Solventes eutéticos profundos naturais aplicados à extração de compostos fenólicos da casca de guaraná (Paullinia cupana Kunth): otimização, encapsulação e bioacessibilidade in vitro

Abstract

The valorization of agro-industrial residues has stood out as a relevant strategy for sustainable development, especially in the recovery of high value-added bioactive compounds. In this context, guaraná peel (Paullinia cupana Kunth), an abundant by product of the Amazon production chain, presents high potential as a source of phenolic compounds. However, conventional extraction methods still present limitations, such as the use of toxic solvents, low selectivity, and high environmental impact. In this sense, this study aimed to evaluate the use of natural deep eutectic solvents in the extraction of phenolic compounds from guaraná peel, as well as to investigate extract stability, encapsulation, and the behavior of the compounds during simulated in vitro gastrointestinal digestion. Initially, different solvent systems were evaluated regarding extraction efficiency, followed by optimization of process conditions through experimental design. The obtained extracts were characterized by infrared spectroscopy, subjected to color stability analysis during storage, and subsequently encapsulated using carrier agents. Finally, the release and bioaccessibility of phenolic compounds were evaluated using a simulated digestion model.The results demonstrated that natural deep eutectic solvents were efficient in extracting phenolic compounds, highlighting systems based on choline chloride. The optimization showed a significant influence of process variables, while spectroscopic analyses confirmed extract enrichment without relevant structural changes. Color stability indicated moderate changes during storage. Encapsulation showed satisfactory efficiency, being influenced by the extract-to-carrier ratio, and digestion assays demonstrated the ability of the system to modulate compound release, with higher bioaccessibility observed for the formulation with lower carrier proportion. It is concluded that the application of natural deep eutectic solvents associated with encapsulation constitutes an efficient and sustainable strategy for obtaining, protecting, and controlling the release of phenolic compounds from guaraná peel, contributing to the valorization of agro-industrial residues and expanding their potential for application.