Comparison of Conventional and Novel Extractants for Carotenoid and Phenol Extraction from Agricultural and Food Waste
Sanja Schwalb, Mario Kerst (*), Matthias Kleinke, Simone Pauling

Rhine-Waal University of Applied Sciences, Faculty of Life Sciences, Marie-Curie Strasse 1, Kleve, Germany
*Mario.Kerst[at]hochschule-rhein-waal.de

Abstract

Carotenoids, prized for their antioxidant properties and vibrant colors, are widely used in the food, pharmaceutical, and cosmetic industries. Vegetable waste offers a sustainable, low-cost source of these bioactive compounds, aligning with circular economy principles and waste valorization strategies. This study evaluates the extraction efficiency of carotenoids from several types of vegetable waste using three solvents: acetone, ethyl acetate, and a deep eutectic solvent (DES). The investigation focuses on the comparison of conventional solvents with the novel DES approach. Acetone and ethyl acetate are well-established for the extraction of lipophilic compounds due to their efficient solubilization of hydrophobic molecules. In our experiments, acetone exhibited the highest yield per extraction, attributable to its strong solvent affinity, followed by ethyl acetate, which produced a comparable yield. In parallel, a DES composed of betaine and glycerol was employed as an environmentally friendly alternative, reflecting recent advances in green solvent technology. DESs offer advantages such as low toxicity, safer handling, and biodegradability, making them ideal candidates for sustainable extraction processes. Furthermore, by combining DES and ethyl acetate in a biphasic extraction process, carotenoids and phenols can be extracted simultaneously. The two extractants can then be separated by simple phase separation. The results demonstrate that the use of DESs can be a promising green alternative for the extraction of carotenoids from vegetable waste, offering a balance between efficiency and sustainability. By comparing these three solvent systems, this study contributes to the development of optimized, eco-friendly extraction protocols that facilitate the valorization of agricultural by-products.

Keywords: agricultural waste- carotenoids- deep eutetic solvents- food waste- phenol

Topic: Bioeconomy in agro-industry