Correlation between Soaking Conditions, Cation Content of Cell Wall, and Olive Firmness during “Spanish Green Olive” Processing

“Spanish green olives” in two important stages of their processing (pH 11 after sodium hydroxide treatment and pH3 pH after fermentation) have been studied by adding increasing concentrations of sodium and calcium chloride to the soak solutions. Correlations among firmness, pH, and the concentration of the different cations were derived. Ca 2+ at pH 11 showed a logarithmic response that changed to linear at pH 3. Na + produced linear increases in texture only at pH 11, being ineffective at pH 3. High concentrations of sodium at pH 11 caused the calcium effect to change to a linear correlation. The results from this study show that calcium displaced sodium from the cell wall structure to a great extent but that there was very little decrease of calcium in the cell wall as a result of the presence of sodium, results that suggest two different ways of cell wall stabilization: one by formation of coordination complexes (only by calcium) and the other by electrostatic means (by both calcium and sodium).