Effect of particle size of sugar beet pulp on the extraction and property of pectin

Four sugar beet pulp (SBP) powders in different particle size were prepared by superfine grinding and ordinary pulverization methods, whose effects were investigated on extraction yield, composition and rheological properties of the pectin extracted by acid-heating method. By decreasing the particle size of raw extraction material (SBP) from 406.33 to 24.93 μm, the extraction yield increased from 15.81% to 20.50% and galacturonic acid content increased greatly from 38.51% to 59.97%. As particle size of SBP increased, rheological properties (intrinsic viscosity [η], viscosity-average molecular weight [Mv], apparent viscosity and activation energy) of SBP pectin were significantly increased. All pectin samples showed a strong shear thinning behavior and the same linear viscoelastic properties. The difference in particle size of SBP affected the dynamic moduli of extracted pectin. Scanning electron microscope (SEM) observations revealed the surface morphology of four SBP powders. The morphology of different roughness could make an effect on the extraction and property of pectin.