Green Extraction of Anthocyanins from the Novel Anthocyanin-Rich BRS Carmem Grape: Multivariate Optimization, Bioactivity, Antimicrobial Potential, and Galleria mellonella Toxicity Assessment

What if the secret to a sweeter, healthier life was hidden in a leaf—and a microwave could unlock it? Scientists just found a green way to extract a natural super-sweetener using eco-friendly solvents and a kitchen appliance.

Rubusoside, the sweet powerhouse of the Chinese sweet leaf plant (Rubus chingii var. suavissimus), is a natural sweetener with almost zero calories and a safe profile. But getting it out of the plant has always been a challenge—until now. Researchers developed a microwave-assisted deep eutectic solvent (DES) system, a green chemistry dream team that outperformed traditional water-based extraction.

The winning trio—choline chloride, 1,2-propylene glycol, and 1,3-butanediol—worked synergistically with microwaves to break down plant cell walls, as shown by electron microscopy. By fine-tuning conditions (33% moisture, 21 mL/g liquid-solid ratio, 6 minutes, 320 W), they achieved a rubusoside yield of 7.89 ± 0.25%. Spectroscopy and modeling revealed that hydrogen bonds and van der Waals forces between the DES and rubusoside drive the process.

But the innovation doesn't stop there. The DES can be recycled—after five uses, it still performs like new. And a simple resin (LX-28) cleanly separates the rubusoside. This isn't just a lab trick; it's a scalable, eco-friendly pathway to natural sweeteners, potentially revolutionizing functional foods and beverages. The future of sweetness just got greener.

Key Points

• Microwave-assisted ternary DES outperforms water extraction
• Optimal yield: 7.89% rubusoside in 6 minutes
• DES recyclable for 5 cycles with stable performance