A green and efficient approach for extracting pectin from citrus peels using a ternary deep eutectic solvent: Process optimization, structural characterization, and comparative property evaluation.

Pectin is a high-molecular-weight polysaccharide widely used in food and pharmaceutical applications. Conventional acid extraction methods are limited by low efficiency and the use of environmentally hazardous reagents. In this study, a novel ternary deep eutectic solvent (DES), composed of choline chloride, malic acid, and ethylene glycol, was developed for efficient pectin extraction from citrus peel powder. Optimal extraction conditions were determined using response surface methodology, yielding a pectin extraction rate of 25.4%. The physicochemical and structural properties of DES-extracted pectin were systematically compared with those obtained via conventional acid extraction. Results showed that DES significantly improved pectin yield. Both samples were identified as high-methoxyl pectins, mainly composed of galacturonic acid, galactose, and arabinose. The DES-extracted pectin exhibited higher antioxidant activity and gel strength, but slightly lower water- and oil-holding capacities and viscosity. These findings demonstrate that ternary DES is a green and efficient alternative for pectin extraction with enhanced functional properties.