Uji Aktivitas Antioksidan Ekstrak NADES Biji Kopi Robusta (Coffea canephora) yang Diekstraksi dengan Metode MAE dan UAE

Abstract

Antioxidants are compounds that protect cells against oxidative damage induced by free radicals, representing critical components in maintaining cellular integrity. Natural antioxidants are extensively distributed in botanical sources, particularly in Robusta green coffee beans (Coffea canephora), which contain chlorogenic acid as the principal bioactive constituent responsible for their antioxidant properties. To harness these antioxidant capabilities effectively, efficient extraction protocols are essential—methodologies that optimize yields while minimizing solvent consumption and processing time. Advanced extraction technologies, including Ultrasound-Assisted Extraction (UAE) and Microwave-Assisted Extraction (MAE), offer substantial improvements over conventional maceration methods through enhanced mass transfer mechanisms and reduced extraction duration. This investigation evaluated the differential chlorogenic acid content and antioxidant activity of liquid extracts from Robusta green coffee beans utilizing betainetriethylene glycol Natural Deep Eutectic Solvent (NADES) through UAE and MAE methodologies. Robusta green coffee beans are recognized for their diverse phytochemical composition, serving as a promising reservoir of natural antioxidants with significant therapeutic potential. Antioxidant activity was assessed using the DPPH (2,2-diphenyl-1-picrylhydrazyl) assay to determine free radical scavenging capacity. The results demonstrated that UAE and MAE extracts contained chlorogenic acid concentrations of 2.69 ± 0.04 and 3.64 ± 0.06 mg/g NADES extract, respectively. Antioxidant activity assessments revealed IC₅₀ values of 3266.63 ± 67.97 μg/mL for UAE and 2598.05 ± 29.42 μg/mL for MAE extracts, indicating better extraction efficiency of MAE for enhanced overall antioxidant activity. However, chlorogenic acid content from NADES extracts using UAE and MAE methods yielded IC₅₀ values of 9.04 ± 0.13 and 9.44 ± 0.07 μg/mL, respectively. The findings establish MAE as the optimal method for maximizing overall chlorogenic acid content and antioxidant activity in NADES extracts from Robusta green coffee beans.