Pressurized natural deep eutectic solvents: An alternative approach to agro-soy by-products

Imagine millions of tons of soybean leaves, pods, and roots—waste that could be turned into a treasure trove of health-boosting compounds. Scientists just found a green, high-pressure way to unlock it.

Every year, soybean farming leaves behind an estimated 651 million metric tons of branches, leaves, pods, and roots. That's not just waste—it's a cheap, abundant source of flavonoids, isoflavonoids, and other phenolic compounds with high value for food and health industries.

But extracting those compounds usually requires harsh solvents and energy-hungry methods. In this study, researchers turned to natural deep eutectic solvents (NADESs)—green, biodegradable mixtures—and paired them with pressurized liquid extraction and gas expanded-liquid techniques. The goal: pull out phenolic-rich extracts from soy by-products without harming the planet.

The winning recipe? A NADES made of choline chloride, citric acid, and water in a 1:1:11 molar ratio, heated to 120°C under 100 bar pressure for 20 minutes. This optimized condition produced fractions rich in both phenolics and flavonoids, outperforming conventional solvents and techniques when compared side by side.

Each part of the soybean plant was then extracted under these conditions, revealing distinct metabolomic profiles. This approach doesn't just reduce agricultural waste—it transforms it into a sustainable source of bioactive compounds, proving that green chemistry can be both smart and powerful.

Key Points

• 651M tons of soy by-products yearly
• Green NADES extraction with pressure
• Optimized: choline chloride/citric acid/water