Zeta Potential and Turbidimetry Analyzes for the Evaluation of Chitosan/Phytic Acid Complex Formation

The aim of this work was to study the possible complex formation between chitosan and phytic acid. Zeta potential and turbidity measurements were used as a basis to confirm the possible complex between these two molecules. The obtained results showed that chitosan at a concentration of 0.1% (w/v) were soluble in 0.1% acetic acid solution. This concentration of the acetic acid was the lowest that allows chitosan to dissolve. A positive surface charge of chitosan was recorded in the pH interval from 1 to 7. The highest zeta potential values were obtained at pH < 5 and decreased significantly at pH 6 and 7. Regarding phytic acid, it was soluble in deionized water and acetic acid whatever the concentration of the acetic acid and in the entire pH range 2-10. Phytic acid had negative surface charge in deionized water and in 0.1% acetic acid, but was slightly positively charged in 5% acetic acid solution. The solubility of chitosan was decreased by the presence of phytic acid. The formation of chitosan/phytic acid complex as monitored by measuring the zeta potential does not allow us to conclude that the formation of this complex is possible.