Abstract: 【Objective】 This study was in order to discuss the influence of metal ions (Ca²⁺ and Na⁺) sodium on the structure and rheological properties of sugar beet pectin under high hydrostatic pressure (HHP), and to provide theoretical basis for the application of sugar beet pectin in food. 【Method】 1% (w/v) sugar beet pectin solution which was prepared by 0.05 mol·L^-1 Tris - HCl solution with adding different concentrations of Ca²⁺ (2, 12 and 20 mmol·L^-1) and Na⁺ (0.05, 0.1 and 0.6 mol·L^-1), was treated under HHP, and the molecular weight, microstructure, viscosity and dynamic viscoelasticity of sugar beet pectin were investigated. 【Result】 Compared with the control one, new peaks were shown at 1 550 cm^-1 and the yield stress σ₀ increased significantly for sugar beet pectin treated at 450 MPa for 10, 20, 30 and 50 min, but there were little changes between the different treatment time. Sugar beet pectin with adding different concentrations of calcium or sodium ions was treated under 450 MPa for 30 min; the changes of its structure and rheological property were different. Relative to no add calcium or sodiumions, the σ₀, G’ and G” of sugar beet pectin increased significantly when adding 2 mmol·L^-1 calcium ions, when the concentration of calcium ions increased to 12 mol·L^-1 and 20 mol·L^-1, there was little change compared with add 2 mmol·L^-1 calcium; adding 2 calcium ions in the sugar beet pectin made the pectin crosslinking, and the molecular weight of sugar beet pectin was increased from 2.25 × 10⁵ Da to 6.07 × 10⁵ Da; with the concentrations of calciumions was increased to 20 mmol·L^-1, the molecular weight of pectin into 5.99 × 10⁵ Da, and there was no significant differences with the sugar beet pectin add 2 mmol·L^-1 calcium ions, and also its rheological properties. Relative to no add calcium or sodium ions, add 0.05 mol·L^-1 sodium ions also made the yield stress σ₀ of sugar beet pectin increase significantly, and with the increase of sodium ion concentration, yield stress σ₀ of pectin was increased significantly. when the concentration of sodium ion was increased to 0.6 mol·L^-1, the G’ and G” of sugar beet pectin was increased obviously, After adding 0.1 mol·L^-1 sodium ions, sugar beet pectin chains formed reticular by crosslinking with molecular weight significantly increased to 11.95 × 10⁵ Da. However, when added 0.6 mol·L^-1 sodium ion, the molecular weight of pectin was decreased to 5.53×10⁵ Da with virgate structure. 【Conclusion】 The calcium and sodium ions might change the structure of sugar beet pectin under HHP treatment, thus affect its structure and rheological properties.

Key words: sugar beet pectin, high hydrostatic pressure, metal ions, structure, rheological property