Enhancing the Extraction of Bioactive Compounds from Coffee Waste Using Thermosonication Combined with Alternative Solvents for Ready-to-Use Products

Coffee chains generate billions of tons of solid waste annually, from which high-added-value bioactive compounds can be recovered. This study evaluated the effects of thermosonication at different power levels (200 and 400 W), combined with heating (50 °C) for extraction times ranging from 1 to 15 min, on the recovery of caffeine and phenolic compounds from coffee residues. Various solvents were assessed, including water, ethanol, and alternative solvents such as deep eutectic solvents (DES), mead, cachaça, and almond-based milk. Thermosonication at 400 W for 2 min resulted in the highest extraction of caffeine and 5-caffeoylquinic acid (5-CQA). Mead provided the highest 5-CQA yield, whereas water was the most effective solvent for caffeine extraction. In contrast, DES promoted the formation of hydroxymethylfurfural during processing. Overall, thermosonication proved more efficient than conventional extraction methods, demonstrating its potential as a rapid and effective strategy for valorizing coffee waste and developing enriched products.