Determination of Inorganic and Total Phosphorus Content in Processed Foods

Abstract

The use of inorganic phosphorus as an additive in various processed foods has raised concerns about possible overdose, especially in view of the increased consumption of such products. Although the total amount of inorganic phosphorus used as a food additive is unknown, >90％ of inorganic phosphorus is absorbed, in comparison with 40‐60％ of organic phosphorus. In the present study, the inorganic and total phosphorus contents of different processed foods were determined in an attempt to estimate the intake of each type of phosphorus. Ortho-, pyro-, and triphosphates were separated by anion exchange chromatography. Elution with a linear gradient effectively separated these phosphates, and >90％ were recovered. Inorganic phosphorus comprised >50％ of the total phosphorus in 4 out of 5 processed foods. The phosphorus to protein mass ratio in some processed foods was >15 mg/g, which is a standard average in food. These findings may be useful for managing patients with chronic kidney disease.