Development and Optimization of an Aqueous Method for Carotenoid Extraction from Sticks of Ilex paraguariensis

Abstract Ilex paraguariensis sticks are agroindustrial by-products rich in bioactive compounds, especially carotenoids such as lutein. In this study, an aqueous method was developed and optimized for the extraction of total carotenoids and lutein, using water and a food-grade surfactant as the extraction solution. Extraction conditions were optimized using a full 2 3 central composite design. The optimized parameters (0.5% polysorbate in the extracting solution and 5 min of agitation in a water bath at 58 °C) resulted in the extraction of 2.91 mg of lutein per 100 g of sticks, together with high antioxidant activity. Compared with a conventional exhaustive extraction method described in the literature, based on the use of acetone and petroleum ether, the proposed aqueous process yielded a 1.32-fold higher total carotenoids content under the reported experimental conditions. This result indicates a higher carotenoids recovery relative to the conventional method, although differences in extraction procedures and potential matrix effects should be considered when comparing the results. In addition, chlorogenic acids were efficiently extracted under the optimized conditions. The lyophilized extract stored at room temperature, without vacuum and protected from light, showed stability for five weeks, with moderate degradation of carotenoids and preservation of chlorogenic acids, total phenolics, reducing capacity, and DPPH antioxidant activity. Toxicological assays using Galleria mellonella confirmed the safety of the extract at moderate concentrations. The developed aqueous process provides an alternative extraction approach that uses water and a food-grade surfactant instead of organic solvents, with potential environmental advantages that should be further evaluated through a comprehensive sustainability assessment. Both the liquid and the lyophilized extracts show potential for applications in the food, pharmaceutical, and cosmetic fields.