Utilization of natural deep eutectic solvents and ultrasound-assisted extraction as green extraction technique for the recovery of bioactive compounds from date palm (Phoenix dactylifera L.) seeds: An investigation into optimization of process parameters

What happens when you combine eco-friendly designer solvents with sound waves to unlock the hidden treasure inside discarded date palm seeds? Science reveals a remarkably efficient way to harvest powerful antioxidants.

Researchers have discovered that pairing natural deep eutectic solvents—specifically those made from choline chloride mixed with sugars, organic acids, or polyalcohols—with ultrasound-assisted extraction outperforms conventional solvents every single time. Out of seven tested combinations, a lactic acid-based solvent proved to be the ultimate champion for recovering valuable bioactive compounds.

To fine-tune this green technique, scientists used a statistical approach called the Box-Behnken design, looking at variables like extraction time, ultrasound amplitude, solvent concentration, and solid-to-solvent ratio. The analysis pinpointed solvent concentration and the solid-to-solvent ratio as the master controls dictating total phenolic content and antioxidant scavenging activity.

Under optimized conditions—15 minutes of extraction, 90% ultrasound amplitude, 70% solvent content, and a 1:30 solid-to-liquid ratio—the method successfully extracted impressive amounts of total phenolics and robust antioxidant activity. High-performance analysis further confirmed that key compounds recovered included 3,4-dihydroxybenzoic acid, catechin, and caffeic acid, proving this green duo to be a powerful tool for valorizing agricultural waste.

Key Points

• Seven NADES coupled with ultrasound outperformed conventional solvents
• Lactic acid-based NADES showed the highest extraction efficiency
• Solvent content and solid-to-solvent ratio majorly influenced extraction