Comparison of the Chemical Composition and Physicochemical Properties of Different Fibers Prepared from the Peel of Citrus sinensis L. Cv. Liucheng

Abstract

Fiber-rich fractions (FRFs) including soluble and insoluble dietary fibers (SDF and IDF), alcohol-insoluble solid (AIS), and water-insoluble solid (WIS) were isolated from the peel of Citrus sinensis L. cv. Liucheng for analysis and tests. The peel was rich in insoluble FRFs (IDF, AIS, and WIS; 476−515 g kg^-1 of peel), which were mainly composed of pectic substances and cellulose, and also contained pectic polysaccharide-rich SDF (94.1 g kg^-1 of peel). These insoluble FRFs had water-holding capacities (15.5−16.7 mL g^-1), oil-holding capacities (2.35−5.09 g g^-1), cation-exchange capacities (454−997 mequiv kg^-1), and swelling properties (14.6−21.1 mL g^-1) much higher than those of cellulose. These results recommended the consumption of these peel insoluble FRFs of desired physicochemical properties as sources of food fibers or low-calorie bulk ingredients in food applications requiring oil and moisture retention. Further investigations on the physiological functions of these peel FRFs using animal-feeding experiments are underway. Keywords: Dietary fiber; alcohol-insoluble solid; water-insoluble solid; fiber-rich fractions; composition; physicochemical properties; Citrus sinensis L. cv. Liucheng; peel