Microwave- and ultrasound-assisted extraction of capsaicin from Capsicum annuum using deep eutectic solvents

ABSTRACT

Methods exist to extract capsaicin from chili (Capsicum annuum L.), but they have poor yield and are hazardous to the environment. The objective of the study was to develop a process for extraction of capsaicin from chili that is more efficient and bio-rationale. Two deep eutectic solvents (DES), choline chloride-urea (CCU) and choline chloride-glycerol (CCG), were used for extraction with MAE (microwave-assisted extraction) and UAE (ultrasound-assisted extraction). In MAE, the highest yield in both solvents was at 600 W and solvent-solid ratio 30 mL∙g⁻¹ for CCU 18.88 mg∙g⁻¹ and for CCG 14.49 mg∙g⁻¹. In UAE, the highest yield in both solvents was at 50°C and solvent-solid ratio 100 mL∙g⁻¹ (2.77 for CCU and 2.59 mg∙g⁻¹ for CCG). The CCU (1:2) was an efficient solvent for extraction of capsaicin from chili and MAE was more efficient than UAE (ultrasound-assisted extraction). The results provide a new method to obtain capsaicin efficiently from C. annuum.

KEYWORDS:

• Capsicum annuum
• bioactive compounds
• environmentally friendly solvents
• green extraction techniques
• method development
• natural products

Acknowledgments

The authors acknowledge the access to facilities by the Department of Chemistry for this research.