Sustainable Single-Stage Solid–Liquid Extraction of Hesperidin and Rutin from Agro-Products Using Cyrene

Hesperidin
and rutin are two sought-after natural flavonoids, traditionally extracted
from abundant natural citrus fruits and tea leaves using large amounts
of ethanol or methanol solvents. Recent trends in extractions have
focused on minimizing the use of solvents and creating simpler cost-effective
processes. This study aims to apply the concept of chemical valorization
in the context of a circular economy, by using agro-industrial waste
and biobased alternatives to traditional solvents, which are of environmental
concern. We use minimum amounts of solvent/sample (5 mL/0.25 or 0.5
g) to extract hesperidin and rutin in a single-stage solid–liquid
extraction. Thirty individual solvents and HSPiP were applied to find
the best solvents/blends for extraction. The type of solvent, sample
preparation, maceration time, and extraction temperature were studied.
Results showed that the biobased solvent Cyrene is very effective
when mildly heated to 65 °C (up to 91%) or mixed with water.
Adding water to Cyrene forms its geminal diol hydrate, this enhances
the solubility and extraction of hesperidin and rutin up to ten times
than those of the original pure ketone form. Quantitative sustainability
metrics from the CHEM21 Toolkit demonstrated that our extraction methodology
is environmentally friendly and offers future potential of isolation
of other flavonoids.