyanidin dimers and trimers were confirmed by HPLC/ESI-MS. The hybrid extract¿s acetonic fraction¿s DPPH and ABTS tests revealed that procyanidins had a greater capacity to scavenge radicals than Trolox (p < 0.05). The findings highlight the potential of sustainable extraction methods for valorizing coffee pulp in functional food and pharmaceutical applications. © 2025 by the authors.