Profiling of phenolic compounds and evaluation of bioactivities in almond hull extracts via subcritical water extraction

What if the secret to a sweeter, healthier future is hidden in a berry leaf? Scientists just unlocked a green way to extract a natural zero-calorie sweetener using eco-friendly solvents.

Rubusoside, a sweet compound found in Rubus chingii, packs high sweetness with almost no calories. But extracting it efficiently without harming the environment has been a challenge. Now, researchers have developed a microwave-assisted deep eutectic solvent (DES) system that does the job better than plain water extraction.

The winning formula? A ternary DES made of choline chloride, 1,2-propylene glycol, and 1,3-butanediol in a 1:2:2 ratio. Under optimal conditions—33% moisture, a liquid-solid ratio of 21 mL/g, just 6 minutes, and 320 W of microwave power—they achieved a rubusoside yield of 7.89%. Spectroscopy and theoretical models revealed that hydrogen bonds and van der Waals forces between the DES and rubusoside drive the process.

Microscope images showed the DES and microwaves working together to break down plant tissues, boosting extraction. After separation with LX-28 resin, the DES could be reused five times without losing effectiveness. This green, recyclable method could make natural sweeteners more sustainable—and our desserts a little guilt-free.

Key Points

• Ternary DES (1:2:2) beats water for rubusoside extraction.
• Optimal yield: 7.89% in 6 minutes at 320 W.
• DES recyclable for 5 cycles with stable performance.