Abstract:In this study, the differences in the basic composition and physical properties (water holding capacity, oil holding capacity and swelling property) among the three types of citrus dietary fibers (DFs) (AQ-Plus (No. 1), Fiber-Star (No. 2), and DFs extracted in our laboratory (No. 3) were investigated. The effects of high pressure homogenization and ultrasonic treatment on the morphological characteristics of the three citrus DF suspension solutions were investigated by determining their particle size, zeta potential, apparent viscosity and micro-structure. The experimental results showed that No. 1 had better water holding capacity (21.58 g/g), oil holding capacity (14.29 g/g) and expansibility (27.46 mL/g) attributed to its higher cellulose (38.02±1.61 g/100 g) and hemicellulose (29.56±0.63 g/100 g) contents, with No. 2 ranked the second and No. 3 the worst. After high pressure homogenization (30 MPa, 60 ℃), the three types of citrus fibers had decreased particle size with significantly increased viscosity and improved zeta potential. With the increase of ultrasonic treatment time, the particle size of three kinds of citrus fibers decreased and their apparent viscosity increased. During the treatment of 0~5 min, the absolute value of the zeta potential of the three citrus fibers suspensions increased significantly with the increase of the ultrasonic treatment time. Further increase of the ultrasonic treatment time, the zeta potential of the three citrus fibers suspensions did not change significantly.
