Effect of high-pressure homogenization on rheological properties of citrus fiber

Abstract

The effect of high-pressure homogenization (0, 90, and 160 MPa) on the nonlinear rheological of citrus fiber with different concentrations was studied via large amplitude oscillatory shear tests. The strain-stress data obtained from the tests were processed by the Fourier transform rheology and Chebyshev stress decomposition methods to investigate the viscoelastic behavior of citrus fiber in the nonlinear region. The results showed that the citrus fiber suspension before homogenization presented Type I large amplitude oscillatory shear behavior, whereas the Type III shear behavior was found for fiber suspensions after high-pressure homogenization, showing enhanced intermolecular interaction. Lissajous-curves of fiber suspension showed that the viscosity in the nonlinear region increased when the concentration increase. Normalized 3rd elastic Chebyshev harmonics indicated that the 2.0 g/100 g fiber suspension at 1000% strain turned from strain-stiffening (0.00208) to strain-softening (−0.27498) through the homogenization. Furthermore, the high-pressure homogenization changed the shear behavior from shear-thinning to shear-thickening.