Measurement of Sodium Chloride in Cheese by a Simple Sodium Ion Electrode Method

Abstract

Sodium chloride in Blue, Camembert, Cheddar, Gouda, Muenster, part-skim Mozzarella, Ricotta, Swiss, and whole-milk Mozzarella cheeses in duplicate was measured with a specific ion meter (Orion – Model 407) and pH meter with expanded millivolt scale (Fisher – Accumet Model 230) with a sodium ion electrode. In preparation of samples, 1 g of cheese was blended in an ionic strength adjustment buffer, filtered through cheese-cloth to disperse foam, and tempered to 21 ± 1°C. Sodium was measured directly on filtrates with the specific ion meter. Millivolt potential was measured on filtrates with the pH meter, and a calibration curve was used to convert millivolts to percentage sodium. Percentage salt was calculated by multiplying percentage sodium by 2.54. Cheeses ranged from .22 to 4.76% salt by Volhard titration. Correlations of the sodium ion electrode method with Volhard titration were .999 both for specific ion meter and for pH meter. Comparative results of sodium ion electrode and Volhard titration methods differed by an average of .04 ± .03% salt with specific ion meter and .05 ± .05% salt with pH meter. © 1984, American Dairy Science Association. All rights reserved.