A novel sustainable approach for the extraction of value-added compounds from Hibiscus sabdariffa L. calyces by natural deep eutectic solvents

What if the secret to capturing nature's most vibrant compounds lies not in harsh chemicals, but in smart, sustainable designer solvents? Researchers are turning to natural deep eutectic solvents to revolutionize how we extract value from hibiscus flowers.

Hibiscus sabdariffa L. is a treasure trove of natural pigments and bioactive compounds highly coveted by the food industry. As the demand for genuinely green chemistry surges, scientists have put natural deep eutectic solvents (NADES) to the test for the very first time on this plant. By pairing microwave-assisted extraction with choline chloride-based solvents, researchers unlocked a remarkably efficient extraction method.

Among the tested combinations, an oxalic acid-based NADES proved exceptionally brilliant. It showed striking selectivity for anthocyanins and even outperformed conventional methanol in yielding total bioactive compounds.

To perfect the process, the team mapped out key variables using a Box-Behnken design and response surface methodology. The optimal sweet spot emerged at a liquid-solid ratio of 1:30 mL mg−1, a temperature of 75 °C, and a water content of 55%. Ultimately, this tailor-made green solvent offers a powerful, sustainable alternative for selective extraction.

Key Points

• First evaluation of NADES for extracting Hibiscus sabdariffa L. compounds
• Oxalic acid-based NADES outperformed methanol in extracting bioactive compounds
• Optimized via response surface methodology at 75 °C and 55% water