Supercritical Fluid and Pressurized Liquid Extraction of Bioactive Compounds from Guarana (<i>Paullinia cupana</i>) Byproducts

This work aimed to valorize the production chain of guarana (Paullinia cupana) using sustainable extraction methods. Supercritical fluid extraction (SFE) and pressurized liquid extraction (PLE) were applied to obtain bioactive compounds from guarana integuments (fresh and dry) and waste from the Brazilian soft drink industry. The effect of pressure, temperature, and time on the yields, composition, and antioxidant activity of the extracts was evaluated. In SFE, the greatest yield was achieved at 35 MPa and 40 °C. Caffeine, catechin, epicatechin, and theobromine were recovered by PLE, which was fast and effective to recover these compounds from guarana byproducts. Catechin and epicatechin showed a strong correlation with the antioxidant and reducing capacity of the extracts. PLE at 100 °C enhanced the antioxidant and reducing capacities of all of the extracts, whereas 80 °C was the best temperature for caffeine recovery. This work opens up new alternatives for recovering valuable compounds from guarana byproducts, meeting the requirements of the circular economy and adding value to the production chain of guarana.