The ability of deep eutectic solvent systems to extract bioactive compounds from apple pomace

Apple pomace, the leftover press cake from cider and juice making, is packed with hidden health-boosting compounds—and a new green chemistry approach might be the key to unlocking them.

What if the waste from your morning orange juice could help fight metabolic disease? Scientists are turning to apple pomace, the fibrous leftovers of cider and juice production, as a treasure trove of bioactive compounds. But traditional extraction methods often rely on harsh solvents. This study explores a greener alternative: Deep Eutectic Solvents (DES), a new class of eco-friendly solvents.

The researchers tested DES systems against apple pomace, measuring two key bioactivities: antioxidant capacity and the ability to stimulate insulin secretion from pancreatic beta-cells. Using the DPPH and FRAP assays, they found that a specific DES mixture, ChCl:EG (1:4), showed a striking antioxidant effect—80.1% inhibition compared to just 11.3% for a control. This suggests DES can efficiently pull out antioxidant-rich compounds.

But the story doesn't end there. Extracts from classical solvent systems actually outperformed the positive control in promoting insulin secretion (p < 0.05), while the ChCl:EG extracts had a lesser effect. This reveals a trade-off: different solvents extract different compounds, each with unique bioactivities.

Overall, the findings highlight the potential of DES as a green, tunable tool for extracting health-relevant compounds from food waste. The next step? Tailoring extraction methods to target specific benefits—whether that's antioxidant power or insulin regulation—to make the most of this overlooked resource.

Key Points

• DES extracts show high antioxidant capacity (80.1% DPPH inhibition).
• Classical solvent extracts boost insulin secretion beyond control.
• DES offers green, tunable extraction for metabolic health.