Extraction of Bioactive Compounds from Spent Coffee Grounds Using Ethanol and Acetone Aqueous Solutions

Area of Science:

• Green Chemistry
• Biotechnology
• Food Science

Background:

• Spent coffee grounds (SCGs) are a rich source of bioactive compounds but are often discarded.
• Global coffee consumption generates substantial SCG waste annually.
• Valorization of SCGs is crucial for sustainable resource utilization.

Purpose of the Study:

• To compare ethanol-water and acetone-water mixtures for extracting polyphenols, chlorogenic acid, and caffeine from SCGs.
• To determine optimal pre-treatment, storage, and extraction conditions for industrial SCG utilization.
• To evaluate the sustainability of SCG extraction processes.

Main Methods:

• Extraction efficiency comparison using varying solvent mixtures (ethanol-water, acetone-water).
• Analysis of bioactive compound yields (total polyphenols, chlorogenic acid, caffeine).
• Investigation of pre-treatment (drying methods), storage duration, and extraction kinetics.

Main Results:

• Acetone at 20% (m/m) demonstrated superior simultaneous extraction of polyphenols, chlorogenic acid, and caffeine.
• No significant difference in SCG quality was found between natural and oven drying.
• Optimal SCG processing within 3-4 months is recommended due to significant bioactive compound degradation over longer storage.

Conclusions:

• 20% acetone-water mixture is highly effective for simultaneous recovery of key bioactive compounds from SCGs.
• Sustainable industrial SCG processing requires attention to storage duration and optimized extraction kinetics.
• Simplified extraction conditions (minimal time, ambient temperature) reduce energy and resource consumption, enhancing industrial viability.