One-step biphasic NADES extraction of phenolics and carotenoids from tomato peels with integrated life cycle assessment

A biphasic NADES extraction system composed of choline chloride:urea (ChUr) and menthol:thymol (MenThy) was developed to enable the simultaneous extraction and separation of phenolic compounds and carotenoids from tomato peels. In sequential extractions, ChUr recovered 198 μg/gDW of phenolics, primarily 4-hydroxybenzoic acid and 4-hydroxybenzaldehyde, and MenThy enabled the extraction of 601 μg/gDW of carotenoids (lycopene and β-carotene), along with a part of flavonoids, namely quercetin (94 μg/gDW) and naringenin (50 μg/gDW). The design of a biphasic NADES system (1:1, v/v) resulted in a 40% increase in phenolic extraction, along with partial phase separation of the flavonoids: 26% of quercetin and 9% of naringenin remained in the MenThy phase. Increasing the ChUr volume to a 3:1 ratio improved partitioning, with 89% of phenolics recovered in the hydrophilic phase (ChUr). A simplified life cycle assessment (LCA) focusing on energy inputs revealed that the biphasic 1:1 system was 28% more energy efficient than the sequential extraction process, and exhibited lower CO₂-eq impacts. These findings highlight the potential of biphasic NADES systems for one-step, energy-efficient extraction and partitioning of bioactive compounds from agro-industrial residues. Further optimization of solvent polarity and composition could enhance the selectivity of this extraction process.