Enhancing the carotenoid recovery from Eugenia uniflora l. pulp: A comparative study of supramolecular solvents, ionic liquids, and deep eutectic solvents

Abstract

Carotenoids are highly valuable compounds for food, pharmaceutical, and cosmetic applications, given their natural biological activities. Due to their hydrophobic nature, the processes of separation and purification present some limitations. This work aimed to promote a comparative study on different classes of green solvents: deep eutectic solvents (DES), ionic liquids (ILs), and supramolecular solvents (SUPRAS). The solvents were compared regarding the ability of each solvent to recover natural carotenoids from Eugenia uniflora L. pulp and the preservative effect of the solvent against thermal and photodegradation. The solvent recycling and its capacity to be reused were also evaluated. The results indicate that SUPRAS (60.45 ± 0.55 %) promoted a higher recovery yield than ILs (29.72 ± 0.27 %) and DES (9.50 ± 0.23 %). Besides, the higher thermal stability of the carotenoids was observed for the carotenoids-rich extracts obtained with DES (at 40 °C, half-life time of 353.39 h and 50 °C half-life time of 279.44 h) and SUPRAS (at 60 °C, half-life time of 143.13 h). The thermodynamic parameters showed superior activation energy for AC: ET and DES-based extracts, besides demonstrating that the degradation processes had positive free Gibbs energy and enthalpy and negative entropy values. For the light stability assays, IL had the highest protective capacity against UV (half-life time 54.6 h) and LED (half-life time 216.6 h) lights. Finally, the best systems were integrated with a liquid–liquid system envisioning carotenoid recovery, solvent recycling, and economic viability evaluation. In this context, the SUPRAS could be reused for up to four cycles compared to three cycles of ILs, besides providing a lower process cost than ILs solutions.