Ultrasound-Assisted Extraction of Methylxanthines from Cocoa Bean Shells Using Glycerol-Urea Natural Deep Eutectic...

Area of Science:

• Green Chemistry
• Extraction Technologies
• Food Science

Background:

• Cocoa bean shells are a rich source of bioactive compounds.
• Efficient and sustainable extraction methods are needed for valorizing cocoa processing residues.

Purpose of the Study:

• To optimize ultrasound-assisted extraction of theobromine and caffeine from cocoa bean shells.
• To utilize glycerol-urea natural deep eutectic solvents for enhanced extraction efficiency and sustainability.

Main Methods:

• Ultrasound-assisted extraction (UAE) optimized using a Doehlert design.
• Glycerol-urea natural deep eutectic solvents (DES) characterized by rheological analysis and infrared spectroscopy.
• Quantification of theobromine and caffeine using high-performance liquid chromatography (HPLC).

Main Results:

• Optimized conditions (45.5% water, 4 min sonication) yielded high concentrations of theobromine (29.18 mg g⁻¹ DM) and caffeine (2.46 mg g⁻¹ DM).
• Extracts exhibited significant antioxidant capacity (ABTS: 230.65 mg TE g⁻¹ DM, DPPH: 74.34 mg TE g⁻¹ DM).
• Greenness assessment confirmed low environmental impact, aligning with green chemistry principles.

Conclusions:

• The proposed UAE method using glycerol-urea DES is a sustainable and efficient alternative for recovering bioactive compounds from cocoa waste.
• The process is cost-effective, uses food-relevant components, and supports circular economy strategies.
• The resulting extract is suitable for food, beverage, and nutraceutical ingredient formulation.