134. The Titration of Milk and Whey as a Means of estimating the Colloidal Calcium Phosphate of Milk

Abstract

1. The titration method for the estimation of colloidal tricalcium phosphate in milk was found to agree closely with the determination of total colloidal inorganic P2O5.2. The method was used to study the solution of tricalcium phosphate in milks of rising acidities.3. Close agreement was obtained between the actual increase in total P2O5 in the wheys of souring samples and that calculated from the disappearance of tricalcium phosphate as found by the titration method.4. The discrepancy between the actual increase in whey calcium in such cases and that calculated from the titration figures was attributed to the solution of calcium from the calcium salt of caseinogen. From figures so obtained it would appear that colloidal calcium phosphate dissolves with greater ease in milk than the calcium of the protein salt.5. A linear relationship was found to exist between the ordinary titration value of milk and the three other values used in this estimation, and also between the curd acidity and milk acidity.6. Average figures are given for the tricalcium phosphate content of the samples studied and for the various titration factors.