Evaluation of sugar beet pectin viscosity, surface activity, conductivity and zeta potential in sodium chloride aqueous solutions

Abstract

Application of hydrocolloids is highly dependent on their structural and conformational properties. Molecular weight, macromolecular geometry, hydrophobicity and electric charge are, therefore, often researched. In the presented study, influence of sodium chloride on conformation and structure of sugar beet pectin in aqueous solutions was first time thoroughly characterized. Viscosity, surface tension, specific conductivity, zeta potential and pH of sugar beet pectin aqueous solutions were monitored and measured following the addition of sodium chloride. Relative viscosity of sugar beet pectin aqueous solutions decreased by up to 29.19% following the addition of sodium chloride. The highest decrease in relative viscosity values was noticed at the lowest sodium chloride concentrations used (0.2 g L−1 to 2 g L−1). The corresponding changes at the lowest sodium chloride concentrations used were also noticed in the obtained specific conductivity curves. Calculated diameter of sugar beet pectin macromolecule decreased by 19.98% following the addition of 10 g L−1 sodium chloride. Surface tension values of sugar beet pectin aqueous solutions were strongly influenced by the addition of sodium chloride. Decrease in zeta potential of sugar beet pectin aqueous solutions with addition of sodium chloride was observed. Presented results suggested that the addition of sodium chloride to sugar beet pectin aqueous solution could cause conformational changes of macromolecular chain suggesting possible transition from linear to globular conformation.