Preparation of citrus fiber from lemon peel residue: Effects of structure and endogenous pectin components on emulsifying properties of citrus fiber.

This study evaluated and compared the differences in structure and physicochemical properties between citrus fibers prepared after different degrees of pectin extraction and untreated citrus fibers. The results showed that the partial hydrolysis and release of internal pectin would cause the physical and chemical properties of citrus fibers to show a tendency to increase and then decrease with treatment time, with a steady increase in crystallinity and thermal stability. The water-holding capacity (15.81 g/g), swelling capacity (12.50 mL/g), and oil-holding capacity (3.33 g/g) of CF-5 h still remained noticeably higher than those of CF. The SEM results demonstrated that at the pectin extraction time of 5 h, the internal network structure of the cell wall of CF-5 h prepared at this time was maximized in terms of looseness. Meanwhile, the emulsion prepared from CF-5 h had the best emulsification properties, which were characterized by the smallest emulsion particle size(d_4，3 = 10.40 μm), the best rheological properties, and excellent emulsion stability. Overall, the citrus fibers prepared after a certain degree of pectin extraction showed good performance in terms of physicochemical properties and emulsification performance.