Structural and physicochemical properties of pectin-rich dietary fiber prepared from citrus peel

Pectin-rich dietary fibers were prepared from citrus peel through alkaline hydrogen peroxide treatment (AHP-CF) or homogenization treatment (H-CF). Structural and physicochemical properties of the citrus fibers were evaluated and compared with a commercial one (Fiberstar). Results showed that pectin content of citrus fibers (CF) increased from 15.23% to 21.52% and 26.79% after AHP and homogenization treatment. AHP-CF had the highest water-holding capacity (WHC) (21.32 g/g), water-swelling capacity (WSC) (32.70 mL/g) and cation exchange capacity (CEC) (1.02 Meq/g) among the fibers. SEM results showed porous or wrinkled surface of the treated CFs. XRD and TG analysis indicated that AHP treatment increased the crystallinity and thermal stability of CF while homogenization treatment was the opposite. Besides, H-CF had similar chemical component, oil holding capacity and CEC with Fiberstar but higher WHC, WSC and thermal stability. These results suggested that AHP-CF and H-CF might be suitable to be an additive used in functional food.